lcrken
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- Joined
- Mar 15, 2009
- Messages
- 5,038

I've been working to repair a Dunstall 810 cylinder for sale to Piero, and thought I'd post some pictures to show why they are such a problem.
Original pictures are here, showing pulled head bolt inserts and oversize helicoils for front studs:
dunstall-810-cylinder-t18897.html
The front stud repair went pretty well. I replaced the 3/8" helicols with Bigserts for 5/16" studs, shown below. They do break through into the push rod tunnels, so require sealing to keep oil from migrating up the studs.
The head bolt inserts were more trouble. I had to remove the liner and clean up the counterbore for the sleeve lip, shown here with the liner out and the machining finished.
These pictures of two of the inserts with the liner out show one of the reasons some of us aren't so excited by the quality of Dunstall cylinders.
Still, I think it will be ok to use once I get the liner back in, at least for someone who really wants to restore their Dunstall bike to original (at least as long as it lasts, anyway).
Ken
Original pictures are here, showing pulled head bolt inserts and oversize helicoils for front studs:
dunstall-810-cylinder-t18897.html
The front stud repair went pretty well. I replaced the 3/8" helicols with Bigserts for 5/16" studs, shown below. They do break through into the push rod tunnels, so require sealing to keep oil from migrating up the studs.
The head bolt inserts were more trouble. I had to remove the liner and clean up the counterbore for the sleeve lip, shown here with the liner out and the machining finished.
These pictures of two of the inserts with the liner out show one of the reasons some of us aren't so excited by the quality of Dunstall cylinders.
Still, I think it will be ok to use once I get the liner back in, at least for someone who really wants to restore their Dunstall bike to original (at least as long as it lasts, anyway).
Ken