What does a worn low speed cam look like?

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rlwellman
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Joined: Mon Apr 12, 2021 3:51 pm
First Name: Rick
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* REQUIRED* Type and Year of Model Ts owned: 1914 Touring
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What does a worn low speed cam look like?

Post by rlwellman » Sat Sep 25, 2021 6:57 pm

Hi all,

I am chasing down dragging bands for my new kevlar band install. I know I have some work and need to get the new bands round. You all suggested I check the pedal cams, too. Brake and reverse look pristine. Low speed starts compressing the band around half way to the floor. It seems like there needs to be a bit of slop in the cam to make sure that the clutch disengages before the band starts to tighten. Nothing looks outrageously worn but what do I know? Is this picture any help?

Thanks,
Rick
low speed cam.jpg


Norman Kling
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Re: What does a worn low speed cam look like?

Post by Norman Kling » Sat Sep 25, 2021 9:16 pm

It should begin to move the band about half way down. Beyond that would be either neutral or high gear. That is correct. The problem with a worn cam and notch is that the tapered surface wears down so that it will not push the band tight against the drum at the proper position, which is about 1" to 1 1/2" above the floorboard. If you tighten the band adjustment enough to get it to lock at the proper height above the floorboard, it will still drag in the neutral or high position. This leads to rapid band wear and overheating the drum. Anyway, when in the neutral position the band should be completely disengaged and in the low position it should be completely tight. Unfortunately if it drags in neutral and or slips in low, there is no position where there is no friction against the drum.
Norm


speedytinc
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Re: What does a worn low speed cam look like?

Post by speedytinc » Sun Sep 26, 2021 10:26 pm

Kevlar bands must be made perfectly round, conforming to the drum. There must not be any loop or high spot in the material when installed on the band PERIOD. If you installed thru the inspection cover they are out of round. This is a drum disaster on the way. I would NEVER install kevlar without removing the hogs head.
Adjust the low band as follows. Back off the adjusting lock nut. With the motor running, adjust until you hear the faint starting of engagement of the tripple gears & back off 1/2 turn. Lock the nut. This the optimal point. If you cant get enough low pedal lock up you have a PROBLEM. Heed my warning. I have replaced several drum for those that didnt listen.


Stephen_heatherly
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Re: What does a worn low speed cam look like?

Post by Stephen_heatherly » Sun Sep 26, 2021 10:42 pm

Another common cause of dragging bands is bent pedals. When the transmission is in high the clutch pedal should be about even with the reverse pedal. If it is not, you can heat the pedal down low at about the point where it bends vertical to come up through the pedal slot and bend it back so it's even with the reverse pedal. Most are bent forward which makes it impossible to adjust the low band so that it engages firmly and yet does not drag when the pedal is released.

Stephen

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