3 questions....

JAPET

JAPET

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Joined
Jan 18, 2015
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59
Location
france
96 600 vmax xt Aaen twin pipes, Boyesen, reed spacers, thin headgasket.

jetting:
What do you think of the color of the spark plugs ??

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clutchs:
Primary spring orange black Aaen, flyweights 8AY 17605 00 , 2.4g rivets, rollers 15.6mm.
secondary stock, green spring, 3-3.
gearing 19/39
when i start , I have 9000 peak rpm,
then steady rpm all of the range of use has 8500rpm.
9000rpm seems much?
moreover, it was still a little at 9000rpm before falling to 8500 and move forward ....
what should i do?
reduce tension in the secondary?
or maybe problem sheave ?
usury ?

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pistons:
on twin 600 , all pistons are the same?
8ca , 8 cr , etc?
my sled has approx xxxx km (i don't now) and when i was changing the head gasket,
I realized that the pistons had a lot of play throughout the stroke ....
Yet they are beautiful because the compression do not go down because the pistons are not black below the rings ....
has changed or not?

thank you in advance for your tips guys !
 
over 25 views and no answers ...... :o|
why no one answers never at my questions ???? :whine:
 
Here is a write up from mrviper about reading plugs
http://www.totallyamaha.com/snowmob...g a Sled/Jetting a sled and reading plugs.htm

As far as clutching I think you want it about 8000 rpm. I am no expert on this but I have done a lot of searching on it. From what I understand you would need to add more weight to the tip of the weights and or use a different primary spring that is softer.

Not sure about pistons. Would be best if you could measure them and the bore to make sure it is in spec. Hope that helps but like I said I am no expert
 
thanks you guys !!
on the data sheet pipes, Aaen said 8500 rpm max power .
PIY12033.jpg

I have the "feel" it was stagnating at 9000, the speed is stagnating a little too , and decline at 8500 ( steady rpm all of the range of use at 8500) and he gets a tow and length of the arms.
So if you look at the sheet Aaen, 8500rpm is good.
this is just the peak from 9000, when the motor engages, that bothers me ....
the extra weight on the arms would lower the starting rpm?

color spark plugs safe or not ?

thank you again !
 
Maybe track spin is causing it to jump up at first? Or the primary clutch may need bushings replaced. Primary could be sticking a little from too much play in bushings. I would say from looking at the sheet 84-8500 rpms is what you want but I don't think it should jump to 9000. Since your rpm is right I don't think you want more tip weight. Maybe one of the clutching guys could help
 
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I would say your plugs look good, try compression testing your cylinders and posting those numbers to start on that question. Your clutching question is confusing me, what is your engagement rpm (when the sled starts moving forward)? That isn't 9000 is it?
 
drew24 said:
Maybe track spin is causing it to jump up at first? Or the primary clutch may need bushings replaced. Primary could be sticking a little from too much play in bushings. I would say from looking at the sheet 84-8500 rpms is what you want but I don't think it should jump to 9000. Since your rpm is right I don't think you want more tip weight. Maybe one of the clutching guys could help
Click to expand...

thank you....hummmmm......I think the bushings are a good idea .....
I put a new rebuild kit and I doubted the quality ....

http://www.ebay.com/itm/YAMAHA-PRIM...Parts_Accessories&hash=item3a9ef50dfc&vxp=mtr

I'll change them again by genuines yamaha.
thank you again ! ;)!
 
eluke said:
I would say your plugs look good, try compression testing your cylinders and posting those numbers to start on that question. Your clutching question is confusing me, what is your engagement rpm (when the sled starts moving forward)? That isn't 9000 is it?
Click to expand...


no, no I misspoke, sorry , :oops::oops: , my English is not necessarily good,
engagement rpm is at around 4000 , rises to 9000 pic to return to 8500.

compression test not serve a much since I mounted thin head gasket,
and compression may be good even with worn pistons because these are the rings that are sealing ...

how much compression testing with thin head gasket on twin 600 ?
 
If it overshoots to 9000 then drops to 8500 through your up shift then you are right at peak power through shift out, which is where you want to be. A proper shift out will have a slight over shoot of rpm from your target rpm then drop to target rpm. I would say track slip on launch causes the higher overshoot but I'd be happy if it holds peak rpm through shift out.

I'm doing some fine tuning myself. I reach target rpm on launch but am slightly under on shift out. I'm removing a little tip weight to bring it up.
 
thanks!
I'll have to change the primary bushings by genuine yamaha, then I'll lower the secondary has 3-2 or 2-2, and if necessary, I would remove a little tip weight to bring it up .
fine tuning is not easy !
 
I tried that same clutch rebuild kit. It is junk. Definitely go with oem stuff for replacement parts on the clutches. Possible that is why it jumps to 9000. The bushings on that rebuild kit were way too tight for me since I had to grind a bunch out to get it to fit. I don't think I would remove any tip weight since you are already at the upper end of the peak rpm range.
 
drew24 said:
I tried that same clutch rebuild kit. It is junk. Definitely go with oem stuff for replacement parts on the clutches. Possible that is why it jumps to 9000. The bushings on that rebuild kit were way too tight for me since I had to grind a bunch out to get it to fit. I don't think I would remove any tip weight since you are already at the upper end of the peak rpm range.
Click to expand...

yes, I would even say that it is a big shit and it should be prohibited for sale !! :whine::whine::whine:
I also had the impression that it is too tight, especially at the bushing of the outer flange, which is plastic instead of bi-metal genuine parts! big shit!
and I would experiment with the bushings news before touching tip weight.
 
A couple of bucks said:
Now that's funny. I will admit there were times I thought I was reading hieroglyphics. But I did get the gist of what you were trying to get across. ;)!;)!
Click to expand...

:mrgreen:
technical terms is really not easy to do understand!
it is not fair to say.....:roll:............. "hello, how are you" lol :lol:
 
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The 600 cylinders have some slop in them. I installed spi pistons and it helped a bit. To be honest I think with the slop in the cylinders a wiseco or other forged piston would be a good fit.

Eventually you risk breaking a piston skirt with it rocking in the bore.
 
sorry but what do you mean by "slop" ... i not understand.:oops::oops:
breaking a piston skirt .... that's what I'm afraid!
 
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