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Post by shane99 on Mar 18, 2024 11:40:07 GMT 1
Hi there everyone
So I have a 350 lc with running issues Runs alot cooler in the left cylinder With thermal sensor 70c left 120 right It runs and pulls away fine only ridden a very short distance, so the things I've done so far,it's on ramairs with allspeeds 27.5pilot jet 300 main Cleaned carbs, checked float bowls 21mm, made sure floats on right side, swapped carbs over with extended balance pipe from left to right, swapped over plugs and caps left to right also swapped reed cages over too. my thinking is leaking from Crank seal, I've got a leak down test from Al but ran out of time will try that next. Is there something else I've missed? Thanks in advance
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Post by abar121 on Mar 18, 2024 15:13:36 GMT 1
Hi there, How is the compression on both sides? Leakdown as you say would be great to do. When switching the carbs, did you also switch the slides over? Check throttle cable routing. Did you use sealant on both sides when fitting the reeds? It's a common place for air leaks. Check each exhaust pipe for restriction, remove the baffle. I had similar on one bike and it was a blocked silencer, after my apparently poor attempt at decoking them, must have loosened up a piece of crap . Good luck.
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Post by chrisg on Mar 18, 2024 16:59:36 GMT 1
Only thing you've not mentioned is the slide needle clip position? that's all i can add.
When was the engine last opened out?
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Post by 4l04ever on Mar 18, 2024 18:44:30 GMT 1
300 mains are probably too small...
You could swap carbs side to side with a long choke pipe just for testing to see if the fault swaps sides or not.
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Post by shane99 on Mar 18, 2024 20:56:06 GMT 1
300 mains are probably too small... You could swap carbs side to side with a long choke pipe just for testing to see if the fault swaps sides or not. I tried that and problem stayed on same side. 😔
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Post by shane99 on Mar 18, 2024 20:57:02 GMT 1
Only thing you've not mentioned is the slide needle clip position? that's all i can add. When was the engine last opened out? The needle clips are in the middle so that's std isn't it?
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Post by shane99 on Mar 18, 2024 20:57:25 GMT 1
Hi there, How is the compression on both sides? Leakdown as you say would be great to do. When switching the carbs, did you also switch the slides over? Check throttle cable routing. Did you use sealant on both sides when fitting the reeds? It's a common place for air leaks. Check each exhaust pipe for restriction, remove the baffle. I had similar on one bike and it was a blocked silencer, after my apparently poor attempt at decoking them, must have loosened up a piece of crap . Good luck.
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Post by shane99 on Mar 18, 2024 21:01:17 GMT 1
Hi there, How is the compression on both sides? Leakdown as you say would be great to do. When switching the carbs, did you also switch the slides over? Check throttle cable routing. Did you use sealant on both sides when fitting the reeds? It's a common place for air leaks. Check each exhaust pipe for restriction, remove the baffle. I had similar on one bike and it was a blocked silencer, after my apparently poor attempt at decoking them, must have loosened up a piece of crap . Good luck. Going to do the leak down test next and a compression check. Yeah switched over the slides as well. Good call on the sealant on the reeds will reseal them before I do the leak test. I had some std exhaust on it before the allspeed and it didn't make any difference 🙁
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mgttz
L plate rider.
Posts: 31
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Post by mgttz on Mar 18, 2024 22:10:30 GMT 1
i would expect a crank seal issue to raise the temprature in the left cylinder and it would potentiolly draw air in. on the right hand side, id expect a crank seal to burn gear oil and the signs would be obvious excess smoke on that side. are you running the premix and is it possible for an lc's pump to meter oil incorrectly to an individual cylinder? if thats the case id try isolate the autolube and try it with premix to eliminate a pump issue. head gasket fitted the right way up? some have restrictions to promote a particular flow path. its been a long while since ive delved into an rd engine so forgive me if i sound like im telling you to suck eggs. another thing to consider is an electrical issue.one of the leads maybe damaged enough internally to cause a weaker spark. same applies to a fractured wire, staring from the stator/pickup right to the cdi and onwards that could effect a particular side. id check the wiring diagram and start doing some checks with a multimeter.
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Post by chrisg on Mar 19, 2024 0:35:33 GMT 1
i would expect a crank seal issue to raise the temprature in the left cylinder and it would potentiolly draw air in. on the right hand side, id expect a crank seal to burn gear oil and the signs would be obvious excess smoke on that side. are you running the premix and is it possible for an lc's pump to meter oil incorrectly to an individual cylinder? if thats the case id try isolate the autolube and try it with premix to eliminate a pump issue. head gasket fitted the right way up? some have restrictions to promote a particular flow path. its been a long while since ive delved into an rd engine so forgive me if i sound like im telling you to suck eggs. another thing to consider is an electrical issue.one of the leads maybe damaged enough internally to cause a weaker spark. same applies to a fractured wire, staring from the stator/pickup right to the cdi and onwards that could effect a particular side. id check the wiring diagram and start doing some checks with a multimeter. Its the left cylinder that's running cooler, so it could well be the crank seal on that side. RH seal could be ok. I,d spray wd40 or brake cleaner on the area around the seal, LHS and see if the revs change when in tick over.
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Post by shane99 on Mar 19, 2024 9:56:16 GMT 1
i would expect a crank seal issue to raise the temprature in the left cylinder and it would potentiolly draw air in. on the right hand side, id expect a crank seal to burn gear oil and the signs would be obvious excess smoke on that side. are you running the premix and is it possible for an lc's pump to meter oil incorrectly to an individual cylinder? if thats the case id try isolate the autolube and try it with premix to eliminate a pump issue. head gasket fitted the right way up? some have restrictions to promote a particular flow path. its been a long while since ive delved into an rd engine so forgive me if i sound like im telling you to suck eggs. another thing to consider is an electrical issue.one of the leads maybe damaged enough internally to cause a weaker spark. same applies to a fractured wire, staring from the stator/pickup right to the cdi and onwards that could effect a particular side. id check the wiring diagram and start doing some checks with a multimeter. Its the left cylinder that's running cooler, so it could well be the crank seal on that side. RH seal could be ok. I,d spray wd40 or brake cleaner on the area around the seal, LHS and see if the revs change when in tick over. That's a good idea about spraying the lhs Crank seal will try that👍😁
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Post by Tobyjugs on Mar 19, 2024 14:43:40 GMT 1
The first thing I’ would do is double check the temperature readings.
It’s very good it hasn’t seized at 120 C
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Post by shane99 on Mar 19, 2024 18:00:36 GMT 1
The first thing I’ would do is double check the temperature readings. It’s very good it hasn’t seized at 120 C those temps where from the exhaust headers😁
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mgttz
L plate rider.
Posts: 31
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Post by mgttz on Mar 19, 2024 22:05:28 GMT 1
Its the left cylinder that's running cooler, so it could well be the crank seal on that side. RH seal could be ok. I,d spray wd40 or brake cleaner on the area around the seal, LHS and see if the revs change when in tick over. That's a good idea about spraying the lhs Crank seal will try that👍😁 i would expect it to run hotter if it was a crank seal. the fact it runs cooler sggests to me that the fuel isnt been metered properly {float height/float valve not shutting off properly ect or some sort of jetting/carburation niggle. or an ignition problem. worth spraying the seal area for the proccess of elmination but id be suprised if it does turn out to be a crankseal. how many miles is on the motor?
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Post by shane99 on Mar 19, 2024 22:48:14 GMT 1
That's a good idea about spraying the lhs Crank seal will try that👍😁 i would expect it to run hotter if it was a crank seal. the fact it runs cooler sggests to me that the fuel isnt been metered properly {float height/float valve not shutting off properly ect or some sort of jetting/carburation niggle. or an ignition problem. worth spraying the seal area for the proccess of elmination but id be suprised if it does turn out to be a crankseal. how many miles is on the motor? the miles on the motor are unknown it had a top end rebuild when I bought but bottom end hasn't been touched so don't know.
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Post by shane99 on Mar 19, 2024 22:50:57 GMT 1
i would expect it to run hotter if it was a crank seal. the fact it runs cooler sggests to me that the fuel isnt been metered properly {float height/float valve not shutting off properly ect or some sort of jetting/carburation niggle. or an ignition problem. worth spraying the seal area for the proccess of elmination but id be suprised if it does turn out to be a crankseal. how many miles is on the motor? the miles on the motor are unknown it had a top end rebuild when I bought but bottom end hasn't been touched so don't know. also it's not pushing out the same force of gases from the end of the exhaust as the right side if that makes sense? But it's not back firing from the lhs make not firing every revolution.
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mgttz
L plate rider.
Posts: 31
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Post by mgttz on Mar 20, 2024 21:25:21 GMT 1
do you have a spare coil you could try? ideally a stator and cdi while your at it to eliminate an ignition problem?
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Post by shane99 on Mar 23, 2024 9:04:12 GMT 1
do you have a spare coil you could try? ideally a stator and cdi while your at it to eliminate an ignition problem? no I don't have a spare cdi or coil unfortunately but when I swapped over the leads and plugs would that not gave given me the answer if it's electrical? Or am I missing something 😁
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Post by shane99 on Mar 23, 2024 9:08:13 GMT 1
Did a leak down test yesterday and it's leaking really bad from the inlet rubber on the left hand side couldn't even get the gauge up to 5 psi without it dropping really fast, sealed it up with gasket sealer and left to dry over night. Hopefully that will cure the running issues I hope🤞
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Post by dusty350 on Mar 23, 2024 9:23:41 GMT 1
Classic place for leaks. I use 3bond on new genuine gaskets and that sorts it. Also make sure the cross over tube is properly seated with good clips fitted. It will leak from there otherwise.
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Post by shane99 on Mar 23, 2024 15:06:38 GMT 1
Classic place for leaks. I use 3bond on new genuine gaskets and that sorts it. Also make sure the cross over tube is properly seated with good clips fitted. It will leak from there otherwise. Fingers crossed this will sort out my lhs cylinder running so badly
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