Ducati.ms - The Ultimate Ducati Forum banner

1 - 8 of 8 Posts

·
Registered
Joined
·
14 Posts
Discussion Starter #1
Hey all,
I was checking compression on my 748r and came up with some really low readings. Compression was checked cold (bike has been sitting over the winter). Readings were about 125psi for the horizontal cylinder and only 90psi for the vertical.

The engine is from '98 and has an unknown number of miles on it (original was replaced). Am trying to track down info on it but in the mean time, does it make more sense to try to fix this old one (if it needs valves or rings) or just slap in a used 748, 916, etc engine? Will be taking it to a shop in a few weeks.

Lastly, is it possible to ride the bike as is? Or do I risk causing more damage?

Thank you for your help!
 

·
Premium Member
Joined
·
4,938 Posts
Do another test but this time put a teaspoon of oil down the plug hole. If it goes up then the rings are toast. If it stays the same then the valves are done. Make sure when you do the test you have the throttle wide open.
 

·
Registered
Joined
·
14 Posts
Discussion Starter #6
do a leakdown test. it'll tell you where the problem is.
Definitely. Haven't done one before but will try to figure it out.

Can loose belts be a cause of low compression? They had a bit of slack when looking them over yesterday.
 

·
Registered
Joined
·
67 Posts
Curious to tag in on this one for tips as I recently tested mine and had a wide range.
My intake bands around both hoses are loose, will this affect much?
Should engine be warmed prior to testing?
For a 999 at least, what would be minimal accepted comp be?
 
1 - 8 of 8 Posts
Top