I have a 1993 XR600R that was pretty beat. The engine is all apart and the transmission is to. Found a bad gear in transmission... Aside from the obvious, piston and rings, what should I replace in the transmission and engine while i have it apart ? Which bearings tend to wear a lot ? Do I need to replace the oil pump ? Any advice would be appreciated.




If you have no fear, you didnt go as fast as you could have ...

I would completely clean out the top end of the engine, re face the valves, or possibly replace them with newer ones, maybe titanium. you should strongly consider changing out the valve springs, maybe the cam if it looks beat up, I have also hear rumors that the cam chain tensioner tends to sometimes fail. When looking at a new piston you may want to think about a high compression piston like the wiseco 10.25:1 compression, maybe even the 12:1 if you have the energy to start the thing. I regret not putting in the higher compression piston when i had the chance, so I strongly recommend considering it. -Matt

PS i just rebuilt my top end, so i have a good idea of your hardship.

I never had my trans apart so i can't give any input in that department except that with all the mods i did to my 600 i never had a single problem with third gear as some people have, and believe me it got tested to the highest degree.

As for the top end i would recommend changing the valve springs, new valves or at least a regrind on the seats, a light port/polish job, if $$$$ is not a problem go with the HRC cam (awsome), also make sure the rockers and sub rockers are not scored, if so replace them or they will eat a new cam. depending on how hard the engine has been pushed, change the timing chain. the tensioner will be fine it is self adjusting.

Be cautious putting in a high compression piston for a couple reasons: 1. the 600 is air cooled and the high compression will really heat the bad boy up! 2. the higher the compression the hotter she gets and in the long run the reliability is decreased. 3. a 10:1 piston in an oversize (101-102mm) bore will require (properly) at least 100 octane or you will get detination.

I strongly recommend changing the oil pump and make sure that all the oil gallies, down tubes, resivours, engine parts etc. are operating room clean! and don't be shy with prelube (cam lube) on all the parts when reassembling the beast. is an excellent resource for patrs at what i found at the time to have the best prices.

good luck feel free to drop me a personal message for any more questions.

If you're interested, I have a jug/piston from a 91 for sale cheap in the For Sale Section... brand new. Check it out or pm me.

My main objective is realiability. I never push it that hard and dont want the headaches that come with high compression, etc. I ride in South America WAY out away from any kind of help and dont want to break down !!! So far on my order list I have.



Piston Pin

Cam Chain

Cam Chain Tensioners

One new 3rd Gear

Oil Pump

Gasket Sets

What about main bearings etc ? Should they be replaced. Anyone think of any other problem parts that should be replaced while ive got this thing compeltely apart ??? I would rather spend some money now than push this thing 50 miles back to civilization !!!




If you have no fear, you didnt go as fast as you coule have ...

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