Chain Length

#1
All right, guys, let me get a couple of things straightened out here and ask a couple of questions. The Generac 7.8 hp engine has a 3/4" shaft but is NOT tapered. It's approximately 2&1/4" long and has a slight flare where it goes into the engine. I'm guessing that I can use a stock 3/4" clutch and slide it onto the shaft. I THINK it'll work as long as once I get it in alignment with the sprocket on the back wheel and drill a slight dent into the shaft for the set screws. What do you guys think? I'm just brainstorming here. The chain I took off the bike measures 52" without the master link. I've looked at a few chains online and they mostly say "3 feet with one connector". This will not work for me, so where the heck can I get a chain with the proper length?
 
#2
Okay Guys, here's a few photos of the Doodle Bug project. As you can see, I DO have the engine mounted on the bike again and the new tires are on. I need some input on where to get a long chain before I can fire it up. I'm also going to have to figure out a way to put a different muffler on it. The old one is HUGE and will not fit. It hits the chain. The shaft pic is just to show it's NOT a tapered shaft like I'd previously said. That's on a totally different engine on another pressure washer I have.

 
#5
Most think/say it's better to not use set screws and allow the clutch to float on the shaft since it's nearly impossible to get sprocket/chain alignment perfect (clutch should self-align if it can move on the shaft, assuming you get it pretty close). The bolt and washer on the end of the shaft keeps the clutch from coming off and the key locks the clutch to the shaft rotationally.

You can buy chain in 5', 10', 50', 100' lengths (or by the foot, however much you want) from various retailers. RLV #35 chain is popular among forum members and I (again) suggest the 10' length which comes with 4 master links so you will have spare chain and master links.
https://www.oldminibikes.com/forum/index.php?threads/predator-engines.167593/#post-1224229
 
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#6
Is your crank drilled/ tapped at the end?
I would never use set screws for a minibike clutch, ok for snowblower pulleys though.
If the crank is keyed, then get a keyed clutch for all the reasons posted above.
With a 3/4” crank, there are shims/spacers/washers available to line the clutch up with the rear sprocket or jackshaft.
 
#9
As for a chain, buy a chain breaker tool. It saves a lot of time and cussing and is just too handy not to own one. You only need this tool and a ball peen hammer to make any chain length you need.
You then buy a length of chain and add/ subtract a link or two if needed. They make 1/2 have links as well for that odd-ball length we all find from time to time.
 
#10
I'm hoping what I ordered works. This chain is in good shape, so I just ordered a new clutch and some master links. If I need to shorten the chain, I'll do it like I used to do when I was a kid working on bicycles. I use a file and a drift punch. Doesn't take much time or a lot of effort. I file the pin on the link I want to remove and then use the punch to knock it out. I'm out of money.
 

Frisco57

Active Member
#11
Most think/say it's better to not use set screws and allow the clutch to float on the shaft since it's nearly impossible to get sprocket/chain alignment perfect (clutch should self-align if it can move on the shaft, assuming you get it pretty close). The bolt and washer on the end of the shaft keeps the clutch from coming off and the key locks the clutch to the shaft rotationally.

You can buy chain in 5', 10', 50', 100' lengths (or by the foot, however much you want) from various retailers. RLV #35 chain is popular among forum members and I (again) suggest the 10' length which comes with 4 master links so you will have spare chain and master links.
https://www.oldminibikes.com/forum/index.php?threads/predator-engines.167593/#post-1224229
I don't mean to high-jack this chain discussion but I've got one set screw installed in the clutch above the key/key way AND the bolt and washer on the the threaded crank. Your advice is not to use any set screw at all? How about on the keyed jack shaft sprockets?
 
#12
I don't mean to high-jack this chain discussion but I've got one set screw installed in the clutch above the key/key way AND the bolt and washer on the the threaded crank. Your advice is not to use any set screw at all? How about on the keyed jack shaft sprockets?
Set screws are designed to hold sprockets and belt pulleys from moving left and right on a shaft. Max torque clutches don’t use set screws for this. They are designed to move a bit left and right on the crankshaft. The bolt and specific sized washer holds it on, and the key prevents any slippage. Sprockets use set screws to keep the key from moving in the key way, left or right.
Hope this helps
 
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