IKF Yamaha Enduro (long course) proposals.

[Erik Halvorson]

Hey guys and gals,

There is a rule proposed for the laydown yamaha class that is on the books. It is said that the rule is to save the racer/sponsor money and it is also said (rumoured) that the rule is to open the door to having an IKF RRGN at Road America and thus the WKA guys will hopefully attend. The proposal is to outlaw the slippy pipe and institute a fixed pipe rule. I beleive the proposal specifies using an RLV A4 pipe. The header and the flex are left open.

My question is, how is this going to save the current racers in Yamaha Enduro? They will all have to go buy a pipe. No savings there. The only person it saves $ for is the person replacing a pipe or just entering the class because a fixed pipe costs less than a slippy.

Next item, There is no restrition on remote carb adjusters. The Slippy pipe lets you tune/fool the engine into making a wider torque range than any fixed pipe can deliver. Agreed, the slippy does tend to stress the engine more than a fixed pipe. With a fixed pipe you can somewhat compensate for the narrow torque band by playing with the mixture canstantly during the race in order to get more torque where the pipe is not designed to make more torpue. This is usually accomplished by using a "carb-trigger" or remote carb adjuster. The risk being that for the beginner or uninitiated, you run a high risk of melting down the engine (sometimes true for the experienced too) and that costs more $. Are there any stats on which causes more engine failures (slippy tuning or carb-trigger tuning)?

If in fact this proposal is to save the karter $ then I propose we outlaw remote carb adjusters too (in Yamaha Enduro classes). I am also for using one of the wider torque band pipes than the A4 which is all top end. The engine was originally designed to turn 12,700 with a run out of 13,200 and here we are spec'ing pipes designed to let it rev into the 14k's. Hmmmm. What is everyone's thoughts on this?

[Deborah Davidson-Harpur]

Glad you brought this issue up. I too, would like to know what people think about this issue.

I hope that when they write down their thoughts on this issue to you, they also send a copy of the opinion addressed to the IKF BOD to the IKF office with their IKF # on it... at least 2 weeks prior to the Oct. meeting.

[John Stafford]

I thought I read the proposal to say "L4". Is that a new generation fixed pipe? If so, then the only one to benefit financially from this deal is the pipe manufacturer. Even if it does say "A4" we don't need a pipe restriction. If this is gonna hurt your wallet then go run the Sportsman class, they have a spec pipe. It's called a "can".

[Bill Kassy]

Although not an IKFer, since I live on the East Coast - I will give you my two pennies on this.

If this a new class, then a spec pipe may work. However, if you are not going to limit flex length and require a certain header then all the effort will be trying to figure out what the best header is, etc. Not a $100 pipe but a $35 at a time header.

At WKC, we picked a pipe and a header and specified a minimum flex length. This class is used as a jump in between the can and the open pipe yamaha classes and has been fairly successful.

If the goal of this class is to reduce the cost of the class, then go with a can, etc. If the goal is to try to limit the tuning and still allow some performance - specify the header, min flex, and a spec pipe. If the goal of this class is neither, then I would recommend not to even try it.

To run at the national level in the Yamaha Pipe class, it requires a fresh motor each race, fresh tires, fairly fresh clutch - thus the attraction of the Euro motors or the shifter classes.

Why spend $450 each race, plus another $150 for tires, when you can go faster in a Euro (new top-end about $150), or a shifter (new top-end $150). Granted the initial outlay is a lot more in either of those classes, and the overall costs are probably similar, but you do get a whole lot more performance out of a 100cc Euro motor or a 125cc shifter motor.

At least with a Euro motor it is designed for the rpms that we run, but not for the length of the Enduro races. The motor is a lot better designed than the KT100. Of course, when an engineer from CRG came to Daytona for the first time to see their 100cc motor run in the Euro-5 class, his first reaction was -"you are flat for how long on the oval?" They couldn't comprehend the stress that a 2 1/2 mile straightaway puts on a 100cc motor.

So the big questions that I would ask is
"Is this class going to increase overall participation or is this class just going to take people from existing classes?" If the answer is the later, then I think you have your answer.

[Erik Halvorson]

John, I don't want to go that much lower ! We run sportsman also but the difference between even a fixecd pipe and a can is huge in the way they pull out of a corner. BUT hey, if we can all come to an agreement, let's have a light and heavy sportsman & dump the yamaha pipe classes. Then we end up with a huge jump in performance between sportsman and 100cc Controlled. Hmmmm, hey, we could always bring back Piston Valve. Typical Euro PV engine is much better than the Yamaha....

[Erik Halvorson]

Bill, the proposal is modifying an existing class. Taking it from Open Pipe (slippy works best all around) to a fixed pipe. There is no other restriction on the exhaust proposed other than that. I don't see how this is going to increase participation on the west coast. Nor save an existing yamaha pipe enduro racer any $. I can however see increased IKF participation if the suggested rule puts our Yamaha pipe class inline with WKA (as in identical rules) and thus open the door for IKF to hold midwest and eastcoast races (maybe co-sponsored with WKA or something). I am willing to try things that are for the better good but I don't want change just for the sake of change.

BTW, IKF's RR classes for Yamaha are:

Sportsman (can) @ 390lbs
Yamaha light Open Pipe @ 350lbs
Yamaha Heavy Open Pipe @ 390lbs

The proposal would make the open pipe classes a spec'd fix pipe. Oh yeah, there is anoher proposal elimintating the light class (and Piston Valve i beleive).

[deborah d-harpur]

There are other RR classes for Yamaha's. The Sit-up Yamahas that is!

Yamaha sit-up
yamaha ltd.classic lt.
yamaha ltd.classic hvy.
yamaha ltd lt.
yamaha tld. hvy

I think both Jr. classes are yamaha too, but could be wrong on that.

also, you can choose to run yamaha's in other classes.

nothing to do with your question on the proposal, but since you were listing yamaha classes, figured us sit-up's shouldnt be forgotten.

I was thinking of running my bodywork sprinter in the yamaha sportsman class, but we are redesigning the kart so I won't.

[Debbie Kuntze]

The proposal does not benefit the Southern Calif. racers. With the track we run (even Streets) a slippy is better for the long straights. Personnaly I run a fixed most times as I don't have time to "fuss" with a slippy set up. (I also run Sportsman and at times a sit up.) Anyway, if someone has a fixed, it's the A4, so EVERYONE would have to buy a new pipe. I definintly see the reasoning for the change, to attract more racers from the midwest and east. But, I don't like the idea of the L4.
IKF has my letter, do they have yours?
Debbie K

[Debbie Kuntze]

BTW-what pipe does WKA and WKC run?

[Ken Johnson]

I fully support a spec fixed pipe for the Yamaha class. Either L2 or L4. IKF is the only org that allows slippys in Yamaha and at that only the West Coast guys run them. In the Midwest IKF races (SWRA) we all run fixed pipes w/o problems or major expenses.
Having run slippys in Controlled for years I can definately say they are not the answer. We're already having a difficult time attracting new laydown racers because they can't fathom being able to drive a kart laying down (really, it's very natural once you've tried it), adding in the nevessity to have to tune your exhaust length at the same time is too much for most beginners. And having to operate a slippy pipe and a carb trigger at the same time? Forget about it, they'll go buy a sprinter and we've lost another chance at growing our class.
Carb triggers are a pain too. But remember, they're not a speed enhancing device, they're a safety device by allowing us to keep out hands on the wheel. If we disallow carb triggers we'll just go back to reaching over and fiddling with the carb while driving.
So, is the real question here speed or cost? Or is it, "This is the way we've always done it so we don't want to change"? Fixed pipes are cheap so it's not the money so long as you only have to buy one. Speed is relative. I can have more fun with my sportsman setup because the driving has to be more precise. To me the biggest issue is promoting the growth of the class, and with all due respect, I don't believe slippy pipes are the answer.
-Ken Johnson www.soa-design.com

[Ken Johnson]

One other thing regarding spec pipes. A lot of people make the argument that all it does is make money for the manufacturers and retailers of the pipes. I disagree. Yes, they do make money on your initial purchase. But, if you have a stable rules package (like Yam Sportsman) that stays the same for 10 years, they lose a lot of repeat business because the only reason to buy a new pipe is if you wear out the old one (hard to do w/o crashing and i don't recommend that).
So who really comes out better in the end?
-Ken Johnson www.soa-design.com

[scott berkheiser]

Ken,

Another point on the pipe manufactors making money on spec pipes. I usually win a free pipe certificate each year from RLV. So I bought the first sportsman can and all the rest have been free. If anyone, it seems like RLV is losing out on the deal.

Scott

[ August 24, 2001: Message edited by: Scott Berkheiser ]

[Erik Halvorson]

Ken, is the L-series of RLV pipe the stamped one?

BTW:
I never said that the Slippy was THE answer to Yamaha performance.
A "carb trigger" is different than a remote (twist type) carb needle adjuster. the twist type is used to tune the carb and the trigger is used to fool the engine/pipe combo into making more power than if it was in a static state of tune (similar to a slippy) and it takes constant tweaking of the needle (trigger)throughout every lap to make it work correctly (always varying the mixture at different rpms to get the max torque). I think this is much more difficult to learn properly for the beginner that the slippy but it is only my humble opinion.

Is the WKA spec pipe class open flex and header or is the header spec'd and a minimum flex spec'd? What are the front runner's turning for RPM? Are guys using the "trigger" or just a remote adjuster? I have no problem reaching over to the carb and twisting the needles but I do know it can be a difficult task for some (such as my dad, Ken Kohanes, who uses a remote twist-type adjuster).

What do you guys think is going to be the best for U.S. RR (long course) karting?

[Donald Dump]

As a WKA guy moving West I would much prefer the fixed pipe. As has been said the West IKF is the only place a Yamaha uses a slippy pipe. WKA does not have a spec pipe class but the Woodbridge Kart Club does. It uses the Sportsman Header with 10 -11 inches of flex with a stamped pipe. At equal weights it is slower than the run what you brung folks but not by much and it makes for close competition without playing the pipe or header of the month club. As for the carb trigger, just like looking at the track over your toes becomes comfortable, constntly playing with the trigger becomes automatic very quickly.

[Erik Halvorson]

Before I submit my proposal letter (if it is not already too late) I thought I would run it by the forum group first.

"Change Yamaha Enduro (laydown) from an open pipe class to a spec pipe class. Required pipe RLV L-4 stamped pipe. Required header RLV 26S (sportman header)."

The reason I put in the L-4 instead of the A-4 is that IF this is really to cut cost for the racer then lets make it the least expensive pipe ($85 verses $114). Regardless of what pipe I think we should specify the 26S header. This will lower the importance of "working" the exhaust port so much and thus lower Blueprint cost (maybe?). Especially if they are deleting the light enduro class (it was on the proposal list) then we will most likely be running the sportsman class as the second class so if we have only one spec's header, that will lower our costs too.

What do you think?