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Unchain My Bike... Or So I Thought...


BusyLittleShop

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Is there a problem with simply adding a roller idler pulley, or is this a preference to try to not run one.............. +1.gif

I think he's just stuck on where to put one as the 45 is an already compact and claustrophobic package.

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Back in the late 80's and early 90's, someone was selling 11mm blower drives. I assume you know this because RCD made your pulley. I have forgot most of what I knew about this. I was a believer in the 14mm that was real common. I think if you do some research with blown alky racers, you might find out if there is another source.

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You know I dont quite understand both the buell and the bmw employ and idler pully? With a grand already sunk into this I think I would find a way to make it work

Thanks HS for the feature post status...

Buell employs an idler pulley whereas the BMW don't... Buell belt can run backwards over a pulley whereas the

BMW belt is not recommended to run backwards over a pulley... I'll work it out because I have yet to see any

problem... however complicated... which when you think about it all the time... did not become solved...

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Maybe I'm just missing something here (distinct possiblity), but what about a tensioner on the bottom side of the swingarm inside of the belt. I couldn't really find a close up of a rc45 swingarm, but from what i could see the exhaust gets real close to the bottom side ( granted that was on a standard rc45, and from what I understand, your's is rather extensively modified so it could well be different ). Go with the mount of the tensioner closer to the pivot point of the swingarm, and the tensioner pulley closer to the rear pulley. Granted I have no answers for how to mount the tensioner. Not sure how keen I would be on drilling mount holes through the swingarm (especially on a rc45...imagine those aren't cheap...) or doing any other type of permanant mounting solution. *shrugs* Just a thought.

Oh yeah, fantastic work on the rear pulley. God that's beautiful. Made me drool.

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Given that the counter shaft and the swingarm don't share the same

pivot tension is not constant during the full range of suspension

travel... for a chain you adjust a bit of slack as the swingarm is

level or the longest length... as the swingarm returns to it's normal

ride height position you should have the slack prescribed by shop

manual... same for a belt... the only difference is that belt run at

zero slack... in fact you place a 2 lb weight on the belt and check

the rate of deflection to archive correct tension... as the swingarm

returns to it's normal ride height position there is still a measure

of tension to insure that the teeth don't skip over the sprocket...

that tension should fall within the prescribe rates by Gates

engineering... if it don't then you're advise to run a fixed idler

pulley to archive correct tension in order to prevent teeth skip...

unfortunately for me the BMW rubber belt is not recommended to bend

backwards over a pulley whereas the Gate belt is...

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gallery_3131_51_26197.jpg

I repeat what I asked before. Is there not room to fit a smallish tensioner pulley on the INSIDE of the BMW belt. What about close to the front pulley on the lower slack side of the belt? The belt will not be subject to reverse bending. You are so close to the allowable center distance that the tensioner will not need to deflect the belt much and therefore there will be very little wrap of the belt around the pulley. The pulley will have to be toothed.

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I repeat what I asked before. Is there not room to fit a smallish tensioner pulley on the INSIDE of the BMW belt. What about close to the front pulley on the lower slack side of the belt? The belt will not be subject to reverse bending. You are so close to the allowable center distance that the tensioner will not need to deflect the belt much and therefore there will be very little wrap of the belt around the pulley. The pulley will have to be toothed.

Thanks for the suggestion but I already thought about it back in Oct... I think tensioning the belt

out would not only interfere with the rest of the bike but promote teeth skipping on the

sprockets...

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I would think a tensioner would be mandatory. All timing belts I know of have a tensioner driven by the back side of the belt. There are locked tensioners and eccentric tensioners that apply tension as needed. I'm no engineer juat a honda technician.

Are you not afraid of chunking belts? I know high power harleys do it all the time. Mr. 45 is stout i'm sure.

I like the idea, no mess, no fuss.

I look at the design more and I see others are right. It would have to be toothed and driven by the toothed or inner belt.

Buell uses there tensioner on the back side of the belt IIRC.

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  • 1 month later...
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Ideally I needed 628mm between centers as evident with Mr.RC45's 17T

43T 110 links of chain prove to show...

gallery_3131_51_100085.jpg

But when I added the Buell 30T 72T 155T setup it measured 561mm

between centers... 67mm too short...

gallery_3131_51_84588.jpg

Would it not be possible to shrink your pullies to lengthen the shorter buell belt?

It would require changing both pullies of course, and I'm not sure how much distance you could gain, but maintaining the gear ratio would not be very hard.

Your 30:72 gives you a 2.4:1 ratio, somethink like a 27:65 would give you a 2.407:1. And I imagine a 65 tooth rear sprocket would be significantly smaller. Not nessissarily small enough, but you can always drop down again if you're custom fabbing it. EG: 24:58 returns a 1:2.416 ratio which would actually be slightly closer to the stock 2.529.

Costs are going back up, but if it lets you achieve your goals then why not? This would also allow you to run the Buell style tentioner, would it not?

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Guest bvoetmann

Have alook at www.vhmotorradtechnik.de

They do it for the VTR.

One problem is the minimum size of pulleys to use with a belt, hence not enough room for the "drive" pulley

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Would it not be possible to shrink your pullies to lengthen the shorter buell belt?

Costs are going back up, but if it lets you achieve your goals then why not? This would also allow you to run the Buell style tentioner, would it not?

If I shrink my pullies to the absolute minimum the buell belt is still too short...

There's no room to run a Buell style tentioner...

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  • 1 month later...
Guest hybrid

you know for a lot less money in materials you can build a spondon style aluminum tubular swingarm in the just slightly longer dimensions.

Chromoly is easy to obtain and cheap enough to build as well. Besides, why spend all that time and money as well as the effort to only change out the drive system. Id go custom arm.

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  • 2 weeks later...
you know for a lot less money in materials you can build a spondon style aluminum tubular swingarm in the just slightly longer dimensions.

Chromoly is easy to obtain and cheap enough to build as well. Besides, why spend all that time and money as well as the effort to only change out the drive system. Id go custom arm.

Larry already has a genuine HRC RC45 swingarm waiting to go on, IIRC, he's trying to source the matching linkage.

Not sure what the length difference is, if any......

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  • 5 months later...
Guest Cruiser

Sorry you are having such a difficult time making this conversion. Closest you can get to 628mm center distance is by using your 30 tooth Driver sprocket and an 85 tooth rear wheel sprocket with the 173 tooth belt. This will give you a center distance of 627.85mm. Just make sure that you are working with the correct center distance to begin with! It would be best if you could provide a center distance range (Min to Max) to make sure the belt will install properly and still be tensioned. If you need additional calculations please contact me. Bruce - gto_65@hotmail.

P.S. I'm a Gates Engineer :fing02:

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Sorry you are having such a difficult time making this conversion. Closest you can get to 628mm center distance is by using your 30 tooth Driver sprocket and an 85 tooth rear wheel sprocket with the 173 tooth belt. This will give you a center distance of 627.85mm. Just make sure that you are working with the correct center distance to begin with! It would be best if you could provide a center distance range (Min to Max) to make sure the belt will install properly and still be tensioned. If you need additional calculations please contact me. Bruce - gto_65@hotmail.

P.S. I'm a Gates Engineer :cool:

No problem Bruce... Honda thinks it's impossible to belt drive their bikes but I'll show them... I apprericate

your suggestion but I don't have the clearance to run an 85T rear sprocket so I'm screwed... but you can

help... there's a little known 11 pitch belt manufacture in Gates Japan rumored to be 160T... that might

work if I drop to 29/68 sprockets for a 2.35 ratio... you see stock RC45 final drive is 17/40 = 2.35 ratio...

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I do not work for gates and I am definitely not an engineer, but I did stay at a Holiday Inn Express last night. - and I just read an article about converting chain drives to belt drive systems and they determined that most bearings on the internals of the engines designed with chain drives in mind would not be sufficient for the amount of tension that belts require to keep teeth properly engaged in the cogs of the pulley. Any consideration toward this line of thought? I'm not sayin' - just askin'. :cool:

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I do not work for gates and I am definitely not an engineer, but I did stay at a Holiday Inn Express last night. - and I just read an article about converting chain drives to belt drive systems and they determined that most bearings on the internals of the engines designed with chain drives in mind would not be sufficient for the amount of tension that belts require to keep teeth properly engaged in the cogs of the pulley. Any consideration toward this line of thought? I'm not sayin' - just askin'. :cool:

Hey! mailman!

Stop complicating things :pissed:

+1.gif :biggrin: :biggrin:

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I do not work for gates and I am definitely not an engineer, but I did stay at a Holiday Inn Express last night. - and I just read an article about converting chain drives to belt drive systems and they determined that most bearings on the internals of the engines designed with chain drives in mind would not be sufficient for the amount of tension that belts require to keep teeth properly engaged in the cogs of the pulley. Any consideration toward this line of thought? I'm not sayin' - just askin'. :cool:

I was actually wondering this same thing, as the force required to maintain belt tension ("overhung" or "radial" load) would be much different than that experienced with a chain.

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Maybe I'm just missing something here (distinct possiblity), but what about a tensioner on the bottom side of the swingarm inside of the belt. I couldn't really find a close up of a rc45 swingarm, but from what i could see the exhaust gets real close to the bottom side ( granted that was on a standard rc45, and from what I understand, your's is rather extensively modified so it could well be different ). Go with the mount of the tensioner closer to the pivot point of the swingarm, and the tensioner pulley closer to the rear pulley. Granted I have no answers for how to mount the tensioner. Not sure how keen I would be on drilling mount holes through the swingarm (especially on a rc45...imagine those aren't cheap...) or doing any other type of permanant mounting solution. *shrugs* Just a thought.

Oh yeah, fantastic work on the rear pulley. God that's beautiful. Made me drool.

Thanks but you did miss the part about rollers...

I already thought about rollers... but the BMW belt is

kind of rubbery whereas the Buell belt is more plastic... the

different being you can run a roller against Buell belt but not

against the BMW belt without taking the life out of it... besides I

don't have the room on Mr.RC45 dense packaging...

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  • 4 months later...
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I'm installing my HRC swingarm and in the process I had this chance to mock up my belt drive

conversion... biggest hurdle is still a 11mm pitch belt with the correct number of teeth... so it's not

ready yet... but all I can say is I'm shall never rest until it is done... right now just enjoy the

possiblities...

gallery_3131_51_43490.jpg

gallery_3131_51_84342.jpg

gallery_3131_51_74162.jpg

gallery_3131_51_20550.jpg

gallery_3131_51_50025.jpg

gallery_3131_51_25956.jpg

gallery_3131_51_22626.jpg

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What a tease, eh?

Looks good enough to be true...

Keep at it. Somewhere out there, someone is looking at an 11mm pitch belt with the correct number of teeth (for you), and wondering what to do with it...

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Larry, have you by chance done the calculations for putting a belt drive onto the 3rd Gen-onwards VFRs? There should be some dimension differences that may make it possible... and there'd probably be a market for them, I'd certainly be interested.

Great to see this thing is still on the workbench, I'm sure you'll get there :laugh:

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