Cool Runnin'

I see, on this forum, Nortons with drilled primary covers, clearly a belt under those holes. Is it necessary to vent the primary if you do run a belt? I ask because I have a Maney belt drive, but want to retain the look of the standard primary, the distructions that came with the drive said nothing about venting, did say to run without the cover to determine if the alignment was correct...

R$

RoadScholar said:

I see, on this forum, Nortons with drilled primary covers, clearly a belt under those holes. Is it necessary to vent the primary if you do run a belt? I ask because I have a Maney belt drive, but want to retain the look of the standard primary, the distructions that came with the drive said nothing about venting, did say to run without the cover to determine if the alignment was correct...

R$

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Been answered many times belt drives come up, and argued just as many times. The answer is… yes/no. :mrgreen:

I tend to like the idea of anything that helps an air cooled engine dissapate heat. Will it make any difference? I dunno...

Yup. Controversial topic. For what it's worth, I've been running a belt drive for four or five years with an original enclosed chain case, have had no problems and have been unable to detect any deterioration of any sort. However, on very, very hot days I have removed a couple of the inspection plugs on the chain case to ensure that some cooling air was circulated into the case. Not sure that it was necessary, but made me feel better.

I have a belt drive on my '73 - 750. Have been told that there is no reason to drill holes or leave off inspection covers. However if you would like a neat piece of jewelry for your belt drive primary check out these.

http://www.eurojamb.com/norton-750-850- ... -1551.html

I, as you can see need the cooling. The RGM unit seem to need it more than the Maney drives. The clutch hub will swell to the point the the belts tightens and effect clutch function. The adjustment is also quite narrow. The belt is more than a 90 degree twist yet tight enough so that is doesn't jump the drive hub when kicking over.

You should get your good and hot and check your tension. Too tight is too bad when the main shaft bends or breaks off. This is of course a weak spot on all AMC units but especially vulnerable in this instance.

I checked with Dreer before getting his version of Tony Haywood belt drive and then Maney on his 40 mm belt drive if safe to run totally dry oil tight sealed in summer up hill flying leaps, to be assured it was perfectly fine and I went on to prove em right on harshly hot run Ms Peel. Holes should be useless art decorations only and if not then you got faulty items of Norton origin or after market. Its not bad thing to vent just a useless to ugly effort, like when someone just leaves the caps out like a gap tooth low IQ hillbilly that don't know no better. posting.php?mode=reply&f=1&t=10843#

If you don't do much water crossings nor ride desert grit paths much then why not spurge on the surgery as mark of self expression. BY far the belt heat is coming form the crank pulley not the belt run itself.