G3LS AR UNIT

[bob121]

Just finished setting up the timing on my friends 55 G3LS. Started to kick it over and got the impression that it wasn't going to go. So, decided to recheck the timing. It was out and turning the motor over, I could see why. Intermittently the mag would stop turning while the engine continued to turn. Standing on the other side I could see the ar unit turning around the mounting bolt with some regularity. Does this mean that the unit is now past its best. Or am I missing something obvious.

[Rob Harknett]

That's odd. Seems the AR unit has not been tightened on the tapered shaft. Re time again, don't forget to jam the AR unit open in the fully position when timing. Note the bolt should be screwed in the AR unit, prior to timing. After timing tighten the bolt onto the tapered shaft

[bob121]

Can't get the AR bolt any tighter. Tried several times. I'll remove it and try again.

[Rob Harknett]

They are fiddly, you should feel when you have the bolt in the AR, when you come to tightening the AR onto the tapered shaft a little pressure towards to mag and fiddling, you should feel the bolt start to screw in. Go as far as you can then use the spanner. Sometimes you think it may never go on. keep trying it will then suddenly decide to go on OK. Start that bolt on its first thread into the AR before putting the AR on the shaft. I am going by my memory. Not done it for ages. But each time I do re time, AR always never seems to tighten on the shaft first time. Sometimes the mag shaft may move when fiddling and have to start all over again.

[bob121]

You maybe misunderstanding. The bolt is going on ok. And it tightens up with the spanner. But as the AR is occasionally spinning around the bolt, I've tried to tighten it further. But it's as tight as it will go.

[clive]

Is it possible that the chain has a tight spot? If so it might be snagging and fully advancing the unit giving the impression of a stationary phase? I would be inclined to undo the bottom sprocket and pop it off the taper and then test if the AR is actually free to move on the magneto. Try tightening the bolt all the way if it is free to rotate on the shaft rather than it being the unit advancing. If it only seems to be the advance moving then slacken the chain a little.
Despite Rob's preference to do the timing on the magneto sprocket I always pop the lower sprocket off as i find it is less likely to slip on the taper whilst tightening and generally i only need to do it the once. ( provided i remember to set it before TDC not after. )

[clive]

You maybe misunderstanding. The bolt is going on ok. And it tightens up with the spanner. But as the AR is occasionally spinning around the bolt, I've tried to tighten it further. But it's as tight as it will go.

Have you got the half slotted washer that has two holes in and sits under the bolt?

[Rob Harknett]

Is it possible that the chain has a tight spot? If so it might be snagging and fully advancing the unit giving the impression of a stationary phase? I would be inclined to undo the bottom sprocket and pop it off the taper and then test if the AR is actually free to move on the magneto. Try tightening the bolt all the way if it is free to rotate on the shaft rather than it being the unit advancing. If it only seems to be the advance moving then slacken the chain a little.
Despite Rob's preference to do the timing on the magneto sprocket I always pop the lower sprocket off as i find it is less likely to slip on the taper whilst tightening and generally i only need to do it the once. ( provided i remember to set it before TDC not after. )

Old habits die hard Clive. As may have often said, all I had to learn from when our bikes were almost new, and I was just 16, were workshop manuals plus a few tips from the old boy across the road. Also from the shop where I got spares.

[bob121]

You maybe misunderstanding. The bolt is going on ok. And it tightens up with the spanner. But as the AR is occasionally spinning around the bolt, I've tried to tighten it further. But it's as tight as it will go.

Have you got the half slotted washer that has two holes in and sits under the bolt?

No washer. I'll see if I can find a part number for it. That makes sense. I never liked the way it looked.

[bob121]

Found them. I was a kid the last time I worked with an ar unit. Learning all over again. Thanks for the responses.