85 250R low end trail setup

[bandaman]

I just picked up this 85 250R and was wondering what you recommend for best setup for low end power? Pipe, reed, jetting, gearing suggestions? At this point in my life I no longer need to ring out every last bit of top end, but I really like some bottom end torque and quick throttle response.
242629

[Outlaw #24]

If ain't nothing wrong with it then Run it! Welcome to 3WW, Where in SE Iowa?

[justin85r]

curious about some mid range jetting my self, full fmf, open box and a 86 flat slide carb soon getting boyseen rad valve

[Ghostv2]

Get a larger rear sprocket to start. Here is a sprocket gearing calculator to determine what ratio (torque vs speed) you would like to run and how much speed you are willing to sacrifice. And to see what's even available.

Then I would move on to a pipe and if you really wanna get into it maybe some porting changes.

Sorry forgot to put a link. http://www.sprocketcalculator.com/

[fabiodriven]

If low end manners are your goal put it completely back to stock.

[RoscoW]

If that picture is current ^^^^^^what he said. You can't beat stock for a reliable, easy mannered and quiet trail machine. Fine tune the jetting to your area and riding (most were rich from the factory) and enjoy

Ross..

[barnett468]

I just picked up this 85 250R and was wondering what you recommend for best setup for low end power? Pipe, reed, jetting, gearing suggestions? At this point in my life I no longer need to ring out every last bit of top end, but I really like some bottom end torque and quick throttle response.
242629

it would help to know what you do not like about the power first and also what the compression is . if the compression is less than around 145, i would check the cylinder, piston, and rings first.

in your case i would also do this in stages.

if you rarely go wide open in 6th gear and your gears and tires are stock sizes, i would get a 2 or 3 tooth larger rear sprocket . if you plan on running smaller diameter tires, try the tires before you change the gearing.

if you don't mind running premium gas, i would install a cr250 head gasket . it is much thinner than the 250r gasket so it will raise your compression . in general, compression is king . more compression equals more power everywhere and better throttle response.

if you still want more power and have the stock silencer and don't mind if it is loud, you can install a straight thru silencer . this will help a lot . both DG and FMF make them.

http://www.ebay.com/itm/HONDA-ATC250R-ATC-250R-TYPE-2-DG-EXHAUST-ALUMINUM-SILENCER-MUFFLER-85-86-/132182911569

here's a decent looking used fmf for only $35.00 but the clown wants $30.00 for shipping.

http://www.ebay.com/itm/FMF-silencer-for-1985-1986-Honda-ATC250R-w-exhaust-hangers-/332241386725

no need for a fancy and expensive prefabulated amulite hexagonal slide variable bore grim reaper carburetor for your app . the stocker may be enough.

if the air filter is deteriorating, you can get a new orig or get a uni filter stock replacement



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[bandaman]

Thanks for the replies. I have not yet been able to ride this beast except for a couple rips around my tiny yard...I was able to find out some more about it though. It's indeed an 85, but it has an 86 TRX engine and swingarm. I believe the TRX has even lower compression than the ATC so the head gasket is something to consider. I have not checked compression, and I haven't even checked to see what it currently is jetted at so I have have a list of things to do. So far, I've only had time to clean it and look it over... I've drilled out and replaced a couple broken bolts, fixed a mangled bracket, and and some minor detail stuff. Plan to get it dialed in soon!

I really do not want to make it louder if possible. The stock silencer is in good shape, but the pipe has been repaired... looks like some gummy patch material?? Can I run an aftermarket pipe with the stock silencer?

[atc300r]

Yes you can run an aftermarket headpipe with stock silencer. I raced my 85 250r last year with this setup and 38 mill carb ran strong . Also on my aircooled Rs I have ran them in drag races with stock silencer and DG or Bills headpipe.

[barnett468]

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There is very little point in running a high perf pipe with a stock silencer, that being said, the trx pipe would likely work better on it but it is not possible to modify one to fit so you would need a complete custom made pipe which is pricey and not worth any benefit you might get from it in my opinion since you are not racing it . If yours is damaged enough to warrant replacing it then that is obviously a different situation.

It's a bummer about the engine because the stock 250r has great throttle response and runs great and is very smooth, they are just not as fast as "The TECATE...The Most Powerful 3 Wheeler In The Universe!". :lol:

If it does have the stock TRX head gasket, I would get a thinner one right away and start from there.

Here's some gasket info from the net but some people recommend to stay away from the fiber gasket . Some say the thinner aftermarket gaskets designed specifically for the trx fit better than the cr gaskets.

"...the 3 pieces OEM is 1.5MM (.060”), the single piece “thin” CR250R gasket measures .25MM (.0098”), the Wiseco “fiber with metal center band” is 1MM (.040”) thick and we carry a BDTM Copper head gasket that measures .63MM (.025”). I know Cometic makes numerous Head gaskets as well…"

The guy in the link below sells the .025 thick copper gasket, however, if your piston and cylinder and rings are all good, it may give you a little too much compression . One way to find out is to disassemble the layers of your stock gasket if it has one then measure the thickness of one of the outer layers then install it and do a compression test then ride it very briefly and listen closely for detonation . I would surface the barrel and head before reassembly to help prevent a leak . You could also spray some copper seal on it as well . Don't forget to monitor the jetting closely to prevent seizing.

http://stores.ebay.com/250rtrikes/



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[atc300r]

No need to modify a trx pipe for the 85-86 250r. You can still buy FMF and DG head pipes new plus a couple others.Check ebay for a nice used stock or aftermarket headpipe. A stock atc head gasket would be good for trail riding.The Tiger 500 is dubbed the most powerful three wheeler in the universe.LOL

[Ghostv2]

No need to modify a trx pipe for the 85-86 250r. You can still buy FMF and DG head pipes new plus a couple others.Check ebay for a nice used stock or aftermarket headpipe. A stock atc head gasket would be good for trail riding.The Tiger 500 is dubbed the most powerful three wheeler in the universe.LOL

What about the wmx500?

https://uploads.tapatalk-cdn.com/20170602/308cdcb304753d3d22e72388f0a38eac.jpg
https://uploads.tapatalk-cdn.com/20170602/9f264ce15408c839aaff863c4106fe19.jpg

I'm sure you guys can figure out who these sweet 500's sitting next to each other belong to. [emoji6]

[350for350]

When I talk about trikes, I always talk about the mass produced ones since I don't know very much about the low production racers. I'm betting that Barnett's doing the same. Although he may know more about the racers than I do which wouldn't take too much!

[yaegerb]

I just picked up this 85 250R and was wondering what you recommend for best setup for low end power? Pipe, reed, jetting, gearing suggestions? At this point in my life I no longer need to ring out every last bit of top end, but I really like some bottom end torque and quick throttle response.
242629

For low end do the following
Stock gearing
Fmf fatty or Paul turner type 6 pipe
Boyesen rad valve
Stock carb or 38mm keihin non air-striker with 164 main and 50 pilot, needle on 3rd clip from top.
Uni filter with EHS air flow lid if they still have any available.

That should get you some arse ripping torque.

[bkm]

When I trail rode my 250r, I ran a CR head gasket like barn suggested. I also ran the stock carb and an older FMF Gold Series pipe/silencer combo with a 12 tooth front sprocket. I would have changed the rear, but being a poor high school kid, the front was cheaper. It was a great trail bike that never felt sluggish.

Sent from my SM-G900V using Tapatalk

[The_Steve_Man]

You would be surprised what an 01-03 CR 250 carb will do for bottom end. Fantastic throttle response and smooth power. And a FMF pipe.



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[barnett468]

No need to modify a trx pipe for the 85-86 250r. You can still buy FMF and DG head pipes new plus a couple others.Check ebay for a nice used stock or aftermarket headpipe. A stock atc head gasket would be good for trail riding.The Tiger 500 is dubbed the most powerful three wheeler in the universe.LOL

Sorry if my comments regarding the TRX pipe were confusing . I was not suggesting that he use one, I merely meant that a stock TRX pipe would be tuned to the TRX engine better than a stock ATC pipe would.

As far as the 500 Tiger being the most powerful 3 wheeler in the universe...well, since the engine is twice as big as the TECATE engine, I will concede that it most likely is more powerful than even any 250, HOWEVER, if one is comparing actual engine size vs power, the TECATE 500, is by far and away the most powerful 3 wheeler in the universe for its size! https://www.mustang.org.au/forum/Smileys/smilies/thumbsup.gif


http://i371.photobucket.com/albums/oo153/hondawasaki/P1030550.jpg~original



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