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Post by russie on Mar 27, 2020 15:10:34 GMT 1
Thought I'd share a painful experience that's had me tormented for the last couple of days. I've just fully rebuilt my 350LC engine and put it back in the bike. I've not been able to ride the bike yet as I've got other stuff like brakes to sort out first. Since reassembling it sounds great but when I allowed it to idle it was dropping off on the right cylinder and would just give the occasional random pop with cool exhaust gas coming out that side. When I opened the throttle, it would pick up back onto both cylinders and chuck a bit of un-burnt fuel and oil out the exhaust until it cleared. As soon as I let it idle, it would drop off on the right hand side again. So I've tried swapping spark plugs, swapping the leads across, had the carbs apart again twice, fitted a different pair of carbs, a different CDi unit, I've even had an oscilloscope on it and my 250LC to compare wave forms from the Low and High speed exciter coils and the pulse coil all to no avail. But, today, I've sussed it and I must say I'm very surprised as to what was the cause of my torture. Anyone want a guess?
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Post by Gitram on Mar 27, 2020 16:12:00 GMT 1
i reckon it wasn't one of the more usual things.. here's a stab in the dark..would it be a 250 pipe on one side and a 350 pipe on the other?
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Post by headcoats on Mar 27, 2020 16:16:42 GMT 1
blocked pilot jet ?
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Post by rigga on Mar 27, 2020 16:26:22 GMT 1
Reeds.
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Post by chrisg on Mar 27, 2020 16:47:53 GMT 1
Twisted crank?
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Post by biffa on Mar 27, 2020 17:01:18 GMT 1
plug leads/ caps
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Post by 4l04ever on Mar 27, 2020 17:21:12 GMT 1
Low speed running coils going open circuit when warmed up.
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Post by steve h on Mar 27, 2020 17:21:43 GMT 1
Choke oriented?
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Post by shaunthe2nd on Mar 27, 2020 18:01:53 GMT 1
Carbs not balanced?
Dodgy throttle cable?
Rag left in engine inlet or outlet?
Cylinder head not properly torqued?
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Post by oldbritguy on Mar 27, 2020 18:03:54 GMT 1
Something inside the air box that shouldn’t be there.
Oily rag/mouse nest 😁
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Post by beardy on Mar 27, 2020 18:26:48 GMT 1
Sounds similar to a problem on mine a while back except mine was left pot. Changed everything to do with ignition. Rewound stator etc.
Eventually put a Power Dynamo on it and that cured it.
But still wonder what the actual problem was as I feel I never got to the bottom of it.
So intrigued with your issue.
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Post by dusty350 on Mar 27, 2020 18:40:16 GMT 1
Mixture screws ?
Dusty
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Post by russie on Mar 27, 2020 18:47:49 GMT 1
**********SOLUTION************REEDS**************
Rigga, go to the top of the class! Never seen the like before. If you look at them they look perfect, the wee cut outs in the reed petals are aligned with the reed stops. It’s a total mystery to me, there is no visual sign that the reeds are defective in any way but the problem 100% moved from one side to the other with identical symptoms when I swapped the reed valves. It was very frustrating but rewarding in the end when I sussed it.
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Post by stusco on Mar 27, 2020 19:51:42 GMT 1
Are they curving the wrong way?
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Post by Gitram on Mar 27, 2020 21:10:31 GMT 1
jings.. good you sussed it tho
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Post by rigga on Mar 27, 2020 22:08:31 GMT 1
I only know as I had the same issue a while back, swapped the reed block out and it cured it, didn't really see any issue with the removed set.
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Post by russie on Mar 28, 2020 18:56:07 GMT 1
Are they curving the wrong way? No mate. They’re definitely installed correctly with the wee cut-outs on the corner of the reed petal aligned with the similar cut-out on the reed stops. I’ve had them apart and they don’t look curved at all tbh. |
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