Hartman oil clutch to sell or trade. Need a dry clutch

[john leone]

Hi guys. I currently have a Hartman 10 tooth oil clutch set up on a Mc91B/1 that I am looking swap or sell. The clutch works great, looks good and is complete and assembled. It has a clutch nut to run a starter. All it needs is new linings. I have about 3 hours run time on this clutch since Steve OHara refurbished it for me. Unfortunately it doesn't suit my needs at all. I am hoping to swap it out for a 9 or 10 tooth inboard low rpm engagement dry clutch, preferably a Rev Grip or Max-Torque. I will need an inboard clutch as it will be set up to run on a Stinger sidewinder. Hopefully someone has one to swap or I am willing to purchase outright.

PM if any interest, Thanks!

[david a luciani]

hey John,

i'd think a wet clutch would be perfect on that rig.
how did you cook off the lining in 3 hrs anyway??
i have well over 6 hrs on my cheetah with an open mc91 and the clutch lining is fine.

if you wanted the clutch to engage at lower rpms that's just an add wt. thing.
most people remove wt. to get the rpms higher before engagement though.

one possibilty is you're using the brake and gas at the same time.
i've seen raCERS WO'VE BEEN DRIVING FIFTY YEARS COME OFF THE TRACK WITH THEIR BRAKES SMOKING ALMOST ON FIRE.
THEY DO TEND TO COOK CLUTCHES TOO!!!
dang caps lock

anyway if you want to do a swap p.m. me i can maybe help you out.
though god knows i don't need another hartman.
i have probably 40+ already with hundreds of parts.

since your lining is wasted we'll need to figure out what it's worth trade wise.
or i can sell you a new lining for 25$ shipping included.


dave

[steveohara]

John & Dave,

John's clutch is already set up with custom made solid billet steel weights that equal around 10 full length hartman plates and the clutch is not fitted with the spring arms. The problem is that it has a 10 tooth drum and even with a big sprocket on the axle the kart has to be travelling at least 35mph to hook up the clutch.
That is a pretty good clip for beginners like John's girls to have to drive to make it work.
Whatever type of clutch, a switch to a 9 tooth drum will help and the problem will be solved completely with a switch to a Rev Grip.
The problem with the Hartman with a lot of weight on the shoes and no spring arms is that the clutch creates a lot of drag even at very low engine speeds and it makes the kart difficult to deal with because the engine won't idle unless the idle is set very high and then the kart wants to take off by itself or spin the wheels if up on a stand. The Rev Grip allows for a normal idle setting and will engage at a much lower RPM so the wear factor will be reduced a lot.
I would recommend that John keep the Hartman clutch and set it aside for now and get a Rev Grip to use until they are more experienced. Once the kart can be driven at a good speed consistently the Hartman shoes can be relined and they can go back to it and enjoy the improved acceleration of the slipper clutch.

Steve O'Hara

[Rob Voska]

If you can't find one I'm sure Jim Donovin at Max Torque will get you going. I think all you will have is some spacer issues of running inboard vs outboard.

[david a luciani]

hi Steve,

is this the guy that swapped the mc40 with you?
if so i have a nice revgrip i'll swipe off my daughter kart if it's him.

isn't he in long island?
if so i'll help him out with the set up as i am close.

and that makes sense as far as the clutch goes.
i was confused about the slip issues but a kid blazing fifty mph might be a tiny bit extreme.

dave
p.s. still have the mc1 saved for that trade for you.
i'm just real slow on motor stuff this year.
D

[steveohara]

Dave,

Yes, the same person. I set him up with a virtually new 91B1, Gary Hartman pipe, Hartman clutch package and set the carb up with one of my custom made slide in venturi rings to help the carb work better at low speeds and the package ran good on the bench test but John had a tough time keeping it tuned so we have set the motor up with the intake setup off of a 49E with a few tweaks. The little fixed main jet carb will help a lot to keep the motor tuned and they just don't need all the high rpm power that the big BDC14 provides. I had planned to swap out his clutch to a RevGrip but I discovered that the clutch I have here is the wrong taper for a Mac.
If you can help get them set up with a Rev grip with the 9 tooth drum I think they'll enjoy the kart a lot more.
My own experience with my son and other young kids is that high rpm slipper clutches just scare them and they want to be able to drive with part throttle a lot of the time and you just can't do that with an oil bath clutch and a BDC14 equipped mac engine.
Thanks for your offer to help get some young vintage karters up to speed!
Regards,
Steve O'Hara

[steve miller]

hi steve O. you mentioned you had a clutch with wrong taper for mcculloch .?? i would be interested in it as i beleave it might be for a yamaha kt100 .?

[steveohara]

Steve,

It doesn't fit the KT100 or the TKM and Komet motors I have here. The taper is much longer (shallower) than any crank I have ever seen.
It's a mystery part.
Steve O'Hara

[john leone]

Thanks, Guys for all the suggestions and responses.
Yeah, as you can see my kids have been really hard on the clutch. Steve you described my situation better than me! You have gone well above and beyond in trying to help me out. Thanks.
Dave, I will send out a PM to discuss further. I already have Steve son's expansion chamber on the kart so why not Dave's daughter's clutch.
Regards, John