Yes your right. I’m thinking of upgrading the exhaust cam and have just got a deal on some barrels and high comp pistons. So I’ll go with the upgrade bearing to be safe.
No going for the roller bearing. Great article on the cams that will come in handy.Hi
The Metric bearing was under spec. and could not cope with the torque from the 750cc engine, so instead of fitting a stronger bearing (they eventually did in 1981) Triumph detuned the cams to kill the low end torque and top end power. (Race profile inlet to kill torque and restrictive exhaust to limit power at the higher rpm).
They ended up still having a weak bearing and the same performance as a 650cc, but with power that only started to come in at 5000rpm rather than at 2500rpm on the 650cc. They ended up with the worst of all worlds.
If you are thinking of upping the performance, then good luck on using that weak timing side ball bearing.
You might find this interesting reading:
Also search for posts by @Truckedup he has a genius for this sort of tuning.
When I say H/C cams I mean not the L/C ones so probably standard cams would be a better term. I think they are 8.6:1.Hi Yazwaz, Certainly nothing wrong with sticking with ball bearing. If… my ball wasn’t such an extreme tight fit on crank I would have used a ball.
I don’t know how factory got the crank into bearing. They have their ways. Roller makes fitting cases onto crank super easy. 2nd reason is I wanted best durability as I put about 5k miles a year on the bike. Still primary reason was the tight fit on crank.
Give some thought to high compression pistons. You must have the octane to support high compression. T140 type motors are prone to pinging & detonation. There are modifications you can do to make high compression work. Hillbilly knows about this. I would recommend getting with him for exact details.
I’ve been looking at the NKE bearings seem well priced without being cheap. Where you happy with the look of them then.I went for this on the TS...
Its not a plastic cage, but a composite cage. It seems to be the way all bearing producers are going for the smaller size bearings.
I am picking up the crank cases this week, so hopefully should soon start reassembly...
I checked out the bearing company, they have a good reputation.I’ve been looking at the NKE bearings seem well priced without being cheap. Where you happy with the look of them then.