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Engine breaking

Rikar]...had to relearn how to approach corners by using my engine rpm's as a brake instead of my brake lever.

Joe]...What I do to diminish this effect on deceleration was to simply keep ever-so-slight tension on the throttle, as if keeping the throttle slight above idle. I find the sled coasts for a long time.
When you want full engine brake application then fully release the throttle.

Another way to reduce the engine brake "feature" is to look at the compressive forces of the secondary spring. [not torsion values]
Example spring for lack of better numbers; You have a secondary spring that when compressed and installed in your secondary it has a force value of 85 lbs at rest. At full-shift the spring has a compressed force value of 120 lbs.
Example spring without factor of torsional value = 85/120.

Take the start force of the secondary spring and reduce it by 20 lbs, can you find a spring that has force values of say 65/120?
If so then install such a secondary spring and continue to use the same torsional value for calibration.

The reduced spring "installed force" is the largest factor on the magnitude of retarding force the engine brake feature provides.

For engineering techy's you could look at the dimensions of the present secondary spring and to know one that has a less install force value, go for a spring that is "longer free-length with smaller diameter wire." however note that it will also have lower final forces. Can go for a spring that is shorter than your present secondary spring however larger wire diameter, note that it may have higher final forces.

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craze1cars]...Unfortunately it's almost impossible to sort one from the other
Joe]...When doing research use key words from either the knowlegable one or the speculator and search for contibutors who support the comments with their own experiences.

craze1cars]...To make matters even worse, the ones who have actually found the BEST answers will NEVER post their answers on the internet for free
Joe]...Then take another avenue and not try to find "the hot setup" or "flavor of the week" which information could be good or malicious and discard values people write and start to learn how to listen to your own sled tell you what is right or wrong with the clutch calibration.

Discuss and want to learn how to troubleshoot and tune the system. To do this the tuner should know what questions to ask the sled then let the sled do the talking in your ride/exercises and relate your data to [the personality of the sled vs. your own clutch details.]

Principles are comprehensive so they are understandable by everyone which; Principles are fundamental law(s).
Does not matter brand - Only matters is...CVT; Regardless of snowmobile, junior drag car, ATV, terrajet, industrial slurry pump....etc.
Recognize problem, look at data[personality] know the clutch components [forces/angles] and change components as the sled tells you to.

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You can troubleshoot what is wrong with your system if you answer these questions...
What you can do is type out the answer in BOLD letters at the end of each question.
The answers give you a snapshot of the fitness of the system.
You can look at the clutching details [spring forces, pretension, flyweight mass...etc] and now have a mental picture of what number/force in the system can be or should be changed to correct the calibration.

Be accurate in filling in blanks at end of questions...

* What are your rpms supposed to be on the tach to achieve "actual" rpms.
* Was the sled sluggish?...Does the engine respond first and a momentary delay before the sled reacts?
* Where was it sluggish?...At what mph along the shift curve is the sled sluggish?
* What was wrong with the rpms?...Higher than rated, lower than rated, drifting higher than rated, drifting lower than rated?
* Where were the rpms wrong?...Low range, midrange, top end?
* Was the performance good in the bottom end but lacked in the top end?...Low mph?
* Did the rpms fall off on the top end?...Did the rpms go from rated and drift lower?
* Did the rpms climb from the start to full shift?... yes or no
* Did the rpms be excessive during the whole run?...yes or no
* Did the rpms hunt going higher and lower?... yes or no. What shape are the secondary buttons/rollers in?
* Was the engine rpms slow to rev/accelerate when you quickly press the throttle?...Did you double check for correct flyweight or pretension
* When you let off the gas then press the gas again, did the engine hang up on a low rpm?...yes or no
* What is backshift like when you cycle the throttle; Is the engine quick to rev?...yes or no
* What mph did you get when topped out?...lower than previous, same?
* What kind of temperature did the clutches produce? Primary temp? Secondary temp?
* Did you check your secondary temperature and primary temperature on the sheave faces?

These questions help to analyze the system as a summary of a detailed breakdown of different parts of the the whole shift curve from start to full mph.
You can derive an answer from knowing principles and the actual details of the clutch parts.

Primary spring -
flyweight mass -
Engagment -
secondary spring -
sec. spring pretension -
helix angle -
gear ratio
 

I have experienced the braking issue when descending a mountain with hard surface and can understand that point of view but...for trail riding, I love the engine brake. It took some time to get used to, but now I use that effect to control my sled.

Back in 03 there were many posts on clutching that mentioned vastly reduced braking. I do not know if they are still available. My searching skills are limited at best.
 
Hey Dynamo Joe
Great post. I have been doing my own clutching for 15 years,and I haved learned alot by doing it.Would spend days dialing a sled in.Wish I would have seen you on the computer years ago.Keep up the great posts.
Rich
 
Dynamo Joe WELCOME!!!! So glad to see you here on this site! I can't recall where I found out about you before...(pretty sure it was Dootalk?) But wherever it was I recall you to be an extremely helpful and knowledgeable clutch tuner. Your own site helped me immensely in learning how to tune my Ski-Doos over the last few years. I'll be starting over now that I'm on a Yamaha but I'm sure the general principals are the same.

I hope you hang around here more frequently...I'm sure everyone will find your input to be extremely valuable.
 
Since Yammy is gunning for #1 :yam:, perhaps Dyno Joe is looking into the Yammy side of things...a turn to the dark side perhaps in his future? :welc:
 
Hello:
I will probably be running across this forum now that I have more time to browse it.

I am looking to the yammy side of things. Made a kit for an RX1 a few years ago.
All I gotta say is, it's fawking FUNNNNNN!!!! Gained 11mph on the lake and actually runs rated rpms now....backshift is incredible if you like that motocross style throttle response.

Have been getting chatted up by a turbo apex guy so am going to do something for him.

Question:
What business names/vendors in the aftermarket industry are doing Yamaha clutch kits?
whether Big players or small backyard players that are known?

Hope y'all can help with a list for me...

thanks
Joey
 
You will significantly decrease the engine braking if you run SLP anti-wear pads in your track - anyone who has been on a Yam 4-stroke without them gets on my RX1 and is suprised every time - even my dealer didn't expect them to make that big of a difference. A lot of the braking feel isn't necessarily from the engine.
 
To eliminate almost all the engine braking ON MY 03 RX first I installed extrovert drivers,cut the holes out in the track and added the extra clips,went with the o-s-o stock yammy primary spring and the silver secondary spring,lock washers in secondary, loose loose track. Now she's an Apex eater without engine braking(oh yea a few other minor mods)









:die =============== :jump: --------------------------------- LaLaLa
 
I seem to recall that on TY back in early 03, there were a lot of guys experimenting with heavy hitters and higher spring rates. One of the perceived negative results a the time was a reduction in engine breaking. That was way before the site crash, I do not know if that info is still on the site. Maybe a question for Mr. Sled.
 
I noticed a big decrease in braking on an Apex Mountain when I switched to hyperfax sliders.

Resistance on the big mountain tracks seems be pretty high.

Mark
 
Yes I do remember a big difference in rolling resistence when I went with a fully clipped track.I was hoping my mileage would go way up but it never made much difference.

One simple method of reducing engine braking is turm the idle up slightly.

Ive tried several different clutch kits over the years and they all reduced engine braking over the stock components.

I prefer the braking myself and actually turn my idle down for MORE braking.Heck id put a jake brake on it if It was cheap and lightweight =)

I have to relace my brake pads this season for the first time, over 12,000 miles on them.
 
My problem is i have a bad back so my susp is set up very soft and my nose dives badly on deceleration. .........like really bad....wants to throw me over the bars bad.i like the fact that my brakes are goint to last forever but my hospital bills are getting out of hand....lol

We all still have that sence of humor we talked about earlier .....right?
 
You have to ride the Yamaha 4 strokes very differently from a 2 stroke.
You have to ride it like you would riding a superbike like the R1, on the bike you only reduce the throttle a tiny bit going into a corner...
When entering a corner or when you are about to slow Down, you do not want to fully release the throttle.
Reduce the throttle a little as first then more as the speed drops.
These sleds you don't want to coast away like the 2 strokes did, the compression Levels are way to high.
 


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