'57 NH Exhaust valve guides

[david.birkett]

Exhaust valve guide rotating easily and slight up and down movement. slipped out easily once coke at the valve end was scraped off. Guide O.D. is 0.625". Draganfly show guide p/no 494-56 but no mention of size. Are oversize valve guides available? Happy New Year to all you Arielists, David.

[JohnnyBeckett]

hi David if drags do not have oversize guides you need , you can get them made to the size you need

[Simon.Gardiner]

David - have you tried Club Single Spares? (At one time there were oversize guides made for some of the ally-head bikes.)

SG

[david.anderson]

The exhaust guide always comes lose on VH alloy heads. It is simply a matter of poor design and inadequate length in the head to properly support the guide. The more mileage that you do the more often it will come lose. I have done a high mileage (50 years now riding the same VH) and I have had that problem on numerous occasions. The head has been bored larger a few times and an increasingly oversize exhaust guide made. It has been necessary to bore the head as the head generally went oval. My most recent repair involved boring the head even larger, pressing in a sleeve and welding it on top then facing and boring again to fit a standard guide. The sleeve hangs into the port a little and hopefully this will provide additional support for the guide.
David

[Roger Gwynn]

Nominal od of hole for guide is 5/8, the interference fit is on the guide .002/.003

[david.birkett]

Many thanks for the reassuring and helpful replies. The o.d. of the guide hole is .6251 at the top and .6251 at the bottom, so not a disaster. Once again this forum has given me the information I need. I'll be messaging single spares. Three cheers for the AOMCC
David.