[johnnyboyz]

Hi, just got a project bike running and it's smoking a little. I thought I'd wait until it's ridden to see if the smoke clears to indicate stem seals or valves.
In the meantime I’ve checked my compression and it’s reading 105-110 across all 4, the manual says it should be 142-199 and that 114 requires attention (*crap). The apparent test to see if the issue is rings or valve related is to put a teaspoon of oil in, which I did in number 1 and the figure went up a little to 120.
Does this sounds like rings or valves or maybe both? I guess I can refurb the head but then idea if all that work and reassembly to find out it’s still low sounds
like a pain…
Thoughts?

 

[Beairsto Racing]

Do a leak down test...that will help you determine if it's rings or valves.
Regardless, it's old & tired...it's all likely going to need to be freshened up.

How long was it sitting? Was it stored properly?

 

[johnnyboyz]

It’s a jap import to the UK so it could have been sitting for years, and I’d suggest it was stored badly.

Can you do a leak down test with a compression tester or do I need a kit?
Actually, just thought that you probably can’t as the gauge locks on the highest value…

 

[Beairsto Racing]

Google leak down test...there will be YouTube videos, kits for sale and countless discussions.
They aren't expensive and will help you troubleshoot your issues.

 

[Beairsto Racing]

When were the valve clearances checked last?

I've improved poor compression #'s more than once, with a good valve set.

 

[johnnyboyz]

I’ve ordered a leak down kit, I’lll test it and get back when I have the results….
Thanks for the help

 

[Doc_Rot]

a good 'ol Italian tune-up can do wonders for old engines sitting for a long time.