Clutching on the cheap

[Alsim]

My sled must be gaining some HP as it breaks in because I am now sometimes bumping against the rev limiter on top end.

I have the COTC set-up with 3.6G rivets in the outer holes of the 8FP weights.

Should I replace the 3.6G rivets with the 4.5G rivets in the outer holes or should I add some weight to the middle holes? If so, how much?

Thanks in advance for the help.

Start with 4.5 on tip

 

[bleedyamaha]

My sled must be gaining some HP as it breaks in because I am now sometimes bumping against the rev limiter on top end.

I have the COTC set-up with 3.6G rivets in the outer holes of the 8FP weights.

Should I replace the 3.6G rivets with the 4.5G rivets in the outer holes or should I add some weight to the middle holes? If so, how much?

Thanks in advance for the help.

I was bangn the rev limiter and switched over to the 4.6 G in the tip and I am not banging anymore. It's amazing cause that little weight makes a big difference

 

[sparky72]

Agreed. I was in the exact same boat. At the end of last yr, at 18-2000 miles, tapping limiter with the 4.5's even. Now I've done the air box mod, so I've ordered the .85 aluminum rivets for the middle. Was out riding a bit in my field and only pulling 84-8500 and haven't put them in yet, thinking it must be the conditions (sloppy snow and + 2* C.)

 

[Reaper]

Finally got it off the rev limiter. 8FP with 4.6g in tip, .85g in center and .85g in base. G-W-G with 2 shims.

All three weight were balance at 74.62g

Hits to 8,400-8,500 quickly climbs to 8,900 and them flattens out at 9,050.

Lugs down to 8,200 in deep snow but climbs to about 8,500

Got a few more mph on top, see about 91-92 now but still hits the wall there! Baffling??

Belt (8DN) only gets to 1/4" from top of sheaves on primary.

I really think it may be secondary spring binding, I did rebate the Dalton 46/40 helix on a mill so not using washer to stage out the secondary.

Think I will try washer just to see if it makes any difference (Pink spring wrapped 6-1).

Still steers heavy like a pig, have had no success dialling that out. Stock ski, tuner ski, 135lb spring with freeplay remove and cranked about half way up the threads.

Adjustments make very small changes in steering effort but nothing that makes it work well.

Next move is to lower front skid mounting to lower hole hole and middle hole in back and see if that takes any weight off the skis.

 

[shagman]

I ran this setup at Grand Mesa all last week.
6# OSP turbo
10500' altitude
8fp. Empty
G-W-G spring with 2-1mm shims
41* helix set at 6-2
9300 rpms. Worked great in 7' of powder.

Sent from my iPhone using Tapatalk

 

[fiddlersgreen]

I lowered my skid and added a set of sly dog powder hounds and got very light steering with some push.
I figured the powder hounds would be more aggressive and heavier to steer but it was actually easier.
I think the lowering of the skid did it!!

 

[Vilas]

Finally got it off the rev limiter. 8FP with 4.6g in tip, .85g in center and .85g in base. G-W-G with 2 shims.

All three weight were balance at 74.62g

Hits to 8,400-8,500 quickly climbs to 8,900 and them flattens out at 9,050.

Lugs down to 8,200 in deep snow but climbs to about 8,500

Got a few more mph on top, see about 91-92 now but still hits the wall there! Baffling??

Belt (8DN) only gets to 1/4" from top of sheaves on primary.

I really think it may be secondary spring binding, I did rebate the Dalton 46/40 helix on a mill so not using washer to stage out the secondary.

Think I will try washer just to see if it makes any difference (Pink spring wrapped 6-1).

Still steers heavy like a pig, have had no success dialling that out. Stock ski, tuner ski, 135lb spring with freeplay remove and cranked about half way up the threads.

Adjustments make very small changes in steering effort but nothing that makes it work well.

Next move is to lower front skid mounting to lower hole hole and middle hole in back and see if that takes any weight off the skis.

I was having heavy steering with 135 # spring but was able to fix it. I put 65 psi in front shocks, 110 on the rear and the rear skid spring collar at 2 turns past when it starts putting pressure on the spring. This was a night and day difference for me. I think I had too much air in the front shocks and too much preload on the spring.

 

[Blue Dave]

Happy New Year everyone! I replaced the 3.6 g rivets with 4.5 g rivets in the tips of my 8FP weights but I am still bumping the rev limiter at top end which is only about 90 mph on the lake. If I spin on launch I will hit the rev limiter as well.

Here is my COTC set-up:
8FP weights with 4.5 g rivets in the outer hole.
GWG primary spring with three 1 mm shims.
46/40 helix with the stock pink secondary spring wrapped at 6-1. (The helix has the spring pocket machined 0.080" deeper to prevent spring coil binding without the need for placing washers under the helix.)

Questions:
1. Add more weight? How much & which holes?
2. Wrap the secondary spring at 3-3 or looser?
3. remove primary spring shims (will this reduce track spin on take-off by reducing the engagement RPM and will it also help lower the top end RPM's)?

Can we please keep this thread only about clutching? There are other threads about handling & suspension set-ups so please keep those types of discussions in the appropriate place so we can keep this clutching thread "clean" .

Thanks again to everyone for sharing your knowledge and experience. I am looking forward to getting my clutching dialed in with your help!

 

[shagman]

Happy New Year everyone! I replaced the 3.6 G rivets with 4.5 G rivets in the tips of my 8FP weights but I am still bumping the rev limiter at top end which is only about 90 mph on the lake. If I spin on launch I will hit the rev limiter as well.

Here is my COTC set-up:
8FP weights with 4.5 G rivets in the outer hole.
GWG primary spring with three 1 mm shims.
46/40 helix with the stock pink secondary spring wrapped at 6-1. (The helix has the spring pocket machined 0.080" deeper to prevent spring coil binding without the need for placing washers under the helix.)

Questions:
1. Add more weight? How much & which holes?
2. Wrap the secondary spring at 3-3 or looser?
3. remove primary spring shims (will this reduce track spin on take-off by reducing the engagement RPM and will it also help lower the top end RPM's)?

Can we please keep this thread only about clutching? There are other threads about handling & suspension set-ups so please keep those types of discussions in the appropriate place so we can keep this clutching thread "clean" .

Thanks again to everyone for sharing your knowledge and experience. I am looking forward to getting my clutching dialed in with your help!

Add 2.1g in mid. That's where I was before I went turbo.


Sent from my iPhone using Tapatalk

 

[Blue Dave]

I don't see a 2.1 g rivet in the list of Yamaha rivets. Is this an aftermarket rivet? I also noticed that because the 8FP weight is 11.5 mm thick the rivets that are shorter than 13.3 mm (11.3 & 10.3) will not be long enough to peen over to secure gem.

Where did you find the 2.1 g rivet and how long is it?

I have some 3.1 g rivets that are 13.3 mm long that I could put in the middle hole. Might be worth a try?

 

[bleedyamaha]

I see you have a rtx dx what size is your drive sprocket I have almost the same set up as you but I have a 14 ltx se and I am seeing 100 on hard pack road. Takes awhile but it gets there.

 

[stingray719]

I don't see a 2.1 g rivet in the list of Yamaha rivets. Is this an aftermarket rivet? I also noticed that because the 8FP weight is 11.5 mm thick the rivets that are shorter than 13.3 mm (11.3 & 10.3) will not be long enough to peen over to secure gem.

Where did you find the 2.1 g rivet and how long is it?

I have some 3.1 g rivets that are 13.3 mm long that I could put in the middle hole. Might be worth a try?

You can always use the 3.1 and drill a small hole through it to lighten

 

[Studroes144]

Finally got it off the rev limiter. 8FP with 4.6g in tip, .85g in center and .85g in base. G-W-G with 2 shims.

All three weight were balance at 74.62g

Hits to 8,400-8,500 quickly climbs to 8,900 and them flattens out at 9,050.

Lugs down to 8,200 in deep snow but climbs to about 8,500

Got a few more mph on top, see about 91-92 now but still hits the wall there! Baffling??

Belt (8DN) only gets to 1/4" from top of sheaves on primary.

I really think it may be secondary spring binding, I did rebate the Dalton 46/40 helix on a mill so not using washer to stage out the secondary.

Think I will try washer just to see if it makes any difference (Pink spring wrapped 6-1).

Still steers heavy like a pig, have had no success dialling that out. Stock ski, tuner ski, 135lb spring with freeplay remove and cranked about half way up the threads.

Adjustments make very small changes in steering effort but nothing that makes it work well.

Next move is to lower front skid mounting to lower hole hole and middle hole in back and see if that takes any weight off the skis.

Just a suggestion to anyone with low speeds, I'd pull both the primary and secondary apart and just check to make sure they move freely throughout the entire range of travel. Not a viper but recently had an issue with a buddies cat 7000 where it was deadlocked at 85, clutches were crazy hot, belt was burning some. After taking the primary apart I noticed right away that it was pretty tight, so I took it to my dealer, not sure what they did but they got it moving nice and freely. Yesterday on a plowed road it ran 98 three times and 99 once with me on it (250 pounds). So the primary clutch alone caused some major speed issues considering getting it to move freely cured a problem that was hurting us almost 15mph.

 

[stingray719]

Just a suggestion to anyone with low speeds, I'd pull both the primary and secondary apart and just check to make sure they move freely throughout the entire range of travel. Not a viper but recently had an issue with a buddies cat 7000 where it was deadlocked at 85, clutches were crazy hot, belt was burning some. After taking the primary apart I noticed right away that it was pretty tight, so I took it to my dealer, not sure what they did but they got it moving nice and freely. Yesterday on a plowed road it ran 98 three times and 99 once with me on it (250 pounds). So the primary clutch alone caused some major speed issues considering getting it to move freely cured a problem that was hurting us almost 15mph.

Barry is absolutely correct here. Our red viper when new was bound so tight I could not move the primary sheeve (with the belt off) in and out by hand. I used steel wool on the shaft.

 

[Studroes144]

Barry is absolutely correct here. Our red viper when new was bound so tight I could not move the primary sheeve (with the belt off) in and out by hand. I used steel wool on the shaft.

On this 7000 I knew there was an issue but thought it only affected top speed, with the clutch fixed up it is all around better tho, smoother up shift and back shift, engagement is the same as before but I could feel right away that it was gripping the belt better and also it cruises at much lower rpm. For as easy as these yammi clutches are to work on anybody can just do some basic checking to make sure everything is working the way it should