i have an 89 xr 250 and I was looking into a big bore kit. I was wondering if anyone has done it to there bike and if it is any good. Im also wondering approximitly how much it would cost counting labor.
Posted by: john stu---------------------
spend you money on a newer bike.......bigger if you want sell it and get a xr400
Posted by: drz250rider---------------------
don't wast the money
Posted by: XR250rdr---------------------
Its a great upgrade for an XR250, but that bike is nearing 20 years old. For just a big bore its not too expensive. You'd be looking at $200 for piston and gaskets then ~$50 for a bore job. But if anything else needs to be replaced it could get expensive quickly.
If the bike is in good shape I'd spend that money on a set of Race Tech cartridge emulators and a rear shock service job.
Posted by: SFO---------------------
where is the pantless one when you need him?
Posted by: 76GMC1500---------------------
An XR400 is a big bore XR250.
Posted by: dirt bike dave---------------------
Quote:
Originally Posted by 76GMC1500
An XR400 is a big bore XR250.
XR 250 has a 73 mm bore and 59.5 mm stroke. It is a 6 speed. A common big bore kit is 77 mm.
XR400 has a 85 mm bore and 70 mm stroke. It is a 5 speed.
The engines share a strong family resemblance, but the 400 is not a bored out 250.
FWIW, I had a big bore piston put into my '90 XR250. It added nicely to power, including to low end. However, the bike still liked to rev, and it was not exactly a powerhouse even with the big bore. IMO, a stock XR400 has much more low end power than a big bore XR250.
Posted by: 76GMC1500---------------------
I meant to say he should replace the XR250 with a bigger bored XR400.
Posted by: BadgerMan---------------------
If you have to do a top end job and bore the cylinder anyway, definitely go with a larger piston. I have a restored 1986 Honda that is an XR263R now. That extra couple mm made a very nice difference on the low end and in the mid range.
Posted by: XR250rdr---------------------
For tight woods use I'd take an XR250 over a 400 any day. I'd rather not have the extra 20+ lbs.
Posted by: honduki---------------------
I like getting up behind them blue bikes in the tight and even passing them. The 280 kit was legendary in its day
I never had one , just FMF megamax, 135 mainjet, removed counterbalancer, CR upside down forks and modified shock
hey honduki, i know this is off subject but how hard was it to put CR forks on your bike. my brother has an xr250 he would like to do something like that to.
Posted by: Patman---------------------
Holy cow how did I miss this one? Adapting forks is easy, balancing the new geometry is a bit more involved.
