64 duo glide belt drive primary drive

[militaryrider]

Has anyone installed a belt drive Ltd in their machine ?
Thinking of changing / upgrading to a primary belt drive,is there a better unit I should look into ?
Any pro's or cons ,should I keep running original drive ?
Looking to "" upgrade "" for maintance issues ,thank you

[T. Cotten]

Belts, Militaryrider,...

Require an oil seal upon your motor sprocket shaft.

That way, when it sumps while sitting, it can fill the cases all the way up.

....Cotten

[Sargehere]

BDL makes an 88-tooth 1 1/2-inch belt drive kit for your 1955-up kickstart bike. I've had one on my pre-55 tapered-shaft UL for many years. It's smooth, quiet, clean and maintenance-free. The "dust" it does accumulate stays in the tin primary case. The kevlar belts are much-improved over what they were on their introduction decades ago; I have zero fear of "throwing a belt." And if you don't install the useless "sprocket guide" or whatever they call it, you can replace a belt anywhere with one common screwdriver, to remove the screws in the outer primary cover and to prise the belt off/on the engine sprocket if necessary.
The sprocket guide provided is a complete waste of metal. If it ever was contacted by the belt, it would be after a failure and all over, anyway, and with it on you must remove the entire engine sprocket to replace the belt.
Depending upon the fit of your frame, you might go with a "twin-pull transmission adjuster," available from V-twin, to align the primary belt and it will never get out of line on its own. I highly recommend the BDL for quiet, smooth operation.

[vph-d]

I agree with Sargehere. Neither myself nor any close friends with tin primary bikes, run primary chains, we all have belts.
VPH-D

[militaryrider]

Gerry , thank you Summitt has free shipping over $99.00 also I have a $25.00 gift card .
Going to order today ,have a good week ,thank you again

[militaryrider]

Vph-d , thank you ,checking today what unit I need 8mm or 11 ,will disassemble ,leave open ,order today ,from Summitt will have by Friday , thanks for your response

[kitabel]

Many belts are thrown by misalignment of the sprocket shaft and transmission mainshaft (which must be parallel).
The belt guide doesn't prevent this - but slices the belt to pieces as it passes by.

[T. Cotten]

Many belts are thrown by misalignment of the sprocket shaft and transmission mainshaft (which must be parallel).
The belt guide doesn't prevent this - but slices the belt to pieces as it passes by.

The trick is keeping them parallel, Kitabel!

Bumps happen.

Really goosing it doesn't help either.

Its a lot easier with a '65+ Indian-design cast primary. Except then they get hot.

...Cotten

[kitabel]

If there's any wiggle room, the shafts will try to approach each other, and the belt will march outward in its quest to hide in the grass.
Pay particular attention to the holes in the frame, transmission plate etc. and shim etc. as indicated.

[T. Cotten]

If there's any wiggle room, the shafts will try to approach each other, and the belt will march outward in its quest to hide in the grass.
Pay particular attention to the holes in the frame, transmission plate etc. and shim etc. as indicated.

We certainly agree then, Kitabel,...

This stuff *moves* all the time.

Except sitting in the garage.

(Unless wrenched at... Then it moves all by itself.)

....Cotten
PS: Face it for most Folks, chains are a lot more friendly. Cheaper in the long run, too.

[aumick10]

I have used a number of belt drives over the years, and generally I prefer them over a chain drive.
However, as with most things, they are not as perfect as the manufactures would have you believe.

As others have stated, it is important to have the pulley aligned in parallel. This is just the starting point.

The typical clutch hub is supported by a bearing inboard that is close to the gearbox sprocket. The idea is to have the center of pull from the primary drive as close as possible to a bearing supported shaft. This works fairly well with a relatively narrow single or double row primary chain. Later models with a cast inner primary have an additional bearing to support the main shaft.

Most belt drives actually have a belt center that is outboard of the clutch hub bearing, depending on the belt width, it can vary a lot. This imparts a bending motion to the main shaft.
The main shaft flexes as the motor torque is varied, which changes the pulley alignments. During heavy acceleration, the main shaft flexes towards the engine sprocket. This results in the belt tracking trying to track off the front pulley.
The front sprocket alignment guide is used to hold the belt on the front pulley during these events. Yes, it does wear out the side of the belt, but it doesn't come off. I think some manufactures use a guide that screws on the outside of the pully.

The engine sprocket shaft can also flex, depending on the design.
In high HP applications, both the engine output shaft and the transmission output shaft have outboard support bearings to keep any drive system inside supported shafts.

In practicality, belt drive have been around for many successful years.
if you are looking for a belt drive for your Duo Glide, an 8mm belt is as much as you need,if it is standard.
As previously mentioned, make sure your engine shaft seal has it's spring towards the crankshaft, and be aware of wet sumping if it happens.


Cheers
Mick

[Rubone]

If you have ever adjusted the tracking of a belt sander the drive belt reacts exactly the same. Slightly oversized or slotted transmission plate holes allow the gearbox to swivel slightly getting the belt to run centered in the front pulley negating the need for guide plates to keep it in place. Your '64 won't flex stuff enough to be an issue (strokers and sidecars excepted!) This doesn't work on '65 up bikes with fixed centers. I've run belts for many years on tin primary bikes and never had issues. The original; belt on my '47 Knuckle is still on there from 1990 and I don't go to all the BS of cooling holes, spacers and other nonsense to prevent overheating. They cool just fine, and as Sarge says modern belts are even better.

[aumick10]

Rubone,

Belt sander typically have crowned pulleys, hence the need for tracking adjustment. The physics are different to a flat pulley, although some may have a 2 degree pitch that you cannot see.
I consider a front belt guide as an insurance policy, cheap insurance.