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General Category => General Discussion => Topic started by: JayDee24ca on August 29, 2016, 10:27:50 PM
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I had to ride home 60 miles the other day , on the '87 SPII, running on one cylinder, due to a busted throttle cable. I had no way to repair it on the road. The bike had no problem holding 55 on the flats and of course dropped down considerably on any incline. I notice now that it has been repaired with a new cable, and dialed in, that there is a noticeable rattle from the engine. Have I buggered something internal? I realize there was way more demand placed on the one cylinder, but I was not really flogging it, and my thought was that so long as the lame cylinder was firing and burning any fuel intake that there should not be a problem. Was I way off in that assumption?
Thanks
JD
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Years ago I had a throttle cable break on my CX100 so I babied it to my destination. Maybe knowing how long you rode it that way makes a difference on if you damaged the hurt cylinder.
Years ago Steve Atwood(from UK) won a US Ironbutt competition finishing on 1 cylinder on his LM II. Don't know if he removed a spark plug doing it.
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Yeah, Dusty, I may well have been totally off, but I had figured that it would NOT be lean, as the AFR should be simply the normal idle mixture, as you say. The cylinder that had the busted cable was simply not contributing to the engine demand, with the reduced air and fuel it was getting. That's kinda why I figured I would be okay. I dunno. Would the engine running at 3000-3500rpm create a larger vacuumthat resulted in more air being drawn in, or would the closed carb slide preclude that from happening?
It starts and runs just fine, but I sure don't like the rattle. I put it up on the hoist tonight and I am going to have a look at things in the next few days. Sure hope I didn't pooch it.
JD
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Years ago Steve Atwood(from UK) won a US Ironbutt competition finishing on 1 cylinder on his LM II. Don't know if he removed a spark plug doing it.
I| had considered pulling the plug, but figured that that would result in raw unburned air fuel mixture washing down the cylinder walls, so I left the plug in.
JD
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can you describe the rattle? is it when the engine is under load, or when decelerating, or when the engine is "floating"? is it a light metallic sound, or a deep sound? from one side more than the other?, from the upper part of the cylinder, or lower from the block area? Have you checked the valve clearance?
Just some ideas......
Rick.
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Rick, I dumped the oil and set the valves at the same time i replaced the busted cable, 200 miles ago. Nothing untoward was seen in the oil, but I figured that it needed to be done after a hard 60 miles like that.
The rattle is inconsistent. it is not a deep rattle, it actually sounds like a loose hollow rattle. It comes and goes as I accelerate from a stop.It sounds to me as I imagine the engine would sound if it were bone dry for oil, but its not. I wonder if it a loose T-chain; I put a new chain and blade tensioner in it about 4000 miles ago.
I put the bike up on the hoist tonight, and tomorrow I'll start it while its up there, so I can have a listen and see if I can determine where the heck the sound is emanating from.
JD
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I'll go with what he said -- your headpipe got vibrated to where it touches the frame and it only does it sometimes, maybe accompanied by mounts working loose. It's either that or what the other guy said -- little end bushings. But there's no straight line from your event to rod problems unless as Bones said, "He had a bad ticker, Jim."
I say check for stuff rubbing -- tank, even? and if it still makes noise, do the start up with the valve covers off. Hold each rocker arm so it can't clatter and see if the noise changes. This would also be a good time to get the stethoscope out. Try to isolate the general area and then get more specific. There's aren't that many things that can rattle in an otherwise normally-running engine. Do it quickly, or everything will have flung oil on it in short order. If everything doesn't have flung oil on it in short order, I'd suspect the problem has to do with oil. You can somewhat contain the deluge of oil droplets by setting valve cover on loosely.
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i say clutch ?
If it is inconsistent , I doubt it is something broken one the engine.
As others said , comp check is the first thing to do , it is easy too.
do you feel the bike has lost power ? smoke ? idle or not ?
any difference at all ?
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By what method were the carbs synched?
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By what method were the carbs synched?
Electronic Harmonizer, and also 4 column manometer.
JD
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JD , what does the sparking plug on that side look like . Any signs of overheating .
Dusty
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JD , what does the sparking plug on that side look like . Any signs of overheating .
Dusty
Dusty, the plugs are not overheated, both nice greyish tan in colour, just the way I like them. I did a cold compression test, throttle wide open, 150/152psi, so that's okay.
I fired the old girl up while on the hoist and was unable to replicate the rattle, no matter what rpm. I have a large jack under the sump, and wonder whether that is deadening the rattle. I do know that the exhaust is not rattling against the frame, as that was a mystery I had when I first got this bike several years back, so it was one of the first things I checked recently.
I was not able to spend a great deal of time at it, as we are heading up to Kitimat on Thursday, and there are lots of chores to be done before we leave. Today I started to strip the fruit trees so the bears don't get all the fruit and break down the trees while we are gone with the dogs. I likely won't be able to pursue this bike issue until I get back late next week.
One thing that I have concluded is that the "broken cable/60 miles on a single cylinder" event is not likely to be connected to this rattle. I see no way that one would cause the other. Input from the folks on this board have confirmed that suspicion. So, I am left with a death rattle I need to replicate and locate.
John D.
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If you only hear on acceleration -- some body part that moves back under acceleration and away from the connection that damps its vibration? Breather box? Something loose inside the exhaust?
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Interesting. I have a rattle I only hear on decel...I'm thinking exhaust baffle or ... ? It sounds like a panel of some sort, I don't know why I think of it as that. It's low on my worry list.
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Slap the mufflers sharply, that will tell you if you have internal baffles loose and clanking
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Interesting. I have a rattle I only hear on decel...I'm thinking exhaust baffle or ... ? It sounds like a panel of some sort, I don't know why I think of it as that. It's low on my worry list.
Could be rod bearings..
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Interesting. I have a rattle I only hear on decel...I'm thinking exhaust baffle or ... ? It sounds like a panel of some sort, I don't know why I think of it as that. It's low on my worry list.
[/quote]Could be rod bearings..
Not anymore :smiley:
Ciao