Auto Advance and Retard unit fouling rear of chaincase

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56G80S
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Auto Advance and Retard unit fouling rear of chaincase

Post by 56G80S »

I'd posted a separate General topic previously just for fun because I knew what I was doing.

Ha Ha.

I did all I needed to do in the cambox.

Decided that the "squish" on the new ring between the rear of the chaincase and the mag (tenth of an inch) was more than I expected but fitted it. Put a straight edge along afterwards to see if the "blade" of the chaincase was warped and it didn't seem to be.

Tried to fit new mag chain but couldn't get the mag platform to close up enough for some reason and not wanting to bend the armature on the relatively recently rebuilt mag put the old "real" Renolds chain back on.

With both sprockets fitted and running slightly loose on their tapers the rear of the AR unit is fouling the chaincase.

There are witness marks there and all I can think to do is take the mag platform off and see if I can move the mag further outboard on it's platform.

Over to you!

Johnny B
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Rob Harknett
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Re: Auto Advance and Retard unit fouling rear of chaincase

Post by Rob Harknett »

Are we to assume this is on a 56 G80? I would check the mag platform washers, spacers etc. The mag itself is fixed to the platform in position. When the platform loosened, it should swing quite freely to adjust the chain. If it does not, what ever is preventing this is probably also the cause of the mag being forced back to the left, pulling the AR unit towards the inner rear case.
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ajscomboman
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Re: Auto Advance and Retard unit fouling rear of chaincase

Post by ajscomboman »

Rob Harknett wrote:Are we to assume this is on a 56 G80? I would check the mag platform washers, spacers etc. The mag itself is fixed to the platform in position. When the platform loosened, it should swing quite freely to adjust the chain. If it does not, what ever is preventing this is probably also the cause of the mag being forced back to the left, pulling the AR unit towards the inner rear case.
The mag is fixed to the platform with bolts fitted through slots to allow the mag to be moved to the left or right for chain alignment, I'm sure that is what John was referring to.
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clive
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Re: Auto Advance and Retard unit fouling rear of chaincase

Post by clive »

If you move the mag further over on the platform to get the sprocket clearance the squish on the rubber seal is going to be worse. I would set up the mag so its in the right plane for the chain, then decide if you are going to use the rubber sealing ring. I cut one out of some black softer rubber allowing a greater "squish".
clive
if it ain't broke don't fix
56G80S
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Re: Auto Advance and Retard unit fouling rear of chaincase

Post by 56G80S »

Thanks a lot for the responses.

Yes, I have changed the mag before following some difficulties (ironically this means I now have two spare SR1's) and although I marked the platform last time I swapped, I appear to have got it wrong. It's only a small adjustment required, maybe only 1/16" or possibly less. It's a shame that access to the four bolts securing the mag underneath the platform are so difficult to access when everything is in place. I'll need to make sure that the chain run is still aligned but Clive has his finger on the point. There's already too much squish on the sealing ring and moving the mag will make that worse!

My experience of trying to cut this kind of material and keep it square and the surface flat is miserable hence reluctant to "doctor" the new ring. I've got some high density packing foam (I use it to surround the battery usually and it does a great job). I'm sure it would do the trick but it is white. Maybe I'll try it and just wrap some black insulating tape round to make it look better.

Tips on this welcome otherwise I'll be spraying grease everywhere.

Rob, I've done the chain adjustment before but there was no more scope in order to fit the new Regina chain, it's odd. But this problem may have been the actual cause of my sticky AR unit, even though perfectly free when loose following your advice, and the resulting occasional kickback!

Current weather means I'm not missing much.

Johnny B
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Rob Harknett
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Re: Auto Advance and Retard unit fouling rear of chaincase

Post by Rob Harknett »

Am I to believe this "squish " referred to is the gap between the mag and rear of inner timing cover ? I am sure it has been said this part was only fitted to comp models. Although I have put a rubber seal on my 55 G3LS. I have mentioned here before. I was lucky enough to find a rubber intended for a Vacuum cleaner. It being of a square profile ring of about the correct dia. and thickness to fill the gap. I never even took the mag off to fit it. I just cut the ring and pushed it in. The joint hidden. It is still in place after some 30 years of fitting it. I would not use foam as that may absorb water. I have owned a bike with SR1 mag since I was 16 in 1956. I have never had the A/R foul the timing cover. If I have ever had the mag off, I have always left the mag fittings a bit loose to allow movement, before finale tightening. This is awkward. I have always wondered if I have got it tight enough. It is in these tight situations I have used more than just one spanner. Perhaps 3 or 4. One with the opening in line, others you may find with openings at slightly different angles. When you reach the limit with one spanner, you may get on the fitting with another, to get another bit of a turn to tighten it. More recently now I have a grinder, I have removed some material off an old spanner to allow more space to turn it. Tools picked up for this purpose for about 10p at car boot sales. Even metric, the size opened up to the size to fit the fitting size required
56G80S
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Re: Auto Advance and Retard unit fouling rear of chaincase

Post by 56G80S »

Thanks again.

Got everything back together yesterday late afternoon. As you suggested, Rob, I left the sealing ring off fo now as like you I'd thought I could cut a ring and fit it. Thing is, the ring does keep the water and road dirt out of the case.

I slightly lengthened the slots in the mag platform and moved the mag outboard by about 1/32" to 1/16". All that was needed. I'd set the valve timing to the 350cc mark on inlet and the ignition timing slightly less than than the full 1/2". Started well second kick and sounds better than ever. Will fit the outer timing cover and set the tappets properly when I can.

If the weather tidies up I'll ride up to Bishop Auckland for work tomorrow.

Johnny B
56G80S
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Re: Auto Advance and Retard unit fouling rear of chaincase

Post by 56G80S »

Just to close this off.

I did cut the sealing ring neatly by placing it over the end of a large box spanner, carefully marking the distance all round and taking it very slowly with a broad blade sharp kitchen knife while still on the box spanner.

Cruising happily at indicated 65mph now. Up to Bishop and back for a really pleasant ride, although arrived at work late, left late and didn't get home before dark as I went the long way round both ways. Still kicking back so the AR not solved but that'll keep until the depths of winter!

I'll have to adjust the headlight but that's another topic.

Thanks everyone.

Johnny B
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