Boring out a 250 sx?

[HoustonAE2]

So I have an 1985 250sx that I LOVE...but it is a 30 year old bike. I am looking to do a restoration on this bike and was curious if anyone has bored out the 250 4 stroke engine with any positive results? I just think it would be kinda cool...

[barnett468]

.

So I have an 1985 250sx that I LOVE...but it is a 30 year old bike. I am looking to do a restoration on this bike and was curious if anyone has bored out the 250 4 stroke engine with any positive results? I just think it would be kinda cool...

Hi;




There has actually been around 10,938,675,653.5 zillion people that have had these bored out. If your cylinder is worn, it will improve performance from what you currently have.

The more you bore it, the more power it will have but the hotter it will run and the fewer bores it will have left.

There is also likely a big bore kit and/or stroker kit available for it if you want.

High perf cams and ex are also available.

If your exhaust is stock and you make any significant high perf upgrades, you at least need to run an improved flow silencer on your stock pipe, however a high perf exhaust might be better depending on what you do.

A larger carb might also be necessary/helpful.


Nice job pig!.

[dougspcs]

Sure, as Barnett stated there is a list of things you can do..if you can locate the parts.

The truth is that performance engine parts are limited for the 250ES/SX. They were just never marketed to the same degree as performance upgrades for say the 200x or 250r were..

Since the ES/SX were a utility trike these enhancement parts never came into being as they did for the trikes that actually did time on the race tracks.

High compression pistons, exhaust options...etc. There are a few and people have done them..but the reports are that the results are not spectacular.

That is to say you won't see your SX at speeds in the range of even a stock 350X..but have some fun with it. That is what this is all about..

[HoustonAE2]

Thanks for the advice. I am torn on what to do, so I will do nothing and just enjoy my trike for a little while longer. They move great on their own. We will see what I do when I finally do it.

Again thanks!

[HoustonAE2]

.
Hi;




There has actually been around 10,938,675,653.5 zillion people that have had these bored out. If your cylinder is worn, it will improve performance from what you currently have.

The more you bore it, the more power it will have but the hotter it will run and the fewer bores it will have left.

There is also likely a big bore kit and/or stroker kit available for it if you want.

High perf cams and ex are also available.

If your exhaust is stock and you make any significant high perf upgrades, you at least need to run an improved flow silencer on your stock pipe, however a high perf exhaust might be better depending on what you do.

A larger carb might also be necessary/helpful.


Nice job pig!.

The problem is, and I am fully willing to admit it is my own deficiency, but i cannot find a full kit to do this...does anyone make one? Or can anyone direct me to a thread that lists what was used to do it?

[YTZ drew]

I know that some parts swap with the TRX300, and I have seen threads on here before about swapping the whole engine out. Try searching for that, I'm sure you will find some good reading.

[350for350]

If you do use the TRX 300 engine, be sure to use one from a 2 wheel drive.