clutching and mpg

[srvfan]

been reading the clutching threads . will any of those changes that help the clutches shift out more for top end allow it to carry less rpm down the trail at say 20-60 mph and improve mileage ? at a steady 45 mph the Viper is turning a bunch more rpm then the vector and using more fuel.

 

[cannondale27]

been reading the clutching threads . will any of those changes that help the clutches shift out more for top end allow it to carry less rpm down the trail at say 20-60 mph and improve mileage ? at a steady 45 mph the Viper is turning a bunch more rpm then the vector and using more fuel.

That would all depend on how it's clutched. Try adding more wieght to middle and heel of weights. And or Gearing.

 

[RJH]

We have not done it to the SR yet but my 99 Phazer has..low RPM cruise.

I fool it to up-shift ....bigger helix #..trial and error..

So driving on the trail....I get up to say 60 or whatever...once I get going smooth....I can back off the throttle ..you can feel it ..the sloppy belt..for a millisecond...up-shift and the rpm drops 1500 to 2000 yet the speed stays the same if I stay smooth...thus saving fuel. If you have to get off the gas..gotta start all over again..it can be hard to drive like that takes time to learn momentum..and be smooth

With this setup....it will still come to life if I get aggressive on the gas as well..

You could clutch it to ..lug...but you will have lost ..the snap..

Some-people think gearing..
..but no matter what gear you put on acceleration stays the ..same ..until the clutch shifts out.

Some may experience a different feel with gearing......which means clutching was off..and the less or more gear has the changed the leverage or load on the clutch making if feel like it should have felt

Not sure when Yamaha figured it out that that can't gear a sled for twice as fast as it is capable of..but the finally did.

So your problem is..nobody can tell you what helix....sucks...I got like a high 40 angle on my Phazer with a stronger spring..

So...to test....just find a flat ..I guess lake.....drive with your test helix..and slowly back off with your thumb..when you find it you will fell it..good luck.


Too bad be couldn't talk carbs..I guess they are gone...

 

[cannondale27]

Funny you mention Carbs RJH. Best $ I have spent is my AFR guage. You would be amazed at the difference tuning can make MPG wise. Most of my miles were put on in the 13.5:1 afr range. This year with Ignition tune I have been way more conservative and am gradually leaning it out from the 11:1 range I started with. Figure a 80-100 mile fillup last year at 13.5:1 I would use 2-3 gallons less than the 800 Cat I was riding with. This year in same distance its about equal and one fill he beat me by a gallon. Surprised us both. Oh and the leaner I have run this sled the faster it is. Still tuning!

 

[RJH]

So..we don't want to steal this thread....in another thread can we talk about that. However I think we have given buddy his answer..

I should add that what he asked will not have a fuel affect as saving fuel is usually in the mid speeds like I mentioned.
Running at WFO..you should not be concerned about mileage..

The clutch dynamics can be better..and will help everywhere. buy that is still another story.

..........................................................................................................................
It is in the back of my mind..what you said....but I'm getting old fast so I best get on with it....

What you do AFC is all over the google but I have not looked deep into it..yet...as there are so many other things going on with the engine...(why did I get a 4/ geeeez)

I am looking for injectors same volume buy many more holes to better atomize

I think I want a AFR gauge...without re flashing I would guess a pre aftermarket box would only let you go the "lowest" limits if the existing box.

This engine is not happy above high 7000's ish and needs help there....goes to 9200 OK but not happy

 

[Studroes144]

Funny you mention Carbs RJH. Best $ I have spent is my AFR guage. You would be amazed at the difference tuning can make MPG wise. Most of my miles were put on in the 13.5:1 afr range. This year with Ignition tune I have been way more conservative and am gradually leaning it out from the 11:1 range I started with. Figure a 80-100 mile fillup last year at 13.5:1 I would use 2-3 gallons less than the 800 Cat I was riding with. This year in same distance its about equal and one fill he beat me by a gallon. Surprised us both. Oh and the leaner I have run this sled the faster it is. Still tuning!

25% throttle, zero boost and cruising at 70 mph, got mine set at 12.8-13.2, 50% throttle making 5ish psi 11.8-12.2. WOT 10.8-11.2 at 10-11 psi. I can go out and ride any day in any condition and get anywhere from 15-17 mpg on a 240 horse sled. It's amazing what you can gain when you're willing to watch an afr gauge and make some simple adjustments. I know exactly what RJH is talking about with getting up to speed and then getting that little extra upshift to drop rpm, wouldn't have ever thought there was a science to it and I wouldn't have ever been able to describe it but when it happens it happens very naturally and definitely feels right. I by no means am in the sport to try and get gas mileage, but if u can get mileage and performance at the same time, why not?

 

[srvfan]

My vector did the up shift trick very well , the viper just seems to hang there and not shift up only couple hundred miles though so everything is tight

 

[RJH]

My vector did the up shift trick very well , the viper just seems to hang there and not shift up only couple hundred miles though so everything is tight

Yes my STX 146 has good OEM shifting if you like to just putt along....works for its intended purpose on that sled..but far from performance..I made a simple change and it went 24 KPH faster ..but overall was wrong still

Not at the saving fuel mode yet..still working on going fast...but I trail ride more than I work on it as it gets me by..