1971 engine : a lot of white smoke from exhaust and breather pipe

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kommando said:
The JCC pistons come with the simple wire circlips which do not work as JCC supplied poor quality ones, but the groove in the piston is profiled to take the wire circlip and so is circular shaped, putting an eyeletted circlip which is designed to fit in a square shaped groove is not the full solution. Now if Wassells are supplying their Hepolite branded pistons made by JCC with eyeletted circlips have they ordered the piston with the matching square groove ? or more likely hoping the eyeletted circlip can cope with a circular groove.
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JCC/Hepolite replacement Norton pistons use 'eyeletted' (Seeger) circlips as that was the original Norton/Hepolite factory specification so the Norton JCC/Hepolite circlip grooves should have a 'square' profile as the original Hepolite factory pistons did.

Other JCC/Hepolite replacement pistons such as those for BSA,Triumph etc. use wire circlips as wire circlips were the original spec. for BSA/Triumph pistons.

Discussed at some length not that long ago the basic problem being the quality of the eyeletted circlips supplied with the JCC/Hepolites: https://www.accessnorton.com/NortonCommando/emgo-pistons.24809/

https://www.accessnorton.com/NortonCommando/emgo-pistons.24809/page-3#post-367513
comnoz said:
I have never seen a JCC/Emgo piston for a Norton with a round wire circlip. I have only seen the type that wrecks shows above. I have fit hundreds of pairs.


Some of them are not tight when they are installed in the groove. If you can take a pick and easily move them around then the reciprocating forces will cause them to move also. Then they wear and eventually come out. Jim
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htown16 said:
Still sounds like detonation destroyed the piston based on the destroyed ring lands . I bet it has 4 corner sieze marks on the skirt. The circlip may have been broken or popped out due to the extreme pounding the piston was undergoing. Unless you determine the cause of the detonation on this bike and your triple you are going to continue to destroy pistons. One of four things is causing this: too hot a plug, too advanced ignition, too lean of a mixture or too low of a grade gas for the compression ration. I don't know what else I can say to convince you of this. It's your bike. If you want to continue to pour time and money into it and have the same result it's up to you. I give up.
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Hi.
I have well understand what you say.
But i cannot change what it works.
Timing is 30 degree to 4000rpm with Pazon.
Spark plug are NGK B7ES.
Mixture seems good, spark plugs are of the right colour and without oil or soot.
About fuel, this is one for all, here.
About triple was not a engine rebuilt but old as it comes to me.
I have a couple of English bikes that run from more than twenty five years without problems with 15.000 km done.
I think that if i had a mistake, and this is possible or sure because i am not a mechanic but only a fan, i had fitted the circlip in the wrong side or in a wrong way.
Piero
 
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it is well documented on this forum that the segar circlips supplied by JCC are poor to say the least .After being allerted of this fact i striped down the top end of my 850 , and replaced them with ones from A/N that snapped home in a very positive way . i am pleased i changed them because the old ones came out as if they were made of plasticene .So people beware the pistons are good the circlips are litter .....
 
Without seeing your pistons it's a bit hard to tell if just the loose clip did the damage or if it's due to detonation. Here's some examples of detonation.
1971 engine : a lot of white smoke from exhaust and breather pipe
Hosted on Fotki
1971 engine : a lot of white smoke from exhaust and breather pipe
Hosted on Fotki
1971 engine : a lot of white smoke from exhaust and breather pipe
Hosted on Fotki
 
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