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99 mm 700 clutches

C
Aug 28, 2008
340
35
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North Central MN
ok yammy masters, got some questions. i am going to try and hurry up and clean the clutches on this 99 mm 700. got the primary popped off last night before i went to sleep. seems like the spring is awfully soft. might just be me though. same with the secondary. seems like it moves pretty easy. could it be that these springs are wore out?

what am i supposed to torque the primary to when i put it back on the sled? also, is there any trick to taking the secondary apart? or putting it back together. never done one so i am kinda worried i am going to screw something up.

this sled is a great machine, but my cousin has failed to do much maintenance to it. it seems like it engages way to fast. you barely have to give it gas. i guess i never checked belt deflection. oh, thats another thing, how do i set the deflection on this secondary?
 
M
Nov 26, 2007
1,257
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Springs can wear out. They are cheap to replace and do an important job.



No real trick to taking apart the secondary. I would just mark both sheaves with a magic marker and line them back up. They are supposed to be balanced seperatly but wouldn't hurt.

The primary has an X on inside of the cover and the other part of the clutch. Line the X's back up, that is how the clutch was balanced.

I took the info for belt deflection of of www.totallyamaha.com in the tech section. I know your a member of TY, Go in and check out the tech section, alot of good info.




How should I set my belt deflection?



Best Belt Deflection = Track Movement:
First lift the sled onto your track stand, start the sled, warm the engine up and "rev" the engine to turn the track. Get the track nice and limber (meaning get the "cold" out of the track and loosen it up from any stiffness it has from sitting). When the sled is on a track stand and the engine is started and idling the track should:

A- Creep slowly.
B- Turn with jerking movements.
C- Track is still but you are able to move it by pushing lightly on a lug with your hand.

You should now already have proper belt height on the secondary after setting your deflection up like this. If you cannot get this kind of deflection change the drive belt to one that fits with proper length. The belt you achieve this with will be the one you want to keep. When buying a new belt, if possible take a seamstress tape with you and measure the belts circumference and make sure it is always the same.

If you laid a flat edge on top of the belt from the center of your secondary to the center of your primary and pushed down on the belt roughly in the middle you should have no more than 1-1/4" of movement when pushing down on it.

Your sled will never bog with these conditions. If you have found that your track moves on the stand at idle, then great! As long as your track moves or needs just a bit of help with just a finger or two you have great belt deflection!

Effects of Improper Belt Deflection:

Too Tight of Deflection:
When the belt deflection is set too tight the belt burns the cogs when sitting and idling anywhere near or below engagement. It also increases the torque at holeshot (which creates a better holeshot) but the top end mph is lost.

Too Loose of Deflection:
The holeshot will suffer and possibly bog and the midrange punch will be slow and doggy. It is possible for the midrange mph to be higher if the engine stays close to the proper operating rpm, but the top end rpm will pull down.
 
C
Aug 28, 2008
340
35
28
42
North Central MN
man i love this website. it is so nice when you are unfamiliar with something and can get help this fast. thats why if i know the answer to something or have knowledge in the area, you damn right i throw in my two cents. want to return the favor whenever i can.

its crunch time for me. i am leaving for billings with the sleds tomorrow morning. kinda my own fault in a way for not doing more earlier. but i have been waiting on parts.

is there a freelength measurement for the springs like there is on skidoo's? on those, you can measure the length of the spring and if its not within tolerance, you replace it.
 
M
Nov 26, 2007
1,257
108
63
There is in the Tech section on TY under "Clutchs and Jetting"
then click "springs and weights"
I can't copy and paste it.

There is a list for tall and short cover. 99-03 had the tall. THe pre 99 had the short.....I am 90% sure that the pre 99's were the short on that but might want to double check it. EDIT:just seen you are working on a 99, that is the tall.

Not sure if the free length will tell you if it needs replaced or not though. I have always just replaced mine every couple years.
 
Last edited:
S
Dec 27, 2007
312
72
28
Aberdeen, SD
The belt deflection is adjusted by removing the secondary and changing the washer width under the three small 8MM bolts that you will see on the back. You can get these washers from a Yamaha dealer. You simply add washers or take out washers to move your sheaves closer or farther apart.
 
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