Gusseting 85 250r frame

[atc300r]

Looking for any info on gusseting 85-86 250r frame.Im planning to race Unadilla trike race this year.Also any tips on front and rear mx suspension setups.

[deathman53]

Rebuild/revalve rear shock and linkage, also get inverts to replace the front end, there are several people on this board who build and sell conversions for it. I have a ktm 105sx front end(bought from a member on this board) on mine and trx250r elka shock on mine, it soaks up things very good.....and turns alot of heads.

[atc300r]

Thanks for the reply .I have an extra 86 rear shock that I want to send out for a rebuild/revalve for my weight. I don't want to spend a lot on the usd fork swap . Im going to have the stock front forks rebuilt with progressive spings. Unadilla has some big jumps.I read that the usd setup is hard on the stock frame steering head.
Rebuild/revalve rear shock and linkage, also get inverts to replace the front end, there are several people on this board who build and sell conversions for it. I have a ktm 105sx front end(bought from a member on this board) on mine and trx250r elka shock on mine, it soaks up things very good.....and turns alot of heads.

[Louis Mielke]

A lot of the old frames are pretty stressed to the max so it is a risk to be concerned about installing a stiffer invert front end. Jason Hall does an excellent job of gusseting stock frames for strength.

[atc300r]

I have seen Jacobs 330r with the inverts on it he rips on that trike.I didn't get a close up look at though. I was hoping to get pics of some gusseting so I don't have to ship a frame out. I can weld and I know a couple guys that weld for a living.

[Dirtcrasher]

As Lou suggested, I'd talk to Jason Hall. Even if you don't want him to do it, just give him a call.

I haven't seen a neck break yet but it will. I already broke off the right side of the upper wishbone on my 350RX, so I have to do some work on the neck this winter running inverts.

The R seems to have allot of stress on the upper main tube, Kintore broke his, but I'm sure it's got stress in plenty of other places.

I don't know how big you are, Jason's son Jacob is a pretty lean kid and mostly muscle. He's a very smooth yet aggressive rider and he hits BIG jumps.

I'm surprised he hasn't gotten another low hour and low stress frame to gusset. I bet he's headed in a different direction now anyhow with Jason Hall having the ability to convert a MX frame to 3wheels now.

And Louis isn't too far behind him; 2 very smart people that couldn't be nicer to work with IMHO......

[barnett468]

I have an extra 86 rear shock that I want to send out for a rebuild/revalve for my weight. I'm going to have the stock front forks rebuilt with progressive spings. Unadilla has some big jumps.

You will likely get a lot of good suggestions for suspension, below is just one option . . Unadillas ATV track is also very bumpy.


FRONT FORKS

For an '85, the stock oil is ATF transmission oil which is around 7wt . . The oil level is 7.3 inches . . Irregardless of what spring you use, I would try 15 wt oil at 6.75 inches . . The heavier oil will slow the forks down when you land, plus it will increase your rebound damping which you will likely need with stiffer springs . . The slightly higher oil level will make it slightly more resistant to bottoming.

I would also call progressive directly to see exactly what they currently have . . They supposedly make at least 2 different rates . . p/n 11-1117 which is 30/40 lbs and p/n 11-1127 which is 30/45 lbs . . . I know guys that weigh close to 200 with gear that can occasionally bottom their forks out with the 11-1127 springs on their 250R's, so if you are near that weight, and/or do big jumps, I would consider stepping up to the next stiffest spring they make if they make one, otherwise get the 1127's, but hopefully others here have used them also and can give you their experience with them.

Either way, the 1127 springs combined with the heavier oil and higher oil level should be able to prevent hard bottoming off reasonably big jumps for most riders.

Here's 2 places to get the lowest price on them.

http://www.amazon.com/Progressive-Suspension-11-1127-22-75-Spring/dp/B000HS4WYU

http://cycleplicity.com/products/18028-progressive_suspension_11_1127_front_spring_kit.as px?utm_source=google&utm_medium=cpc&utm_content=18028NOFITMENT&utm_campaign=GSNOFITMENT&adtype=pla&kw=&utm_term=&adpos=1o1&network=g&gclid=CKW20OfUvskCFZKCfgodnsALdQ


Cut some pcv tube to use for front spring spacers that are 1/2 and 1" longer than the ones you start with in case the front is too low or the springs are too soft and it sags too much etc.

Take a 10 gallon air can so you can add air to the forks if they are too soft . . I wouldn't use more than maybe 7 lbs.

Take a high quality low pressure air gauge.

Take some 15 wt oil in case you need heavier oil.


REAR SHOCK

I would at least contact Race Tech Suspension for suggestions on the rear based on your weight and swing arm length etc . . Their labor cost to clean and rebuild most shocks is only $100.00, and they are one of the biggest and best suspension rebuilding and modification companies around.

Their turn around time is also usually less than 1 week, so why take chances with anyone else whom may have far less knowledge and experience, and whom may also take much longer to return your parts.

They are also the inventors of the very popular Gold Valve Emulators, so no one knows how to tune this system better then they do . . This valve can be added to your stock forks or rear shock and it will improve performance, or they can revalve your stock shock valving.

Phone 951-279-6655

http://www.racetech.com/


Race Tech also did the suspension for this 250R Magazine build.

http://atvondemand.com/1985-1986-honda-atc250r-motocross-project-part-1/
.

[Jason Hall]

A couple good places to gusset the 85-86 250R is the square tube above where the exhaust pipe comes through the frame. The main tube under the tank. Also the side tubes that come down to the swingarm pivot area. Most of the R's that I have seen break have been jumped big and bottomed out hard. When the suspension hits the stops Hard the stress on the frame is a lot worse. Also like Louis stated rust is a big problem. Most of the time you can't see the rust because it is inside of the tubes. I would try to find a clean west coast frame to start with. Another weak spot is the footpeg mounts on the 85 frames. A 86 is much stronger in the peg area.

[barnett468]

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I see Jason has given you some info . . I started this a couple hours ago and maybe if Jason sees it and can add or change anything, it might help you a bit more.

I have never seen an instantaneous catastrophic frame failure . . On the broken frames I have seen, they always started with a crack that went unchecked until the failure occurred . . At Kawi, we inspected every bike we tested for cracks at specific time intervals . . If a crack occurred, we would measure its length then mark the end of it then beat the crap out of it some more until eventually we felt it was unsafe to ride or the test was over . . After this, I would repair the cracks then add gussets where I thought they were necessary then we would beat the crap out of it again etc until it no longer developed cracks.

The point being that no matter what you do to strengthen it, it still may crack somewhere else because the stress/load has simply been moved to a different place from where the gusset was added, so every bike that gets flogged should be inspected for cracks periodically no matter how many gussets are added to it.

You could also check with HREATV to see if they make any kits for it or see if they have other parts you might want.

http://www.hreatv.com/productionparts.html


Below are couple shots of Jasons bike I shamelessly plagiarized off the internet . . I would guess he will send you more if you ask him, but from what I can tell, which isn't a lot, it doesn't look like he has done any reinforcing on the steering head . . It is also nearly impossible to break to steering head off one of those or most any bike unless the frame is rusty as mentioned, and/or gets bottomed hard as Jason mentioned, and if anything was going to break on the front, it would most likely be the down tube and the wishbone tubes.


DOWN TUBE

If Jason doesn't do anything to the steering head or down tube and you are worried about it breaking, one option would be to simply get a piece of 5/16" thick flat metal the width of the front of the down tube that will run from the gusset/bracket on the bottom of the tube all the way up to where the factory gusset/bracket is near the top, which is just below the Honda sticker on the side of the frame in the first photo, then weld it to both gussets and fully weld the sides and bottom to the down tube . . You will need to cut a slight V into the bottom of the new plate so it follows the contour of the bottom gusset/bracket.


BRACKET REMOVAL

It looks like he removed the small mounts that are on both sides of the steering head which can also be seen in the photo of the right side.


REAR SECTION SEAT AND FENDER SUPPORT

He made the rear section removable as he mentioned, however, you can put small triangle brackets on the rear section where it meets the frame like the 350x below has, but they can be smaller than that . . 3/16 inch material is thick enough . . You can also put holes in them to lighten them like Honda did on the top one seen in the photo.


SWING ARM BRACKET AND REAR VERTICAL FRAME TUBE

It looks like he attached a gusset to the leading edge of the existing swing arm gusset then extended it upward and down ward.


MAIN BACKBONE TUBE UNDER TANK

If Jason means that this tube can break somewhere between the steering head and where the rear part of the frame attaches, you can get a .125" wall tube that has the same id as the od of the backbone, then cut it in half lengthwise and long enough so it will weld to the steering head and the top bracket near the rear frame, then weld the sides completely.


1985 FOOTPEG BRACKET

I don't know where these mounts break, but my guess is that they can tear the metal around the perimeter of the nut insert which is on the inside of the bracket . . If this is the area they break at, it looks like, a flat piece of 3/16" thick metal the same size as the bracket could be placed on the face of it then fully welded . . The radius on all sides of the bracket will act like a pre-made groove for the weld to fill in . . Obviously this will move the footpegs out 3/16" but big deal.


FRONT STEERING ANGLE

It looks like he used non staggered triple trees . . If so, this brought the steering angle way in, and along with the leading front axle, it made it much more like....dare I say it....A "TECATE...The Best Turning 3 Wheeler In The Universe". http://www.mustang.org.au/forum/Smileys/smilies/thumbsup.gif


http://i237.photobucket.com/albums/ff42/Jasons450r/86ATC250RDone.jpg~original

..........http://i237.photobucket.com/albums/ff42/Jasons450r/330R3-1.jpg


1986 250R FOOT PEG MOUNTS

http://i.ebayimg.com/images/g/vyQAAOSwdvpWDCXM/s-l1600.jpg


1985 250R FOOTPEG MOUNT

http://i.ebayimg.com/images/g/XSIAAOSwcBhWXiTa/s-l1600.jpg


SOME NICE WIDE FOOTPEGS LIKE THIS MIGHT HELP SAVE YOUR FEET ON HARD LANDINGS BY SPREADING THE LOAD OUT OVER A WIDER AREA

http://img.photobucket.com/albums/v302/noslo98/250r.jpg


1985 STEERING HEAD GUSSET

http://i.ebayimg.com/images/g/XjsAAOSwAKxWXiS9/s-l1600.jpg

http://i.ebayimg.com/images/g/JTQAAOSwnH1WXiTC/s-l1600.jpg


ATC 350X WITH TCP GUSSET KIT

http://atvondemand.com/news/wp-content/uploads/2013/10/honda_350x_vintage_mx_project_2012-023-e1381335014252.jpg

[barnett468]

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What are you going to run for rear tires?

[atc300r]

Thanks for all the replies. Jason I didn't get a chance to meet you and Jacob at Airmx back in October. I raced the 200 class #81. Barnett Im using 18x9.50x8 flat track style tires right now. Im thinking for mx either 18x9.50x8 holeshots or Razrs. second choice turf tamers. Im more concerned with the frame down tube ,backbone and rear frame that Jason metioned above.Im also buying a plus 4 adjustable LSR axle. I have a couple extra frames that I can gusset Im not going to use my 85 250r that Iv had since 85. The 350x frame above gives me a good idea where to start.224515 224517 224516

[barnett468]

.

Thanks for all the replies. Barnett Im using 18x9.50x8 flat track style tires right now. Im thinking for mx either 18x9.50x8 holeshots or Razrs. second choice turf tamers.

Ok, I would not run a flat track tire there and instead would run the ITP HOLESHOT MXR6 tire over the Turf Tamer Classic MX mainly because of the lug pattern/spacing . . My guess is that the Turf Tamer will still be decent either way though . . I would also run 4 ply tires and a 9" rim if you have any that size . . The 9" will also provide a little wider selection of tires, many of which are 4 ply . . The 2 ply tires just roll under in the turns a little more which makes the bike more tippy and harder to slide, especially on tracks that have xlnt traction like some areas of Unadilla does . . Also, it will be easier to slide if the swingarm is longer than stock.

If you do run a knobby, I would run one that where the lugs are rounded on the outside to make them slide easier and all the tires below generally have that feature . . Tires that have sharp lugs on the outside will try to dig in more instead of sliding which can cause great displeasure . . Also horizontal rows of lugs will slide easier than staggered ones like the Turf Tamer has if all else is equal, and lugs that have a fairly big amount of space between the horizontal rows like the MXR6 and the bottom tire have will slide easier but hook up better in a straight line than a staggered lug pattern will if all else is the same.

ITP HOLESHOT MXR6 18x10x8 2 PLY

http://www.bikebandit.com/tires-tubes/motorcycle-tires/itp-holeshot-mxr6-atv-tire

http://content.motosport.com/images/items/large/ITP/ITP000L/X001.jpg


ITP TURF TAMER MX 18X10X8 2 PLY

https://www.rockymountainatvmc.com/p/723/34911/ITP-Turf-Tamer-Classic-MX
https://images.rockymountainatvmc.com/images/prod/275/i/itp_12_tir_tur_tam_cla_mx-rea.jpg

ITP HOLESHOT SX 18X10X8 2 PLY

https://www.rockymountainatvmc.com/p/1446/12977/ITP-Holeshot-SX-ATV-Tire

https://images.rockymountainatvmc.com/images/prod/275/i/itp_06_tir_hol_sx_rea.jpg


This rear pattern would also slide fairly easily but they don't come in your size.

https://www.rockymountainatvmc.com/rm-rider-exchange/wp-content/uploads/2013/08/atv-tires.jpg

[barnett468]

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I'll post more detailed frame mod suggestion in a little while.

[barnett468]

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ok, hopefully Jason will post again but if he doesn't, i can tell you with 110% certainty, that if you do any of the mods the way i described them, these areas will never, ever break, it just ain't gonna happen.

As far as the forces on the bike go, the down tube is mainly getting pulled . . A lesser force is twisting . . In other words, if you pull or push on the forks from the side, this is the twisting force I'm referring to . . The thickness of the 5/16" plate I suggested for the down tube is roughly equivalent to the thickness of the down tube if you were to add all four sides together . . This means that the tensile strength, or resistance to breaking from being pulled on will be double . . This is a ridiculous increase in strength . . It also means that it's resistance to twisting and deflecting to the side will be greatly increased.

Adding the 1/2 tube to the full length of the backbone will increase its strength by around double . . Adding a plate to the face of the '85 foot peg bracket will increase its strength by around at least double.


EXISTING STEERING HEAD GUSSETS

There is around a 1 1/2" hole in the side of each gusset that is attached to the rear of the steering head where water and dirt can enter . . I would install a piece of .125 wall pipe in this hole that is long enough to connect the holes in both halves of this gusset and weld it y them . . If the gusset is two pieces and not welded on the back end where they come together, I would weld the two halves together.

There is an opening in the bottom steering head gusset that the Honda sticker is applied to . If you install the plate to the front of the down tube, the front of the existing gusset will be welded to the plate but it will still be open on the side at the bottom just below the sticker . . I would weld this to the existing down tube.


LOWER TUBES TO DOWN TUBE

There is one formed lug on the end of both wishbone tubes that connect to the site of a bracket on the bottom of the down tube . . This looks like it was furnaced brazed to me . . If Jason says the weld that attaches this lug to the bracket can break, I would simply weld them to the bracket.


BACKBONE REINFORCEMENT

The new half tube added to the top of the backbone will end where the tank mount bracket is on the top of the frame . . There is a factory half tube gusset on the bottom side of the backbone directly below the tank mount bracket . . Add a piece of half tube to the bottom of the backbone that is 3" long and shape the end so it follows the shape on the end of that gusset, then butt the new piece up to it and weld the two pieces together . . If that factory gusset has any weld on the bottom side where the new piece will be butting up to, which it probably doesn't, carefully grind the weld away so the new piece can weld directly to that existing gusset instead of having a gap so it has to be welded to the frame . . This will reinforce the weak spot between the end of that factory gusset and the new one you put down the entire length of the backbone . . Welding the new piece to the frame instead of the existing gusset will leave a weak area between the end of both pieces.

There is another gusset that connects a tube that comes from the front down tube to the bottom of the back bone . . This gusset may not be fully welded to the back bone . . You can weld any open areas to the back bone if you want.to.


REAR VERTICAL FRAME JASON MENTIONED

If you want to reinforce those tubes, but for whatever reason you don't want to do it on the front side like Jason did you can achieve about the same thing by doing it on the back side.

Remove the fairly useless existing upper gussets that have the round hole in them.

Make the new gussets similar to the ones in the TCP 350X photo, but where the top and bottom one meet in the middle of the frame, just shape them so they extend from the frame by around 1/2" . . A one piece gusset will also be a little better but you can make two of them then butt weld them where they come together then grind the weld flat.

You can locate the left side one on the outside of the existing air box box bracket, then cut a hole in the gusset so you can access the forward air box bolt.

On the right side, you can eliminate the brake master cylinder mount and mount it to the new gusset instead.

Make these big gussets from 3/16" thick mild steel plate and weld them on the inside and outside . . Drill just about as many lightening holes in them that you want . . This will also give it a "WORKS BIKE" appearance.

This will kill two birds with one stone and preserve the appearance of the front of the frame tube which is far more noticeable.

You can make a plate that will weld to the front of the swingarm pivot bolt bracket . . Start it just below the center of the bolt and extend it downward then forward onto the lower tube around 1 1/2" beyond where the existing bracket ends . . Make it the same thickness as the swingarm mount and make it 1/2" high on the lower tube and have it taper to 0 where it ends with around a 45 degree taper.


MOCK UP PHOTOS

If you want, you can make the vertical frame gussets out of cardboard or manilla folders and use that as a template . . You can also tape these templates in place and take photos of them if you want, then I and others can offer opinions on whether they are too small or bigger than they need to be etc.

If had some way to draw them in on a photo and post exactly what I would suggest, I would be happy to do that but unfortunately I don;t have anything practical to do that with.



http://i.ebayimg.com/images/g/0bIAAOSwHQ9WXiTh/s-l1600.jpg

http://i.ebayimg.com/images/g/4-UAAOSwNphWXiTP/s-l1600.jpg



LOWER FRAME REINFORCEMENT

Instead of extending the swingarm pivot mount onto the lower frame tube, you can make a triangle shaped piece to lay on top of the open triangle area where the small angled tube connects t the side and rear frame tubes . . Make it from 3/16" mild steel and cut 3/8" off f the three points on it so there will be a slight gap between the points and frame when installed and leave this area open . . Make it so it does not sit on the very top of the tubes but so it will be about level with the top of the tubes when installed . . This is mainly for appearances sake . . You can drill a 3/4" to 7/8" hole in the center of those plates if you want . . If you put them on the bottom side of the frame, they will trap water and dirt.

This will reduce the chance of the tubes breaking in that area plus it will reduce the frames potential to compress.

http://i.ebayimg.com/images/g/vyQAAOSwdvpWDCXM/s-l1600.jpg

[barnett468]

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ok, I figured out a cheesy way to illustrate the gussets i'm suggesting you can install if you want . . the proposed gusset is the white area.

..................................... http://www.3wheelerworld.com/attachment.php?attachmentid=224537&d=1449195895

[barnett468]

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ok, the white is one version of the "BFP" gusset i was trying to explain . . the lightening holes were added at no extra charge.

http://i.ebayimg.com/t/NEW-SWISS-MADE-AUTHENTIC-GUCCI-WATCH-18-KARAT-GOLD-PLATE-AND-STAINLESS-75-OFF-/00/s/MTIwMFgxNjAw/z/3LYAAOSwHQ9WYR1J/$_57.JPG


This is what the gusset would look like if you painted it with the wrong shade of red.

http://i.ebayimg.com/t/NEW-SWISS-MADE-AUTHENTIC-GUCCI-WATCH-18-KARAT-GOLD-PLATE-AND-STAINLESS-75-OFF-/00/s/MTIwMFgxNjAw/z/jbIAAOSwp5JWYR1l/$_57.JPG


Here's the TCP gargauntuan model.

http://atvondemand.com/news/wp-content/uploads/2013/10/honda_350x_vintage_mx_project_2012-023-e1381335014252.jpg

[El Camexican]

You may want to keep the following in mind before starting to weld:
- It's always easier to copy something that is already track tested (i.e. the Hall's machine)
- Welding thick things to thin things (i,e, 5/16" plate to 16ga. tube) makes thin things prone to cracking due to them cooling much faster than the thicker material
- Adding 20 pounds of metal to your frame will slow it down and change the way your suspension works
- A frame should have some flex

Good luck!

[atc300r]

I don't plan on adding 20 pounds to the frame just beefing up a couple areas. I know a guy on a trx site that makes and sell gusset kit for the trx. Im going to contact him and see if he will make me a set for the areas on the trx frame that are similar to the atc frame like the footpeg area and rear subframe area. and swingarm pivot. the rest I will go by some of the suggestions by Jason Hall, Barnett. Thanks again for the input guys. 224729

[onformula1]

They are pretty easy to make, just make yourself up some templates, then keep them in a folder in case you need them for another trike or loan them to a buddy.

224732

[barnett468]

.

I don't plan on adding 20 pounds to the frame just beefing up a couple areas.

I know a guy on a trx site that makes and sell gusset kit for the trx. Im going to contact him and see if he will make me a set for the areas on the trx frame that are similar to the atc frame like the footpeg area and rear subframe area. and swingarm pivot. the rest I will go by some of the suggestions by Jason Hall, Barnett. Thanks again for the input guys.


ADDITIONAL WEIGHT FROM GUSSETS

Yeah, even if you added all the gussets I posted AND the ones Jason Hall used AND the gussets in the TRX kit in the areas not covered by mine or Jasons, you still wouldn't even have 10 lbs in gussets and welds.


FRAME CRACKS

As I mentioned earlier, although adding gussets transfers some force to a different area on the frame, you will not have an instantaneous catastrophic failure by adding them, and as others have mentioned, in general, it is better to pre-empt a potential problem by adding them to known weak areas on a suspect frame or one of unknown history than it is to simply pray that it won't break in half off that 20' jump at 50 mph smashing the frame AND you into the ground . . Again, simply periodically look for small cracks, and believe me, a portable fold up magnifying glass is a big help . . Some of them also have a light which is even better.


350X GUSSETS

It seems that you are committed to do this, so as others and I have suggested, maybe give Jason a call or pm and ask him what he thinks if you want . . Also, if you want, ask him to look at my ideas and offer his opinions on them if he wants to get that far into it . . I'm certainly not going to cry if he says they suck, lol, I just want you to achieve whatever your goal is with this.


USING TRX GUSSETS ON A 350X

I don't really have an opinion on this, and a 4 wheeled TRX is definitely a bit different than a 3 wheeled 350X anyway, but one thing to keep in mind is the thickness of some of the TRX gussets . . If some are 1/8" thick or less, you might want to use slightly thicker ones like 3/16" in some areas.


CHROMOLY VS MILD STEEL FOR GUSSETS

Even though chromoly is stronger than mild steel, mild steel will be fine in this app . . I would suggest you use chromoly if you ca get it easily and affordably, otherwise just use mild steel.


GUSSET FITMENT

It is not necessary to make the gussets fit into a "corner" where two tubes converge/intersect . . It won't do much to increase strength or reduce cracking in that area and is occasionally a pita, which are some of the reasons I suggested you cut a little of the corner off of them and showed that in most of my images . . Unfortunately I forgot to do this on the image of the rear upright frame gusset on the top.


TEMPLATE MAKING

The manila folders I suggested for doing this earlier will work fine, however, if you make the rear mounted gusset for the rear frame the way I showed it, construction paper might work better due to the size and bend in the gusset, and you could make that gusset with one piece instead of two this way if you wanted to.


FRONT DOWN TUBE GUSSET/REINFORCEMENT

I thought this over a bit, and my previous suggestion was one of two that I was going to make, and after thinking about it some more, I would use something a bit thinner on the front than the 5/16" thick piece . . This has nothing to do with welding thick metal to thin metal since doing this is easy if one is an experienced welder as I'm guessing you know, and we did it a zillion times at Kawi for various reasons.

I'm thinking that even though the 5/16" thick piece I suggested will reduce twisting and side flex more than a thinner piece, increasing the tensile strength is a bit more important, and sacrificing a bit of strength in the twisting and side deflection area won't be a big deal since the strength in those areas will still be increased if a plate of almost any thickness is installed . . For his reason alone, I think that for your particular app you should consider using a piece that is 3/6" thick instead, plus it might not look as out of place, and it imo, it is also important to not look tacky. :lol:

It's quite likely that they make metal in a width that is close enough to the width of the down tube that you won't have to cut it to width.


REINFORCING THE SWINGARM PIVOT BRACKET

This is nothing new and was first done in the '80's on some high perf street bikes but was first done on a dirt bike by Kawasaki way back in 1990 when they boxed it in . . This can be seen in the photos of the 1990 KX 250 below.


FRAME FLEX AND "UNIFORM FLEXIBILITY"

This is a complicated and fairly lengthy subject, and I am NOT a foremost authority on, however, I do have a reasonable amount of experience in this area and it is one of the things I was involved with at Kawi.

The more rigid a chassis and suspension are, the more stable the vehicle will be, but the firmer/harsher the ride can become.

The degree of "flex" a vehicle will have is figured in when designing a vehicle, and is mainly dependent upon the intended use and price point of the vehicle . . The stiffer a chassis and suspension are, the more it costs to produce, and it's not practical to design a super rigid chassis for a non racing bike because it is unnecessary and will also increase the cost to a point where its excessive for cost conscious buyers compared to other vehicles.

If you have ever owned a pre 1980's model long bed truck, and looked at the bed in the rear view mirror when entering a sloped driveway, you will have seen it move independently of the truck by so much that you might think the frame is broken if it was the first time you drove one, lol.

Reducing the flex in one part like the forks or swingam will exaggerate/increase the amount of flex in the non reinforced parts like the frame . . This was a major issue I had to consider and deal with when re-engineering the original 1986 Tecate prototype because it was so "flexy" at higher speeds and under high loads it was actually scary to ride.

The reason it was like this is because it was designed by someone in Japan other than the original designer whom really had little idea what he was doing and was unaware of just how hard these things were ridden in the US . . This was complicated by the fact that instead of using the only rider they had that was qualified to ride it fairly hard, they used a guy that would probably be a middle of the road novice in the US . . One of the things it originally had on it was basically an '85 front end and tire.

Anyway, whether one thinks it's good or a bad thing, the Tecate is the most rigid factory produced 3 wheeler ever made, which is partially evidenced by the massive forks and massive aluminum swingarm . . Keep in mind, this is still basically a "recreational" bike.

Many current vehicles like MX and high perf street bikes are now far more rigid than they used to be, and this trend started in the mid 80's with a few different mfg's which culminated in 1990 with the use of a chromoly twin spar frame on the KX 250 which most other mfg's eventually emulated, and which I know was not designed with flexibility in mind . . That bike also had basically flex free 41 mm forks and a fairly low flex swingarm . . In 1990, Jeff Ward won 4 of the outdoor National races but just missed winning the Championship because of a problem in one race where he ended up 13th.

..................................... http://www.pulpmx.com/sites/default/files/u165/csteel_71_001.jpg
......................................http://www.pulpmx.com/sites/default/files/u165/csteel_71_010.jpg

[barnett468]

.
Here's a cheesy image of the proposed half tube supports for the back bone . . There is one long one on top and a short one on the bottom that welds to the bottom gusset and the frame and the top half tube.

If it were mine, I would probably carefully cut the rear tank mount off the top of the tube, then grind those welds flat, then extend the top half tube all the way to where the existing top gusset is and weld it to that gusset, not to the frame, then maybe weld it to the the side tubes if possible, but better yet, or in addition, put a small 3/16" thick "L" bracket the width of the side tubes and long enough to extend 1" onto the side tubes and back bone, then weld it to the side tubes and the existing lower gusset ad the new top half tube . . It looks like it should overlap both tubes by around 3/8" which is enough . . Once you weld the L bracket to the side tubes, put a medium size tack weld on the front edge where it meets the upper half tube and lower gusset, then then whack it with a 3 lb hammar to make it conform to the curved shape of those parts.

You can smooth some of the bigger weld lumps down in this area if needed to get the half tube close enough to weld to the top gusset and side tubes, and you will need to shape the end of the half tube a little to make it fit . .

I'm hoping that what I'm saying will be self explanatory when you look at your frame.

Also, the front of the top half tube doesn't need to go all the way to the steering head if you don't want it to because the back bone has the big gusset on the bottom . . You could stop it around 6" before the steering head if you want so you won't see it at all.

http://i.ebayimg.com/t/NEW-SWISS-MADE-AUTHENTIC-GUCCI-WATCH-18-KARAT-GOLD-PLATE-AND-STAINLESS-75-OFF-/00/s/MTIwMFgxNTk5/z/nucAAOSwnipWZ9Dc/$_57.JPG

[barnett468]

.
I'll post some better more accurate images tomorrow.

[atc300r]

Wow its been almost a year since I started this thread. Havent given up I concentrated on TT racing this year plus some home repairs. I received some parts in the past few weeks. Im going to post a want ad in the classifieds for some more parts I need. Iv got about 90 percent of what I need from friends, 3ww,the 2 trx250r sites and craigslist. There is a new MX track opening within 20 minutes from my home. High Voltage Hills mx Grieg ny. I went to open practice this past Sunday and raced with Greg Huntley and his wife Missy and friend Cory. There were four trikes and about 4-5 quads we all raced together. Today received these. 235961

[hadudj]

Hi,

This is my first post on the forum. I bought a 250R and I'm going to race it in the Norra 500 next year. I bought the inverted forks and I'm in the process of having them shortened. Also picked up a BVC triple clamp. Today I was told this setup is extremely hard on the bike and now I'm likely going to crack my frame. Is a gusset job really required for this race. I'm not going to be jumping and I think the goal is to not beat the piss out of the bike so you can finish the race. Any thoughts on this? Also, being a bit new I'm not sure how to get a hold of this Jason Hall guy, how can I get his number?

Thanks,
Doug

[oldskool83]

every trike and atv frame should be gusseted. I think there is a bunch of guys who sell 250r gusset kits on ebay. Most times its around your shock mounts, sub frame and swingarm areas, plus the up front frame where the go from 1 to 2 down from the neck.

[Dirtcrasher]

Hi,

This is my first post on the forum. I bought a 250R and I'm going to race it in the Norra 500 next year. I bought the inverted forks and I'm in the process of having them shortened. Also picked up a BVC triple clamp. Today I was told this setup is extremely hard on the bike and now I'm likely going to crack my frame. Is a gusset job really required for this race. I'm not going to be jumping and I think the goal is to not beat the piss out of the bike so you can finish the race. Any thoughts on this? Also, being a bit new I'm not sure how to get a hold of this Jason Hall guy, how can I get his number?

Thanks,
Doug

They're just gussets, you can find pictures in Google images and make them yourself if you have time rather than money.

I've been gusseting frames for a long time, but shipping anything let alone a frame is getting expensive. Just use some carboard from a cereal box and design your own. You don't need a plasma table/laser or water jet, just some 3/32 and 1/8th steel, a way to cut it and a mig welder.