Sidewinder Top Gear

[ROCKERDAN]

You have to clutch different for the harder belts. It will take more pinch to prevent slippage. So less helix and/or more driven spring and more weight in the front clutch.

Every single time I have gone to a harder drive belt it has performed BETTER over the softer belts no matter the make or model of machine, but it takes a different recipe to make it quicker and faster. Harder belts distort less when pinching them thru their cycles of gripping the clutches. They always actually run quicker ET's and better speed but you can't just throw it on a set of clutches not calibrated for the harder belt compound and expect it to work.

The 8DN has worked great over all the years of the Apex both stock and big power turbo. Same for the Nytro, Vectors and even the Vipers who have converted to them. Put it on, clutch and gear for it and stick with it. It only a minor bit longer (like 1/8-1/4" longer) which will gear the whole ratio down from start to finish ever so slightly.

I'd guess a gram or two in the primary added along with a couple degree less helix and maybe a stiffer secondary spring and all will be golden. I'm actually planning to try the 8DN myself right out of the gate here this winter. I think it may really help with response, backshift and performance with the right clutch combo.

I hear ya Mike....and agree.

I only spent a weekend messing with one, and it revved the same, so did not want to add weight. I know of a few guys I talk with that cant blow one, while they will blow shorter belts. But the performance was so lackluster back to back with no clutching changes, i just run 8dn for spares and when Im not worried about performance. Sure would be great to make them perform as they are cheap....But I think the length is messing the ratio up overall maybe? They are over 3/8" longer then stock belt which is a fair bit.

Dan

 

[staggs65]

I hear ya Mike....and agree.

I only spent a weekend messing with one, and it revved the same, so did not want to add weight. I know of a few guys I talk with that cant blow one, while they will blow shorter belts. But the performance was so lackluster back to back with no clutching changes, i just run 8dn for spares and when Im not worried about performance. Sure would be great to make them perform as they are cheap....But I think the length is messing the ratio up overall maybe? They are over 3/8" longer then stock belt which is a fair bit.

Dan
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Is there a width difference Dan? I don’t recall and I’m 800 miles from home.

 

[ROCKERDAN]

Is there a width difference Dan? I don’t recall and I’m 800 miles from home.

Widths on both YAM belts are near identical....

But when you get to the ultimax(which Im running now) they are wider.

Couple belt charts below to help with other brand specs...

Dan


Ultimax specs

Cat Belts

 

[1nc 2000]

Widths on both YAM belts are near identical....

But when you get to the ultimax(which Im running now) they are wider.

Dan

If your running a wider belt Dan are you moving your secondary offset out the difference in belt widths?

 

[KnappAttack]

I hear ya Mike....and agree.

I only spent a weekend messing with one, and it revved the same, so did not want to add weight. I know of a few guys I talk with that cant blow one, while they will blow shorter belts. But the performance was so lackluster back to back with no clutching changes, i just run 8dn for spares and when Im not worried about performance. Sure would be great to make them perform as they are cheap....But I think the length is messing the ratio up overall maybe? They are over 3/8" longer then stock belt which is a fair bit.

Dan

Just because its revving the same RPM means nothing Dan. It can be slipping and still holding RPM. Hence the reason to "tighten the belt" with less helix or heavier secondary spring and more weight.

Lets just say it slips by an added 2-5% The performance is getting lost in slippage. So, get rid of the slippage. As a plus, a heavier secondary spring and or/less helix angle will also give better backshift, which the Winder is lacking anyway. The belt does not come up and get into a lower gear near quick enough with softer belts etc.

So going to a 8DN hard belt, should do everything better except run as much O.D. if you can grip it well enough. IMO it will E.T. quicker once you get the clutch recipe correct.

The added length will just gear it down from low to high ratio is all. Once you clutch for the 8DN it should be just as good or even IMO even better than the 8JP. the 8DN has worked awesome for the big HP Apex just fine for many years!

I've run all types of belts and machines over the years and as I said earlier, I've had much greater success with hard belts for quick E.T.s on all my drag sleds. They also stay more consistent as belt temps climb.

 

[staggs65]

Just because its revving the same RPM means nothing Dan. It can be slipping and still holding RPM. Hence the reason to "tighten the belt" with less helix or heavier secondary spring and more weight.

Lets just say it slips by an added 2-5% The performance is getting lost in slippage. So, get rid of the slippage. As a plus, a heavier secondary spring and or/less helix angle will also give better backshift, which the Winder is lacking anyway. The belt does not come up and get into a lower gear near quick enough with softer belts etc.

So going to a 8DN hard belt, should do everything better except run as much O.D. if you can grip it well enough. IMO it will E.T. quicker once you get the clutch recipe correct.

The added length will just gear it down from low to high ratio is all. Once you clutch for the 8DN it should be just as good or even IMO even better than the 8JP. the 8DN has worked awesome for the big HP Apex just fine for many years!

I've run all types of belts and machines over the years and as I said earlier, I've had much greater success with hard belts for quick E.T.s on all my drag sleds. They also stay more consistent as belt temps climb.

Yes, I didn’t mention consistency. Very good point, the 8DN gave repeatable performance run after run on my Viper where the 8JP could be all over the place. It was an easy decision on the Viper since it was the old tried and true Yamaha clutches and my primary was machined for full shift with the longer belt. I hope you share your results with us with the 8DN and the new clutches. It was a very common change on the Vipers, less discussion on it here for some reason.

 

[74Nitro]

The 8DN was first introduced on the 98 SRX. I went to the technical update course from Yamaha and have the 1998 book. The 1997 700sx came with the 8CH belt which I think was made by Dayco. In 98 the 700sx came with the 8DN(Mitsuboshi) and dealers were told that in order to update the 97 700 to take the 8DN belt, the rivets were to be switched in the primary weights which added about 1.5 grams.
Last year my 8JP blew with under 400 kms, so I switched to the 8DN, which I always thought was a good belt, and also economical.
Belt pinch should be better this year with the new helix angle, it would seem to me that Yamaha concluded there was some belt slip that was leading to premature belt failure....?

 

[ROCKERDAN]

If your running a wider belt Dan are you moving your secondary offset out the difference in belt widths?

I left 1mm of float or so....they are not a ton wider.