Topic: Belt Drive Conversion. Yes I did search. :)

[cbass*gxc]

Sorry its kind of long.  Been thinking about it for awhile.

So I got to thinking after someone mentioned something about keeping my whitewalls clean on the left side of the rear tire where the chain is and was wondering if anyone has done this yet.  Of all the post about it here there were a few who thought about it and seemed to have been talked out of it.  It seemed that the biggest concern was the tension when the bike would hit a bump, but my bike is a hardtail and I wouldnt have to worry about that.  As far as clearance issues on the front sprocket, I have access to a plasma cutter and could cut out part of the side cover.  The only few reasons for the cover now seem to keep your pants out of the sprocket and the chain gunk off your pants.  Well with a belt you wouldnt need to worry about the gunk and as I look at the cover there is about a half inch clearance on both sides of the chain, so I could leave the cover on, with no cutting or cut off (clean) the rear part of the cover.  My chain now is 7/8" wide so what another 1/8"?  The clearance between the chain and the frame is about 1" and the clearance between the tire and the chain is about 1 1/2", so I dont see it being a big problem.  The only problem I see would be having to take the swingarm off to change the belt.  But to be honest if I have to sacrifice having to take the 3 bolts out on the rear swing arm to low noise or no gunk on the bike or me, I would do it.  Yes you may say what happens if a belt breaks while out on the road, how am I going to change it?  Well if my chain breaks, I still have to find a non o-ring chain in stock, in the length I need and find someone who has the tools to fix it.  The belts are light enough I could carry an extra one with me and I would say that anyone who has tools to change a chain probably has tools to take out a few bolts.  As far as price goes it may be a couple hundred bucks but I only have $700 in it now so whats another $300.

Again sorry for it being so long and hopefully I can get some incite in to this.

Thanks in advance
Jay

[754]

I did mention a belt drive idea I had a while back, I did a bunch of figuring.

I had come to the conclusion that a Kawi 440 may work, HD big twin is too big a diameter. I found a fellow on herethat was on a forum for them bikes, he started to help, but then unfortunatly passed away..

Anyway what I was trying to find out was dia of the front pulley, width.. amd most important, center distance,, as going much shorter would not look any better..Dont think there is a large choice of lengths as in HD.

Hope you got a 750, because it has room sort..of..

As to a 300 $ ... belt maybe, but not sprockets for that price I would think

[cbass*gxc]

Here is the rear belt hub for a kawi 440.  Couldnt you get something like this and re-drill holes to match the bolt pattern of a Honda?  You may have to make some plates for either side to help support it, but I am sure you could figure something out.




And for the front sprocket I am sure I could find someone who can make me one or maybe the 440 engine sprocket would work.

As for the belt here is one that is for a 77-82 Kawi 440 Snow mobile.  I would think they would be the same.  I dont know the actual length of my chain but I bet its close.

http://www.mfgsupply.com/m/c/HP3012...html?id=nTnzQkr7

Maybe it would be alot of work but it would be damn sweet if it was done.  I figured someone here could make a front sprocket and a rear sprocket for that matter.  I will look in to it more tomorrow.

[754]

Get some measurements of the front pulley, there is only so much room without cutting and welding. Remember it is not a srtaight shot in, procket may have to be 2 piece.

 Get a basic measurement of center to center of sprockets.

 Get tooth count.. driven over driver = ratio

 

[kghost]

Lets see....New chain and sprockets = $150

Belt drive...$300...

I believe I'll just keep cleaning the lube off my rear wheel after I lube it.

Doesn't get grundgy after the first 100 mile spin off period.

But as an engineering project it sounds fun.

Let us know how it turns out.

[Jay B]

A snowmobile belt won't work at all. A Motorcycle drive belt is a flat toothed belt that actually pulls on the teeth of the belt. A snowmobile belt is a huge V-belt and variable width pulleys pull on the sides of the belt, giving continuously variable gearing. The "teeth" are just there to give the thick belt some flexability. I've got an '01 Road King and 4 snowmobiles, so I've got examples of each around here.

[GammaFlat]

I saw this topic come up a while back (may be deleted by now ?) and someone said that there's not enough room width-wise to fit a pulley.  I don't recall if it was the front or rear that was of concern. 

The other issue that came up was loss of power.  I believe folks were saying there's a horsepower penalty for using a belt over a chain.  [EDIT - I might be thinking about shafts  ]

All that said, if there were a tidy solution, I'd be interested. 

[cbass*gxc]

There are quite a few belts out there for around $150 and there are alot of chains out there for the same price.  I may see if I can get the kawi440 setup and see what I may be able to come up with.  It would be a fun project do to and a one of a kind mod.  Gamma that post is still on here, it was one of the ones that I read yesterday.  That may be something I work on next winter when I have alot of time to not ride.

[doobiebro]

I have considered this also.  I think it is a great idea.  As for the price, a drive belt (if properly aligned and tightened) should last many times as long as a chain, thereby negating the higher price.  Also, if you consider that a belt will not stretch but only a few millimeters at most, you never have to adjust it after the first 100 miles or so.

Gates has a good write-up on their website on their belts and sprockets.  Check out http://www.gates.com/brochure.cfm?brochure=7916&location_id=11539 for info on the belts and then follow the links on the left to read about their sprockets.

The only issue that concerns me is how the drive belt can handle the horsepower and torque of a 750 engine.  But, with only about 75 hp, I may be concerned over nothing.  Now, as for a loss of horsepower, belts are supposedly more effecient than a chain so I would expect no loss in hp and perhaps a small increase in hp delivered to the wheel.

There is an interesting write-up from someone that did this conversion on a Kawa Vulcan.  Refer to http://vulcan.wolfcrews.com/800_belt_mod/.  He had to do some mill work on the sprockets to get the alignment correct and to mate the Gates sprocket to his original sprocket and spline, but I don't understand the need for this if you get the correct Gates sprocket.

Keep us posted on your research and let us know how it works out.

[goon 1492]

+1 That is the first thing i heard bad about white walls is how tuff it is to keep clean, that is a good write up bro I would be interested in this too. Also I wouldn't worry about cutt open the front sprocket cover, we used to do that to all the dirt bikes so when we were two hours away from a truck out in the middle of nowhere and the chain popped off we didn't have to cover to contend with, we could get the chain back on with ease.

[goon 1492]

One good bit of advice too that i learned with all my custom rc nitro cars and trucks, when you make your sprockets do at least three of them so you have backup if something goes wrong with the first one.

[Geeto67]

If you were doing this on an F bike (rear disc brake) what is wrong with flipping the rear wheel around and running a jackshaft that takes takes the chain input from one side and outputs it to a belt pulley on the right side.

Sure you are still using a chain but it would be much shorter.

I think performance machine can custom make you a belt drive sprocket from a billet blank (they used to do it for harley guys all the time). It will be expensive but easy.

[cbass*gxc]

Ya that is a great write up on that Vulcan conversion.  I need to read it a few more times to completely understand everything, but I think it could be done.  I may look into it in the next few months and see what I can come up with.

Ya getto that is what I was thinking.  I am sure someone could make a custom sprocket that would take the place of the factory front sprocket and not have to do any changes.  And the rear sprocket would be pretty easy to fit as well.

[754]

You guys are missing a few things, I have spent a few hrs with a set of cases for mockup and you are missing a few points.

First you need a belt, I asked for a simple measurement off a Kaw, a tape will do, or find a longer belt. If the c to c  of the Kawi is 3 inches shorter, it will never go on a stock Honda frame.

Second, pulley is on, a spline, stock Gates will not be.That is a problem we can solve, perhaps 2 pc.

Next the pulley does not have a straight shot onto the shaft, this is not a matter of trimming the cover, it may involve cutting and welding the case..s

And its not a chain, it has to go on with the sproket or on and over after sprocket is on, this is a HUGE stumbling block on this Idea..  it is simply not the same a threading on a chain with a link.

 So as I said, I need to know the centre distance of the Kawi, and if it is not close, a longer belt in 1 inch width, and the dia of Kawi front sprocket.. I know the HD is too big dia & width.

[cbass*gxc]

Anyone have a kawi that they can measure for us and see what the c to c is?

[754]

Jackshaft will be longer.

Sure you can get a sprocket machined, if you have a blank, but bring at least 500.00

I can make a 2pc, it is simpler if the sprocket has a thick shoulder.. but Kawi spline may be close?? dont know,

Sounds like none of you physically have tried to measure this, if you do you will see the dia problem and how you are limited squeezing the pulley in with the belt wrapped around it..

[754]

As far as the torque goes, we can only dream of making enough torque to hurt one of these..

[cbass*gxc]

Ya I may try and get some of the pieces ordered from the kawi and see how they fit.  I would like to get some more feedback first before buying.  I posted on a few other forums to see if anyone has a 440 that can measure it for me.  I was thinking the same thing about the torque, I would not think these bikes would have too much torque for a belt see as these engines dont have nearly the torque of some of the twins.

[cb650 bobber]

My Company is direct with gates. I may be able to save you money on the belts...

[Geeto67]

Jackshaft will be longer.

Sure you can get a sprocket machined, if you have a blank, but bring at least 500.00

I can make a 2pc, it is simpler if the sprocket has a thick shoulder.. but Kawi spline may be close?? dont know,

Sounds like none of you physically have tried to measure this, if you do you will see the dia problem and how you are limited squeezing the pulley in with the belt wrapped around it..

Yes there is a diameter problem but just like with sprockets if you make one pulley smaller you can compensate for it by making the other larger. You would have to run without the chain cover on the motor and I am still not sure how strong a pulley would be being that small but, hey, it is a start. I think that is why a jackshaft with a sprocket at one end and a belt pulley at the other would work better for clearance issues.

And the custom pulley idea was more of the "throw money at it" solution. yest it will cost. yes it will get the job done. will it be worth it? who knows...

Honda had a belt drive tiny bike - CM125 in the early 1980s. Chances are the output spline will be close to the cb750 (if the shafts are the same). The drive belt was tiny on that bike though.

[754]

Once the front pulley is installed there is probably not enough room to slide a belt across it & onto the pulley.

I used my test cases whick have the chain portion(that breaks) cut out but still there, I used a HD sprocket with the centre cutout and had it actually in there, so I could see the actual room left. It will have to be around a 1 inch belt and a smaller dia than the pulley I used. You can make more room by cut and weld, Honda for some reason built out a lot of unneeded aluminum in the area oustside of the sprocket.

Indusrial use pulley usually come with a small round hole, ie unfinished, but can be mated to an old sprocket centre...

[cbass*gxc]

Well guys that is the kind of info that I was looking for.  I am going to do some searching today and see what I can come up with.

[paulages]

Once the front pulley is installed there is probably not enough room to slide a belt across it & onto the pulley.

if you're not changing as often as a chain, you could just pull the shifter assembly cover off also when you change the belt.

[754]

That is not the problem.. getting it on at all..is the problem..

It is obvious many of you have not taken a hard look at the actual cavity around the sprocket shaft..

[HondaMan]

Here's some interesting background for you, on the belt-drive conversions: the CB750 was tested by Gates, on one of the employees bikes, while Harley was having them derive belts for their V-twins. I was part of the development project!

Gates Rubber, here in Denver, when located at the old plant at Mississippi and Broadway, had many biker employees. Ralph Duke was (still is) the headmeister of the Belt Test Lab (now in Dayton, OH). Gates decided, during the Harley project, that other bikes might be good candidates, too. Among the employees' bikes tested in the program: the CB750K3, the Suzy 750-4 equivalent (GX750, was that ) (early versions had chains, later shafts), a KZ1000 Kaw and a 900-4 Kaw, a 400 Kaw twin, and the 350 Honda twin. Gates made 2 sets of toothed sprockets for every bike, at great cost. The only one that was NOT a 1-piece sprocket was the CB750K3 countersprocket, because the extra-wide sprocket could not be installed without pulling the engine (frame is in the way). That one was 2 pieces, and reportedly took over 3 hours to install. After just 8 hours of testing, the non-roundness of the 2-piece c-sprocket tore up the belt, and the CB750K3 was cast out of the project. Too bad: I wanted to try one....

All the other bikes got belts, and the kits made it to market during the 1980s.

In the 1990s, the project was revived when Harley asked for a longer-life pair of belts for their new generation V-Twins, the ones you see today. The Dura series of toothed belts were created in this round. I helped Ralph to install the wireless strain gages into the rear hub of the new 883cc Sportster prototype bike that was used for the tests. The final test I knew of was when they rode up to the Eisenhower Tunnel, recording car immediately behind the bike, storing wireless strain gage data the whole 160-mile-long up-down trip, in the rain. They had done several other dry rides, wanted to see how much change the wet made. The loss of traction in the wet was dramatically recorded in the waveforms, and was enormously interesting to analyze, which Ralph invited me to come and help perform.

That was one of those "cool projects" that we just could not work on enough!