I dropped my bike in the water a few days ago. OK, I totally submersed it actually. Oddly, it ran while totally submersed.

Well, I dried it out the best I could - dropped the oil and refilled with sacrificial, dried out the airbox, pulled the exhaust and tipped the bike towards the rear while on the lift, drained the carb bowl. Turned it on it's side and cranked it with the plug out to clear the cylinder.

Let it dry for a few days and tried to start it. No-go. Tried again a couple days later - no-go again.

So today I did a compression test and found 85-90 psi with full throttle. IIRC, the manual says 64 psi is enough to be in the range of "good compression" but I have my doubts.

After checking and re-checking the compression I pulled the carb. I have yet to pull it apart but 1st inspection doesn't look too bad. I also don't see any grit in the boot between the carb and head. Clearly, I'll work that carb over really well.

My question for the collective - is 64 psi actually OK? Haven't done a compression check on a bike lately, but I seem to remember a target of 115psi or so.

I haven't given up on the possibility of bad gas or no gas at all with a clogged idle circuit or stuck float. BUT, I'm disappointed in the compression readings.

Experience?

here's an update for you. The carb looked good - at least the head side looked good. Upon removal of the cap and bowl it's obvious how much dirty water entered the carb. The bowl has a pretty good coating of gunk throughout. Also, the main air jet - that's the one on the right as you're looking into the airbell, right? - was completely clogged with mud. Bottom line - I can see a bottle or 2 of the pine-sol in it's future.

Unfortunately, that doesn't explain the low compression

 

One thing to keep in mind when doing a compression test is the KACR. You won't get true compression readings. This is why the manual will say 64 psi is usable.

 

Thanks relic.

I thought holding the throttle open was supposed to overcome that issue by disabling the KACR. But, I've never seen the KACR, so I'm not really sure how it works. Give me a kicker and a manual CR any day....

Guess I'll clean the carb, replace the gas and try again, because there is no way that carb was moving fuel and air successfully.

 

Guess you're right about the compression test. I was too lazy to pull out the leakdown tester, but I left my 86 psi of pressure in the cylinder (on the compression tester) and checked it a couple hours later at 86 psi. Maybe it's just bad gas and a cruddy carb afterall.

 

kacr lowers it, also holding the throttle wfo on a cv carb doesn't lift the slide out of the way so could give a low reading.

quality of the tester and where the trap valve is in relation to the gauge makes a big difference too. If the trap valve is up near the gauge ,you have to whole volume of the hose added to the cylinder. No abig deal on a car motor but on a small engine it can be big.

 

Yeah, that makes sense. I think I need to put the leakdown tester on it on second thought. The compression tester just holds that max reading until you bleed the internal perssure out of the tester. So, seeing 86 after a few hours doesn't mean much in retrospect.

 

Check your other inputs and then goback to compression.
Spark, Fuel, Air and then Compression.
Get a can of starting fluid.

 

I just went out and checked my compression. It was 118 with throttle closed/125 throttle open. 53 deg F. Bike was cold. 3000 miles on bike.


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not exactly the warm-fuzzy I was looking for....

 

do you have spark?