Posts: 239
Threads: 14
Joined: Feb 2017
Reputation:
2
Location: Valley Forge, PA
Brad,
To my eye, it looks like your sprocket fits #41 chain. Vintage race karts use #35. [Per the ANSI standard, the first digit refers to the pitch (span between rivets), in 8th's of an inch. #41 = 1/2", #35 = 3/8".] Before ordering any parts, be sure which one you're working with.
If your axle sprocket is for a #41, you really need to change to a smaller pitch, because of the small sprocket sizes and high RPM seen on a kart. That's why modern karts use #219 chain (0.300" pitch). (Yeah, I know, that number doesn't follow the ANSI standard.)
Rev-Grip's have sintered (metal) shoes which allow them to endure abuse (slipping) with little or no damage. However, even with a Super Spring, the engagement RPM will be lower than optimum, and equivalent karts with MaxTorque clutches will routinely pass you coming out of the hairpins.
Doug
Posts: 433
Threads: 53
Joined: Jan 2016
Reputation:
2
Location: southern tier new york
id have to look but I think the 5/8ths part is the hub and the 9 tooth driver has a 9/16s bushing same as rev grip that fits over mcculloch out board rev grip hub with extended bushing on hub ..
cost wise ....either way no matter what I would try save and use the rev grip clutch ..you wont regret it ..even if you send driver to me or someone ...we can weld new sprocket on it ..and I can tell ya how to grid the shoes and cut spring... got to cut spring special length use metal screw hold it to gather no hooks..but I cant tell ya how I grind and cut shoes Lol.. ..mine are set for around 6500 on an820 an7800-8000 for mccullochs ..
Posts: 99
Threads: 21
Joined: Nov 2016
Reputation:
1
I ran rev grips pretty much exclusively back in the day, but that was on dirt where you weren't looking for a lot of slip, it was either in or out. Not a good clutch for road courses, but if you decide to use it, I have a bunch of parts (for Macs). Let me know if I can help you out.
Posts: 433
Threads: 53
Joined: Jan 2016
Reputation:
2
Location: southern tier new york
09-03-2017, 03:42 PM
(This post was last modified: 09-03-2017, 03:45 PM by steve miller.)
Bill ., I luv them ill buy everything you wanna sell ..
I use them on every kart I ride sept my invader and im switching that to sportsman ..
you gotta customize or millerize the shoes cut some cross hatches in the faces cut the spring they will work ..
but im only 140 lbs I could prolly run direct drive and wouldn't matter much ..
Posts: 384
Threads: 27
Joined: Jan 2016
Reputation:
6
Location: Livermore, CA
Brad,
Good that your clutch came off the engine you want to run it on. You know it fits.
Now. you do need to confirm the type of chain the sprocket fits.
#35 is what we run in vintage.
If it is #35, then the wear on the teeth won't keep you from getting some good use out of that drum.
If you keep the chain lubed, it'll run for quite a few hours before the drum is finished.
BTW, I have developed the practice of lubricating the chain by squirting a little PJ1 on the clutch drum sprocket, then spinning the axle to distribute the lube onto the chain and onto the axles sprocket. I do this about three times, until the chain looks wet. I used to spray the entire chain, and then spent lots of time removing the PJ1 that was slung off the chain when on the track. I figured that something like 80% or more of the lube I sprayed on the chain was slung off in operation. Anything more than a thin film of lube serves no purpose in any event. I get minimal drum sprocket wear and about 90% less mess lubricating the chain this way. I do the same thing on my KT100 Emmick Avenger modern race kart as well.
You will note that you can run a needle bearing drum from 10 tooth on up on Rev Grips. That's why I run nothing but 10 tooth drums on my 820's.
There is no doubt that Jim Donovan's Max Torque clutches will give you much better performance, but I am saving mine for when I mount up my Bonbright Vintage 820's.
I am hoping that Miller will share with us his tricks for messing with the Rev Grip clutches. He's quite an innovative individual.
Jim Waltz, West Sacramento, CA
Posts: 123
Threads: 29
Joined: Jan 2016
Reputation:
0
Location: west central Indiana
I checked the fit with a #35 chain and it is actually a decent fit. I thought it would be loose.
I had actually not planned on using this engine but I just spun it over with the plug resting on the head and I got a nice white spark out of it. I bought a carb rebuild kit at comet yesterday for it. So all I need is a starter cup or nut for the Clutch side. I'll just run this clutch for starters and try it. I don't feel confident running it for long thought. I guess I'll need a starter to. The list never ends!
Thanks for all of your help and tips!!!
Brad
Posts: 433
Threads: 53
Joined: Jan 2016
Reputation:
2
Location: southern tier new york
09-03-2017, 06:29 PM
(This post was last modified: 09-03-2017, 06:53 PM by steve miller.)
only trouble is when worn that bad on a 9 tooth they actually hook the chain and catch ..but it will run ...
jimmy I cant tell all secrets cuz as of now more folks don't like rev grips than do ..so I can still buy em decent ..but if I spill beans on making one work ..(for Me ) ..then everyone want to keep them or buy more ..drive price up ... lol.. hehehe ...
if I new how post vids be interesting see comments on how I do some of the stuff I do ..
Posts: 123
Threads: 29
Joined: Jan 2016
Reputation:
0
Location: west central Indiana
That's not good!
I don't want to get going off on a bad clutch issue. I'm sure I will have enough issues so maybe a new clutch would be worth the expense.
Posts: 384
Threads: 27
Joined: Jan 2016
Reputation:
6
Location: Livermore, CA
09-03-2017, 10:04 PM
(This post was last modified: 09-03-2017, 10:12 PM by Jim Waltz.)
Brad,
Or just find a new drum.
Chuck Giacobbe had some 9 tooth on Ebay just recently.
strockerace on Ebay.
Miller,
See PM.
Jim Waltz, West Sacramento, CA
