500 Two-Stroke Tech

Definitely one of the more pointless things I've done with my life!
Onwards!

Today I managed to get my hands on another compression tester.

And.....

100psi all round, not perfect but acceptable I believe?

Now, to crack on with the leak down test.

Cheers,
Paul.

There's a leakdown tester amongst this lot somewhere...... https://i.postimg.cc/T19yXFWY/20190202-130137.jpg There it is...... https://i.postimg.cc/Bbs8k4bV/20190202-135516.jpg https://i.postimg.cc/jdxwhxGW/20190202-135522.jpg Obviously the 10 bar gauge range was a deliberate mistake! I only put 0.5...

Can you give us a pic of the tester you are using now? https://i.postimg.cc/N03281cY/20190202-141119.jpg https://i.postimg.cc/nVY97jwb/20190202-141141.jpg https://i.postimg.cc/RZbHFkpW/20190202-141149.jpg I re ran comperssion on all 4 cylinders using my drill on the flywheel nut and got 45 psi on t...

Pennies sent.

On the receiving end of help.
Again.
Thank you for the site.
Again.

Paul.

sounds like cheap faulty testers?

I hope so, although they weren't the cheapest.

You can try putting oil in each cylinder and testing again. If the numbers rise you have found your problem.

Sorry, what would that indicate? Worn rings/bores?

Thank you,
Paul

Well today I did another compression test... Both left hand cylinders showed 45psi again, as all cylinders did before I took the top end off. And then the tester failed, so I took it back to the shop and it was replaced. I suspected that the tester was faulty and giving a low reading, so having a re...

Some advice, if I may. You may, I'll always take advice...... I was wondering about a comp test on the bench but figured it was going to be too difficult to get the motor sat sturdily enough. Maybe my drill on the flywheel nut will have enough power to turn the motor with the plugs removed? I measu...

Ready to go back in.
Again.

That was my understanding too, thanks for clarifying.

Well, today I got back in the garage and measured everything on the top end. Then I measured it again. Everything is well within tolerance. So I've made a start putting it back together. Again. I read somewhere that crankcase seals can affect compression. I'm struggling to see how that might be so, ...

Dave,
The manual says you should get 128 psi.
Working towards that with my own bike.

Cheers,
Paul

Phildu, Thanks for that, I don't have any way to test the cdi on another bike unfortunately. I do have another cdi, but I can't remember why I changed it. As silverstrom says, at the minute I have the top end off due to very low compression. Maybe I'll look into my "old" cdi and see what w...

Yes, I'm using the workshop manual. In the engine build section there's no reference to an expansion ring, or any differences between the rings. But I did find a better description in the appendix. So I'm confident that the rings were installed correctly. They've never been upside down! I was kind o...