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Getting a bit of a low end bog, and not getting top end power. My RPM's max out at about 6700 when they used to max out at about 7200. Compression is 110 per side. Engine is 485 fan.
My belt is a bit worn and is sitting down about 1/8" into my secondary clutch. Also, the dogs on the secondary clutch have some slight wear. I would say they're worn about 1/32". Could the combination of these two signs of minor wear cause these symptoms? Both cylinders hold thier compression very well.
Also, what do you think about these two plugs and the colors? Everything seem acceptable? The plug on the left is from the clutch side, and the right is from the fan side.
Thanks.
 

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plugs look okay, maybe a bit rich, but on todays pump gas..thats a good thing..
But I`d throw in some new ones anyway..
 

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the plug on th right is just like one of mine. my fan side plug always has a buncha black oil up the thread and on the washer i couldnt figure out why. enough got up on it one day to kill the plug.
i got the same clutch problem goin on as well. i get about 100 or 110kms top speed
 

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hello...new to the site...
your bog is most likely caused by the belt riding too low (worn) in the secondary clutch...

it's like starting out in the wrong gear and will loose you some on top as well...you could remove shim in rear of clutch but a new belt would be recommended....also...plugs look acceptable if not slightly rich on the one..
 

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I think the the plugs look fine as they are just a little tan on the bottoms, The right plug may have not been tight . I would change the belt and clean and lube the clutchs good then go from there. PS do you still have snow to try it out on?
 

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hello...new to the site...
your bog is most likely caused by the belt riding too low (worn) in the secondary clutch...

it's like starting out in the wrong gear and will loose you some on top as well...you could remove shim in rear of clutch but a new belt would be recommended....also...plugs look acceptable if not slightly rich on the one..[/b]

Welcome to the site SHJ. I agree with you on the low end bog being caused by the warn belt. That worn belt is causing lots of problems. The compression is a bit low as well and could also be contributing to the problem, but I don't believe that it's a huge issue.

Good pic of the plugs, but there has to be more to the story to get a read off of them. Was that pic taken after a high speed 'chop' or after a normal idle and shut down? It makes a big difference. If that was after a normal idle down, I would say that the PTO side (left) is running a bit lean and the one on the right was a bit to the rich side. If it was after a high speed 'chop', then I would have to say that the PTO is just a wee bit rich and the mag is at least one jet size rich. Now these opinions are based on the assumption that your carbs are clean and properly adjusted.
 

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yep....this is right...assumed he followed the plug test/run procedure..

to take a true plug reading you should do the following forquarter (pilot), half(needle exiting the seat),three quarter (full taper of the needle)and full throttle testing (main jet alone):

get an air temp reading (to show relativity to your plug readings)

find a long open straightaway......for at least 1/2 miles hold the throttle steady in the desired circuit for testing i.e. 1/4,mid, 3/4 or full throttle....

while holding the throttle steady carefully hit the kill switch only releasing the flipper when you've fully stopped...

pull the plugs to read now...

there are three areas to inspect..the insulator...electrode and ground...

on a ngk plug...

as a rule of thumb....carmel is an ideal color on all.....wet or sooty black is rich and grey is too lean...however
if you have the slightest bit of grey on the electrode and on the ground strap before the metal "makes a turn" towards the threads....this is what would be referred to as "spot on jetting" for that given temperature, elevation and relative air density

hope this helps
 

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I would defenatily look into replacing your belt and maybe rebuilding your clutchs, depending on your miles, I had a similar problem with my Phazer, I found a few things and fixed them, rebuilt both clutchs, brand new belt ( good Quality one )and cleaned my carbs really good...It made a huge difference, but with all the changes I am not sure which one fixed the issue......
 

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If your belt doesn't look messed up you can just take out the secondary clutch spacer (standard belt deflection adjustment) and it will bring the deflection back where it should be. Or just put in a new belt. I wouldn't do anything else until trying that. I would go with the OEM Yamaha belt as a general rule they fit the best and eliminate a lot of problems with the belt being close but not quite right that you get from aftermarket belts. I've been very happy with the OEM belt on my Vmax.

There is the possibility that your secondary already has the spacer removed and your belt is just that worn out. If that's the case then when you install a new belt it will be too tight and you will get squealing at idle and lowered idle speeds. Cross that bridge when you get to it because it's unlikely, but that's a possibility. It's a standard adjustment but you may need a spacer, shim, or some kind of washer from a dealer, depending on your type of secondary.

I'll withhold my opinion on those plugs except to say I like the dark one and that's approximately what I want to see in my engines. The light one looks way too light to me but I seem to be in the minority on that opinion...check for intake leaks and consider running premium if you want to feel safer about it. Your compression is fine, I don't think your problem is engine related.
 

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Discussion Starter #11
Sled is parked for the season now. But I did take out the spacer in the clutch and it made no difference at all. Looks like clutches and carbs during the off season. Maybe I'll just trailer it to the dealer for some routine service and maintenance. The sled is a 93, so I wouldn't mind an oil pump rebuild as well just for peace of mind.
 
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