I see out in the world of puchs different types of trans gears and was wondering why. Reverse , Straight and Standard cut gears. why would someone use these types of gears?
Thanks
E50 different cut gears
Re: E50 different cut gears
It's mostly to do with noise and strength.
The "standard" and "reverse cut" gears are essentially the same thing which is a type of helical cut gear. Helical cut (stock E50 style) gears are generally stronger and quieter operating with less gear whine, however there's axial loading which robs an almost negligible amount of power while putting side pressure on the bearings and cases.
Straight cut gears are generally lighter and directly transfer more of the power than helical cuts but tend to be noisier and not as strong. (edited)
Re: E50 different cut gears
Yeah what Jared said because basically you got one bearing with a thin snap ring holding your crankshaft that’s only made for Side thrust loads on only a 2HP engine if that so it can flex Back-and-forth,
When you push the starter clutch the snap rings can flex and crank can move to the mag side, when you accelerate and decelerate it can just go back-and-forth back-and-forth In some cases wearing out the aluminum cases in the bearing areas.
Some people send their cases out to a machine shop to get another snap ring groove machined into it for to use 2 snap ring bearings for more sideways thrust strength and some people like me glue the crank bearings to the case though that’s pretty much only a one shot deal,
Straight cut eliminate side thrust problems and allow all the power to go directly though they are noisy and are not as strong as helical cut gears
Re: E50 different cut gears
Straight cut are aftermarket and are 100% the only way to use a drawn cup roller bearing instead of a bushing. It just never gets tight enough with the standard gear/bell. Reverse cut gears were made for 3 bearing engines, since they load the main gear outwards they don’t need the inner bearing on the main gear. Supposedly the 3 bearing case crank bearings last longer, but idk about that. Pretty much any of the homoet/simo high rpm piped puchs usually roast the crank bearings in a few thousand miles. Too bad even “quality” brands like skf and fag are made in Taiwan and China now.
Re: E50 different cut gears
> Daniel '' Wrote:
> -------------------------------------------------------
> Straight cut are aftermarket and are 100% the only way to use a drawn
> cup roller bearing instead of a bushing. It just never gets tight enough
> with the standard gear/bell. Reverse cut gears were made for 3 bearing
> engines, since they load the main gear outwards they don’t need the
> inner bearing on the main gear. Supposedly the 3 bearing case crank
> bearings last longer, but idk about that. Pretty much any of the
> homoet/simo high rpm piped puchs usually roast the crank bearings in a
> few thousand miles. Too bad even “quality” brands like skf and fag are
> made in Taiwan and China now.
Kinda like with Daniel is saying they should’ve made the crank bearings like they do on a Za50 that support side loads and what’s nice on a za50 is a clutch cover bearing supports the clutch bell though I wish instead of a bushing on crank in the clutch bell it was a needle bearing Instead
Re: E50 different cut gears
Re: E50 different cut gears
So straight cut basically is only for few % more power from engine?
For longevity alone is better to get or machine 4 bearing into case?
Re: E50 different cut gears
Idk about more power, maybe less wear on certain parts. Those needle bearing bells eat cranks pretty bad. We pulled one out of Alex’s race engine and after wearing through the shims the cartridge for the bearing had begun to machine it’s way through the crank. It was very close to tanking the entire bottom end. The trick with puchs is to not stall the clutch to 30mph often. A case with an outer bearing and a manual clutch would be so rad, but we are complaining about bearings wearing out now lol. Imagine actually side loading the bearings on every launch, not just with starting the engine.
Re: E50 different cut gears
Knew I should have got the bushing version.
Re: E50 different cut gears
Less wear come from better material or hardening process not because of different cut?
Could be possible then to use some surface hardening process on oem gear also?
Re: E50 different cut gears
So whats the thing with that straight cut gears? Why they are better than standard ones? I mean, why they make aftermarket and stronger gear in straight cut instead of just standard, helical?
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