36MX4 Compression

[Luckydug23]

Hi all.....Suspect my compression is low on the 360.. kicks super easy, in fact by hand, but is increasingly difficult to start. Does start now and then after seemingly endless kicking and runs for a bit, quite well) before quitting..so I know timing is good, spark is good and pretty sure carb is good, although could be a fuel level issue.
Can anyone assist with the optimal compression range possibly somewhere between 170 -210?
All assistance is appreciated
Regards Paul

[IanCordes]

Hi Paul. I thought someone more knowledgeable on 360s than me would have replied to you by now, but I don't like to see a question unanswered. If I were to try to hand start my 250 I expect it would break my wrist; assuming I could get it over compression, which is highly unlikely! As you can turn your 360 over by hand, I suspect that, even if anyone does know the optimum compression figure, in your case it would be irrelevant. Time to lift the head and barrel, I reckon, and see what is going on, stuffing rag in the crankcase mouth as you lift the barrel, just in case.....

[Luckydug23]

Thanks Ian..Resigned myself to the realisation them rings were stuffed and the need for a full barrel-ectomy! Found I had 1 & 1/2 rings !..Unfortunately did not have enough common sense to stick a rag under the barrel so am now in a denial phase frantically searching the (rather messy) workshop floor for the missing section.

[IanCordes]

Ooops! Not so lucky, Dug..... You are on your own with that one.

One method of retrieval which may work is to fill the crankcase with thick oil, then rotate the crank, in the hope that the debris gets picked up by the oil on the crank webs, presenting itself to where you can fish it out. Unfortunately, by the sound of it, you are not sure if anything has gone down, and if so, what? Without knowing that, you cant be sure everything has been removed. Only one way to find out for sure

I feel I should send you a handkerchief to dry your eyes. You could then keep it to stuff in your crankcase next time......

[garybam4711]

Where are you located dug Only asking as I have some over size rings
gary

[Brian Catt]

The trick I have seen more than once.....turn the bike upside down and rotate the crank to see if anything falls out. Usual precautions with fuel of course.

[Luckydug23]

Thanks all….I’m in Australia Gary thanks for the offer but have decided to go to 20+ and a new piston….might give Ian and Brians methods a go too for a bit of piece of mind

[Luckydug23]

Engineer has asked what the piston clearances are..top /skirt. Anyone have any idea?