New to me toy.
- Thread starter Vincent
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Vincent
New member
Sorry to hear.
I've been blessed with 180km of riding so fare.
But clearly many of my southern friends have not. Crummy to hear. I always wish for all to enjoy the hobby at the same time.
I've been blessed with 180km of riding so fare.
But clearly many of my southern friends have not. Crummy to hear. I always wish for all to enjoy the hobby at the same time.
Vincent
New member
I ve ripped my clutches out. After 300 km of sledding I'm fed up of throttling back as to maintain proper reving. So started dissassemblimg them and doing a much more therough cleaning. I removed one weight and started weighing the difference my new 4.5g Yamaha rivet with a 6mm washer has compared to the OEM rivet at the tip. My goal is to lower my WOT from 9000 to 8500 rpms. Am I on the right track?
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A couple of bucks
VIP Member
That'll be drop ya 200 rpm.
Vincent
New member
A couple of bucks
VIP Member
1 gram = 100 RPM
A couple of bucks
VIP Member
What's your helix wrapped to?
Vincent
New member
Seems to be at 6 and 1 so 70. I mite try 60 for fun. Green spring btw
On hardpack WOT I'm almost at 9000rpm, in loose snow conditions I easily Revs past that.
On hardpack WOT I'm almost at 9000rpm, in loose snow conditions I easily Revs past that.
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A couple of bucks
VIP Member
The 3 extra grams you are adding plus dropping from 70 to 60 should put ya right in the ball park.
Vincent
New member
Vincent
New member
Lastnight I washed all my clutch parts in soap and water with scocht bright pads. Really being therough on the sheave surfaces. Polished down my helix ramps. Washed belt. Reassembled the secondary and set the spring to 60. Checked each primary weights for proper clearance. They all needed a little triming on the washers and rivet ends. Had to removed about 0.2g each. Reassembled the primary. Used blue locktight on every bolt and set screw.
Installed everything back in my sled and went for a ride. Max Rev on hardpack is now 8500rpms. The clutchs works so much better! Snappier, torquier, more reactive. Pulls like a freight train!
Everything compliments everything. Strong healthy motor, proper clutching, new track. The package has improved by leaps and bounds with every step. My clutching mods cost 5$! Seriously five bucks. Just three rivets, washers, and a few hours of TLC.
Thank you everyone! I couldn't be happier!
Installed everything back in my sled and went for a ride. Max Rev on hardpack is now 8500rpms. The clutchs works so much better! Snappier, torquier, more reactive. Pulls like a freight train!
Everything compliments everything. Strong healthy motor, proper clutching, new track. The package has improved by leaps and bounds with every step. My clutching mods cost 5$! Seriously five bucks. Just three rivets, washers, and a few hours of TLC.
Thank you everyone! I couldn't be happier!
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A couple of bucks
VIP Member
Doesn't all of the attention to detail to your clutches put a smile on your face?? Makes ya feel accomplished.
Whenever I balance my weights, I match up heavier rivets to lighter weights. Because we all know that a spec .8 gram rivet might just weigh .95 or whatever. I'll do the inner hole first and once those rivets are bucked, I adjust the two slightly heavier weights to match the lightest one. Then the tip get done the same way.
Whenever I balance my weights, I match up heavier rivets to lighter weights. Because we all know that a spec .8 gram rivet might just weigh .95 or whatever. I'll do the inner hole first and once those rivets are bucked, I adjust the two slightly heavier weights to match the lightest one. Then the tip get done the same way.
Vincent,
I've been following this thread and your clutch adjustments. If I understand correctly, you want to lower your WOT RPM to 8500. There’s several things I don’t understand. Can you answer a few questions?
From the limited seat time I have on my sled, I’m guessing when you’re cruising along some trail, you don’t maintain 8500 RPM, but you may hit 8500 RPM briefly when accelerating.
The pictures you posted labeled, “Marker line tell the tale”, what tale does this tell? I'm guessing that leaving some marker lines on the sheave means your clutch never fully engaged. What symptoms did you experience with leaving marks on the sheaves? If your sled never reaches full engagement, does this mean your sleds RPM can exceed 8500 RPM? This would be similar to a car or motorcycle with a slipping clutch, a lot of RPMs, but not a lot of forward propulsion.
You said your helix was wrapped at 70 and you changed it to 60. Does 60 have less preload or twist on the spring than 70?
I still trying the wrap my brain around the finer points of how the clutch system works. I understand the basics, but don’t understand how changes like spring rate, preload, and added weight change the operation.
I've been following this thread and your clutch adjustments. If I understand correctly, you want to lower your WOT RPM to 8500. There’s several things I don’t understand. Can you answer a few questions?
From the limited seat time I have on my sled, I’m guessing when you’re cruising along some trail, you don’t maintain 8500 RPM, but you may hit 8500 RPM briefly when accelerating.
The pictures you posted labeled, “Marker line tell the tale”, what tale does this tell? I'm guessing that leaving some marker lines on the sheave means your clutch never fully engaged. What symptoms did you experience with leaving marks on the sheaves? If your sled never reaches full engagement, does this mean your sleds RPM can exceed 8500 RPM? This would be similar to a car or motorcycle with a slipping clutch, a lot of RPMs, but not a lot of forward propulsion.
You said your helix was wrapped at 70 and you changed it to 60. Does 60 have less preload or twist on the spring than 70?
I still trying the wrap my brain around the finer points of how the clutch system works. I understand the basics, but don’t understand how changes like spring rate, preload, and added weight change the operation.
Vincent
New member
That's exactly it. When you cruise around your sled will normally run around 5500 to 6500 rpms. When I would give a shot of throttle my sled would easily Rev up to 9000rpms . Well past our motor's peak hp. You didn't even need to run WOT and it would Rev too high. Even a quick half throttle shot in loose snow and my engine would Rev to 8800rpms. Again too high out of our 700's powerband or usable torque.
By adding more weights on the primary and taking a little pressure of the secondary spring. I've added more mechanical leverage threw centrifugal force to help my clutch shift up. My engine "feels" more load and can't Rev as high, because the primary now squeezes the belt much earlier. The end result is a more controled torque curve, and better acceleration.
The marker lines were after high speed runs and it was clear evidence that my primary wasn't fully shifting or loading the motor properly. It's like I was stuck in a lower sliping gear everytime I demamded acceleration.
HTH.
By adding more weights on the primary and taking a little pressure of the secondary spring. I've added more mechanical leverage threw centrifugal force to help my clutch shift up. My engine "feels" more load and can't Rev as high, because the primary now squeezes the belt much earlier. The end result is a more controled torque curve, and better acceleration.
The marker lines were after high speed runs and it was clear evidence that my primary wasn't fully shifting or loading the motor properly. It's like I was stuck in a lower sliping gear everytime I demamded acceleration.
HTH.
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BornYamaha
Member
Very good explanation
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Sent from my SM-G920V using Tapatalk
Vincent
New member
Vincent
New member
I'm well over a 1000km this season. Last week I installed some much needed new carbide runners. Problem was it darted terribly after. Me and my buddy rode 200km last weekend and it was exhausting. More suspension tuning was required. Dropped the front straps 1/2", tightened up my toe out on my skis and set my front shocks to their lowest settings. It's now much better to ride and handles wonderful! For my weight and at times aggressive driving style the overall package is awsome. ( for the 16 year old sled it is anyways )
Now I want to tune the engine and by that I mean the carbs bit better. It runs well, but it's always had a bit of midrange "Gurggles" to it. No bog or hesitation. The engine always Rev well, but I d like to try to correct it. I've tried just pulling the choke slightly to see if it corrected it numerous times. It always just gurggled worst. So I never felt it was a lean condition.
Till recently I did a hard & fast trail run for over 10km. Accelerating from 30km/h in corners up to 80-90km/h in the streights. Lots of 3/4, sometimes full throttle pulls.
At the end of the trail I slowed down and hit the kill switch. Checked my plugs for fun. They all showed grey ash colour. So ya, lean!
I'm pulling the carbs, cleaning, veryfing all jets and settings. Not sure where things are set as I didn't know as much about these carbs when I first cleaned them last March.
So here I go! More snowmobile tuning fun!
Advice always appreciated. I run NGK br9eya plugs btw.
Now I want to tune the engine and by that I mean the carbs bit better. It runs well, but it's always had a bit of midrange "Gurggles" to it. No bog or hesitation. The engine always Rev well, but I d like to try to correct it. I've tried just pulling the choke slightly to see if it corrected it numerous times. It always just gurggled worst. So I never felt it was a lean condition.
Till recently I did a hard & fast trail run for over 10km. Accelerating from 30km/h in corners up to 80-90km/h in the streights. Lots of 3/4, sometimes full throttle pulls.
At the end of the trail I slowed down and hit the kill switch. Checked my plugs for fun. They all showed grey ash colour. So ya, lean!
I'm pulling the carbs, cleaning, veryfing all jets and settings. Not sure where things are set as I didn't know as much about these carbs when I first cleaned them last March.
So here I go! More snowmobile tuning fun!
Advice always appreciated. I run NGK br9eya plugs btw.
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