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Narrdo

05 WR 450 engine problems still

9 posts in this topic

Hey folks, I posted a couple of months ago about my engine problems. I you all may recall I was having engine oil problems where soon after an oil change (like 5 minutes) the engine oil would be black and runny. Many suggested cleaning engine, splitting case, piston and rings....

I was going to start from the top down and look at valves first and do some adjustments, then move on if I have to. Today I stripped off the tank and body work and did a cold engine compression test.

I did the compression test a couple different times and got 60 PSI max. :confused: Now before your chin hits the floor in total amazement. I just want to add that the bike still runs. Second or third kick, and it will start and run, power up and still do wheelies. Does anyone know the what an exceptable compression range for this model should be?

Is this possible, to have a running bike with such a low compression? Other than piston and rings, what else could cause a low number. Stuck Valve?

Any comments or suggestions would be appreciated.

Narrdo

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Hey folks, I posted a couple of months ago about my engine problems. I you all may recall I was having engine oil problems where soon after an oil change (like 5 minutes) the engine oil would be black and runny. Many suggested cleaning engine, splitting case, piston and rings....

I was going to start from the top down and look at valves first and do some adjustments, then move on if I have to. Today I stripped off the tank and body work and did a cold engine compression test.

I did the compression test a couple different times and got 60 PSI max. :confused: Now before your chin hits the floor in total amazement. I just want to add that the bike still runs. Second or third kick, and it will start and run, power up and still do wheelies. Does anyone know the what an exceptable compression range for this model should be?

Is this possible, to have a running bike with such a low compression? Other than piston and rings, what else could cause a low number. Stuck Valve?

Any comments or suggestions would be appreciated.

Narrdo

How about AUTO-DECOMPRESSION on the exhaust cam. See if you can pull the valve cover and turn it over while holding that lever out during the compression test.

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Narrdo,

I dunno what the acceptable range is for the WR either, but I recently watched a friend check the compression on his CRF450X when cold and he too got 60psi.

The Honda CRFX manual quotes 58 psi for a cold compression check for the X and with same engine capacity and similar compression ratio as the WR my guess is you are in pretty good shape.

If the bikes running well I wouldn't worry about it.

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Hey folks, I posted a couple of months ago about my engine problems. I you all may recall I was having engine oil problems where soon after an oil change (like 5 minutes) the engine oil would be black and runny. Narrdo

Ooops, I didn't read this bit carefully enough when I just posted that reply!

It all points to fuel getting past the rings and into the oil.

But if the rings / cylinder was worn I would expect to see some oil loss via white / grey smoke when starting or running?

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Thanks for the responses, I checked the De-compression valve and it seems to be working fine. The timing was a little off, but not much. Being three years old, its probably due for some adjustment, but they all seem to be working fine. Im still thinking that there could be a problem with the pistion or the rings.

Anyway I may keep poking around, but Im out of money to throw at it so its probably going to sit for the season, unless someone wants it.

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it may be coolant getting into the oil.

also are you using motorcycle oil? car oil turns black very fast

i tested my bike out 60psi so i rebuilt it

wiesco and complete top end guess what 60psi

for some reason i dont feel like the standard compression check will work

my .02

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You are not going to be able to get an accurate compression reading on a modern 4-stroke with the auto-decomp mechanism. A more accurate indication of the the condition of the top end is to do a leak-down test.

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somebody got it right I bought a compression gauge for my 04 wr 450 its useless should have bought a leak down kit it cost around $150. Its good for cars and boat much better than a compression check give much better info.

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If you wanna check it using the PSI guage just hold the auto-decomp lever out. You only have to hold it out for a short duration as it is just a nipple on the cam. Pull the valve cover and look for it. When you see it on the lobe, pull that lever out and watch it suck back flush. Now you know where it is and you can pull the lever out as it rotates near the bucket so as to allow the piston to hold full compression. I think that it should be around 170 if you can pull this off. I am, unfortunately, speaking in theory so if you make it happen post back with success\failure. If I ever try this I will certainly post back on a compression thread, maybe this one.

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