350RX no more...time for a YZ426

[SWIGIN]

After alot of thought I decided to finally switch from a 350x motor to a YZ426. It almost pained me to think of my quad with a Yamaha power plant but it is time to do something different....and it's nice to be able to go buy new OEM parts at will.

Here is ''Jack'' ( my RX is named Jack) as a 350RX.

http://i39.tinypic.com/34zkcyb.jpg

http://i44.tinypic.com/308jnyx.jpg

http://i42.tinypic.com/2d8hxj6.jpg


And here is Jack within 24 hours of being torn down.

http://i39.tinypic.com/3135a1h.jpg

I had to heat up the frame in this spot and dent the tube slightly for the motor to fit. This was the only frame mod needed for the motor to fit, and I did even out the dent later.
http://i41.tinypic.com/zyhyd4.jpg

[SWIGIN]

After I got the new motor to fit, I took it over to HRE for new motor mounts. We decided to use chromoly tubing for all the mounts.

http://i42.tinypic.com/zt7joi.jpg

http://i44.tinypic.com/25z5vrk.jpg

Here is the 250R radiator with Walsh scoops and decals I made at work.

http://i40.tinypic.com/2s9eft0.jpg

http://i41.tinypic.com/x2rqiw.jpg

http://i41.tinypic.com/5ul8uh.jpg

[baycitysteve]

whatcha doin with the X motor ???

[aldochina]

if the 350 motor was stock it will prob be a whole new ballgame with the 426!! cool conversion, both of them! what is required to do the 350x mod to the r frame?? nice to be able to fab up the mounts and stuff you need professionally! makes all the differance in the world!

[Bryan Raffa]

Nice Swap.. you will like that motor!!

[rdlsz24]

That's the YZ450F engine's older brother correct?

Rob

[brapp]

awesome when you get it done we deff gotta run a mx track somewhere.

[SWIGIN]

whatcha doin with the X motor ???

My brother took it back.

[SWIGIN]

if the 350 motor was stock it will prob be a whole new ballgame with the 426!! cool conversion, both of them! what is required to do the 350x mod to the r frame?? nice to be able to fab up the mounts and stuff you need professionally! makes all the differance in the world!

No it was not near stock but it will still be a whole new ball game! My frame was built as a RX so it was not a conversion...till now.

[SWIGIN]

That's the YZ450F engine's older brother correct?

Rob

Yup, but it is a 5 speed motor and not 4 like a 450. I am big boreing it to a 445cc so it will be 450ish.

[SWIGIN]

Nice Swap.. you will like that motor!!

Thank you!

[SWIGIN]

awesome when you get it done we deff gotta run a mx track somewhere.

Well I have my track, did you ever build yours?

[Jason Hall]

Swigin, not all the yz450's were 4 speeds, I'm pretty sure just the 03-04 were. I have a YZ400 engine with a stock YFZ450 exhaust cam In a 87 trx250R frame. If yours doesn't have the auto compression release, the YFZ cams are Cheap and work great In the YZ engine as long as you retard It one tooth (Very Common YFZ cam mod). Once you retard the YFZ cam , It's basically the same cam specs as the YZ450 engine. Mine makes great power, the yamaha 400, 426, 450's make explosive power. They remind me of a big bore 250R, except they have Lots more low end torque.

[SWIGIN]

I don't follow dirt bikes at all...lol

So only 2 years were 4 speeds, good to know .

I'm going with hotcams since they have the auto decomp built in and the timing marks work. I have seen it said on Thumper Talk that the 450 cam is not much better performance wise then the 426 cam.

My buddys have 400 and 426 hybrids, heck, the one guy was the third guy at the nationals to race one back in 98 or 99. So I have been around them for awhile, I just got the bug to have one...lol

[Jason Hall]

I personally don't like Hot Cams at all, they are Very noisy (at least In CRF & TRX engine's). I have a 05 YFZ450 engine with Webb Cams, and It's a bit noisy also. As If you can't tell, Valve train noise make me Crazy LOL. Good luck with what ever way you go, I've said It many time's, I love Yamaha's new 4 stroke's. If you can find me a nice set of stock 08 YFZ cams, I will make you a deal on the Webbs that I have. They have Very little time on them.

[SWIGIN]

Here are some more shots.

Chromoly head stay.
http://i40.tinypic.com/xbh30w.jpg

I decided to run the header heat guard, but I had HRE powder coat it the same color the frame will be.
http://i42.tinypic.com/wujus3.jpg

HRE calls this area of new tubing ''the room'' It adds strength to the rear tube and protects the low hanging case area.
http://i40.tinypic.com/14bko6q.jpg


These motors have a real low hanging drain plug area, so I decided to reuse the dirt bike skid plate....or at least the bottom piece of it anyway.
http://i39.tinypic.com/auyrh0.jpg

We decided after trying in vain to get the air tube routed between the frame and CR500 shock that we will steal an Idea from Laeger and bend the left side subframe rail.
http://i40.tinypic.com/5lpf82.jpg

[SWIGIN]

I personally don't like Hot Cams at all, they are Very noisy (at least In CRF & TRX engine's). I have a 05 YFZ450 engine with Webb Cams, and It's a bit noisy also. As If you can't tell, Valve train noise make me Crazy LOL. Good luck with what ever way you go, I've said It many time's, I love Yamaha's new 4 stroke's. If you can find me a nice set of stock 08 YFZ cams, I will make you a deal on the Webbs that I have. They have Very little time on them.

I have never noticed a 5 valve motor get noisier from hotcams. Hotcams never really turned me on either but from what I hear they really stepped up quality lately.

[SWIGIN]

Tonight I finished up my subframe, this is a hunk of 1 1/2 round stock that I machined down to fit inside of the subframe and angle 22 degrees to fit the mount .
http://i41.tinypic.com/332v6u0.jpg

The bolt was too long so thats why there is a spacer under the head.
http://i40.tinypic.com/2920ft2.jpg

We also got the air boot problem solved.....we built one out of aluminum.
http://i44.tinypic.com/34rsy6e.jpg


Tomorrow we hope to finish the swingarm and mount the oil tank and then pull the motor and weld everything solid.

[SWIGIN]

It took all day today but we got Jack done and it's back home. I need to finish alot of small stuff and I'd like to basicly put the quad all back together just to make sure everything works and fits like it should.

More pics to come.

[SWIGIN]

Here are some more pics of the frame and different things HRE and I made for Jack. I ended up loosing my swingarm bolt in the move from HRE to home last night ( I left it sit on my bumper and drove off...lol ) so I just whipped up the new one in the last picture.

[SWIGIN]

I forgot to show the coil mount.

[Vealmonkey]

I can't wait to see all the changes in person. Jack was understatedly pretty trick before, but he's going to another level and a generation newer as well. Wayne, how did your buddys frame turn out that was on the table when I was up there last time? That was a really neat update as well.

[SWIGIN]

Thanks Pat

My buddys yz426 hybrid that was on the table is all together and running. He only was beefing up the frame so he had no down time from engine building and pipe making ect.....wish mine was that easy...lol

[tri-Z ripper]

Very nice and excellent quality work!!! I truly hope you have kids, why you ask? to be able to share and produce stuff like this needs to be passed on. To many people hack things together. I love seeing the Quality builders on
3WW and 3WO build amazing machines. makes me wanna sell everything i own to have a machine shop!!!!

[SWIGIN]

Thank you sir!

[zmpolaristech]

Very cool build man, and beautiful job on the frame mods!

I agree with Jason thow, I would stay away from Hot Cams. Something about their lobe profiles, they are very hard on the valve train and def make ANY bike noisier...just my opinion.

[SWIGIN]

I also need a new graphic kit for Jack, so I came up with this, let me know what you think!

My boss has plans on selling these kits for most any sport quad so your input is valuable.

[SWIGIN]

Very cool build man, and beautiful job on the frame mods!

I agree with Jason thow, I would stay away from Hot Cams. Something about their lobe profiles, they are very hard on the valve train and def make ANY bike noisier...just my opinion.


Like I said, they have stepped up there game since they came out and the guys on Thumper talk really like them. Not to mention that I know guys who have run them for years with no problem, I'm going to try them.

[SWIGIN]

I finally took the time to fit my modified Laeger chrome swingarm to Jack. HRE had to cut out the front bearing tube and weld in 2 smaller tubes since the rear of the new motor mounts to the swingarm.

I did not want to lose my chrome swingarm so instead of powder coating the whole thing I decided to just paint the front few inches with my charcoal gray paint. And of course I had to add some blue flames to the sides of it, turned out pretty good I think.

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[SWIGIN]

Guess what, that swingarm bolt I lost.........

I found it 2 days later laying on the white line on the side of the road with the nut still on it perfectly fine...lol



I couldn't make my mind up on if I wanted an oil cooler or not. my buddys who have YZ hybrids don't run a cooler except for one. And the ones that don't run a cooler have no problems with heat.

Well it turns out they all run 400ex oil tanks and I guess the oil lines are run differently then my YFZ 450 oil tank. After looking it over real good it is just as easy to plumb in a cooler then not, so I made up some cooler brackets this weekend and I'm about to go tack them on with my MIG then when the frame goes back to HRE for powder I'll have him TIG them like the rest of the frame.


The pic with the 2 mounts are the first mounts I made but they ended up being too short.....
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[SWIGIN]

I'm calling the oil cooler done, you could spend days on tweaking lines and stuff but everything has clearance so good enough. I also machined out a piece that fit over the coil mount that limits rotation. I was talking to HRE today and he thought I should make something to stop the coil mount from rotating if the bolts ever came loose.... not a bad idea.

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[jason85atc250r]

whatcha doin with the X motor ???

It's going into my 86350x for Astubula. it's ported big time with TC high rev cam 11 to 1 comp.

[SWIGIN]

Here is the graphic kit in real life. This is the prototype and I am tweaking a few things on it yet but as far as first shot fit it's about perfect.

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[aldochina]

graffix came out awsome! as did all the frame mods!

[SWIGIN]

graffix came out awsome! as did all the frame mods!

Thank you sir!

[SWIGIN]

I decided I was done playing with the chassis for now so I tore Jack back apart so I could open up the motor.

I was shocked how simple these things are compared to the motors from the 80s. Kinda reminds me of my old Quad racer bottom end. No thrust washers falling out and trying to remember where they came from...lol

I might get new oil pump parts since the rotors are scored up, and the oil had water in it so one gear has a good bit of rust on it so that might get replaced as well. The water pump seems to be very unhappy so that's where I think the water came from. I was also kinda shocked at how clean the bottom end was inside, after working on 350x motors for many years this 12 year old YZ motor seems like new to me.

I also decided to upgrade from my 86 R spindles and brakes to some 400ex spindles and YFZ450 calipers. The calipers are a direct bolt on with no mods and this way I can still have twin piston calipers.

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[SWIGIN]

I went over to HRE yesterday because my other buddy is in the middle of upgrading his hybrid quad and they were firing up the powder coating oven, so I had to join in the fun.

I just took my motor mounts and oil tank since they are the only thing getting new powder other then the frame and Jacks frame is not blasted yet.

The motor mounts got the same blue that the frame will be getting. It's a purplish blue like Yamaha blue but I have a real problem with taking pics of blue things and having them look right.

The oil tank got a new coat of silver vain to match my steering stem and A arms.

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[SWIGIN]

I've wanted to make my own bumper for years, most aftermarket bumbers don't turn me on. So I had HRE order up some aluminum tubing and we bent this up. In the one pic I threw the old bumper behind the new one just to show the size of the new one. I always thought that Duncan bumpers were a tad to small so I made the Duncan fit inside of mine.

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P.S..... I forgot to add that I still need to make the upper mounts....lol

[ezmoney1979]

That thing is looking great! Nice job!:beer

[SWIGIN]

Thank you!

[SWIGIN]

I got my upper mounts done tonight after work. I used some 5/16'' aluminum plate that I had laying around. I'm pretty happy with my first bumper build! I just need to take my frame back over to HRE and have him weld the mounts on and it's done.

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[JasonB]

man this is an awesome project! seriously innovative, nice fab work and everything looks great! cool project

[SWIGIN]

man this is an awesome project! seriously innovative, nice fab work and everything looks great! cool project

Thank you!!

[SWIGIN]

Today I took my frame and bumper back to HRE to weld my upper mounts on. After he was done welding it and it cooled he was talking about fireing up the ovens so I had to have him coat the bumper. I went with chrome powder, it's the base coat for the translucent colors and it's very shinny.

We also heard a rumor that Easy-off oven cleaner will take off powder coat, so I bought a can and tried it on my subframe....it does not work. So I blasted it and we coated it with the Reflex blue like the motor mounts.

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[SWIGIN]

My cams and shim kits came in as well. Soon the crank will be done and my recoated big bore cylinder should be back any day now. I'm getting REAL close to firing this thing up!

[SWIGIN]

Today I decided to attack the tranny and cases. I took all the bearings out of the main cases and scrubbed them with super clean and a tooth brush. The tranny bearings all got cleaned in kerosene to flush them out and reinstalled. Then I installed my new main bearings and cleaned the tranny parts and installed them.

As soon as my crank is done being rebuilt (should be any day now) I can put the bottom end together! My cylinder and frame should be showing up in a few days as well, I am starting to get EXCITED!

I'll post pics tomorrow.

[atc007]

What a ride this is gonna be! Santa should be bringing a shiny new Big Bore in 1 or 2 days. Nice work as Always!

[SWIGIN]

What a ride this is gonna be! Santa should be bringing a shiny new Big Bore in 1 or 2 days. Nice work as Always!


I hope you are right but the begining of this week could be crazy as far as new shiny parts showing up...lol

[SWIGIN]

Here are the pics from Saturday. The cases cleaned up real nice and after figuring out the magical way to install the tranny, shift forks, and shift drum into the cases basically all at the same time it went well.

The last pic shows the bushing I needed to make for the swingarm bolt. The YZ must use a 16mm bolt and the R uses a 15mm bolt so I had to make a thin bushing and press it into the cases. In the past guys would just make a single bushing and press it into the cases but when you need to split the cases this bushing is a PITA to deal with. So I made mine in 2 pieces so the cases come right apart.

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[SWIGIN]

atc007 was right, I received my cylinder today!

145640


The stock bore for a 426 is 95mm, I went with a 2mm big bore (97mm) to take my motor up to a 444-445cc.

Most guys call this a 444cc motor, JE calls this a 445cc so I don't even know for sure but I would think that JE would know what there piston does.

[atc007]

Holy close to the water jackets batman! If the piston and sleeve will take it,,,that will def wisk away the heat. A real work of art isn't it? Should be fun from here out!

[SWIGIN]

Holy close to the water jackets batman! If the piston and sleeve will take it,,,that will def wisk away the heat. A real work of art isn't it? Should be fun from here out!

I know right...lol

These ''new'' 4 strokes just blow me away with how far advanced they are over the older ''normal'' 4 strokes. My buddy has run the same size big bore in his quad for about 10 years with no problem so I sure hope mine will take it...lol


P.S..... MAJOR update coming tomorrow!

[SWIGIN]

I have just over 2 weeks till our trip to Breezewood so when I heard that this would be ready for pickup today I was STOKED!

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I think I'll be able to make it a roller this weekend and get all these darn parts off my floor, and hopefully get the motor together before next weekend. that will give me one week to tune the thing before we go.....

[atc007]

Very nice!!!! Waiting on pics,as always!

[SWIGIN]

Thanks guys,here is the day 1 progress.

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With switching to the 400ex aluminum spindles and having long travel shocks I had to back cut the bottom of the spindles to clear the A arm. When you have 13'' of travel you run into this kind of thing...lol

[SWIGIN]

Tonight my crank came back from being rebuilt so I stopped working on the chassis and threw the bottom end together. Since the swingarm bolt goes through the motor I really wanted to at least get the bottom end together and bolt it into the frame so I can tighten everything in the rear end. The top end can be installed in the frame but I'll probably at least put the piston and cylinder on since that will be easier while on the bench.

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I'm still waiting on both EX valves and a little clip for my oil pump so I can't put the head or clutch side parts on yet.

[oldskool83]

will this thing rip more then the RX when i road it? Looks like you gonna have a sweet bike.

[SWIGIN]

will this thing rip more then the RX when i road it? Looks like you gonna have a sweet bike.

My 350x motor was probably pushing mid 30s for HP, a stock 426 puts 46ish HP to the rear wheel in a dirt bike. Plus I have head work, cams, pipe, big bore and more....lol

I have seen motors like mine make near 60HP....lol

[oldskool83]

thats cool. i knew the yz400 and 426 motors were good and power full just didnt know power ratings.

[legacy51]

That is looking pretty sexy! Just wondering but are the newer 450 engines much better than a 426? The 426's are about 10 yrs old now and it would be interesting to compare that to a new 450 engine.

[SWIGIN]

That is looking pretty sexy! Just wondering but are the newer 450 engines much better than a 426? The 426's are about 10 yrs old now and it would be interesting to compare that to a new 450 engine.

Thanks for the kind words.

Better how? A 426 built like mine has more cubic centimeters then a YFZ450 and will kill it power wise.

[SWIGIN]

Here is Jack as of tonight, just need to finish the pipe and add fluids basically.

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Today was rough as my butt was dragging from working on Jack late all last week, I just wanted to sleep in and be lazy today but my buddy (boss) and I got a ton done today.

[yaegerb]

Very nice work! That's gonna pull hard! In 05 and 06 I raced a 450 YFZ, god I miss my bike. Keep up the awesome work

[SWIGIN]

Thanks

A few of my buddys have basically the same motor in there hybrid quads and they do run real strong. I will hopefully have a ride report on this one by the week end.

[SWIGIN]

Well, I rode Jack on Monday night for the first time with the YZ motor. It was VERY lean everywhere with the CRF450 carb so the test ride didn't last long at all.

Tonight I went from a 166 main to a 180 and from a 42 pilot to a 50 and it's much closer. Saturday I'll take it over to HRE and fine tune it there. He has jetted these kinds of hybrids for well over a decade, plus he has a almost endless supply of jets.

1 week to go till our trip to Breezewood proving grounds!

[SWIGIN]

Jack is officially done and running 100%!

I took Jack over to HRE to jet it in and while it was there we took care of a few minor things. Today I'll take Jack over to my track for it's first day of abuse...lol

[Swinger]

Nice looking machine bud. Do you camp at the proving grounds? Been trying to get a weekend there with the family and friends but everyone schedules clash. Do they let trikes there?

[SWIGIN]

We rent the big cabin but yes you can camp on site. I think 3 wheelers arefine there but I'd call and ask before going.

[oldskool83]

hows the sound of the fitting exhaust lol?!

[SWIGIN]

It sounds good and fits together great....now....lol

[SWIGIN]

Here is Jack getting ready to be ridden for the first time after tuning it in. This is my first quad that thinks it's a 3 wheeler, the front end is either in the air or trying very hard to be in the air...lol

http://i48.tinypic.com/14tv4t0.jpg

http://i46.tinypic.com/dcwy38.jpg

http://i45.tinypic.com/2cf6zhf.jpg

http://i49.tinypic.com/13yl0g7.jpg

http://i47.tinypic.com/t540tz.jpg

Jack seems to make me less tired with the YZ motor compared to the 350x. Even though the YZ has gobs more HP the little old 350x used to just ware me out. You can ride the YZ motor more lazy since it pulls a gear forever. My high strung 350x motor had to shifted very fast and need to stay in the upper RPM to make any power.

I'm saying this after only riding it 1 day but I really feel less beat with the new motor.

[jon jon]

i see we both run the number 5 lol nice looking bike

[SWIGIN]

Yeah, that was my AMA number so I kept it, thanks.

[atc007]

Beautiful work again man. Gorgeous bike,,and I am Sure,,a real blast to ride!! Enjoy....!

[SWIGIN]

Beautiful work again man. Gorgeous bike,,and I am Sure,,a real blast to ride!! Enjoy....!

Thank you sir, come on down for that thing in my shed and we can go ride Jack.

[SWIGIN]

Well, I made it back home in one piece, but Jack did eat an axle bearing on the last day. Other then the bearing it worked and ran better then I thought! I am sore but not as bad as I was last year with the 350x motor. I guess not having to work it as hard to get around the track is saving me some pain.

Action pics soon to come.

[atc007]

I'll bet he turned more than a few heads too !!! Awesome job..

[SWIGIN]

The guy who came along to take pictures took over 500 pictures so I'll never get around to resizing them all, but here is a series of shots of the uphill double/table top near the finish.

http://i45.tinypic.com/iz5260.jpg

http://i49.tinypic.com/10h6g6c.jpg

http://i47.tinypic.com/2uhxy1c.jpg

http://i47.tinypic.com/5bdz52.jpg

http://i48.tinypic.com/15qp1tu.jpg

[atc007]

What a friggin BLAST ! Thanx for the pics Wayne.

[SWIGIN]

Here's another series of a 35' triple that I will be adding to my track. Im posting from my PS3 and for whatever reason I can't get the pictures in the correct order.

[SWIGIN]

For the record I just wanted to say that the myth of Hotcams being noisy or whatever is totally bunk.

I guess if you don't shim them correctly they (or any cam) would make noise but mine are stone quiet.

[oldskool83]

very nice wayne, why do your air photos always look like the fornt wheel is toein in bad? i know they arent lol

[atc007]

He's running a LOT of suspension on that thing!!! Beautiful ride for sure! The 110 is home safe and sound! Thanx again Wayne!

[Tri-Z 250]

I got a fourtwosix (2wheeler) put the HotCams in my engine...they work mint. Bike starts just like my old 465RM...gotta roll it over to the sweet spot, then kick it. Much nicer than the original lever decomp ruteen. I've yet to play with the adustable intake...Smooth from the rip, which is what I wanted to do...I guess you can make em a bit more snappy for total roll-on power.

[SWIGIN]

very nice wayne, why do your air photos always look like the fornt wheel is toein in bad? i know they arent lol


Like atc007 said, I have 13''of travel and when you have that much you almost can't get ride of having some toe in when the tires are off the ground.

To make it worse, right before that trip I put 400ex spindles on Jack and they made it toe in alot more then the R spindles when in the air. Just last week I had HRE make me a new steering stem to fix the problem....or at least minimize it.

[SWIGIN]

I got a fourtwosix (2wheeler) put the HotCams in my engine...they work mint. Bike starts just like my old 465RM...gotta roll it over to the sweet spot, then kick it. Much nicer than the original lever decomp ruteen. I've yet to play with the adustable intake...Smooth from the rip, which is what I wanted to do...I guess you can make em a bit more snappy for total roll-on power.

I can't get over how easy my 444 is to start. I knew I didn't want a 3rd lever and learn a complete new starting routine so IMO the Hotcams are the only way to go.

[oldskool83]

i knew it had alot of suspention up front. either way its nice, id love to see it in person one day with the new power plant.

[Louis Mielke]

The Proving Ground does allow three wheelers, Dan even said I could run with the 30+ guys on my trike if I wanted to. One of these days I'm gonna take him up on that.

[SWIGIN]

Yeah, our camera man cruised around on my brothers mint 250sx all weekend.

[brapp]

hey i ahve been workign ont he mx track up here and things are comign to gtether its nothign litkm that place but its startign to take shape.,, and i had a custom lrd prototype aluminum frame 400ex geometry and a crf450 out of an 02 was one of my last race quads i had.

[threewheelin-feelin]

hey im just curious what the reason for putting a 350x motor in a 250r chassi? and instead of doing a 426 project now why not just get a yfz450...im not trying to put anything down im just wondering the advantages to both conversions

[SWIGIN]

Well, I don't know anything about dirtbikes, and I thought all YZ450s were 4 speeds. And I hear some of the new 450s have no oil tank. I knew what a 426 was and with a big bore it's about the same cc as a 450.

The 350RX hybrid was a popular thing in the 90s. No one made a decent MX 4 stroke so we racers made the RX.

[SWIGIN]

I just wanted to show that old out of shape guys can fly.....when they feel like it.

Finish line jump @ breezewood proving grounds.
http://i42.tinypic.com/1zfmuqe.jpg

Thanks to 3Queen for snagging this shot!