770/780/790/860 secondary cluthes

[riotwarrior]

Was on phone today with Roy from Quality Drive Services about clutching.

with my 780 primary and a 770 secondary I'll have at est 4000 RPM 27 MPH in high range and at 4000 RPM 5 MPH in low range...

Ya that's the setup I'm going with. that's just about a perfect range for me, that lill kubota will be one hell of a puller and I can imagine that at 1800 in low range how slow low will be.

Now Rose is off to Oroville to pick up the 780 Primary on Saturday. That will be nice...

I managed to remove the old clutch of the Tecumseh. That engine is getting a redux of the mounting setup. I'm thinking studs and nuts this time to make life easier, along with some solid bushings to stop slop of the engine on the mount plate.

Now to work out the rest of the clutching and mounting and so forth... Woo hoo...so stoked.

damn machine is just coming along nicely.

Now on to some comparative info....

This is all based on a 780 Comet primary or the drive/engine clutch...that's what all these calculations are based on a 780 primary and / ??? secondary as follows

Thus here we go with 4 different setups and gear ratio spreads.

780 / 860 secondary
860 = 11.25" diameter
4.42:1 low range and 1:1 hi range with 1 3/16" belt...different if 1 1/4" belt used

This 790 series is the series I currently have however instead of a torque sensitive clutch I have a speed clutch which SUCKS, there is a 790 torque sensitive model as well but not the one I have.
780 / 790 secondary
790 = 8.5" diameter
3.35:1 low range and 0.5:1 hi range or .5 OD

780 / 780 secondary
780 = 9.25" diameter
3.71 low range and 0.7:1 hi range or .71 OD

780 / 770
770 = 9.85" diameter
3.95:1 low range and 0.76:1 hi range or .76 OD

The 780/770 is offering the best of low and hi range spread for me in my opinion.

Pricing is good for the 770 as well and parts are available.

Now to work out if it fits or if I need to move or refab the transmission mounts.

Thanks for reading..

OH BTW, does anyone have a 770 with 3/4" pilot bore they may want to sell????

[Nubs]

Your PM box will have the answer

[riotwarrior]

Your PM box will have the answer

Looks like it's all the stuff I'm lookin for n then that!

Time to get on the measuring and such. DOH