Slight subtle knocking on decel and rough running.

[Kaisersoze]

New idea to throw out there and would like feed back on this please.

After snooping around and researching ANY potential issue that could come up. Im thinking that maybe the cam tensioner might be going on the bike and causing slack on cam chain. Im not saying it skipped a tooth, but excessive slack would cause chain lash = noise if im not mistaken and if it was slacked enough it could throw the valve timing off just enough to make it run rough because the timing would lag slightly everytime the cam chain had to catch up. Plus, this might explain why at higher RPMs the problem seems less pronounced. More tension right? And why it seems so exacerbated when engine breaking as the RPMs drop, because additional load (weight of bike and inertia) make it hang that much more on the slack parts of chain.

Any thoughts? Plausible?

Also, any good posts on checking tensioner? I searched but none are really specific on how to do it and manual does not have a section on checking it, just removing it with cams.

 

[REO Scorpio]

I replaced mine as a shot in the dark to alleviate the noise. It didn't, but might for you.

I think you're going to have to remove it to check The functioning of the tensioner. Pretty straight forward to remove. I had to remove the clutch cable holder as well as the line to the water pump in order to get my claws in there to remove the two bolts. You can then wind it using a small flathead screwdriver an check the plunger mechanism to see if it's smooth. I think the service manual covers this part. If it rattles when you gently shake it, that may be a problem as well.

If you have to check the chain or guide, it's a lot more involved and I not the guy to talk to there.
Scorp

 

[Kaisersoze]

Okay, so I checked the tensioner and it was a little "sticky" but after pouring some oil from the extra that i had left in my garage into it, the action was smooth as butter. But alas, after replacing it and starting the bike the problem remains.

I talked to a yamaha dealership nearby about checking valves, cams, and cam chain. I told them i'd strip the bike down to see if they could cut me a deal and it came down to this. $100 to check the valves, cams, and cam chain. $300 if they had to adjust the valves because its about 2 extra hours work taking the cams off and everything.

Not a bad deal right?

Im tapped out on ideas so I'd let everyone know what happens.

Thanks again to everyone for their contributions to this thread. Hope to see you guys on the road soon.

I replaced mine as a shot in the dark to alleviate the noise. It didn't, but might for you.

I think you're going to have to remove it to check The functioning of the tensioner. Pretty straight forward to remove. I had to remove the clutch cable holder as well as the line to the water pump in order to get my claws in there to remove the two bolts. You can then wind it using a small flathead screwdriver an check the plunger mechanism to see if it's smooth. I think the service manual covers this part. If it rattles when you gently shake it, that may be a problem as well.

If you have to check the chain or guide, it's a lot more involved and I not the guy to talk to there.
Scorp

 

[sharethesecret]

But I suspect you may have an ignition fault or even an injector fault or bad fuel.

Two knew things to try:
Dump the gas and place fresh fuel in from another source (or ride it off).
Swap ignition coils and see if anything changes.

You don't have to dump or "run off" bad gas. A Fitch dropped in your tank will make the bad gas good and refine it. Keeps the fuel burning more efficiently for the life of the bike...and the result is better fuel mileage- and you never have to put Stabil or other chemicals in your tank.

When I put the Fitch in my bike, I went from 45mpg to 50mpg.
Get them from Remis Power Systems Inc. - Battery & Charger Sales, Service & Repair

Just sayin...

Mel

 

[Kaisersoze]

*********UPDATE***********


Brought bike to dealership, they checked valves and timing and everything was fine except for one exhaust valve on number 2 cylinder off 2 thousandths of an inch. Mechanic said it was nothing to worry about so I figured not worth the extra 200 bucks to pull the cams and everything for that. Total cost for checkup: 100 dollars. Not terrible.

Gonna try to put bike back together today and see how she runs. If problem persists. Im gonna pull exhaust and make sure its not blocked up and gonna replace gaskets in case of leak.

 

[FinalImpact]

New idea to throw out there and would like feed back on this please.

After snooping around and researching ANY potential issue that could come up. Im thinking that maybe the cam tensioner might be going on the bike and causing slack on cam chain. Im not saying it skipped a tooth, but excessive slack would cause chain lash = noise if im not mistaken and if it was slacked enough it could throw the valve timing off just enough to make it run rough because the timing would lag slightly everytime the cam chain had to catch up. Plus, this might explain why at higher RPMs the problem seems less pronounced. More tension right? And why it seems so exacerbated when engine breaking as the RPMs drop, because additional load (weight of bike and inertia) make it hang that much more on the slack parts of chain.

Any thoughts? Plausible?

......

Your theory is partially correct. A bum tensioner will hurt deceleration performance because it can affect cam timing but is far less likely to impact acceleration performance.

Its more likely that a stretched chain would cause a power loss than a faulty tensioner. The tensioner is on the back of the chain where it's slack, so while accelerating the length of the chain doesn't change between the Cranks Drive Sprocket and the Cams driven sprocket so it won't retard the cam timing or make it lag. A stretched chain on the other hand will retard the cam timing and cause a power loss and make more noise. Note: I'm not saying yours is stretched, I'm just saying thats how it works.

The problem is, without a degree wheel or removing and measuring the chain, its difficult to measure chain stretch. At a glance I don't see it in the service manual. (could be there tho).

Here I'm looking at this from the "how does it run", not how much noise does it make.

 

[Kaisersoze]

Thanks for the input bro. I appreciate all the help everyone has been giving. It runs pretty much fine now. Its not 100% but since the mechanicals are all in order and its not a vacuum leak issue, I've decided to live and let live for now. I just want to ride b4 the summer is over! :BLAA:

Gonna work on some cosmetic stuff when i get a chance and i'll get some b4 and after shots up on here. Saw that post with that little bondo magic to clean up road rash and cant wait to try it. The textured black is gonna look sick.

The bike has a lot more vibration then before (but I think thats because I have more screws left over from fairing than previously! ). In all seriousness its still got balls when i hit the throttle and sounds 600x better then before. So i'm going to throw on some x-heavy bar ends to kill the vibration and all should be well.

:thumbup:

 

[RJ2112]

You don't have to dump or "run off" bad gas. A Fitch dropped in your tank will make the bad gas good and refine it. Keeps the fuel burning more efficiently for the life of the bike...and the result is better fuel mileage- and you never have to put Stabil or other chemicals in your tank.

When I put the Fitch in my bike, I went from 45mpg to 50mpg.
Get them from Remis Power Systems Inc. - Battery & Charger Sales, Service & Repair

Just sayin...

Mel

Mel,

I went to the site and took a look at what technical info there is......

I have to say I am skeptical. Took chemistry in school a few decades ago, and have an understanding of catalysts. That's an aide to a chemical conversion which may or may not already be happening. The catalyst is not consumed in the conversion.

I don't see how what amounts to a tea bag that you drop in the tank is going to increase the octane of fuel, or stabilize it. From my perspective, this makes as much sense as putting a really strong magnet on your fuel line.

If you are getting 10% better MPG (5) where they are claiming only 1-2.5 this is almost certainly due to your riding behavior changing.

Just sayin' .

 

[FinalImpact]

Mel,

I went to the site and took a look at what technical info there is......

I have to say I am skeptical. Took chemistry in school a few decades ago, and have an understanding of catalysts. That's an aide to a chemical conversion which may or may not already be happening. The catalyst is not consumed in the conversion.

I don't see how what amounts to a tea bag that you drop in the tank is going to increase the octane of fuel, or stabilize it. From my perspective, this makes as much sense as putting a really strong magnet on your fuel line.

If you are getting 10% better MPG (5) where they are claiming only 1-2.5 this is almost certainly due to your riding behavior changing.

Just sayin' .

Agreed - :thumbdown:
And it lasts the life time.... ahaaaaaa - sure. . .

but to each their own and if it works for you. go for it. I'm just saying not all fuels are equal. Some DO work better than others.