Just did a top end rear cylinder rebuild on a 120 Ultima. Put about 150Km on it and did a compression test. Both cylinders test at 175 psi. I'm happy with the consistency but does anyone know what a good pressure actually is for that size of engine?


Also checked one of the two exposed head bolts and got 1/4 turn out of it...... Should probably pull the rocker box and Re torque the rest?

 

Engine displacement doesn't really have much to do with cranking pressure.

175 is good for reliable daily driver.

The consistency is good but I wouldn't have done just one cylinder on a V-Twin.

 

Doing just one is kind of odd. Did something happen to the one cyl?

 

Yes, the intake lifter failed on the rear cylinder. Sent the pushrod up, broke the rocker arm and punched a hole in the cover.

Only did one cylinder because there's only 500 km on the build. No I didn't do the build

 

My 127 did the same thing I only did the rear cyl as well. Ran good shipped it to a new buyer.

 

Do you still run Ultima?

 

I currently have a s&s but I have owned 2 previous ultima motors

 

Just curious as to what your opinion and experience was like with the Ultima stuff? And how it compares to the S&S....


I've only put about 1000km on this 120, I've had obviously a few hiccups but am still really liking the power, look and sound of the bike. I am having a strange intermittent power loss issue. Lose ignition power randomly but all I do is pull over, wait a minute and it always starts right back up. Makes it really hard to troubleshoot and it's a pretty seldom occurring issue.....

 

Engine size does not determine the CR's. Factors such as cams, pistons, heads, and gaskets are the determinates that affect CR. Yours are consistent between cylinders. That's good. If the bike runs well you fine. As far as re torqueing head bolts, why? Torque specifications and procedures are intended for reassembling a top end prior to operation. Not sure what will happen if you operate the engine and then do it again.

 

I went through the same issue power loss then run on 1 cyl. It was the cheep Ultima ignition I went through 2 of them before I switched to crane.
I have only had this s &s for a few weeks it was not pre assembled and it has ALot of headwork done to it. I really liked the power of my Ultima motors but I would never buy a Ultima starter or ignition imcludimg coil .again. did your 120 come with the Mik or the R1 carb?