My RX-1 Works
Veteran
Turbo Clutching
I don't have a Turbo yet but I have rode one last season. I know what a turbo feels like to ride. These clutching setups that you guys are using all work, but the question I must ask all of you is why do you have the most powerful broadband snowmobile engine in the world clutched like my MM700 with triple pipes were it starts making good power at 8800RPM and peak power at 9200RPM . Do you really think this represents the power curve of a Turbo RX-1?
I don't have a Turbo yet but I have rode one last season. I know what a turbo feels like to ride. These clutching setups that you guys are using all work, but the question I must ask all of you is why do you have the most powerful broadband snowmobile engine in the world clutched like my MM700 with triple pipes were it starts making good power at 8800RPM and peak power at 9200RPM . Do you really think this represents the power curve of a Turbo RX-1?
Works,
Look a few posts back and you will see I am pulling MUCH more than 9,200.
Why am I going above the peak HP range and all the way to 10,800? Well that is at 10 lbs of boost. I also ride at 5lbs of boost and at 5lbs I pull right at 10,200. To my knowledge there is now way to have one clutch setup that will pull 10,200 with both 5 and 10 lbs of boost.
Look a few posts back and you will see I am pulling MUCH more than 9,200.
Why am I going above the peak HP range and all the way to 10,800? Well that is at 10 lbs of boost. I also ride at 5lbs of boost and at 5lbs I pull right at 10,200. To my knowledge there is now way to have one clutch setup that will pull 10,200 with both 5 and 10 lbs of boost.
Snow Fever
Expert
There is alot more to to clutching then what the tach reads, diffrent weight profiles produce diffrent loads by the forces generated by the clutch. For instance, the stock weights all be it great to use in the summer when your on the lake fishing and you tie them to your fishing line to get your lure to sink to the bottom should have never been put in a sled let alone in a RX-1 Mountain. They are big and heavy but produce very little force compared to their mass due to the profile, what they do, do is act like a fly heavy fly wheel and make the engine breaking that occurs from this motor less pronounced. I know that was Yamaha's thinking. Now when you put in an aggresive profile you can lower the over all weight, get a harder pull and a much faster reving engine when going on and off the throttle. NOT theory but FACT! I took a set of Polaris 66gram weights machined out the pin hole and put them on my Yamaha 600mm that had a Turbo on, and it reved 9000 rpm, the weights I ran in that sled using the same spring as when I tried the Polaris weights were 89Ls weighted to 58 grams. Thats 8 grams less per weight and the sled pulled 8100rpm, had better throttle reponse and pulled way harder. A buddy of mine has a 700 Cat and was running 56 gram Artic Crap weights, he then tried some Thunder Shifts with moderate gains. I told him to machine up some bushings to make the 89Ls holes for the pins the same as the stock Cat weights and try them. He did it and now runs 48gram 89Ls and his sled has better throttle response and goes way better then it had ever before. Don't read too much into how much weight you can spin but consentrate on whether or not the weight is working. Put in the weights and spring I run with my Turbo which are way lighter then the stock weights into a stock RX-1 and it will puke trying to spin them. Hope this explains the principals behind weights a bit
My RX-1 Works
Veteran
Turbo clutching
Spray25 I did read your post carefully, your RX-1 running at 10,800RPM is actually 9049RPM at the clutch, because the MM700 is a peaky motor , a high preload spring is used, with a high spring rate and a high total force. Yamaha has clutched the RX-1 like the engine is a 2 stroke. High preload springs with a high spring rate contol the primary clutch by NOT ENGAGING THE CLUTCH , BY NOT PLACING FORCE ON THE BELT, BY SLOWING THE CLUTCH FROM UPSHIFTING. The spring is an opposing force to the weights. Spray25 you run a spring with 143KGs of force at full compression. It would be funny to see how your Turbo would run with the 88kg total force spring I am using in my stock engine!?
Spray25 I did read your post carefully, your RX-1 running at 10,800RPM is actually 9049RPM at the clutch, because the MM700 is a peaky motor , a high preload spring is used, with a high spring rate and a high total force. Yamaha has clutched the RX-1 like the engine is a 2 stroke. High preload springs with a high spring rate contol the primary clutch by NOT ENGAGING THE CLUTCH , BY NOT PLACING FORCE ON THE BELT, BY SLOWING THE CLUTCH FROM UPSHIFTING. The spring is an opposing force to the weights. Spray25 you run a spring with 143KGs of force at full compression. It would be funny to see how your Turbo would run with the 88kg total force spring I am using in my stock engine!?
Works,
So far the lighter spring and lighter weight combinations I have tried did not impress me. The setup I listed has by far out performed all of the others I have tried to date. For some reason the turbo seems to like the weight. It seems to make it spool faster. Like Snowfever was getting at.... turbos clutch a LOT diferrent than non turbo RX's.
Regardless of clutch rpms my engine still produces peak HP at 10,200-10,300.
BTW thanks to Snow Fever and Treewhacker for there clutching input. They were the ones that turned me on to the 8BU's.
So far the lighter spring and lighter weight combinations I have tried did not impress me. The setup I listed has by far out performed all of the others I have tried to date. For some reason the turbo seems to like the weight. It seems to make it spool faster. Like Snowfever was getting at.... turbos clutch a LOT diferrent than non turbo RX's.
Regardless of clutch rpms my engine still produces peak HP at 10,200-10,300.
BTW thanks to Snow Fever and Treewhacker for there clutching input. They were the ones that turned me on to the 8BU's.
My RX-1 Works
Veteran
Spray, I hope I wasn't giving you the idea that I want to through out your primary clutch, it sounds like its working pretty good still. I was just thinking that maybe a different spring might work even better. Something like a Green/Gold/Green (Yamaha short spring) with 5 shims. It has a 15KG preload for a very early clutch engagement & it has a spring rate of 2.75KG/MM instead of 3.25KG/MM it would place more force on the primary at every RPM level. It would cost $15 , and take five minutes. Nothing ventured nothing gained.
My RX-1 Works
Veteran
Am I speaking *())(** , or does anyone understand what I am saying? Who says that an RX-1 turbo requires a super high engagemant like a 2 stroke or a high spring rate. It is no wonder that you say that the clutch likes weight. Of the 53 or so primary springs that Yamaha makes the one that you are using Spray is about the worst. AS for the boost , this is only my thoughts, but I would clutch the sled to 10,300RPM at full boost, and if the engine is only turning 9700-9800RPM at low boost that would be okay it would save the motors engine life in both positions and give maximum performance in the high position. Maybe I am a genius, or a nutbar?
Works,
I have my sled clutched for how I ride "most" of the time. "Most" of the time I ride on low boost which turns at roughly 10,200.
I do not agree about my primary spring being the "worst". I don't think ANY of the springs they make are the "worst". It depends on the application the spring is being used in. Again, I was NOT happy with the results I got from softer springs. Right now I have speant enough time tuning and want to ride. At some point I'm sure I will once again experiment with diferrent springs.
My engagement is not overly high. I engage right around 4,000 engine RPMs.
You will find with clutching there are numerous ways to skin the same cat and diferrent people have diferrent opinions on what feels righ to them.
I have my sled clutched for how I ride "most" of the time. "Most" of the time I ride on low boost which turns at roughly 10,200.
I do not agree about my primary spring being the "worst". I don't think ANY of the springs they make are the "worst". It depends on the application the spring is being used in. Again, I was NOT happy with the results I got from softer springs. Right now I have speant enough time tuning and want to ride. At some point I'm sure I will once again experiment with diferrent springs.
My engagement is not overly high. I engage right around 4,000 engine RPMs.
You will find with clutching there are numerous ways to skin the same cat and diferrent people have diferrent opinions on what feels righ to them.
My RX-1 Works
Veteran
Spray, I know the feeling of wanting to ride, thats why we got the machines in the first place. After about 15 days in a row of tuning last year I was pretty much sick of it. All I know for sure is that no matter how well the clutch is calibrated it could always be a little bit better if you knew what to change, thats the hard part!! Here is one last very cruel detail about clutching. the primary could be perfect , and it still doesn't run because the secondary is poorly calibrated. I allways try to get the primary in the ballpark , then look at the secondary. This is my final post reply, have a enjoyable and safe second half of the riding season.
Good Bye Mountain Talk Forum
My RX-1 Works
Good Bye Mountain Talk Forum
My RX-1 Works
ken_climb
TY 4 Stroke Junkie
My RX-1 Works said:
Mountaintech
TY 4 Stroke God
Snowfever, Are you still running that 44-38 helix , and if so where did you get it? RX FUN
Mountaintech
TY 4 Stroke God
The turbo is up and running. I'm using 8BU-00 with 4.5 in the heel and 3.6 in the tip, short P-P-P primary, silver secondary @ 6-2 . My RPMs are 10900@ 700 feet and 10200 climbing @ 7000 feet. Thanks for everyones input, keep the info flowing! RX FUN
Similar threads
