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Post by clarkey on May 19, 2022 16:31:06 GMT 1
Hi,
New to the forum although its always been my go to when seeking fixes previously. However I couldn't find any posts that answered my issue.
I have a 1980 RD350LC, standard except for Allspeeds. When I got it, the bike would start and rev, but wouldn't pull properly. Looked here, and as a result I have cleaned the carbs (US cleaned) , new standard jets and new floats, set correctly. The bike then ran a lot better, starts 1st or second kick, but would not rev through the range - feels like its holding back. Stripped the carbs several times more but still the same. It revs freely when in neutral.
So I then looked at the timing. Bought myself a gauge so I can set it accurately at 1.8mm BTDC.
When I set it to 1.8mm BTDC, my timing mark on the flywheel is 70mm BEFORE the timing mark on the Stator when rotating right, and 40mm AFTER the timing mark when rotating left ( I think left gives BTDC?), so I have nowhere near enough adjustment on the stator to get the timing correct. I have removed the flywheel (which is another story !!) to check if it had slipped off of the dowel, but it hadn't. I spoke to a very helpful guy who works on 2 strokes, but not LC's, and he said the crank is fixed so he cant see how it could have moved.
I also checked the timing with a strobe (at 2K RPM) , and it confirmed the above.
I checked the TDC on both pistons and these are equal distance away from each other when marked on the flywheel, as I saw a post to say you can do this to check that the crank hadn't twisted.
So I am at my wits end trying to understand what could be the issue. If I can work out how to do it, I will post some photo's. I bet I am being a complete idiot !!
Any advice would be greatly appreciated.
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Post by chrisg on May 19, 2022 17:07:17 GMT 1
I set my timing at 2.0mm btdc. However I think your doing something wrong with the dti or somethings badly out.
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Post by clarkey on May 19, 2022 17:24:34 GMT 1
Hi, New to the forum although its always been my go to when seeking fixes previously. However I couldn't find any posts that answered my issue. I have a 1980 RD350LC, standard except for Allspeeds. When I got it, the bike would start and rev, but wouldn't pull properly. Looked here, and as a result I have cleaned the carbs (US cleaned) , new standard jets and new floats, set correctly. The bike then ran a lot better, starts 1st or second kick, but would not rev through the range - feels like its holding back. Stripped the carbs several times more but still the same. It revs freely when in neutral. So I then looked at the timing. Bought myself a gauge so I can set it accurately at 1.8mm BTDC. When I set it to 1.8mm BTDC, my timing mark on the flywheel is 70mm BEFORE the timing mark on the Stator when rotating right, and 40mm AFTER the timing mark when rotating left ( I think left gives BTDC?), so I have nowhere near enough adjustment on the stator to get the timing correct. I have removed the flywheel (which is another story !!) to check if it had slipped off of the dowel, but it hadn't. I spoke to a very helpful guy who works on 2 strokes, but not LC's, and he said the crank is fixed so he cant see how it could have moved. I also checked the timing with a strobe (at 2K RPM) , and it confirmed the above. I checked the TDC on both pistons and these are equal distance away from each other when marked on the flywheel, as I saw a post to say you can do this to check that the crank hadn't twisted. So I am at my wits end trying to understand what could be the issue. If I can work out how to do it, I will post some photo's. I bet I am being a complete idiot !! Any advice would be greatly appreciated. |
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Post by clarkey on May 19, 2022 17:26:12 GMT 1
Sorry Chris - pressed the quote button by mistake!! Yes I did think the same and ~I have checked the dti multiple times.
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Post by oldelsieboy on May 19, 2022 17:49:38 GMT 1
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Post by muttsnuts on May 19, 2022 18:26:05 GMT 1
might have the wrong flywheel !
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Post by clarkey on May 19, 2022 18:59:56 GMT 1
Thanks OEB - I did look at that thread whilst I was doing it.
Muttsnuts - there's a thought. I will check in the manual tonight when I get back.
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Post by chrisg on May 19, 2022 19:25:36 GMT 1
Sorry Chris - pressed the quote button by mistake!! Yes I did think the same and ~I have checked the dti multiple times. Not teaching on how to suck eggs but are you reading the units correctly. I have made a similar mistake some years ago. Can you get a vernier to check your reading, but as MN says it maybe an incorrect flywheel. Are you going 2mm btdc and not after tdc?, just a thought. kick the engine over slowly to get the correct rotation, then opposite rotation is btdc. (if that makes sense) |
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Post by JonW on May 20, 2022 5:07:48 GMT 1
I wonder if the timing is not as far out as you might think and the fact you didnt clean your balls out is the rev'ing issue? (you didnt say you did them, so I assume not?)
Does sound like the wrong flywheel tho...
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Post by steeley on May 20, 2022 7:48:54 GMT 1
Hi , could the rotor have had another key way cut in it because the original was damaged . I had this done to my lc rotor some years ago . Ooops double post .
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Post by midlifecrisisrd on May 20, 2022 8:42:09 GMT 1
If the timing was that far out I don't think it would run
Like jonw says did you clean yer baws
Steve
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Post by clarkey on May 20, 2022 9:29:05 GMT 1
Thanks Guys - yes I did clean me balls - well the larger ball in each carb. I will post some pics as soon as I can work out how to do it. The strobe light confirmed that the timing was well out. I did as Chris suggested, and based on the engine rotation the timing was / is retarded buy 9 degrees, but it started 1st or second kick no problem. The flywheel looks the same as the manual and has a code stamped on it : 032000 128 02U VCC27 if that means anything to anyone?
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Post by clarkey on May 20, 2022 10:42:16 GMT 1
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Post by clarkey on May 20, 2022 15:17:29 GMT 1
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Post by arrow on May 20, 2022 15:42:23 GMT 1
Your dti is different to mine. So are you saying that if the big pointer moves two complete turns, then the small pointer only moves by just two increments? Mine;  |
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Post by arrow on May 20, 2022 15:46:48 GMT 1
And two turns later;  |
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Post by clarkey on May 20, 2022 16:21:00 GMT 1
Thanks Arrow - Yes each complete turn on the big pointer moves the small pointer by one point. So I am measuring 2mm by 2 complete turns. I have had a strobe on it as well, and looking at the stator timing mark, the light was flashing between 50-70mm to the left - basically near the top of the flywheel ( and that was on full adjustment).
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Post by arrow on May 20, 2022 16:28:52 GMT 1
Most odd. I'm at a loss. Be interesting to see what the issue was, once sorted.
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Post by clarkey on May 20, 2022 17:23:27 GMT 1
Thanks Steeley - I can see anything to suggest the rotor has been cut / changed - all looks original.
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Post by oldelsieboy on May 20, 2022 17:29:06 GMT 1
Once you have found Top Dead Centre (TDC) are you turning the flywheel clockwise to lower the piston 2mm Before Top Dead Centre (BTDC)?
OEB
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Post by clarkey on May 20, 2022 17:50:56 GMT 1
OEB - yes that's right. But either way, to change it 2mm from TDC only takes a small amount of turn and gets nowhere near the timing marks. There is 2 pickups on the flywheel, which I assume is 1 for each cylinder. Should I try timing it against the other cylinder? I would like to prove whether I have the correct flywheel - no idea why someone would change it - but I don't know how I can do that.
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Post by tony2stroke on May 20, 2022 17:54:03 GMT 1
Is your flywheel TDC marker at TDC according to the dial gauge, do they match, or is the TDC mark out when the dial gauge says TDC, if you get my drift.
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Post by clarkey on May 20, 2022 17:57:43 GMT 1
Hi Tony - just so I get this right - do you mean when the timing mark on the flywheel is in line with the stator mark? if you do, then no its miles out.
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Post by tony2stroke on May 20, 2022 17:59:51 GMT 1
The drilled holes in the side of the flywheel are for balancing.
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Post by tony2stroke on May 20, 2022 18:01:06 GMT 1
At TDC according to the dial gauge, is the flywheel telling you its at TDC.
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Post by clarkey on May 20, 2022 18:30:59 GMT 1
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Post by tony2stroke on May 20, 2022 19:01:46 GMT 1
Just to explain something to you, I bought an electronic ignition for my Lambretta LI150, on fitting it would not time up to the corresponding timing marks, I wondered what was wrong as it was backfiring and banging, checked the whole system, found the flywheel boss had been put on 180 degrees out, timed it accordingly to 180 degrees out and scooter ran great, so it was the boss riveted in wrong from manufacture, I phoned the company, which didn't believe, sent it back to them as I wanted it all to line up right for future owners, anyway they said sorry, never seen that before and sent me another, all was fine with that one.
Problem is here you don't know what previous owners have done or tried to do, The flywheel can't slip on the boss, the pick up plate looks to be in the correct position, nothing obvious to see from your pics.
Presuming you are doing checks correctly in line with the manual.
At this stage I would check nothing is loose and flywheel sitting right on crank, then I would scribe my own TDC mark and time it up from there, scribe new TDC line, then time to 2mm and scribe another line, wipe the paint or chalk off old timing marks, re- chalk or paint mark on your new timing mark (not the TDC mark) and check with strobe light to be sure, this would be my way of going about this now.
Once done like this the timing will be spot on, the original marks may not line up, but does that really matter as long as it runs right.
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Post by steeley on May 20, 2022 19:43:04 GMT 1
I am with Tony on this . As i said i had a rotor key way cut years ago and went down this way . I knew the stater plate was in the right position so once i was happy i marked the rotor for future use .
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Post by clarkey on May 20, 2022 20:17:03 GMT 1
Thanks Guys - let me have a go at this tomorrow and I will let you know how I get on. I really appreciate the help.
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Post by tony2stroke on May 20, 2022 21:28:06 GMT 1
I just looked at a load of flywheels on ebay, they all have the same main numbers as yours 032000 128 02U VCC27 apart from the 02U part, there are other numbers, 01U 01B, 11U, 03U, sorry I can't give you any more info than that, one would assume that the 02U is correct as there is 01U and 03U listed as RD350LC, though that doesn't really prove anything.
This sure is puzzling.
As your 1st advisor said the crank can't slip in a way to alter the timing on the left side, its just not possible.
Someone may have re-cut it or the crank maybe as steely said, if they did a good job and hid the old marks would you notice.
The pick up plate is in around the right place, or at least the pick up looks to be there or there about, that's the only bit that matters here (the pick up and the magnets on flywheel).
At 2mm BTDC there should be a magnet in the pick up zone, (the little round raised bits on the flywheel).
In conclusion, the only logical culprit is the flywheel, for whatever reason not lining up right, I would rely on the left side to make your own timing marks, just going through my thought process on this.
I don't see how it runs now though with the timing that far out, it doesn't make sense, unless they do run that far out ?
If anyone can pick a hole in my thoughts please do, so we can help this guy out.
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