Honda hop ups for 250r

[crf7212]

ok every one i got an 87 trx250r on thursday and im wanting to know some good stuff to do. kinda on the cheaper side. i already have a full fmf system and boysen reeds so what else????? thanks.

[ATJ_Number_1]

ok every one i got an 87 trx250r on thursday and im wanting to know some good stuff to do. kinda on the cheaper side. i already have a full fmf system and boysen reeds so what else????? thanks.

Get the head shaved. The 250r head is one that any local machine shop can do. Just make sure they re-cut the squash area back in. Nothing wakes it up like added compression. If you can take the lid of the air box do it and jet accordingly. You can remove the snorkel then and plug the hole with a spray paint can cap. They fit perfectly and look clean.

[crf7212]

how do i know wat year it is?? can i tell by vin numbers?? the shop i got ifrom said it was an 86 or 87 they thought. cuz theres a big diff between 86 and 87 cylinders.

[crf7212]

whats the highest i can bore a standard 250r cylinder to?????

[ATJ_Number_1]

whats the highest i can bore a standard 250r cylinder to?????

86-85 you can go 3.5mm over.

87-up 2mm

[ATJ_Number_1]

how do i know wat year it is?? can i tell by vin numbers?? the shop i got ifrom said it was an 86 or 87 they thought. cuz theres a big diff between 86 and 87 cylinders.

Pretty sure you can measure the height of the cylinder. I'll see if I can find a number for you.

EDIT: It's been so long Now I''m wondering if it's a different pin height. I'll let you know if I remember. Sorry

[CQR]

If you look down the intake port(behind the reeds) and see 2 bars going down from top to bottom, you have an 87-89 engine, the 86 was a wide open intake port. The 86-87 cases were a grey color, the 88-89 cases were black.

87-89

86

The pistons, pin location, and rod are different.

There is a height difference in the cylinder, but I never knew the specs.

What is the 10th digit of the vin?

http://www.maultechatv.com/techguides/10thdigitvin.php

[CQR]

A good port job will really wake that thing up. (not ESR)

[BadBird69]

A good port job will really wake that thing up. (not ESR)

I like to port my own jugs and heads,I ported my sons '06 blaster with info from this site and had very good results!

Why not esr?? I dont know much about them,other than the ads in the mags...

http://www.macdizzy.com/atc.htm

[CQR]

I have seen some good stuff from ESR in the past, But recently, A guy I know built a 350 bigbore with ESR stuff, and nothing worked. The bore was too tight for the piston at BDC. We had a ported 295 that would walk the bigbore. Once we sent it in to be re-ported, I had a hard time keeping up with my 350.

[crf7212]

well i figured out its a 88 or 89. its got fmf full system duncan racing carb uni air filter and boyesen rad valves and its been bored to like a 261 or somethin like that with a wiseco piston. i was looking at pics on the computer and the cdi had some kinda timing curve adjustment on the stock cdi. wat would happend if i messed with that a lil???? really interested in that. any help would be great. thanks.