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+--- Thread: Cm870 jake issue (/showthread.php?tid=783)
Cm870 jake issue - Rig Wrench - 08-22-2016
Currently workin on an cm870 tat I'm havin issues with the jake rockers, cylinder 1-3. This is a 3 solenoid system. Cylinders 4,5 and 6 work perfect. Cylinder 1 just seems to bounce back and fourth, no noticeable change in anything. Number 2 works perfect, cylinder 3 seems a bit delayed, but its acceptable. So far I've tried new solenoids, new rocker shaft, swapped jake rocker with number 2. All with no improvement, I even ran the engine with no solenoids to make sure I was getting good oil out the ports. Not that I had a way to measure it, but it seamed to flow the same as number 2/3. Any help is greatly appreciated.
Thanks
RE: Cm870 jake issue - Hammerhead - 08-22-2016
If you've changed the rocker shaft, have you changed or checked the condition of the rocker arm check valves?
What about the Jake rocker check valve springs?
If these have been replaced or are good, what about the rocker arm bore that the check valves ride in? Is it possible that they are worn to the point they won't retain sufficient oil pressure?
If all of that is good, can you check the oil supply pressure and volume?
RE: Cm870 jake issue - Rig Wrench - 08-23-2016
I changed out the rocker arm with one from another cylinder that was working properly.not sur how i can check volume or pressure at the jakes
RE: Cm870 jake issue - Hammerhead - 08-23-2016
Nor am I, have you checked Quickserve to see if there is a troubleshooting flow chart to follow?
Since you've changed the shaft and swapped rockers with no results, that's where I would go.
RE: Cm870 jake issue - Rig Wrench - 08-23-2016
Yea, tried quickserve. No help. I'm at a complete loss. Cylinders 4-6 work perfect. 1-3 not worth a chit. It was kind of weak befor. 60k miles ago I did rod and main bearings, along with solenoids, and shimming the oil pump and it was great. For about 3 weeks. Then got week again. I feel like its not getting enough oil psi up front, but I have no way to tell
RE: Cm870 jake issue - axe - 08-23-2016
(08-23-2016 )Rig Wrench Wrote: Yea, tried quickserve. No help. I'm at a complete loss. Cylinders 4-6 work perfect. 1-3 not worth a chit. It was kind of weak befor. 60k miles ago I did rod and main bearings, along with solenoids, and shimming the oil pump and it was great. For about 3 weeks. Then got week again. I feel like its not getting enough oil psi up front, but I have no way to tell
Sounds like a trip to Gearheads might be in your future.
RE: Cm870 jake issue - ktmcandog - 08-28-2016
Ive had a few in the shop for clacking when idling and spotted the suspect exhaust rocker flopping with the engine running cover off. The problem seems to be wear between the shaft and problem rocker as there,s a hole in the shaft that a spring loaded ball grabs on in the rocker arm to prevent movement when the rockers unloaded on the base circle of the cam. Replacing the shaft and rocker lever was the cure---ktmCandog!