How hot is too hot?

[daveyf]

Thanks GP 240.

It was just top end rebuild with new crank and bearings. Got a 25mm PHBH carb as part of the kit from Gransport and kept the AF clubman exhaust. I did notice a split in carb rubber as I had overtightened the jubilee clips. I replaced the rubber and it still seems to run hot. So having retorqued cylinder head and replaced carb rubber I will try knocking back timing a degree as suggested as the next step.

I suppose what I really want to know is how hot should the engine feel? If its normal for casings and rear hub (have checked and brake not rubbing) to be too hot to touch then I don't need to worry. But like you said I dont want to be holing a piston on my new kit.

[psychedelicropcircle]

If the clutch is connecting with the KS shaft that can generate heat in that area.

[GP240]

hmmmm tough one to call really,

stupid question but it has engine oil ? (I know but got to ask).

does the revs hold up when you come to pull clutch in ? (weak mixture/air leak).

any sound of pinking at higher revs ? (timing too advanced).

hard to kick over (too high of comp head/piston).

If it's goin in for a dyno then it might get sorted, it is fekin hot tho lol.

[daveyf]

Thanks GP240, yes it's got oil, no pinking, kicks over fine, checked the squish when I did it and it was ok although cant remember what it was....it does seem to be running nice and plug nice and dark brown, think wil try knocking timing back a tad.

[GP240]

ok but let us know if you notice it running cooler, might try it myself lol.

are you using a strobe or marks for timing. Gunson timing lamps (cheEp-bay) are good at around 25nicker.

[Donnie]

I'd personally like to know where you got the 25mm PHBH?? Could be a nice modification one of them???

[daveyf]

Sorry PHBL25 or something like that........

[swarb93]

I'd be looking for an air leak somewhere. Probably half the self built 2 stroke motors out there have a leak, and a few of the 'shop' built too. There are only a few faces to check. Make your own leak test kit (there's a version explained in the Sticky manual).