Belt drive (cooling) (2009)

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Hi experts

Doe's the belt drive systems require cooling . If so what is the best way


Many thanks

Davy
 
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Most folks open up the side cover and put screen or mesh over the openings. Some cut the front of the inner chaincase open as well and yet others make a totally new chaincase with lots of mesh or screen for air cooling.
 
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I see most of these kits going for $460+ all it they are is just 2 pulleys , a belt and a cheap sheet metal cover, does anyone make more affordable kits? I have a 71 commando 750
 
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I've run a RGM Belt drive since the mid 80's when RGM first started selling them and done thousands of miles with no cooling and with no apparent problems, just remember not to run the thing that tight as they tighten up when hot and that seems to be what causes problems.
In all these years (and probably more than 70 thousand miles) I've replaced the belt twice, and had a belt shred itself because the gearbox mainshaft bearing failed after a bit of "spirited" riding. I've replaced the sealed clutch bearing twice in that time also so I think thats not too bad. I've also ridden the bike through some (very) hot countries during that time.
I do wonder if "cooling" the chaincase on a roadbike could cause more problems with dirt and water ingress. Maybe ok if your playing at being a racer but OTT on the road methinks........discuss!
 
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Any cooling would be for the alternator not the belt. For sure no air scoops are necessary. Folks have done long miles with no cooling mods. Some say just remove the seal door at the back of the inter cover. I did not like that at went all out to do a cooling mod that does not show.
Belt drive (cooling) (2009)

Belt drive (cooling) (2009)

Belt drive (cooling) (2009)

Belt drive (cooling) (2009)
 

Fullauto

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I took the teeth off a Hayward belt due to a too tight belt adjustment. The new belt has been on for thousands of miles now with no ventilation and no problems in our quite harsh heat. I had the outer primary off a couple of weeks ago and it all looks good. I ran it for a while with the inspection caps off. Riding in the rain caused water to enter the primary and the next day the clutch plates were welded together. I had to strip the clutch and seperate them. Hence, no ventilation and no problems.
 
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Hi Davy,
As Norbsa mentioned some just remove the sheet metal sliding seal from the inner cover, that is what I did and have no problems. I did worry that water may enter during a washing or extended rain ride, so, in the lowest part of the outer cover ( just under the front pulley) I drilled a small hole for drainage just in case.
Here's another thought, on Ebaymotors (motorcycle parts and accessories) you can almost always find several outer covers in varying condition for reasonable prices, keep your original cover intact, buy a scratched up cover for cheap and then drill it or carve it to your hearts content.
GB
 
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How you take care of the cooling issue depends on which belt you're using. Neoprene belts have to be run dry and are probably more sensitive to heat so you need to vent them. The RGM (Hayward) urethane belt can be run wet or dry and probably isn't as sensitive to heat. Neither one of them need lubrication. The main source of the heat in the primary is the alternator but it's nothing compared to the heat that's getting sucked over from the engine directly to the case. Luckily, the surface area of the primary is huge and aluminum bleeds off heat like a champ so it's probably a wash. I like to run the primary closed to keep dirt and water out. I use ATF in the primary because I read somewhere that the ATF splashing around gets on the alternator and establishes a thermal connection for it to the case. Whether the alternator is warming the case or the case is warming the alternator is anybodies guess. BigStu comes to my mind whenever I think of Syncoflex belts. You can find out about belts by doing a search on this list on syncroflex.
 
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I vented mine after a stator (Wassell from Norvil) started to overheat and fry. Replaced with a Sparxx but with ventilation and for the last 18months with an electronic reg/rectifier from Norbsa02. Since then there are no signs of overheat but don't know if the Wassell stator was faulty or had low temp insulation (Class A/B 105C/120C maybe), if the electronics have helped other than stopping the battery cooking (old zener was not functioning well). Have any BD users had stator issues? Seems like not as it's not been mentioned. This is mine with 22000 miles on the belt.
Belt drive (cooling) (2009)
 

ntst8

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Gino Rondelli said:
I've run a RGM Belt drive since the mid 80's when RGM first started selling them and done thousands of miles with no cooling and with no apparent problems, just remember not to run the thing that tight as they tighten up when hot and that seems to be what causes problems.!

RGM belt here too, not so many miles but it was fitted by the local RGM reseller who stated venting not required.
Some of the venting arrangements are a nice look, but i would worry about muck getting in if ridden in all weathers - which happens whether i want to or not due to our changeable weather around here.
 
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Belt primary here too, for the past 10 years.
Live in the southwest United States, get damn hot here.
I leave the primary completely covered at all times. No issues.
But what do I know? I don't make my own clutch cables.
 
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Keith1069 said:
I vented mine after a stator (Wassell from Norvil) started to overheat and fry. Replaced with a Sparxx but with ventilation and for the last 18months with an electronic reg/rectifier from Norbsa02. Since then there are no signs of overheat but don't know if the Wassell stator was faulty or had low temp insulation (Class A/B 105C/120C maybe), if the electronics have helped other than stopping the battery cooking (old zener was not functioning well). Have any BD users had stator issues? Seems like not as it's not been mentioned. This is mine with 22000 miles on the belt.

The problem with the zener regulator is that the alternator will always be under load even if no demand is placed on it, so yes, it will overheat especially at high speeds. The dumb thing is whatever power is being generated has to be shunted to ground by the zener if it is not used, the alternator will heat up, the zener will heat up and all this takes power, not much, but power not doing anything to help the bike go faster. 745 watts is 1 HP, a 120 watts alternator takes 1/6 HP as long as it is producing that 120 watts. An electronic series pass regulator will only let the amount of power needed to power the electrical circuits that are turned on, so without any lights only a fraction the the alternator is used, the rest is not heating up an aluminum footrest bracket thus warming up the earth.

Do your part to curb global warming, ditch the zener :lol:

Jean
 
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Do your part to curb global warming, ditch the zener
Thanks Jean, I think ? that is what I figured although I was more concerned with the battery cooking. Strange thing is the Sparxx stator ran for quite a while with the zener ok. That's why I mentioned the insulation standards. I worked for the Prince of darkness for 23 years and latterly with a US/Canadian DC motor company. Standard practice was to use 130c insulated copper wire for vented cooled motors and 180c for totally enclosed, all 12/24v DC stuff.
 
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The problem with the zener regulator is that the alternator will always be under load even if no demand is placed on it, so yes, it will overheat especially at high speeds. The dumb thing is whatever power is being generated has to be shunted to ground by the zener if it is not used, the alternator will heat up, the zener will heat up and all this takes power, not much, but power not doing anything to help the bike go faster. 745 watts is 1 HP, a 120 watts alternator takes 1/6 HP as long as it is producing that 120 watts. An electronic series pass regulator will only let the amount of power needed to power the electrical circuits that are turned on, so without any lights only a fraction the the alternator is used, the rest is not heating up an aluminum footrest bracket thus warming up the earth.

Do your part to curb global warming, ditch the zener :lol:

Jean
Great post Jean ,very informative. I have just had an alternator disentegrate on my Norvin[running 50mm belt primary] this resulted in a 60m long strip of rubber on the highway and an increased heart rate, luckily stayed upright. I will be ditching the standard zener and rectifier and fitting podtronics unit. Not sure about the quality of the new ''lucas'' stators/ rotors though, they were only about 3months old, made in India, Taiwan?
 

SteveBorland

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I see most of these kits going for $460+ all it they are is just 2 pulleys , a belt and a cheap sheet metal cover, does anyone make more affordable kits? I have a 71 commando 750
Hmm, if you think it's so simple a job, then please go ahead and make your own - I suspect you will discover that there's a bit more to it than "just 2 pulleys"
Hint - there's not many Norton spares people driving a Rolls (although I seem to remember The Bearded One did this at one point?)

On the other hand, you could try keeping an eye on Fleabay....

/Steve.
 
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Great post Jean ,very informative. I have just had an alternator disentegrate on my Norvin[running 50mm belt primary] this resulted in a 60m long strip of rubber on the highway and an increased heart rate, luckily stayed upright. I will be ditching the standard zener and rectifier and fitting podtronics unit. Not sure about the quality of the new ''lucas'' stators/ rotors though, they were only about 3months old, made in India, Taiwan?
Does your Podtronics unit not also regulate by shunting the alternator current?

That’s how it’s usually done, with permanent magnet motorcycle alternators.
 

Fast Eddie

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Great post Jean ,very informative. I have just had an alternator disentegrate on my Norvin[running 50mm belt primary] this resulted in a 60m long strip of rubber on the highway and an increased heart rate, luckily stayed upright. I will be ditching the standard zener and rectifier and fitting podtronics unit. Not sure about the quality of the new ''lucas'' stators/ rotors though, they were only about 3months old, made in India, Taiwan?

I would suggest reading this before buying a podtronics unit:
https://granttiller.com/regulator-rectifiers-alternators

Secondly, whichever alternator / rotor you buy, the most important thing is to ensure a proper gap. Seems many of the new ones are too tight from the get go, and thats before any possible misaligned mountings etc.

I always go for a .040” undersize (.020” gap) and use a strip cut from a milk carton wrapped around the rotor to ensure a good gap whilst tightening things up.

I have found it necessary sometimes to open up the mounting holes in the stator, which I personally prefer over ‘accurately’ smacking the studs with a lump hammer.
 
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Fitting packing around the rotor is vital - otherwise the stator gets pulled by the rotor magnets. The Norton alternator mounting studs do seem to be a bit variable for concentricity, although I've never bothered to assess it properly- just opened out the stator holes like FE!
Funny how I've never had the problem on Triumphs - twins or triples.

I'd also like to understand how to regulate the output current on a permanent magnet generator without a Zener ;)
Enjoying a good belt drive thread here.
 
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FastEddie- is your link actually saying that modern Japanese bikes have alternators that get too hot?

The MOSFET-based reg/rec mitigates against a lot of the issues that were linked to the older SCR-based technology and they are being fitted as standard on many of the newer Japanese bikes....



...It is well worth noting that the MOSFET regulator/rectifiers that are currently on the market are all short-type...



...In the dead-shorted state though, the alternator stator will still be getting overly hot...
Is it written by an enthusiastic amateur?
 
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