MtnEX
09-19-2008, 01:10 AM
Well, I had been posting a lot here about an engine noise I was having... even put up a video with sound...
Well, I do think I might have just solved the noise mystery I had.
Not sure, but thinking it's highly possible.
I now think I was getting the noise due to a combination of these 4 items...
1- Operating temperature
2- Questionable fuel delivery
3- Slick oil
4- Timing chain, guides, tensioner & tensioner lifter
In previous threads, I did not have access to the timing tensioner lifter on the back of the cylinder. But the day I took a dive into my carb, once the carb was off I had open access then...
Here's where it gets interesting....
When I took the tensioner lifter plunger out of the back of the cylinder.... well I could put it most of the way back in with the thing fully extended. My timing chain is surely stretched or worn way out. It all probably should be replaced and soon, although I don't know what the service limit is.
Now it gets better, because when I put it back in, finished the work on the carb and put things back together.... well I have not heard the noise a single time since. Not once, so far....
I think the reality could be that with that much play in the chain, anything at all that would add to or create sporadic motion or free over-run motion.... well that would aid in causing the chain to make that tap/clack/knock sound. Even something like decelleration or just letting off the throttle from a neutral rev...
Just the slack-tension slack-tension action of the chain itself, or the chain sort of slapping into something... maybe the guides, tensioner, or some surface in the engine.
I think it was so bad when I had the synthetic oil in because everything was cooled, contracted, more slippery, and therefore lower friction and slower to heat and expand.
That would explain why going to lesser oil made it pretty much go away. It was no longer constant when cold... just at random once in a while.
I think air/fuel delivery and ignition was the actual cause of the random noise on the lesser oil. Just a hardly detectable lesser or better charge/burn... just enough to cause the disruption of natural smooth engine revolutions.
Heck, this might be the explaination for MANY of the unsolved engine noises out there... main points being, have you checked your cam chain and pilot jetting lately?
So what do you all think?...
Mystery possibly solved?
This guy is out in left field?
Well, I do think I might have just solved the noise mystery I had.
Not sure, but thinking it's highly possible.
I now think I was getting the noise due to a combination of these 4 items...
1- Operating temperature
2- Questionable fuel delivery
3- Slick oil
4- Timing chain, guides, tensioner & tensioner lifter
In previous threads, I did not have access to the timing tensioner lifter on the back of the cylinder. But the day I took a dive into my carb, once the carb was off I had open access then...
Here's where it gets interesting....
When I took the tensioner lifter plunger out of the back of the cylinder.... well I could put it most of the way back in with the thing fully extended. My timing chain is surely stretched or worn way out. It all probably should be replaced and soon, although I don't know what the service limit is.
Now it gets better, because when I put it back in, finished the work on the carb and put things back together.... well I have not heard the noise a single time since. Not once, so far....
I think the reality could be that with that much play in the chain, anything at all that would add to or create sporadic motion or free over-run motion.... well that would aid in causing the chain to make that tap/clack/knock sound. Even something like decelleration or just letting off the throttle from a neutral rev...
Just the slack-tension slack-tension action of the chain itself, or the chain sort of slapping into something... maybe the guides, tensioner, or some surface in the engine.
I think it was so bad when I had the synthetic oil in because everything was cooled, contracted, more slippery, and therefore lower friction and slower to heat and expand.
That would explain why going to lesser oil made it pretty much go away. It was no longer constant when cold... just at random once in a while.
I think air/fuel delivery and ignition was the actual cause of the random noise on the lesser oil. Just a hardly detectable lesser or better charge/burn... just enough to cause the disruption of natural smooth engine revolutions.
Heck, this might be the explaination for MANY of the unsolved engine noises out there... main points being, have you checked your cam chain and pilot jetting lately?
So what do you all think?...
Mystery possibly solved?
This guy is out in left field?