Rookie Question: Does a belt drive primary have any form of compensator?

[Molly]

Still trying to eliminate the jerkiness that's present when cruising along. Bike runs beautifully but the problem is intrusive. Respected HD mechanic locally told me the play in the primary belt was about right and it would tighten a little when up to temperature.

Wondering if there's a cush-drive of sorts where the compensator is on a chain primary? Figured if there was it might be worn.

A rookie question and, no, I've not sourced a factory manual yet (Clymer doesn't seem to have much to say on the subject). As always, appreciate your guidance and thanks in advance.

[motorhogman]

What speed is " cruising"  I have had Primo belt drives with the idler tensioner system and Karata belt drives ( no idler )  on shovel heads. Never experienced any jerking at any speed from either. No compensator.  Your belt looks loose to me from your pictures. I agree they will get tighter when up to running temp.  Just don't recall my non idler belts having that kind of play when cold.

[drifter]

Looks like fabrication time.  You have part of the hardware in place, attach an 'axle' to the bottom of the adjuster, get a long narrow roller to slip over the 'axle' and set the adjustment.  Yep, the devil is in the details. 

[david lee]

ive had no problems with the primo belt drive with idler. to me sounds like a rear chain problem

[motorplex88]

This is a wild a$$ idea as I don't know what belt system you have. After watching your video I wonder if you have a 96 tooth belt on there when you need a 99 tooth with an idler. That is if it's a 1.5 x 11mm. Also agree with checking rear chain tension.

[FSG]

I wonder if you have a 96 tooth belt on there when you need a 99 tooth with an idler

now there's a thought ......  start counting Molly   

[72fl]

In my Opinion Jerkiness is usually caused by the Final Drive and Lugging in to High of a Gear

[Excalibur]

At cruise you're using a touch of throttle so I'd review the light throttle carb setting. Also accurately check timing, especially don't run too much advance with state of today's fuel.

Good luck. Hope it helps.

[Ohio HD]

I'm guessing that this bike has points and condenser, and is a cone motor? Check out the advance weights and springs. The springs could be weak or damaged and may cause the timing to be erratic.

[Hossamania]

I thought there was a lot of play in the primary belt in the video, but I've not owned one. I know my buddie's seemed a lot tighter than that one.

[motorplex88]

Yes. Also in my opinion to much play in primary belt. Other thoughts are valid. Process of elimination.

[Molly]

This is a wild a$$ idea as I don't know what belt system you have. After watching your video I wonder if you have a 96 tooth belt on there when you need a 99 tooth with an idler. That is if it's a 1.5 x 11mm. Also agree with checking rear chain tension.

The seller sent me this info on the belt.

Sorry. Can't rotate it on my phone.



You cannot see attachments on this board.

[capn]

BDL does sell the 8mm with an idler pulley.You can buy a replacement idler from them.They will answer the phone.

[FSG]

belt 506915

idler 505335

Motorcycle Storehouse Ltd

Unit 2 Oakden Drive
Denton, Manchester, M34 2QN
United Kingdom
Phone: +44 (0) 161 337 43 90
Company number: 06167740

[xlfan]

BDL, REPL. PRIMARY BELT. 1-1/2", 132T- (MINUS), 8MM PITCH

This is the so-called '-' belt. For the '+' belt see 970974. Note: The difference in belts between 65-78 and 78-83 FL, FX models is due to a minor difference in primary housing length. Available belts are therefore designated as a - (minus, slightly shorter / MCS 506915) or + (plus, slightly longer / MCS 970974) belt, although the number of teeth is identical.

This is what the seller claims for that part number.

[JW113]

I'm looking at the BDL web page for Shovelhead drives, do not see any 8mm driver with an idler. Does anyone know the part number of the BDL kit that uses one?

http://beltdrives.com/products/closed-belt-drives-for-shovelheadpanheadknucklehead

-JW

[capn]

My bad. They make the 11mm drive with idler.

[JW113]

I looked at the Molly video in the other thread, and I sure don't see that there is enough play in that belt to even use and idler. It's loose, yes, but not *that* loose.

I know we've hashed this out before, but this is exactly why the stock HD primary belt set up had slotted holes in the inner primary at the engine to primary bolts. So that the belt tightness could be adjusted. One solution for Molly may be to simply slot those holes, along with the hole for the case flange.

-JW

[Deye76]

ive had no problems with the primo belt drive with idler. to me sounds like a rear chain problem

I ran a Primo with the idler on my Panhead for 9 years. Never a problem.

[JW113]

I don't think there is an issue with idlers, but the drive set up has to be designed for one. Meaning the length of the belt has to be long enough for a bow in it, for the idle. The 8mm BDL set up is not designed for an idler as far as I can see. If you ran a longer belt, then sure. But in the OP's video, I sure don't see how you're going to get an idler in there.

-JW