s man wrote:......Hey Gos do you think those cams would maybe cause the valve to drop off the stem. Phil told me that one had dropped ?? I would say It wouldnt like big revs, it would suffer valve failing if reved more than 8500/9500??
My Z never got reved over 9500, & was really safe. But didnt have the lift that has.??
......
Its possible Steve, but only if the engine copped a massive over-rev from a missed gear.....the lift on those cams is better than stock for that motor, but on the Tighe cam-grind charts for these old motors, the 253B grind (which I am almost 100% sure are these cams) - are listed as 'Mild Road'. You can still go up a bit and keep using shim-over-bucket, before you hit the really big cams that require the use of z650 followers (shim-under-bucket).
As long as the revs on this motor were kept at 10k or less, it should be fine I think.......probably had a few missed gears in its time, and I am yet to split the cases and have a look *down below*
- NFI at this stage what sort of nick the selector forks or drum, or any of the gear dogs are in. Fingers crossed - everything will be sweet. The problem with these gearboxes is that big hp outputs through stock gearboxes, can cause all sorts of drama to the selector forks and corresponding grooves (wears both of them to buggery) - which in turn leads to missing gears - and then the dogs on 2nd gear start to wear out - and you basically can lose 2nd and even 3rd pretty quickly after that. Makes for an interesting race.......not.
In a completely unrelated to
this bike - but related to a gearbox - story -
- the bloke who owned the Black Pearl for almost 10 years, had to have 5th gear on the output shaft replaced back in the early 90's - the bike had done so many miles - in top gear - that the case-hardening had actually worn off the gear !!
this is not a common problem
- but does reflect the massive amount of kilometres that the Pearl has done in its lifetime ( well over 1/2 a mill now).
Phil - great to meet your bro today, yes it was chilly out in the 4th - and funny that Paul found that story about himself in that 1980 Two Wheels - now that someone else has found a story in a magazine over 30 years old - within 5 minutes - I am happy that the library works !