I fixed the links - thanks for the heads-up.

If you replace a #14 head with a #17 or newer, and plan to re-use the original 1986/87 vertical prechambers, you have a 50/50 chance of having this problem. New vertical prechambers will NOT help. You can avoid the problem entirely by converting to angled/inclined prechambers AND injectors, but unless you get them free with the used #17 head, it's just too expensive to switch.

There are no complete new heads - only bare heads. A new #22 head is $2000 list, $1600 wholesale. The #22 is nice because it has the improved oil galley in front of the #1 cylinder (see photos at the links above).