Expert opinions on AMA 144 rule?

[CJG]

I was just curious what you guys(Rich and Eric) think about the AMA allowing 144cc two-strokes to race against the 250F's? Good idea? Bad idea? Too little too late? Is 144cc's enough? If you were made emporers of the AMA what would you do, if anything, to even the playing field? What about the 250/450 class? Do you feel that anything needs to be done in this class, and, if so, what would be a fair displacement for the 250's?

Sorry for all the questions, but I'm really curious what the engine gurus think about these new changes. Thanks in advance.

 

[JustinC]

i have a question about the 144. i read at ktmtalk.com that boring out a 125 to a 144 enlarges the exhaust port causing the ring to bulge out every time it passes over the port, and this bulging leads to very short piston and ring life. is there any truth to this?

 

[theMotoMan]

It is my understanding the AMA wanted to give an advantage to the 4-strokes so that people would want to switch over to a cleaner-burning, more environmentally friendly motor. It seems like they are accomplishing their goal, so I'm not sure if they will try to even the score by allowing larger 2-strokes.

Having said that, I'd still like to know what the experts say about a 144cc vs. the 250F, including reliability, etc.

 

[steve125]

i have a question about the 144. i read at ktmtalk.com that boring out a 125 to a 144 enlarges the exhaust port causing the ring to bulge out every time it passes over the port, and this bulging leads to very short piston and ring life. is there any truth to this?

It can actually makes the EX-port smaller and it needs to be opened back up. Porting is always part of the big bore kit.

I have done many 144's and havent had a single problem.

 

[Jeff Howe]

Steve,

Any chance you may have chronicled a 03 YZ 144 here? How about you send me an email with some details?? I'm thinking I'm going to build one for kicks soon and would like to do it right.

 

[bclapham]

Steve,

Any chance you may have chronicled a 03 YZ 144 here? How about you send me an email with some details?? I'm thinking I'm going to build one for kicks soon and would like to do it right.

Steve is the YZ144 master. :cool: We just need to convince him to come on out to Red Bud for 06.

 

[Eric Gorr]

I think that the whole matter is a poorly planned fiasco. Why didn't the AMA do their homework up front when the Japanese manufacturers came to them with the idea of changing the displacement to give an advantage to the 4-stroke? Thats the first question I asked because I worked for an F-1 vendor at the time and knew what kind of power could be produced from a trickle-down F-1 engine. I also questioned the reliability aspect and the cost of racing. The AMA touts the hollow promise of looking after the best interests of American riders and businesses, "keeping the cost of racing down". Thats bovine fecies! Its like nobody has any clue about technology, its ramifications, and the cost of racing. I can't tell you how many dads have just thrown in the towell and pulled their kids out of motocross because their kid downshifted over a jump and handed daddy a bill for $2,500 because the valves went through the piston and out the bottom of the cases. The advent of 4-stroke 250s has drawn a line in the dirt between Rich Daddies and Poor Daddies and significantly raised the price of racing.

As the AMA allowed 4-strokes to compete with double the displacement they also pulled the 2mm maximum oversize rule and eliminated crankshaft stroking forever. The 2mm oversize rule enabled an industry to grow in America. It brought in foriegn investment, employed a lot of people, spurred new product development. Good things for American motocross. Now I agree that 2mm changed the face of minibike racing for the worse, but all it did to the 125s and 250s was drive them down farther.

Do you guys have any idea how many 2-stroke 125s and 250s are sitting on showroom floors and in warehouses? And not just 2005 models, I'm talking as old as 2001 motorcycles. There are thousands of motorcycles that will have to be shipped to countries like Estonia, Slovakia, and Quator just to be sold for pennies on the dollar. Motorcycle shops are going broke at an unprecedented rate because they're stuck paying interest on motorcycles that the AMA made obsolete.

I remember when the 3 companies that lobbied for this rule change, told me of their intentions. I laughed, I didn't think they had a snowball's chance. I'm glad it happened but quite frankly when the AMA yanked the 2mm rule, sales of 144s jumped dramaticly because people felt that if they were going to cheat, they were going to cheat bigtime.

If they AMA really looked out for our interests they'd create a separate class. 125 2-stroke and 250 4-stroke. Forget the displacement parity, making people buy new bikes then asking them to spend and average of $1,000 to build a 144 is just plain goofy. You'd think that the AMA would want to create extra classes so there will be more amateur champs and more revenue from entry fees. Splitting the classes will give people the choice to determine if they have a rich or poor dad. I'm not putting down the dad who has financial resources to put his kid on the best equipment. There is a group of kids with enormous talent that needs to be fostered, and 250Fs are always going to be National Pro Class. If they want to be pros, they need to learn to ride 4-strokes starting at the schoolboy level. So the rule excluding 4-strokes from schoolboy and junior classes is a step backwards. It makes dads buy a 2-stroke 125 and a 4-stroke 250. And its tough for the kids because they can't make the transition between the 2 vastly different bikes.

Overall I'm glad the AMA changed this rule because it legitimizes all the 144s out in the field and encourages riders to be honest with prospective owners when they sell their used bikes.
On the dark side I expect to see a wave of engine tuners offering 144 conversions for ridiculously high prices, and a corresponding slew of magazine tests touting performance gains on par with the price of these kits.

I've been building 144s longer than any tuner in thei business. I built the first one in 1976 with my RM125A, using a 2mm oversize Wiseco from a 1975 model. The AMA has always allowed big bore 125s in motorcycle racing like hare scrambles, enduro, hillclimb, and dirt track. We've had a strong business in the Vet classes too. A 125 chassis is the best handling mx bike and raising the displacement is a natural evolution. Its also technically difficult. Everytime a new model comes out we have to reconfigure so many variables to get the best compromise of performance and reliability. Perhaps this new rule will encourage new product development in aftermarket exhausts, pistons, heads, and reed valves. One thing is for sure, lots of people are going to shell out a ton of money with inexperienced tuners and break a lot of parts before the dust settles. And hopefully the AMA won't retract this new rule when some Japanese motorcycle manufacturers decide that it hurts their business.

Here's a suggestion for the powers that be at the AMA. If you're really serious about keeping the cost of racing affordable, how about setting up an investigative commitee to analyze the effects of planned obsolecence engineering practises specific to 250Fs. There is significant evidence that SAE and JSAE standards are being violated, causing injuries to riders and raising the average operating cost per engine hour. I think its time to take a cue from NASCAR and establish some design standards on these over-priced motorcycles.

 

[CJG]

Wow Eric, thanks for the reply. You bring up a lot of points that I hadn't even begun to consider. I'm very sorry to hear of all the people who are having to give up racing altogether because of the long-term costs of the new four-strokes, but it's something I knew had to be happening. $2,500+ to rebuild a blown engine is outrageous.

Expecting the AMA to do the right thing is pointless. I've never known the AMA to do the right thing for off roaders before, so why should they start now. That's why I'm no longer a member of the AMA and refuse to ever join again, until they can offer me something more than the priviledge of racing AMA sanctioned events. My money is better spent being a member of the BRC. They actually try to help us off roaders. Sadly, they just don't have the money or power of the AMA to make a huge difference for all riders. The AMA has enough financial clout to really make a difference, they just don't want to do it. They didn't even want anything to do with motocross in the beginning, until they saw that there was money to be made in it.

I really like your idea of appointing a panel to research the "planned obsolecence engineering practises specific to 250Fs". But if that panel is composed of AMA board members I have no doubt that their findings would be extremely flawed. They're supposed to work for their members, but, in reality, they work for the manufacturers. Somehow I doubt that any real effort will ever be made to create parity in the classes, because that would just hurt the pocketbooks of the AMA's employers.

I really enjoyed your interview on Pit Pass radio. Rich mentioned a possible one-on-one, in-depth interview with just you on the show. Any word on that happening? Again, thanks for the reply. Your insight into this issue is greatly appreciated. :cool:

CJG

 

[steve125]

My best friends son just turned pro this year. All the new 06 4 strokes are out, but Dad went 2 stroke to end the season. Picked up a new 06KX 250 and used 05 KX 125 thats soon to be 144'd. His son is so hard on bikes that the 4 strokes have proven very unreliable. He gets 2 free bikes a year from the local shop. And as he puts it, no way would he pick them up now(the 4 strokes) they would be clapped out before next season even starts.

Dad finds the new KX 250 quite refreshing. We hope it will help his son's skills/charge. Yeah he has to work harder, but hes young and its good for him. 2 weeks ago he won a local A race, he was the only 2 smoke, that was cool. :cool: The valve train issues cost Dad big $$ over this summer and he needs/wants a break from all that. It's not just the money, its the down time the bikes need to be repaired. He'll pick up his new 4 strokes in early spring, something hes really not looking forward to.

oh and great write up Eric!

 

[MikeT]

how about setting up an investigative commitee to analyze the effects of planned obsolecence engineering practises specific to 250Fs. There is significant evidence that SAE and JSAE standards are being violated, causing injuries to riders and raising the average operating cost per engine hour.

Eric, can you expand and further explain this issue to those of us who are not really sure what you are talking about here? I'd like to know more about this.

 

[RM_guy]

Very interesting discussion with good insight from Eric.

The thing that bothers me is that the push towards 4 strokes was due to environmental concerns with emissions. Granted 4 strokes can meet that standards easier but there was also efforts to get 2 strokes in the game but they are all on the back burner or canceled because 4 strokes are the defacto standard now.

When the first YZF400 came out I thought, that sounds like high maintenance, and secretly wished for it’s demise. When they took hold and then the YZF250 came out I made a note to never buy a used 4 stroke because chances are they weren’t maintained and the next buyer is in for a huge headache and lightening of the wallet. $2500 to rebuild a top end is just crazy. When they stop making 2 strokes I keep mine and nurse it along for as long as I continue riding.

Not only are 4 stokes harder and costlier to maintain, they are outrageously noisy. Part of what gives it more power is an unrestricted (read noisy) exhaust. So now we have a technology that was suppose to be better for the environment but is way louder that what it is replacing. And to make a 4 stroke quieter you loose more power than making a 2 stroke quiet so the power begins to equal out.

I guess my point is that there didn’t seem to much planning on moving to 4 strokes. It was a knee jerk response to the environmentalist and 4 strokes are perceived to be a cleaner way to go. Now were getting hammered for loud bikes that the greenies encouraged us to go to. Sounds like the greenies did more planning on how to get rid of dirt bikes completely than the AMA did to protect our rights in the future.

 

[Rich Rohrich]

And to make a 4 stroke quieter you loose more power than making a 2 stroke quiet so the power begins to equal out.

You need to do some homework. :coocoo:

. Now were getting hammered for loud bikes that the greenies encouraged us to go to.

Your view can't possibly be this myopic. Do you honestly believe there would be none of the current land/track closures if modern four-strokes had never taken hold? 100+ decibel engines bother people regardless of the source. Bring some sound test equipment to the track some day and you'll see there are lots of culprits inculding the track maintenance equipment.


People who don't want drag strips, circle tracks, MX tracks, or any other motorized sports near their homes couldn't care less if it were steam engines running. The sound, dust, traffic, etc are all sore points for them.

 

[dante]

You need to do some homework. :coocoo:



Your view can't possibly be this myopic. Do you honestly believe there would be none of the current land/track closures if modern four-strokes had never taken hold? 100+ decibel engines bother people regardless of the source. Bring some sound test equipment to the track some day and you'll see there are lots of culprits inculding the track maintenance equipment.


People who don't want drag strips, circle tracks, MX tracks, or any other motorized sports near their homes couldn't care less if it were steam engines running. The sound, dust, traffic, etc are all sore points for them.

He's (RM Guy) not saying their would be no closers of riding areas... He's saying they are just louder, and that does make a big difference... Were I live kids have ridden dirt bikes everyplace in town for years, now they are trying to put an end to it... After years and years of kids riding, now it's a big problem... Why do you think that is? Also sound testing of four strokes, and two stokes does'nt work because of the lower, bass tone of the four stroke... That four stroke sound carries way farther, they echo off the hills, and you can hear them from miles and miles away... Two stokes buzz past my house everyday, as soon as they pass by you can't hear them... But the four stokes jeeze it's crazy how long you can still hear them as they pass the house...

 

[Rich Rohrich]

Also sound testing of four strokes, and two stokes does'nt work because of the lower, bass tone of the four stroke...

Seems like a lot of folks (the AMA included) have a lot to learn about sound testing. ;)

Here's a good start for anyone who is really interested in some facts as opposed to a bunch of agenda driven hand wringing and misinformation : http://www.grc.nasa.gov/WWW/AcousticalTest/Industrial/Vibration_Control.html

:cool:

 

[Chili]

Your view can't possibly be this myopic. Do you honestly believe there would be none of the current land/track closures if modern four-strokes had never taken hold? 100+ decibel engines bother people regardless of the source.

While noise and dust will always be issues I can attest at a personal level the effects of exchanging a 125 for a 250F can have on some riding area's. We had an area that was essentially illegal to ride at because it was within the city limits but on the outer edge of housing on one side and an industrial park on the other. Rode there for years with nary an issue with any of the homeowners until this year when one of the boys needed a 250F instead of his 125. Took 3 weeks before a long time resident called the cops and had them shut down.

 

[Rich Rohrich]

There is no question that low frequency tones can travel farther in open air. It's an awfully big stretch to assume that one four-stroke is the only trigger caussing some home owner to suddenly get bent out of shape. We should have had a 96 db or lower cap years ago in the two-stroke only days. Adding four-strokes to the mix with 103-106 db aftermarket systems only makes a bad situation worse.

 

[Ryone]

Seems like a lot of folks (the AMA included) have a lot to learn about sound testing. ;)

Whatever any other reports say, I'll believe my ears (which have never failed me) as to which stroke is more obnoxious... the 4 stroke.

A 2-stroke can be modified so that it's as loud (decibel wise) as a 4 stroke... but the 2T doesn't hurt my ears :think:

Ryan

 

[Okiewan]

but the 2T doesn't hurt my ears

Ever been around one of those un-packed 80's?

 

[Ryone]

Ever been around one of those un-packed 80's?

Yeah, they'll make your ears ring, but they're not representative of the rest of the 2T's on the track.

Ryan

 

[Rich Rohrich]

Yeah, they'll make your ears ring, but they're not representative of the rest of the 2T's on the track.

Ryan

Says the guy running the extra loud SHORTY silencer on his bike. :blah:

LOL, that's pretty funny. I'd love to see an honest survey of how often people repack their 2T silencers. ;)

 

[marcusgunby]

The problem is the aftermarket, they make 4 stroke systems at something like 106db when most 2 stroke pipes are closer to 99db.

 

[Rich Rohrich]

The problem is the aftermarket, they make 4 stroke systems at something like 106db when most 2 stroke pipes are closer to 99db.

No question that the American aftermarket guys should be slapped for the junk they are selling. They make enough profit to reinvest in proper long term solutions, but it's clear they don't have much interest in doing the "right thing" just the profitable one.

 

[Ryone]

Says the guy running the extra loud SHORTY silencer on his bike. :blah:

LOL, that's pretty funny. I'd love to see an honest survey of how often people repack their 2T silencers. ;)

Yeah, I run a Shorty... no, it's not even CLOSE to being as loud as a STOCK 4T. What's your point?
I think MOST people at the track pack their silencers at least once or twice a year... I do it about three times a year.

I'd also love to see a survey of how many 4T exhausts have been left stock ;)

Ryan

 

[Chili]

There is no question that low frequency tones can travel farther in open air. It's an awfully big stretch to assume that one four-stroke is the only trigger caussing some home owner to suddenly get bent out of shape. We should have had a 96 db or lower cap years ago in the two-stroke only days. Adding four-strokes to the mix with 103-106 db aftermarket systems only makes a bad situation worse.

Given my reply I agree how you could see it as a stretch. Unfortunately we have a family connection to this disgruntled homeowner who pointed to the 250F and the same riders unbaffled xr50 as the reason they had a change of heart.

 

[Chili]

I think MOST people at the track pack their silencers at least once or twice a year...

I'd be willing to bet money against that. In our racing group of friends I can honestly say when the kids were on 80's I was the only parent to repack a silencer out of the entire group.