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Loss of top end, some remedies.

SUPERTUNER

TY 4 Stroke Master
Joined
Aug 16, 2003
Messages
1,257
Location
Waterbury, Connecticut
Website
www.easterncycleperf.com
Often in business, we all encounter problems with marketing products. I think by and large that most of the folks that are presently in the business that have been around for awhile sincerely want happy customers. With all the talk recently of top end speed loss using my air kit, I realize that something has to be done and I want everyone to know that I am trying to address this problem as much as I can.

All I ask is that everyone respects my statements. I respect everyone else enough to take time from my schedule to address your problems. There must be some creedence given to the things that I know are absolutely true. If you have the desire to come on here and challenge things that people say, keep in mind that this means to some of us that you are basically calling us liars and that I am afraid I must take offense to. So please, let's keep this topic free and clear of all "challenges" and keep it strictly of the technical nature. If you cannot accomplish this simple task, please do not read on and please go to another topic elsewhere on this forum or another forum of your choice. I honestly desire not to upset anyone. Here we go...

Things that I know for a fact are absolute truths:
1. The ECP Air Kits do EXACTLY what they are advertised to do.
2. The entire very offending torque curve is improved thereby not only improving engine efficiency but also clutch efficiency. (but there is a catch with this one)
3. The dynamometer does not know how to lie.
4. Only people controlling these dynamometers know how to lie and I am not one of those types.
5. Most of us are smart enough to realize that the dyno is not the only test method required for testing high performance products and services.
6. When you install certain high performance products, often there are other things that must be changed in order to optimize the questioned product.
7. More air packed into an engine with the proper amount of fuel will absolutely, positively make more horsepower.
8. If you are attempting to tune an area of your engine, clutch or otherwise and nothing is responding, this means there is a "governer" somewhere disallowing it to respond and means that you are addressing the wrong area of the sled. Example... If you go up 4 jet sizes and the sled does the exact same thing, jetting is not the issue.
9. It takes 100 pennies to make a dollar. (this means that everything on your sled has to be working togetherand not fighting one another)
10. A mind is like a parachute, it works better better when it is open.
11. When the results do not match the theories, believe the result and get a new theory.

CLUTCHING:
I believe that some of the problems associated with certain people experiencing top end speed loss is due to clutch alignment. This is not to say that everyone that loses top end clutches are misaligned but I think it is fair to say that this might be the truth in at least some of the cases. When we get a sled into our shop, we conduct the installation exactly as my instruction sheet states. This includes re-synchronizing the carburetors. I find it amazing the amount of people who do not conduct this VERY important procedure, yet when I ask them if they followed my istallation guide, they tell me yes. After some "digging" the truth comes out that they did not indeed perform this. Anyway, when we perform any mod, we are careful to check other things that might be affected by the installation of any power enhancing product or service. One thing very affected is clutching.

There are 3 major parameters of clutch alignment...center to center distance, perpendicularity and parallelism of the primary and secondary sheaves.

Center to center:
The shop manual lists the c-c as 10.57 inches.They also list however an acceptable tolerance of 10.51 - 10.63 inches. They need to list acceptable tolerances for several reasons. First, there are assembly tolerances that have to be acceptable on the assembly line in that not every single assembly tchnician is going to istall every engine of every sled exactly the same way. Another reason is due to the fact that the belt manufacturers have tolerances as well and too long or too short of a belt will influence the required c-c distance. Now understand that the factories do not bother with keeping every single item in alignment regarding optimum performance for the life of the vehicle. They sell trail sleds. Trail sleds are meant to go down trails and get you out into the woods to enjoy the sport. The factories do not care about a trail sled going 100+ MPH on the trail as that in their eyes is not repsonsible riding. However, if you are reading this, you are in all likelyhood a performance junky. What we do in dragracing is find a center to center that works. We then make sure that every single belt that we buy meets the length requirement for that preset c-c. This attention to detail removes one of the variables from the performance equation. If the sled doesn't go fast, we know not to bother wasting time on the center to center as a culprit. I suggest making 2 pointers out of bolts that thread into the PTO shaft and the jackshaft. These need to be adjustable in order to be set the same distance from the edge of the chassis to allow you to measure in a straight line. Turn these botls in a lathe to get amachined center point that will allow you to get exact measurements. Set the center to center at the predetermined measurement. I suppose 10.57 inches would be correct because it is halfway between the tolerance parameters. If you need to adjust the engine in the chassis, either take this to a shop capable of this kind of work or read the manual on how to remove the engine in order to know what bolts to loosen to adjust the engine alignment. Tighten the bolts and re-check the c-c and make sure it has held in place.

Offset and paralellism:
The factory repair manual lists offset as .590 inches. There are special tools designed by Yamaha (and every other manufacturer) to set offset. The offset is required to be set at a predetermined number to allow for the closing of your primary clutch versus the opening of your secondary clutch. What I like to do is determine what the offset is with the factory tool and then use a straightedge to set offset and paralellism at the same time. If the offest is off, basically your belt will try to twist and bend around a curve thereby making the belt go into a shape that it does not like. The belt wants to be used in a straight condition. What we do here at ECP is take a known flat/machined straightedge and lay it across the backside of the primary clutch. This straightedge needs to to be long enough to cover the top half of the primary diameter and extend back past the secondary clutch. Making sure the straightedge is not on any burrs and sits flat on a machined surface is desireable. With the straightedge on the primary clutch, take a machinists scale graduated in thousandths and measure from the face of the straightedge to the front leading edge edge of the secondary sheave and document the number. Then perform the same measurement at the backside (trailing edge) of the secondary to the face of the straightedge. By choice, you would want these measurements to be the same. On some of our dragsleds where we have solid motormounts, there is no engine deflection. On trail sleds, the engines are rubber mounted. This keeps the vibration from cracking the chassis'. It also makes for a more enjoyable ride as vibration doesn't end up being felt through the handlebars as much. Okay, now that your offset is set and your paralellism is set, we could move on...right? No you cannot! Why? Because we have not dealt with the problem of shaft deflection. What happens when you engage your clutch on a sled is the belt tries to pull the primary clutch and the secondary clutch together. The resisteance of this can make the primary clutch and the secondary jackshaft deflect. So now all your perfect setting for center to center, offset and paralellism are no good! Couple this to the fact that your rubber motormounts allow the entire engine to deflect and you could be off on your paralellism a bunch! What I do to counteract this is set up an built-in purposely placed misalignment. With the straightedge along the backside of the primary, put a little more space where the straightedge passes the front of the secondary verus the back half of the secondary. Let's say you have .625 at 12 o'clock on the secondary clutch sheave to the straightedge. Your built in paralellism misalignment would make the measurement at the front of the secondary to the straightedge let's say .645 and at the rear .620. This way when the clutch engages and deflection of all these components occurs, the driveline at the clutches is pulled into alignment under load.

Perpendicularity:
Now it is time to see how the engine tilt is as compared to the jackshaft. Take the straightedge and measure at 12:00 as it passes the secondary clutch. Document that measurement. Now measure the same way at 6:00. These 2 measurements should be the same or at least real close. If they are not, your belt will be required to "corkscrew" everytime it makes each revolution.

Let's suppose for a moment that you have a center to center that is on the short side of the tolerance or worse yet, out of the tolerance. When the primary clutch engages, your already grossly off parameters become much worse. By controlling these parameters and keeping them as close to perfect during actual useage will improve belt and clutching efficiency.

With the increased power that the ECP Air Kit adds, what might be a borderline tolerance is now way out of whack everywhere. This might explain why when people go back to the stock airbox, the sled goes faster top speed...because there is less power to throw the driveline out of measurement in all the axis'.

I also will agree with the theory of potential exhaust system issues. With too restrictive of an exhaust, the additional air induction created by the Air Kit may require a less restrictive exhaust method to take advantage of the kit.

I have noticed a trend that the folks complaining the most about lost top end are also the ones pushing more oil than others from the crankcase breather. I have no technical data to back this up other than it being an observation.

I have a drawing showing this detailed clutch alignment measurements. If anyone wants to post it here on these forums, I will gladly fax or mail it to you if you have the ability to post pictured here.

Remember, you should be well schooled in wrenching to perform these critical adjustments/repairs. The hard part is keeping all of the measurements set properly while adjusting one other one. I intend to look into manufacturing a device to assist us in setting and keeping the clutch alignments in proper place. I have checked the sleds that have our Air Kits on them and pull great top speeds and the clutches are all in a good state of alignment. I have however during the typing of this, called a friend at a local-to-me Yamaha Dealer and asked him to check one he had in the shop (he knows the way I like to check mine as described here)
and he indicated the one he checked "is way out of whack". Just an FYI. Very few of the sleds are set properly regardless of brand.

Hope this helps you guys and gals. There will be a quiz on Tuesday! :lol:

I would like to thank Matt Habada and Mike Hyman and Terry Davis for assistance with some of this R&D.

Freddie
www.easterncycleperf.com
 

All of these parameters which Freddie is addressing are crucial to your sleds performance. I would strongly urge all of you running the filters or not to check your clutch settings Freddie mentioned. I checked mine over the weekend and found out my center to center is definetly wrong. You wouldnt think that with a solid mounted engine that you would have to worry about this, but you do. After you get your settings corrected, I would recommend installing some type of engine tensioner like the ones found on a SRX. This will help with keeping your center to center settings within factory specs. To my knowledge Yamaha does not offer the tensioner. Any handy man welder on here looking for a project?...BBY
 
Freddie, your persistance in making everyone happy is excellent. All companies have problems, it's how these problems are dealt with that seperate the companies.

I still think the solution will end up being something simple.
 
LB, i have not looked yet to see what it would require. I wouldnt think it would be too diffuclut to come up with a solid style engine tensioner that we could bolt down by the crankcase...BBY
 
welterracer said:
BBy.. did you do some testing with the ECP kit on your sled??

If so what were your results and what do you think is the main cause of the loss of Top speed!!

Thanks!!

See, this is what I mean welter. You talk like everyone is experiencing what you are experiencing. You guys really have to think before posting something on the world wide web. Someone would come on here and read this and think everyone is lost on top end speed by the addition of my kits and this simply is not true. In fact there are more people going faster on top end than slower after the addition of the air kit.

For the record, I have had reports back from some customers that have gone in the high 1teens and even the low 120's on radar.

So how many of you have checked your clutches yet? What were the results of the checks?
 
Now is that to say that I need an aftermarket exhaust to get the full benefits of ECP filters, in addition to making sure my clutches are aligned? Now it is more like a car engine - add a cam, better port the heads, increase the cfm's and the exhaust flow to be able to use it.

The wish list keeps getting more expensive by the minute :lol:
 
Well I have to say thanks to Matt And Fredie . :D Last year I could not beat a 600 HO ,I now know what most of you are fealing at this point.This year the f7 was the one to beat in my class.After I put my heavy hitters and ecp kit on ,this rx1 is know beating the f7 in a 1000 ft run.I put a lot of hours in testing and makeing changes to get it this way.My center to center was off by 3 1/2 mm ,way to go yamaha. :cry: To day I race a 8oo ho 5 times in 1000 ft run and beat him 3 times .I well add more weight next time and see what happends.Good luck to all who are having problems in top end. :D :D
 
I dont know if this helps but we loss some mid-range and top-end by 7mph. in tests against other rx-1s by using the dayco 4432 ultimax 3 belt. When the stock Yamaha belt was put back on we gained the top-end back. Woodtic
 
woodtic said:
I dont know if this helps but we loss some mid-range and top-end by 7mph. in tests against other rx-1s by using the dayco 4432 ultimax 3 belt. When the stock Yamaha belt was put back on we gained the top-end back. Woodtic

Belts can definately make a difference. My 99 MachZ was really sensitive and ran best on Doo's Gold belt.
 


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