I give in, belt still slipping

[maccblade]

I really thought I could crack this one on my own but the belt still slips when I start off. If I pedal to start with upto a quick walking pace the motor can be used without slipping but any slower means that the belt slips. I have the motor mod fitted which I have bent slightly to give max pressure, the belt is a replacement 18mm, the motor is very securely in place and there is no play or wear in the final drive sprocket on the motor. Everything else is sorted and I can still use the thing but I really want to stop this belt slipping...help...please.

[Karl]

With a new belt and mod bracket it looks like you've covered most of the common problems so I can understand your frustration - just keep the matches and petrol away from your c5 for the time being. 

As you look at the c5 with the boot removed, is the motor pushed as far possible to the left ? To make sure I'd loosen the retaining bolt and check, making sure the gearbox is sitting securely on the "wall" .This is also the best method for fitting the mod bracket, moving the motor out the way then making sure the bracket pushes the "wall" toward the centre of the c5 (hope this makes sense). Then push the motor back in place and tighten the retaining bolt.

There is an outside chance you might be missing the end bearing in your gearbox, rare but we have seen one . This allows movement in the small drivewheel - unlikely,but possible.

[maccblade]

Thanks for trying but I have covered all you sugest. I have even tried packing out the motor holder underneath to get the belt slightly tighter. This worked a little but the motor then twisted and I bet it was dioing the bearings no good at all. I am sure that with trial and error I could sort it but each time the belt slips I have visions of "hooking" the cogs on the motor wheel.

[motormadmick]

Just a thought, i think i understand what you are saying, is the motor dead parallel to the axle and not raised at the right hand side, i think this would cause the belt to come off. Mine was adjusted so tight it raised the right side up and the belt came off i dunno if this is your prob

[maccblade]

No, I understand where you are coming from but the motor is in line as it should be. The belt is not coming off the sprockets, just slipping round as the motor cuts in untill I am doing about 5mph.

[motormadmick]

belt worn? teeth on the motor worn?

[maccblade]

Brand new 18mm belt and teeth not worn, thats why I need the help!

[Karl]

If all the components are as described, then it has to be down to alignment and set-up



I'd suggest taking it apart and trying again from the beginning. You are right to be cautious about running it with the belt slippage - it will cause damage if you continue to do so.

Slacken the retaining bolt, move the motor towards the centre, re-fit the mod bracket, ensuring the "wall" is well away from the leading edge of the gearbox, push the motor back outwards as far as it will go and retighten the retaining bolt.

The belt should be a tight fit, to the point where you are having to rotate the drive cogs by hand to assist getting it on.

If all this fails then we are at the limits of what we can do over the internet 

[maccblade]

Cheers. I'll give it a go...watch this space! Nice to know there are so many people out there prepared to help out as soon as I asked for it.
Thanks

[Wizbat]

Ullo
This is a bit of a long shot but have you had a look at the bearing that the main axle passes thru as it goes thru the motor mount?
If it has seized and worn away the nylon of the mount into an oval then every time you pull away the axle will push up and forward at the same time, shortening the distance between the two belt cogs.