Rebuild??

[Jeff 330CI]

I recently bought a 2001 CR 250. The previous owner claims the engine has not ever been rebuilt because there is only about 20 hours on the bike. I believe him because the bike is in showroom condition. My question is should I rebuild the engine because it is an 01 with the original piston or leave well enough alone. The compression is 155psi and runs perfectly.

If I rebuild what type of kit should I get? The bike is stock with a pro circuit platinum pipe.

Thanks guys.

 

[2 strokes for life]

If it aint broke dont fix it. In most cases this makes sence and in this one it also dose. If its got 155 then your good.

 

[darringer]

155psi seems low to me. Depends on your altitude. My stock 99CR250 would pull consistent 210psi at sea level. For the price of gaskets, why not open it up and measure everything? That way you will KNOW what condition it's in. Better safe than sorry.

 

[maddmax]

I would recommend that you rebuild the top end. If the piston breaks you will spend alot more money. If you decide to open it up, make sure you have the proper tools.

 

[Yz250JdT250]

hmm. where i live, 210 psi would require race gas :whoa:

 

[Yz250JdT250]

If youre not a very aggressive rider, then the bike should last a while i think. I have a 1998 yz125 and ive put two seasons on it, beating the piss out of it. And ive never touched the motor :) . BUT the compression is dropping now and im rebuilding it for this season.

 

[Jeff 330CI]

Thanks for the input guys.

What fuel oil ratio should I run on a stock 2001 CR250? On my tuned 99 CR125 I was running Amsoil synthetic 50:1 should I go to 40:1 or 32:1 with this stock bike?

 

[snb73]

If it aint broke dont fix it. In most cases this makes sence and in this one it also dose. If its got 155 then your good.

I agree. If it's running well don't mess with it. You can visually check the condition of your piston and cylinder by pulling the pipe and looking in the exhaust port with a flash light.

My 2003 RM250 had 210 lbs on the last rebuild, it's ported though. Take your compression reading again. Hold the throttle open and kick it until it won't go any higher.

Most 250's like 40:1. I use Mobile MX2T, it's a fully synthetic premix that can be found at most chain auto stores. (walmart, autozone, ect...)

If you want piece of mind you could rebuild the top end (piston, rings, gaskets, wristpin bearing). A top end kit is around $130.

Here are a few good online stores I like:

http://www.rockymountainatv.com/

http://www.motosport.com/offroad/index.php

http://www.bobscycle.com/

http://www.denniskirk.com/jsp/common/Frontpage.jsp?ovmkt=8FM037RKKF3ISUT70N533UDMDK

 

[rockers109]

155psi is low. But you also don't know what the compression was when it was new. I would at least take off the top end, check for wear and at least replace the rings if everything checks out good. That will also give you a chance to check the crank bottom end bearing for wear.

 

[Jeff 330CI]

If I take the time to pull it apart it will be going back together with all new parts. I think I will rebuild.

Thanks guys.