1994 Intruder 150hp Compression Question

[luckyinkentucky]

My father in law who is officially computer illiterate has asked me to post a question here, so here goes nothing.

He has a 1994 150 Intruder that he recently had the compression checked for. Five of the chambers tested at 100 and the last one tested at 90.


2 questions!

1) Other than the plug what could be causing the 90 to fall behind the rest other than physical damage?

2) Could he fairly easily bring this engine back up to the 120 to 140 range? What would need to be done?

Thanks for the patience everyone.

 

[reload]

Re: 1994 Intruder 150hp Compression Question

I would try a decarb. What do you mean the plug causing the low compression on the 90?

 

[JB]

Re: 1994 Intruder 150hp Compression Question

1) The plug? The plug is out when compression is read. The cylinder is within spec (10% range). If there is a anything wrong it is probably just carboned up a bit.

2) I think a decarb would raise them all a bit and bring compression into a smaller range, but it is not bad as is.

Far too much importance is given to psi numbers in a compression test. Differences in guages and technique can make as much as 50psi difference. The important result is the range, which should be 15% or less.

 

[luckyinkentucky]

Re: 1994 Intruder 150hp Compression Question

Sorry, I wasn't thinking on that comment about the plugs.