07 RMZ250 transmission problems!!!

[Holeshot Scott]

:rotfl: :rotfl: :rotfl:

As far as being rude, I appoligize. Understand that we came off of another unsuccesful weekend and was irritated by the statement that the bike was being rode wrong. That is what the Suzuki rep told us. I do appreciate any and all help. I understand I could take the bike apart. I wouldn't know what to look for nor does my dealer. We do not understand transmissions well enough to "redesign" anything. We have owned and rode all 4 major brands. We have had different problems with all but none to this extend. They were mostly small issues that someone had come up with a solution for. I do agree with the fact that this particular Suzuki is an engineered POS! Things have come a long wat since the TZ250. I'm 42 years old and have rode some of these bikes. I guess I had too much confidence in todays technology. First year bikes have always been something I stayed away from. This year should have been no exception. Last years Suzuki, (although mostly Kawasaki) held up very well even though it was not rated well. Should have kept it. As for my rant being silly, I'm simply looking for a fix that I or the people I'm onvolved with have no answer for. I will tear the bike down. I just need to know what to do once I get there.This silly rant reminded me of something Gordon Jennings wrote years ago. He basically said successful racers realized early on that the TZ250 that came out of the crate was only bolted together to make it convenient to ship, and the first order of business to make it race ready was to take it apart and BUILD a race bike out of it. Old Gordon must be spinning in his grave laughing at guys like you.

Time to face facts. You bought the biggest "POS masquerading as a race bike" that has come out of Japan in a very long time. If you insist on playing racer/tuner with these badly engineered TOYS, you better face the fact that as SFO pointed out, you need to take them apart BEFORE you race them to work around the issues and the manufacturing variances that Suzuki is know for on this model.

Just because it's bolted together in a form that looks like a race bike doesn't mean it's RACE READY.

Being rude to the people out here trying to help you with very solid advice won't change that fact that YOU made a bad decision and bought an engineering disaster with pretty yellow plastic on it.

 

[Chili]

I've watched this thread closely as my son had been considering an 07 RMZ250, which he now owns. After spending considerable time reading anything I can about these bikes I've come to the conclusion that there is definitely a group of people that have had some shifting issues, some reported it got better as the bike broke in, some still feel it's a poor shifter. Holeshot Scott's the only one I've found so far that has reported mulitple catastrophic tranny failures that would require two bikes to make it through a raceday.

Broken clutch plates on the other hand appear to be a wide spread problem on the 07 RMZ250.

 

[Holeshot Scott]

I've watched this thread closely as my son had been considering an 07 RMZ250, which he now owns. After spending considerable time reading anything I can about these bikes I've come to the conclusion that there is definitely a group of people that have had some shifting issues, some reported it got better as the bike broke in, some still feel it's a poor shifter. Holeshot Scott's the only one I've found so far that has reported mulitple catastrophic tranny failures that would require two bikes to make it through a raceday.

Broken clutch plates on the other hand appear to be a wide spread problem on the 07 RMZ250.

We are not the only ones having this problem. I'm speaking for others that I know. My son's friend, who rides for the same bike shop has taken his out four times He has a practice bike and a race bike. Another kid we know that races has taken his out once. His dad owns a performance shop and has been in this business for 30 years. The individuals I am talking about though are all "A" riders. If you are slower rider and do not ride the bike for all it's worth, you may not have a problem. These guys do pound on there bikes but they have done the same with every bike they've had. I just truly believe that this bike is not designed well enough right now to take that abuse. My son absolutely loves everything else about the bike. I think they will fix the problem but it will be on next years bike.

 

[Chili]

Have you guys experienced the clutch plate issue or any other problems besides the tranny?

My son is not an A level rider but we certainly have several A/Pro riders on 07 RMZ250's so I'll watch how they hold up for them as the season progresses up here.

 

[Rich Rohrich]

I just truly believe that this bike is not designed well enough right now to take that abuse.

Unfortunately I'm convinced you are correct, and this has been essentially true since the bike was introduced a few years ago. It's a bike riders love right up till the point where it starts breaking.

It's getting fairly common for shops to turn away rebuild work on the early model RMZs just to avoid the potential liability.

The Yamaha and Honda 250Fs have a much better track record, not perfect by any means but much more stout and affordable over the course of a race season.

I don't think there is a simple fix for the average racer who rides an RMZ250.

 

[Ol'89r]

Scott.

My comment that the bike was not being ridden right was not meant to upset you. It was merely an observation of what I have seen as a pattern behind some of these failures. I work on a lot of these bike for some of the local riders. (Although, like Rich said, I am reluctant to take in an RMZ 250.) Here in So Cal, we have some of the most aggressive riders on the planet so, it is a good test bed for durability.

Most all of the excessively worn and broken gearboxes I have seen were due to shifting the bikes like a two-stroke. With a 2-stroke, you don't have the extra reciprocating and rotating mass that you do in a 4-stroke. (Cams, valves, counter-balancers, etc, etc.) This extra mass, along with the added torque of a 4-stroke, adds to the force against the gears when the bike is shifted without the clutch. It is compounded if the bike is short-shifted while still in the meat of the powerband. When the bike is shifted into a higher gear, the force from all of this mass is suddenly transferred into the gearbox. When the dogs clunk together under these conditions, they wear the edges or they break. When they wear they wear at a taper until the taper forces the gears apart. Fourstrokes used the have very beefy gears in them. Now, in an effort to make the bikes lighter, the gears are more like a 2-stroke gearbox and simply can't withstand rough treatment.

If your rider doesn't feel comfortable using the clutch, have him try to back off of the throttle for a split second (snap the throttle) when he shifts or hit the kill button at the same time he shifts. If he short shifts the bike, have him try to run it closer to the rev limiter before he shifts. All of these methods will help the gearbox last a little longer. Using the clutch is easiest on the gearbox.

The rough shifting on some of the RMZ's is due to burrs on the shift drum where the detent rides. Many of these get better with time as the roller wears in but, if you have the gearbox apart, you could smooth down that area and it will help. Also, by welding up the neutral detent a little will prevent him from hitting neutral when it is not wanted.

Shimming the gears as SFO suggested is a good idea. Many times the dogs do not engage all the way into the mating gear. By re-shimming the free rolling gear closer to the sliding gear, it may give you better engagement with the dogs. A fully engaged dog is less likely to slip out than one that is only engaged half way.

I realize when you pay over 6 G's for a race bike you expect it to be race worthy, but so far the perfect race bike hasn't been built. We have always had to take what the factorys provide us and make little improvements on it to make it race worthy. It's just part of the game.

Good luck. :cool:

 

[motometal]

Second thing I learned in machine shop,make your own cutters!A relaxed version of a dovetail and an indexing head.Like I said,a machinist should be able to do this,and maybe a grind test or a metallurgist to identify the material.It is possible to change the hardness,but this becomes a tricky area and why I do not have a titanium (or unobtanium)transmission!

Generalizing, most transmission gears (and many shafts for that matter) are 8620, which is a low carbon alloy steel. Very good stuff. Of course, this would be a Japanese version but there is a good chance it's in the ballpark, chemistry wise. This material (which is butter soft when the teeth are cut) is then carburized, normally to high 50s/low 60s HRC. It takes pretty good tooling to cut this, ceramic or at least something designed for hard turning/cutting.

 

[endurohero]

One of the families that I help out with the maintenance and tuning of their engines had recently been beat hands down buy a less skilled rider on a pro cuircit Kaw 250f so they dropped the 144 suzi and financed a 250rmz ,so far the z has 27.1 hrs on the meter no racing just break-in and carb tuning and suspension tuning time .(not one 10 min moto or practice)The first time he really pushed the bike hard it bounced out of third and now is toast . It really sends the message home to me that these bikes need to be torn down before riding to correct any manufacturing discrepancies before ridden at all.What a Bummer. This brings back memories of CZ ,Bultaco early huskies ,bridgestone and ossa,good thing everybody has fat amounts of disposable income to spend on "modern four stroke technology".Our sports future looks so bright I want my eyes poked out with a dirty 8mm t handle.TTFN :yell: