My Gulf with 10.500 Miles - Noise remained the same since the beginning -Deflection measured at the point of the rear mudguard 30 mm. Overhang on rear sprocket (Supermax) 1 mm Tried Omega 85/140 Super EP Gear oil but didn't make any differences in noise compared to normal oil. Now Redline which also makes no differences. Noise diference with Supermax compared to original alu sprocket not noticeable (for bevelbox noise) Sprocketnoise is now much less. When cold a bit noisy but not too bad. When hot screaming at certain loads but (sometimes) (very) quiet when load is getting a bit more or a bit less.
Rineke's M3W with 8.750 Miles - Noise remained the same since the beginning -Deflection measured at the point of the rear mudguard 25 mm. Overhang on rear sprocket (Supermax) 2 mm Tried Omega 85/140 Super EP Gear oil but didn't make any differences in noise compared to normal oil. Now Redline which also makes no differences. Noise diference with Supermax compared to original alu sprocket not noticeable (for bevelbox noise) Sprocketnoise is now much less. Bevel box when cold a bit noisy but not too bad. When hot screaming at certain loads but sometimes quiet when load is getting a bit more or a bit less. If compared the two cars the loads when the box is quiet is not the same ! E.g. when I'm driving 105 km/hr steady with certain wind Gulf box is quiet but Rineke's box is screaming at exact same speed. This box has now an small oil leak problem at the incoming shaft but will first look if this remains the same or will get worse.
Please see the attached photographs, I suggest that the belt deflection is measured using a 7.5kg weight tied around the belt. If you measure from the splash guard we’ll be able to get a clear and constant measurement. For obvious reasons I’ve used a vehicle that’s stripped for the photographs.
I’ll then carry out the same measurement on a new car ready to leave the M3W shop and we’ll have a base figure to work from, hope this makes sense to everyone?
I noticed you are taking measurements from the upper belt run. If the car was last driven in forward gear this should be under tension / vice versa for reverse. Is this relevant to taking the measurement i.e should we inch forward slightly to get the tension set before taking the reading , or am I talking rubbish as usual ?
Please see the attached photographs, I suggest that the belt deflection is measured using a 7.5kg weight tied around the belt. If you measure from the splash guard we’ll be able to get a clear and constant measurement. For obvious reasons I’ve used a vehicle that’s stripped for the photographs.
I’ll then carry out the same measurement on a new car ready to leave the M3W shop and we’ll have a base figure to work from, hope this makes sense to everyone?
Mark Evans
So that looks like broadly 10mm sag on the top run then. Not too sure how easy it might be for us to see that top side of the belt when the car is just on jacks. Would you be able to do that perhaps on the bottom run, as it might be easier to repeat at our end? Great help though, thanks!
I think what people might be missing here is that deflection is measurable with a scale/rule as in Mark's pictures, but the missing link here is how much force did it take to deflect the belt "X" amount of travel?
Belts are belts and I KNOW these are not Harley's, but Harley uses a belt force weight of 10# to reach their desired amount of belt deflection.
With the proper tensioning gauge everyone would be apples to apples. Without a consistent force at the desired deflection, it's still no better than a SWAG.
There are tons of these available here and in the UK. All have measurement scales so you can see the amount of pounds needed at a specific deflection of the belt.
This is my opinion only, but from what I've seen it's just a shot in the dark without a proper tensioner gauge.
Just an idea ...... Can this guard on the front sprocket be the culprit to the noise ? See my picture
About the deflection I measure the lower part of belt from the floor where it's standing on the ground push the belt with my fingers as far possible up measure again and the difference is the deflection. The belt is not made of elastic so we don't need a certain weight or something like that. Or do I see this wrong ?
But .......... from all this, I think we made the biggest step forward that we finally got the feeling that we've been heard by MMC. Mark. Thanks for that !
It seems obvious to this non engineer that belt tension is only one of many factors and perhaps not even relevant. These boxes are quiet when cold, and whine when warmed up, and speeds above 45 MPH when under light load. That seems to be common to most if not all. Expansion and light load.
