Z1OwnersClub GB

Have just done a compression test.

Bike has been standing for a couple of weeks and then previously only started for a couple of mins and prior to that not run for several weeks.

All came in around the 95 psi which is below the 100 psi min quoted in the manual.

Squirted some oil into the chambers and re-did the test and they all then came in around the 120 psi pressure.

So the question is which of the tests is the one to go for and represents a more typical situation? 90/95 psi would tend to indicate that all the bores/rings are a bit tired but 120 psi would indicate all is well and leave alone?

Did you do the test with the engine hot and the throttle wide open? if yes to both 95 psi is below service limit, but i have seen bikes run at that pressure quite happily.if its running ok and not smoking like a 2 stroke just ride it..Paul J

Engine cold.

No carbs fitted at the moment, so wide open.

There is some slight smoking on start up, which may be due to hardened valve seals.

If engine is cold would expect that 95 psi to go up a fair bit,valve stem seals are no big deal as long as it clears after few miles,if you want a better test do a leakdown test which will show state of bores,rings and valves..Paul J

Forgive this tack, but do you ride it every day ? do you want to thrash the arse of it ? do you want to race every pocket rocket on the road ?....if the answer to these is no then don't fuss to much and just ride and enjoy it, it will run forever and if you doubt my words then you obviously did not see that German Lad that came to the Anniversary rally last year

Hi Keith think i know the bike you mean,looked dog rough but got there ok and kept running..

KeithZ1R wrote:Forgive this tack, but do you ride it every day ? do you want to thrash the arse of it ? do you want to race every pocket rocket on the road ?....if the answer to these is no then don't fuss to much and just ride and enjoy it, it will run forever and if you doubt my words then you obviously did not see that German Lad that came to the Anniversary rally last year

The answer to all is no, but I'm in the process of doing a complete strip and rebuild of the bike.

I plan to do the top end as it has done a recorded 41K with no history of any engine work having been done but did not want to go beyond that unless it was necessary?

Thought it prudent to do the compression test before starting to strip the engine to get some idea as to its state to help me decide how far I need/should go.

As i said, leakdown test could save you a lot of time and expense,your call though!