Jump to content
Sign in to follow this  

engine problems on 04 rmz 250 please help

Recommended Posts

hey guys well this is my first post on here4 and i need some help i had the valves adjusted on my 04 rmz 250 about a month ago and it prob has 8-9 hours on it scince the adjustment now ive noticed my bike is lacking compression and its is now hard to start or wont start at all i was wondering do u think i may need to get the valves re adjusted again or is it maybee time for a new top end also

Share this post


Link to post
Share on other sites
hey guys well this is my first post on here4 and i need some help i had the valves adjusted on my 04 rmz 250 about a month ago and it prob has 8-9 hours on it scince the adjustment now ive noticed my bike is lacking compression and its is now hard to start or wont start at all i was wondering do u think i may need to get the valves re adjusted again or is it maybee time for a new top end also

Just some thougts here.

- It definitely sounds like the valves have tightened up again. Just by your description.

- Once you shim the original valves once, you are on a slippery slope. A valve job is just around the corner.

- The bike is an 04. Sounds like you got you use outta it. I would say it is time for a new top end. :applause:

Share this post


Link to post
Share on other sites

ya, definetly do a top end. on my 04 crf250, my friend that had it before me did a top end without doing valves and after about 5-10 hrs it lost compression and wouldnt start. got new valves then it ran like a champ and still runs good. from what i have heard and learned if u do 1 thing do it all.

Share this post


Link to post
Share on other sites

yeah, replace it all.... new valves, springs, buckets etc.... especially if you haven't done so already. I'd do the piston too when you have her opened up.

I've done my valves twice in my 04, replaced them with stock both times. This winter I'm gonna replace them with stainless. Not that I'm not happy with the stock ones, but I figure since I got a year outta the stock stuff, maybe I'll get more time outta the stainless. :applause:

good luck.

Share this post


Link to post
Share on other sites

Make sure a machine shop checks your valve seats. Its critical on these bikes. You can spend money on everything else but new valve wont seal properly in warped or pounded out seats. It may cost an additonal $70 or so but your top end will last much longer and run better with maximum compression. Its a common misconception that compression problems on four strokes are piston related. Valves and seats are the issue most of the time.

Share this post


Link to post
Share on other sites
Its a common misconception that compression problems on four strokes are piston related. Valves and seats are the issue most of the time.

This is so true……I rebuild a lot of motors and this is the case most of the time, You will loose some compression and HP a lot faster than you realize after installing a new piston and ring set, but when a loss of compression is real noticeable and fairly quick, it's usually the valves.

Share this post


Link to post
Share on other sites

by new top end what are y'all refering to? I have the opertunity to get an 03 Rm250 real cheap but the guy says it needs a new top end and it has no compression. I would get a service manual and do the work myself but would like to know what I'm getting into and how hard it is before I buy it. Thanks for any help.

Share this post


Link to post
Share on other sites
by new top end what are y'all refering to? I have the opertunity to get an 03 Rm250 real cheap but the guy says it needs a new top end and it has no compression. I would get a service manual and do the work myself but would like to know what I'm getting into and how hard it is before I buy it. Thanks for any help.

On a 2-stroke all you need is a piston kit and a couple gaskets, and be sure the power valve is cleaned real good, Pretty basic stuff…

Share this post


Link to post
Share on other sites

i had an 03 rm and it ran like a champ and a topend kit is 150 with gaskets,but the 03 is known for being hell to jet properly i know mine was always rich,and enjoy the splooge.

Share this post


Link to post
Share on other sites

you should check the cams and make sure that the cam gears did not turn on the cam as thay often will. this will make the bike almost impossible to kick start. just check it..

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×