Adjusting primary belt/chain tension

Transmission, clutch, chains and belts
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Kuda
Posts: 342
Joined: Tue Aug 01, 2006 5:41 pm
Location: Maryland

Adjusting primary belt/chain tension

#1

Post by Kuda » Mon Oct 17, 2005 6:28 pm

How in the heck to you get tension *and* keep it straight?

Just another newbie question. Had to remove the primary belt (Primo) to rebuild clutch last weekend. And I'll have to do it again next weekend when the long rollers that I needed come in. But the question has to do with adjusting the belt tension. I loosened up the 4 bolts under the trans plate, but I had a hell of a time getting enough leverage to actually move the trans back *and* tighten the bolts back up. Is there a trick to it? And is it possible to torque the tranny off center enough (i.e cocked in the frame) to screw up belt/chain alignment? How in the heck to you get tension *and* keep it straight? Thanks,

-Kuda
'49 FL



panhead
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Re: Adjusting primary belt/chain tension

#2

Post by panhead » Mon Oct 17, 2005 8:03 pm

Did you use the gearbox adjusting screw?

caschnd1
Posts: 589
Joined: Tue Apr 25, 2006 3:45 pm
Bikes: 1949 FL Chopper

Re: Adjusting primary belt/chain tension

#3

Post by caschnd1 » Mon Oct 17, 2005 8:53 pm

Kuda,

As panhead mentioned, you should have an adjustment screw at the back of the transmission on the right hand side. This will allow you to pull the trans back on the plate. HOWEVER, this screw pulls on one side and tends to leave the transmission crooked in the frame. Not as big a deal with a chain primary, but with a belt it's more important. If you get the trans aligned right with the motor, you won't have nearly so many problems with clutch dragging issues. Also, your belts will last longer. One final word of advice, don't over tighten your belt. When I ran a Primo, I would leave a good loose spot in the belt centered between the pullies. That will tighten up as the bike warms up and things expand. You don't want it tight when it's cold.

-Craig

P.S. There are aftermarket tranmission adjustment brackets for about $25 that allow you to pull/push on both sides of the transmission and get it lined up with the motor pully. I'd recommend using one, but that are a bit of a pain to install (require the transmission to come out).

Kuda
Posts: 342
Joined: Tue Aug 01, 2006 5:41 pm
Location: Maryland

Re: Adjusting primary belt/chain tension

#4

Post by Kuda » Mon Oct 17, 2005 8:56 pm

Er...no? I did say I was a newbie, right? ::) I've got the Panhead Service Manual (a reprint), a reprint of the owner's manual, and a copy of the Clymer's on order, but I didn't see anything about adjusting the primary chain, just the final chain...

-Kuda (startin' to feel even more foolish)

Kuda
Posts: 342
Joined: Tue Aug 01, 2006 5:41 pm
Location: Maryland

Re: Adjusting primary belt/chain tension

#5

Post by Kuda » Mon Oct 17, 2005 9:03 pm

"As panhead mentioned, you should have an adjustment screw at the back of the transmission on the right hand side. "

I'll take another look when I get home, but since this is a real mix and match bike (last owner bought it in pieces, had 3 different shops assemble it, never got it finished), I can't assume anything is original or right...

"One final word of advice, don't over tighten your belt. "

Will keep that firmly in mind, thanks.

"There are aftermarket tranmission adjustment brackets for about $25 that allow you to pull/push on both sides of the transmission and get it lined up with the motor pully. I'd recommend using one, but that are a bit of a pain to install (require the transmission to come out)."

Actually, I might even have one now. The current bracket is chrome and looks to be billet <spit> but I can't tell for sure. No obvious way to adjust it other than pulling on the trans, but I'll look again when I get home. As soon as I get it running right it's all coming apart again anyway, so I'll pick up a good one when I do. Thanks again to both of you...

-Kuda

bookn
Posts: 4
Joined: Fri Jul 13, 2007 3:03 pm

Re: Adjusting primary belt/chain tension

#6

Post by bookn » Sat Oct 22, 2005 3:46 am

Kuda, Karata recommends 1/8" to 1/4" belt deflection with 10lbs force to be the correct adjustment for their belt drives. If you're running an open primary it helps to have an extra set of hands if you don't have an adjuster built into your transmission plate; you can overcome this by yourself with a little ingenuity though. Keep in mind that the pulleys must be square to each other or with an ever-so-slight run-out towards the outside of the front pulley. I use a couple of squares and a straight edge to check for alignment.

fourthgear
Posts: 1365
Joined: Mon Apr 11, 2005 1:12 pm
Location: north florida

Re: Adjusting primary belt/chain tension

#7

Post by fourthgear » Sat Oct 22, 2005 1:55 pm

Did you only loosen four nuts and not the bolt on the kicker side? That would have made it real hard to move and adj.. If yours has five that is.

Kuda
Posts: 342
Joined: Tue Aug 01, 2006 5:41 pm
Location: Maryland

Re: Adjusting primary belt/chain tension

#8

Post by Kuda » Sat Oct 22, 2005 3:30 pm

Went back under the bike armed with the Clymers (I know, but it's the only one I could find right now). I can see the bolt hole for the trans adjuster, but it's empty, and the bracket is missing too. The previous owner had a big metal bracket for passenger pegs in the two rear-most holes of the adjusting plate, so I'm guessing he took off the adjuster tabs/bracket. Back to the store I go. Thanks for all the helpful replies...

-Kuda

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