Dunstall 850 overhaul

When my lifter pad delaminated while I was idling in the driveway, it did NOT go anywhere. It sat right in place on top of the cam and made a slap/rapping noise that sounded bad enough to me that I knew I was going in for a look. When I pulled the barrels off, I looked down and saw the entire pad sitting on top of the cam lobe and thought, "where the hell did that come from?" Then I looked at the underside of the barrels and saw the missing pad on one of the lifters, and it all made sense. I imagine if I turned the bike over slowly, it would just go, "click, click, click"...

If I was you, I would removed the valve cover and use a pushrod up against my head to hold against the intake valve tip while someone rotates the engine. The pushrod will conduct the sound better than air, so you can use it against parts of the engine to see if the "click" is coming from a particular valve, or a particular part of the engine.

Personally, I'd pull the head and barrels. When I lost the stellite pad on my commando, I had the barrels off in 3 hours. Luckily Jim Comstock took an interest in my dilemma and hooked me up with what I needed. It's just not worth the risk of trashing the cam and whatever else...
 
so after very careful engine and cam rotation, the click only occurs as the #1 intake cam is over the peak of the ramp and dropping onto the backside of the cam. based on search results . we're gonna run it. no teardown...
 
Last edited:
Dunstall 850 overhaul


Dunstall 850 overhaul
 
o0norton0o said:
When my lifter pad delaminated while I was idling in the driveway, it did NOT go anywhere. It sat right in place on top of the cam and made a slap/rapping noise that sounded bad enough to me that I knew I was going in for a look. When I pulled the barrels off, I looked down and saw the entire pad sitting on top of the cam lobe and thought, "where the hell did that come from?" Then I looked at the underside of the barrels and saw the missing pad on one of the lifters, and it all made sense. I imagine if I turned the bike over slowly, it would just go, "click, click, click"...

If I was you, I would removed the valve cover and use a pushrod up against my head to hold against the intake valve tip while someone rotates the engine. The pushrod will conduct the sound better than air, so you can use it against parts of the engine to see if the "click" is coming from a particular valve, or a particular part of the engine.

Personally, I'd pull the head and barrels. When I lost the stellite pad on my commando, I had the barrels off in 3 hours. Luckily Jim Comstock took an interest in my dilemma and hooked me up with what I needed. It's just not worth the risk of trashing the cam and whatever else...
Click to expand...

I have has the lifter bore wear and give me a clicking sound and the lifer rocked in its bore. So, maybe you should lift the cylinders.
John in Texas
 
time to get the timing side buttoned up... but can't find the pair of TS gaskets i had set asside...:(
 
Sharp looking rotor. That's gonna make me lose sleep thinking about that one.
 
I recall reading somewhere that you should pull the front iso thru-bolt and then tweak the upper suspension spring till the internal iso tube lines up nicely with the frame mounting holes. That way, the SPRING is bearing the weight of the engine, not the iso resting on the thru-bolt.

Looking real nice!
 
You must log in or register to reply here.
Back
Top