HEADS UP!!!

Site upgrade in progress... Core site functions are working, but some non-critical features/functions will be temporarily unavailable while we work to restore them over the next couple of weeks.

Please post any bugs you encounter, but before you do, check to see if it's already listed.

Thanks for your patience while we work to improve the community.

Sign in to follow this  
Followers 0
Ariel101

Compression test on a 2008 WR450 reads 50 PSI

7 posts in this topic

The bike has 6600 miles. I ride mostly technical trails (average speed of 20 miles/hour) and don't rev it up to its higher limit. Occasionally moderate motocross riding. Oil changes every 320 miles. No apparent oil consumption between changes. Valves are checked regularly and haven't needed alignment, ever. the mechanic got 50 psi compression test, but didn't make a compression leak test. I rode the bike since and don't notice drastic change in performance, unless this degradation build up over time and i got used to it.

1. whould the bike perform well on such low compression?

2. is this test relevant at all? wouldn't the auto decompression make it meaningless?

3. are there other signs for low compression I should look for? before returning back and having a compression leak test

thanks

Share this post


Link to post
Share on other sites

Your auto-decomp negates any findings of a compression test.

Share this post


Link to post
Share on other sites
Normal reading

More along the lines of a meaningless reading. As DG stated, the AD mechanism bleeds off compression. A leak-down test will tell you what you want to know about your top-end.

Share this post


Link to post
Share on other sites

The only way to get proper numbers performing a compression check is to remove the exhaust cam and cam chain. Not worth it. You can do a a leak down test that will tell you whether or not your valves or piston rings are in need of some attention. If you hear leaking from CC breather, your rings and possibly piston need to be replaced. If you hear air escaping from either intake or exhasut manifolds your valves are the culprit.

From what you've described, your rding style etc. you've got nothing to be concerned about. It's a WR after all!

John

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

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0