The Yamaha YPZ primary clutch in the Exciter-I is not an good clutch.ramblnman said:
The Yamaha YPZ primary clutch has poor durability.
The Polaris P85 primary clutch is known for its strength and durabillity.
The Polaris ( "10" series ) weight profiles are the most efficient at transferring power !!
.....Why not use a better product on your Yamaha ?
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any clutch on a exciter does not have much durabilty because it is a 2 cylinder vibrater and will wear out bushings fast no matter what you run on it period anyone who has owned one for a while and takes pride in it to keep it running at peak knows this ! and the yxr clutches are far superior to any comet/polaris clutch on a yamaha period! that is all i will reply to your theories ..sorry for hyjacking your thread answering the monday morning quarterback that has not given a comet setup for you to even get you close to what you need.. but just watches you stumble stanage.
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stanage
Member
Hey Guys, while I understand there is no perfect clutch, with either clutch setup, comet or YPZ, the fact remains that I have a comet on my machine, and Im certainly not going to a YPZ, for the simple reason I dont have one...
I understand the clutches need to be perfect for the "vibrator", so thats what I did with the secondary - new buttons, cleaned up the ramp, adjusted the deflection with shims... The primary is taking me more time because I ordered the wrong puller. Im in a catch 22 right now... don't want to order springs and weights till I figure out why this machine ain't rolling, but it's all useless till I get my gearing... sigh.... Im so impatient becasue everything is taking so long...
What you guys have to keep in mind is that this sled was a POS when I got it... I fixed what I could and improved a whole bunch more, but i seem to have had this coil/cylinder problem from the begining and never really took the time to analyse the symptoms and do some troubleshooting. I have NEVER gotten this sled over 70 or80km/h... Ported or not...
I've always had that clean spark plug on the MAG side, even though I have good spark, and the machine runs on that cylinder...
And to throw in a bit more, the coil was always on the machine with the kimpex facing down, so I never saw it... looked stock to me, never had a coil go bad before!? I'm a little hard headed and a little bit lazy.. not always a good combination but I eventually get pissed off enough to fix things...
I will update ya'll once I get that coil in tonight!!! PEACE!!
I understand the clutches need to be perfect for the "vibrator", so thats what I did with the secondary - new buttons, cleaned up the ramp, adjusted the deflection with shims... The primary is taking me more time because I ordered the wrong puller. Im in a catch 22 right now... don't want to order springs and weights till I figure out why this machine ain't rolling, but it's all useless till I get my gearing... sigh.... Im so impatient becasue everything is taking so long...
What you guys have to keep in mind is that this sled was a POS when I got it... I fixed what I could and improved a whole bunch more, but i seem to have had this coil/cylinder problem from the begining and never really took the time to analyse the symptoms and do some troubleshooting. I have NEVER gotten this sled over 70 or80km/h... Ported or not...
I've always had that clean spark plug on the MAG side, even though I have good spark, and the machine runs on that cylinder...
And to throw in a bit more, the coil was always on the machine with the kimpex facing down, so I never saw it... looked stock to me, never had a coil go bad before!? I'm a little hard headed and a little bit lazy.. not always a good combination but I eventually get pissed off enough to fix things...
I will update ya'll once I get that coil in tonight!!! PEACE!!
Cool down !
1. This is bullshit !
I know of a lot of Exciters/Phazers/VK540 etc sleds with very high milage without any problems what so ever with the primary clutch
----> But they have one thing in common and that is that noone uses a YPZ clutch.
The YPZ clutch have a very bad reputation.
2. Yes , the YXR clutch is much better then the YPZ but not even close to the very tough built Polaris primary clutch.
The Polaris primary clutch has proven itself to whitstand high power engines.
and can take a lot of vibrations.
---> The YXR clutch it not so good at whitstand high power engines.
3. It is not my theories , It is my experiences...
I have been in the snowmobile industry since 1984 and have learned a lot on the way.
4. I see no point to give any clutching advice since Stanage does not got his gearing and not having the engine to run properly yet.
...However the clutch advice you have given so far is from PSI and not from yourself !!
ramblnman...... , You need to cool down !ramblnman said:
1. This is bullshit !
I know of a lot of Exciters/Phazers/VK540 etc sleds with very high milage without any problems what so ever with the primary clutch
----> But they have one thing in common and that is that noone uses a YPZ clutch.
The YPZ clutch have a very bad reputation.
2. Yes , the YXR clutch is much better then the YPZ but not even close to the very tough built Polaris primary clutch.
The Polaris primary clutch has proven itself to whitstand high power engines.
and can take a lot of vibrations.
---> The YXR clutch it not so good at whitstand high power engines.
3. It is not my theories , It is my experiences...
I have been in the snowmobile industry since 1984 and have learned a lot on the way.
4. I see no point to give any clutching advice since Stanage does not got his gearing and not having the engine to run properly yet.
...However the clutch advice you have given so far is from PSI and not from yourself !!
stanage
Member
Lasse said:Good choice.
LOL, you guys crack me up! I can only work with what I got, so whatever we can do to make this thing go with the comet is what were going to do!
On that subject, here is an interesting tid bit of info.... I've been reading Olav Aaen's clutch tuning handbook ,and have finally read through to the end! What a read!
Looks as though the black/pink and black/white secondary springs I have; have the same spring rate. 721kgmm/rad It's only the free length that is different. 85mm on the pink, and 93.5mm on the white.
So, from what I read, the stiffer the spring, and the higher the pretension, the higher the sideforce, which takes more RPMS to pull the belt down - but gives a faster backshift. Soooo, if I use the white spring, I increase the sideforce, which means I will need more RPM's, but will have a faster backshift. If I use the pink spring, with the same pretension, I need less RPM's to pull the belt down, but I have a slightly slower backshift... oh boy... lets get back to that once I fix the motor...
Ramblnman in right. A Polaris clutch on a two cylinder Polaris will need weights, pins, bushings and rollers twice a year. On a three cylinder Polaris they last a long time.
thefullmonte
New member
The Polaris clutch undoubtedly has the most aftermarket support throughout the industry. Followed closely by the TRA. And you can argue the advantages of each until hell freezes over. lol
The Polaris 10 series weight has one of the best ramp profiles and is often duplicated. Is it perfect? No, which is why adjustable weights have been developed, but again a story for another day.
Compare the stock exciter ramp profile and you will find it to be very close to a Poo 10 series. The weight distribution of the stock weights is also very good. The unique thing that Yamaha likes to do is to create a ramp profile that follows the torque curve of a specific application. In theory we could say this is awesome . Unfortunately, in real world usage it isn't always so.
Although the Yamaha clutches aren't the most popular, I've never really experienced issues with them either. As with any clutch, maintenance and proper balance is crucial. An improper setup can prematurely destroy any clutch. Worn parts and excessive heat spell failure.
Modern Yamaha clutches hold up to 300hp turbo applications. Would a YPZ? Not even close. lol The P-85 has been a great clutch for Polaris, but even it is in dire need of new technology. One simple thing the P-85 does good is evacuate heat better with it's open design. Much like stanage said.......Sometimes you just have to run what you've got.
The Polaris 10 series weight has one of the best ramp profiles and is often duplicated. Is it perfect? No, which is why adjustable weights have been developed, but again a story for another day.
Compare the stock exciter ramp profile and you will find it to be very close to a Poo 10 series. The weight distribution of the stock weights is also very good. The unique thing that Yamaha likes to do is to create a ramp profile that follows the torque curve of a specific application. In theory we could say this is awesome . Unfortunately, in real world usage it isn't always so.
Although the Yamaha clutches aren't the most popular, I've never really experienced issues with them either. As with any clutch, maintenance and proper balance is crucial. An improper setup can prematurely destroy any clutch. Worn parts and excessive heat spell failure.
Modern Yamaha clutches hold up to 300hp turbo applications. Would a YPZ? Not even close. lol The P-85 has been a great clutch for Polaris, but even it is in dire need of new technology. One simple thing the P-85 does good is evacuate heat better with it's open design. Much like stanage said.......Sometimes you just have to run what you've got.
DO YOU NOT READ POSTS BOY!.. I DONT RUN COMET BUT I AT LEAST SHARED WHAT INFO I HAD FROM PSI ON THE SUBJECT WITH COMET..THAT IS MORE THAN YOU DID .. AND LASTLY .. i dont need to cool down .. im cool enough!!Lasse said:ramblnman...... , You need to cool down !
1. This is bullshit !
I know of a lot of Exciters/Phazers/VK540 etc sleds with very high milage without any problems what so ever with the primary clutch YES LASSE YOU ARE RIGHT.. THATS BULLSHIT!!
----> But they have one thing in common and that is that noone uses a YPZ clutch.dont really care what you people in sweden run!The YPZ clutch have a very bad reputation. NOT HERE!2. Yes , the YXR clutch is much better then the YPZ but not even close to the very tough built Polaris primary clutch. BULLSHIT..The Polaris primary clutch has proven itself to whitstand high power engines.SO!
and can take a lot of vibrations. ---> The YXR clutch it not so good at whitstand high power engines. TELL THIS TO YAMMIEGOD AND ALL THE OTHERS MOPPING UP OUT THERE WITH THEM!!
3. It is not my theories , It is my experiences...WITH THE STATEMENTS YOU HAVE POSTED ..YOU ARE NOT THAT EXPERIENCED WITH YAMAHA CLUTCHES ..FOR SURE!!
I have been in the snowmobile industry since 1984 and have learned a lot on the way.
4. I see no point to give any clutching advice since ( WITH WHAT YOU SPEW MAYBE YOU SHOULDN'T!!Stanage does not got his gearing and not having the engine to run properly yet.
...However the clutch advice you have given so far is from PSI and not from yourself !!
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never said ypz is better than comet/polaris p85.. just said i would use a yamaha over a comet.... i'm pro yamaha and have always tuned them to run real good on my exciters.. but the yxr is way better on exciters..thefullmonte said:
yes,good for you stanage!!reading that is the best way to understand the cvt!! you will figure it out fast after you get that sled running like a top !stanage said:
thefullmonte
New member
Ramblnman, I think you are reading into this too much. I was not implicating that you had said that either. I can tell you and Lasse are having some disagreement here. My intent was to show both sides as having valid input to the discussion.
To your comment, I was simply trying to say that they (Yamaha) have come a long way in their clutch design. Much like stanage I run what I have. If it was up to me I would be designing a completely different primary drive. The whole idea is outdated in my opinion.
You can find strong and weak points with any clutch design. I've run at least 3 different Yamaha clutches over the years. I've tuned 108's and have extensive experience with Polaris clutches. I even have experience with Cat and Doo. And I can honestly say that I've achieved good results with all of them.
I've had a phazer that ran strong for many years on a ypz clutch. No complaints. I've seen and run big HP on a P-85. I've also seen them destroy themselves on low HP. Do some clutches work better than others? Sure, of course they do. Doesn't mean you can't achieve similar results with something else.
I can find you more than 1 path to the same result with clutching. You can make a TRA perform like a P-85 and vice versa. I see some different opinions here, but much useful information being shared. Disagreeing isn't bad, but one has to acknowledge that although the other opinion isn't yours that it may also be right.
To your comment, I was simply trying to say that they (Yamaha) have come a long way in their clutch design. Much like stanage I run what I have. If it was up to me I would be designing a completely different primary drive. The whole idea is outdated in my opinion.
You can find strong and weak points with any clutch design. I've run at least 3 different Yamaha clutches over the years. I've tuned 108's and have extensive experience with Polaris clutches. I even have experience with Cat and Doo. And I can honestly say that I've achieved good results with all of them.
I've had a phazer that ran strong for many years on a ypz clutch. No complaints. I've seen and run big HP on a P-85. I've also seen them destroy themselves on low HP. Do some clutches work better than others? Sure, of course they do. Doesn't mean you can't achieve similar results with something else.
I can find you more than 1 path to the same result with clutching. You can make a TRA perform like a P-85 and vice versa. I see some different opinions here, but much useful information being shared. Disagreeing isn't bad, but one has to acknowledge that although the other opinion isn't yours that it may also be right.
thefullmonte
New member
4x4x4 said:
Not picking on anyone here, but if this is what you are experiencing then something else is wrong. I personally have had two 800 twins with est. 150 and 160hp. These were mountain sleds that I would use to boon dock for hours in deep snow. So they were put to the test. In over 2000 miles I never had to replace any of those items on either of them. Proper cleaning, maintenance and off season storage.
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stanage
Member
I'm just gonna let u guys figure it out... Im a big boy and can take in what I need and weed out the rest.
Ok, so I got my new coil, but the engine still won't rev past I'd say 5500 rpm, even with the belt off! I'm going to take a look at the stator tmrw...
Ok, so I got my new coil, but the engine still won't rev past I'd say 5500 rpm, even with the belt off! I'm going to take a look at the stator tmrw...
thefullmonte
New member
stanage said:
Any way you could shoot us a short vid of it running? I would like to hear what it is doing. Is it bogging? Are you certain it is dropping a cylinder when running? What are the plugs looking like? Have you checked compression? Does it start easily?
stanage
Member
thefullmonte said:
I'll post a quick vid tonight. It bogs at WOT - 5500RPM and beyond. TORS is bypassed. Doesn't really sound like it's missing a cylinder, but here's what the plugs look like. Why does the MAG side not have anything on the base ring??? WTF!!!!
MAG side:
PTO Side: 
Compression is 110 on both cylinders, and it starts on the first pull.
Stuff Im checking tonight includes:
1) Checking/Cleaning the needle jet on the mag side. It has brand new 330 mains... so those aren't clogged, I use an in-line gas filter anyway.
2) Cleaning all the wires under the oil reservoir and individually wrapping them.
3) Replace/check the choke plungers and check the cable slack/adjustment
4) If time permits, I'm ripping off the oil injection and magneto and will take a good hard look at the stator. If it all looks good, magneto will go back on and I'll start the engine without the oil injection and run pre-mix 50:1. I will also attempt to get a good look at the crank seal on the MAG side because when I replaced everything last year (or the year before) it was that side that had melted down, and the seal was never changed.
thefullmonte
New member
PTO side looks like a new plug? Can't tell for sure, but also looks wet? I think you are on the right track. Check the choke plungers also check that the needle and seat are good. Wouldn't hurt to verify the float height is correct.
Sounded like you verified that the coil was indeed working for both cylinders in a prior post.
You might be able to spray a little contact cleaner around the mag seal to see if rpm changes. Just spray it in there. If it is leaking it will suck it in.
Lets get you out on the snow.
Sounded like you verified that the coil was indeed working for both cylinders in a prior post.
You might be able to spray a little contact cleaner around the mag seal to see if rpm changes. Just spray it in there. If it is leaking it will suck it in.
Lets get you out on the snow.
stanage
Member
I read back over my notes and noticed that I had it revving to 7500RPM before I made clutch and jetting changes... going to go back over all that tonight too. I wish I had some lighter weights to try in the primary clutch. It seems like when I added 10grams, I almost dropped 1000rpms. So if I put the smaller weights In I could climb back up to 6500?? I'll try the blue spring first with 58grams, and then go back to 48 gram wights and the red sping.
Im not worried about gearing at this point because the belt is off... I wonder too if the problem could all be in my primary clutch... I noticed it was "sticking" when I let off the throttle at 5500rpm, and not releasing as quick as I would have thought. Perhaps it's binding when it opens up, so it won't shift out all the way??? You'll see in the vid I post tonight, i don't see the primary shifting all the way out, and when it re-opens it sticks!?
Lasse's charts says if I want more RPM's up top, I need less aggresive fly weight curvature, and a spring with more rate, but same engagement speed. Doesn't really say I should change the weight itself...
My current Comet red primary spring is as follows:
O.D: 2 1/16
Height: 3 1/4
Spring rate: 130
Engine preload: 92
Full Shift: 254
The Dark blue polaris primary spring I have is as follows:
Engagment load: 120
Shift Load: 264 and 300 (P85 and P90)
Spring rate: 144lbs
Free Length: 3.52 inches
So, since it has more rate, it might be better suited for my application? The only problem is that is has a higher preload... can't remmember what that does...
Im not worried about gearing at this point because the belt is off... I wonder too if the problem could all be in my primary clutch... I noticed it was "sticking" when I let off the throttle at 5500rpm, and not releasing as quick as I would have thought. Perhaps it's binding when it opens up, so it won't shift out all the way??? You'll see in the vid I post tonight, i don't see the primary shifting all the way out, and when it re-opens it sticks!?
Lasse's charts says if I want more RPM's up top, I need less aggresive fly weight curvature, and a spring with more rate, but same engagement speed. Doesn't really say I should change the weight itself...
My current Comet red primary spring is as follows:
O.D: 2 1/16
Height: 3 1/4
Spring rate: 130
Engine preload: 92
Full Shift: 254
The Dark blue polaris primary spring I have is as follows:
Engagment load: 120
Shift Load: 264 and 300 (P85 and P90)
Spring rate: 144lbs
Free Length: 3.52 inches
So, since it has more rate, it might be better suited for my application? The only problem is that is has a higher preload... can't remmember what that does...
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stanage said:
Stanage you might found something....i remember my old comet was stuck in the same way last year and i couldn´t go over 80 km/h with that either. Thought it depended on the carbs but now when i see this, i think it can be an explanation to your problems....... i changed it to another 108 exp this year and the problemis gone. But then again i changed alot of stuff on mine the previous year.... but that´s a thought
