what do you think about 87 250trx..REbuilding

[all4jesus1122]

hello, i just bought a used Honda 87 250TRX, for 500$ it was raced i. it has been upgraded alot

NEW
+3+1 American Star racing front end with 400EX Shock conversion,
extened swing arm with +4 Durablue Axle, Renthal handle bars

i think it has been bored because there is new seals. or at least was reabuilt once.
it runs rough

My question is what should i upgrade and put into this. i have been riding my whole life, but i am new to working on bikes myself but love to do it and can.

I want to know what carbs, exhaust, enigne parts, performance parts ect. should i put in to it

should i rebuild the whole engine.


I do alot of trail riding, and like to get up and go.


how much do you think these up grades that came with it cost total.



do you think i should just get a 400ex or rebuild this.

[Tri-valleyracin]

for $500 its hard to pass up. buy it make it look good sell it and buy a 400ex.

[lee37vernon]

isn't that a 250 x ?? looks 4 stroke to me ! look at the exhaust ..

your probably asking in the wrong section but i'd say tidy it and sell it for what you want if you have something in mind ..

[all4jesus1122]

i want to make this the fastest 250x out there

can i bore it and what would be a good bore and does boring it make it more supecteable to cease


what parts should i add on to it

i already have a t-4 pro circuit exhaust

would a keihin 38 millileter be good.. with that ehaust


what piston should i use...what compression

[Dan229]

You can spend a ton of cash on that thing and do all sorts of things to it. There are guys on here that have 7-10K in their bikes. It just depends on what you want to do. To make it the fastest 250X out there you are gonna have to spend a lot of cash

For about $3000 you can get a professional big bore with porting, good after market shocks, and good plastic for it and be pretty much set or you can just worry about the engine work and spend about $1500 on big bore and porting.

Like I said, just depends on how deep your pockets are and what you want. You can burn up several thousand dollars on these things in the blink of the eye if you wanted to...

This thread on engine build up is really good too. http://www.exriders.com/vbb/showthre...hreadid=195797

Dan

[bwamos]

Originally posted by all4jesus1122
i want to make this the fastest 250x out there

How much money are you looking to spend. To make it the fastest.. it's going to cost you a LOT. I will be much cheaper to buy a 450r.

$1000's in the engine alone won't even make it the fastest.

can i bore it and what would be a good bore and does boring it make it more supecteable to cease

You can bore it out to 80mm with a big bore sleeve without reducing reliablility much.

But if you want "the fastest out there" you are going to have a pure drag racer and about 2hr's of reliablility.

what parts should i add on to it

For the fastest.. you're going to have a top engine builder build your motor w/ a LOT of flow bench time and custom work.

i already have a t-4 pro circuit exhaust

Good pipe but not gonna cut it for the fastest.

would a keihin 38 millileter be good.. with that exhaust

Depends on what you do to the motor.

An FCR off the 450r is great if the motor is big enough. The 400ex carb is a great upgrade that's cheap.

what piston should i use...what compression

For the fastest.. you're gonna be running very high compression on ethanol.


Now if you wan't realistic advice.. and want a very fast 250x that can compete at a reasonable price and be low maintenance.

80mm piston 11:1 compression, big bore sleeve, 400ex carb, K&N or UNI filter, open airbox, CDI w/ increased rev limit and timing advance, headwork (professional port/flow, oversized valves, etc..), approprite cam, heavy clutch springs, and your pipe is fine if it's a full system (header & silencer).

Suspension is also necessary.. if your suspension sucks, more power is uesless.

But the cheaper solution is to just buy a 400ex. In all honesty.

[2muchquad]

Im sure he doesnt REALLY mean the fastest but he does want top performance.Get a 80mm bore kit,a cam from web or megacycle,sparks,or even those clowns at powroll.Powroll will have the piston kit as well.a piston and cam will probably run you $300 and some change and get a FULL exhaust system.Add a 400ex carb which you can get for $25 off ebay at the right time and you'll double your current hp for around $600 not including the $150 for the sleeve installation and bore for the bigger piston.Doing it yourself will save you a grip on labor other than the machine work.That should quench your thirst for power for a while until you feel like spending bucket loads of cash on a 450r which you'll want to make that faster too,its a ongoing cycle

[all4jesus1122]

2muchquad,

yea thats exactly it

i want to spend around 500 dollars to make it alot faster than most 250x

sound like i need to rebuild the engine with a bore of 80mm??

HOW MUCH WILL A 80mm bore risk the ceasing the engine

my friend will sell me t-4 procircuit for like 200 is that worth it or can i get one better for cheaper

IS A KIHIEN CARB GOOD OR SHOUOLD I JUST GET A 400ex???

would you recomend a weico piston and what compression do you use

[bwamos]

As long as you replace the sleeve with a big bore sleeve you're 80mm piston will last a LONG time. Been running the same one in mine for 7 years now.

300ex's are dang near bullet proof.

Don't bore out the stock sleeve for the 80mm.. the sleeve will be too thin and prone to warping/cracking. The logevity of the piston & cylinder will go way down.

You'll want a 80mm 11:1 compression piston.

Get a 400ex carb and save the extra cash for suspension.

300ex carb will be fine until you port the head though.

[250X_project]

1st off I would build it up, just because that's 1/2 the fun. Make it your own instead of spending thousands on the run of the mill 400EX/450R ect..

2nd that 38mm Kiehin you talk about is just your everyday 400EX carb.- just a fancy way of saying it (as in my sig )

For best parts- Powroll, FST, TC, Sparks, KibbleWhite valve springs (a MUST with high lift cam)....

For exhaust I would never spend $200 on a used pipe. Try eBay.... it's all about luck and timing, at times you can go under $100. eBay has lots of engine parts as well. Good luck!