07 RMZ250 transmission problems!!!

[Holeshot Scott]

Has anyone else been having transmission problems on the new 07 RMZ250? My boy races motocross and has one of these as well as a 07 450. A friend of ours has two 250,s and a 450. The bikes were bought from the same dealer. All three of these 250's have had to have the transmissions worked on. The gears become round off in second and third. Our dealer called Suzuki and they are not taking care of it. Our dealer is basically footing the bill since he sponsors my boy and our friend. They are in the "A" class and ride hard but that should'nt matter. That's what they're made for. Just wondering if anyone else has had problems.

 

[Martin Cole]

We haven't had any problems with our RMZ yet - but it's still early days. Something to keep an eye on anyway.
MC

 

[Holeshot Scott]

I just got through talking to the dealer from which I bought the bike. He said he had someone from Suzuki call him and said that American Suzuki has been in Japan having discusion over this matter. Not sure what will happen. (possibly a recall) keep an eye on things. What happens first is that it will start popping out of gear. Not fun when coming up to a huge triple!

 

[Martin Cole]

I'll get our dealer, who is also sponsoring us this year, to check it out with Suzuki GB. If there are any indications of a problem I will post them. The only complaint my son has is that it is difficult to find neutral when he pulls up after a session on the track - but it has been like that since it was new.
MC

 

[adam_co]

the neutral thing happened on my kx and i changed the tranny oil and it was ok

 

[conn424]

is this something to be concerned about---because i just spent 6000 on this bike?

 

[Desert simpson]

I just bought a second hand 2k7 RMZ250 and I have the same problem with gearbox jumping out of gear. I thought it was just me - but it happened twice last ride.

The neutral is just difficult to find, new transmission oil didn't help.

Please let me know if anyone has opened up their gearbox and found out what the culprit is....

 

[Holeshot Scott]

Our dealer took the gearbox apart and found two of the gears were wore to a point that they would not stay engaged. Replaced the gears and put it back together. Don't know how long it will last. Mind you we hadn't even wore out the stock tire. Bike had maybe four hours on it!

 

[Desert simpson]

That doesn't sound too good! I've noticed recently that it's really easy to miss shift. I have to make changes really deliberate. Its not jumping out of gear yet....

 

[whenfoxforks-ruled]

Sometimes when they find an error,they will not admit it,but a replacement part will show up. Good luck

 

[sp1tekiller]

The neutral thing sounds normal. My '05 450 is difficult to find neutral, seems common from what I have heard.

 

[Holeshot Scott]

The neutral thing sounds normal. My '05 450 is difficult to find neutral, seems common from what I have heard.

We are not talking about FINDING neutral. We are talking about it finding neutral on it's own. Especially when you don't want it to!

 

[mike perry]

tranny problems

This is out of my area of expertise- but I was speaking with a customer yesterday- James at JMS Machine- and he had a customer with the problem you're describing. When he disassembled the tranny he found the detent springs to be on the weak side. He modified some springs from another application to supply more force and keep things in place.
so far it's been working.

Maybe this is something Rich or Mark Ochs has seen?

Mike Perry

 

[motometal]

stupid question: are the dogs on MX transmission gears ever back cut? This would help. Also, some times when they pop out of gear, the shift forks bend.

Transmissions on MX bikes have been, in my opinion, "bulletproof" for years, but now between efforts to further lighten the bikes, and the four strokes making more power, problems are popping up. :|

 

[whenfoxforks-ruled]

Undercut is the ticket, dirtbike transmissions are a lot better than street,in my opinion

 

[Ol'89r]

stupid question: are the dogs on MX transmission gears ever back cut? This would help. but now between efforts to further lighten the bikes, and the four strokes making more power, problems are popping up. :|

Or popping out. ;)

Most of the customer bikes I have seen with this problem is due to the rider shifting the bike like a two stroke. They don't use the clutch or even back off of the throttle when shifting. You can get away with this on a two stroke but, with a four stroke and the additional torque that a four stroke puts out, it puts more strain on the gears. Every bike that I have had in the shop with this problem was due to this type of shifting. It wears the edges of the dogs, forces the gears apart and eventually bends the shift forks like motometal said.

Back cutting the dogs is a good idea but only on a worn gearbox. On a new gearbox you would grind through the hardfacing on the dogs and make them weaker. If the factorys designed the gears with a back cut, the gears would stay in gear but it would be hard to shift without backing off the throttle or using the clutch and everyone would complain about that.

Try having your riders modify their shifting habits.

If your having problems hitting neutral when you don't want to, try welding up the neutral detent on the detent washer so that it is not as deep.

 

[Holeshot Scott]

You sound just like the Suzuki Rep! Trying to blame it on the rider. These boys have been riding 4-strokes ever since they came out and have never had this problem. It sounds to me like the dealers don't want to take responsibility because the manufacturer is not standing behind them. Two rides on our friends race bike and he took the tranny out Monday! Tell me that's from not shifting it right. You should be able to shift them any way you want. It's a race bike and should be able to handle the abuse. If there's not a problem, tell me why Pro Circuit is making an entire replacement tranny for these bikes? Having trouble hitting nuetral? Yeah it's because the gears are worn! Or maybe we should take your advice and tear down a brand new bike so we can slap some weld in there. Great advice. 6 transmissions since the bike were new! Nope no problem here! The last one locked up over a big double and he endoed. He got hurt but not seriously. THIS TIME! All I have to say is if someone gets seriously hurt over this deal this whole issue is going to get allot more serious! Enough said.

Or popping out. ;)

Most of the customer bikes I have seen with this problem is due to the rider shifting the bike like a two stroke. They don't use the clutch or even back off of the throttle when shifting. You can get away with this on a two stroke but, with a four stroke and the additional torque that a four stroke puts out, it puts more strain on the gears. Every bike that I have had in the shop with this problem was due to this type of shifting. It wears the edges of the dogs, forces the gears apart and eventually bends the shift forks like motometal said.

Back cutting the dogs is a good idea but only on a worn gearbox. On a new gearbox you would grind through the hardfacing on the dogs and make them weaker. If the factorys designed the gears with a back cut, the gears would stay in gear but it would be hard to shift without backing off the throttle or using the clutch and everyone would complain about that.

Try having your riders modify their shifting habits.

If your having problems hitting neutral when you don't want to, try welding up the neutral detent on the detent washer so that it is not as deep.

 

[Ol'89r]

You sound just like the Suzuki Rep! Trying to blame it on the rider. These boys have been riding 4-strokes ever since they came out and have never had this problem. It sounds to me like the dealers don't want to take responsibility because the manufacturer is not standing behind them. Two rides on our friends race bike and he took the tranny out Monday! Tell me that's from not shifting it right. You should be able to shift them any way you want. It's a race bike and should be able to handle the abuse. If there's not a problem, tell me why Pro Circuit is making an entire replacement tranny for these bikes? Having trouble hitting nuetral? Yeah it's because the gears are worn! Or maybe we should take your advice and tear down a brand new bike so we can slap some weld in there. Great advice. 6 transmissions since the bike were new! Nope no problem here! The last one locked up over a big double and he endoed. He got hurt but not seriously. THIS TIME! All I have to say is if someone gets seriously hurt over this deal this whole issue is going to get allot more serious! Enough said.

:yikes: Woah, Dude! :coocoo:

Don't get pissed off at me. I was only passing along a little information. I am not a dealer. I own and operate a small aftermarket race shop here in So Cal. I work on a lot of MX bikes both two and four stroke. This has been my experience with the new four strokes, especially the Kaw's and Zuki's.

I didn't say there was not a problem. There is a problem. In an effort to come out on the market with a competitive mx bike, Suzuki built their 4-strokes to lightly, especially the 250's. The gears are too light and the way to make them last is to modify your riders shifting habits or buy an aftermarket gearbox from PC. The choice is yours.

If you want to get po'ed at someone, get po'ed at your dealer for blowing you off. Or get po'ed at Suzuki for building a race bike that has a gearbox that is built too light for the power of the engine. Or get po'ed at yourself for not doing the research before buying the wrong bike for your kid. But don't get mad at me.

The welding up of the detent is a tried and true method of fixing the neutral problem. Race mechanics have been doing this for many, many years to improve shifting in race bikes of all kinds. It was just a suggestion, take it or leave it. :think:

Don't shoot the messenger.

 

[whenfoxforks-ruled]

81 cr250,along with their bs radiators on the front plate they spit out of gear and blasted the trans.Honda paid for fixing this booboo and recommended undercutting the dogs.Did not have to retreat the gears.The blind female slots was interesting,and the trans lasted fine.1 to 1 1/2 degree undercut does nothing to change shifting loads between gears and as bad as it seems sneaking into gear is a little different than slamming it into gear.I do not believe a straight cut dog would stay in gear for very long in mx competition and sure as hell would NOT want to ride a bike that MAY pop out at a high stress period,like the face of a jump!These gears need to be undercut and done fairly precise,its not like filing your clutch basket,or maybe you will think about not filing that basket next time,its a nice setup on a milling machine and any automotive type shop should be able to fix them.Suzuki fess'in up is another story,Honda has always been pretty decent about mistakes on bikes with no warranty.See how long till the gears change part numbers all of a sudden!

 

[Holeshot Scott]

This sounds like a good solution for gears that are in good condition but the problem with the Suzuki gears is that they start to wear on the edges. Instead of a square corner it becomes beveled. Popping out of gear is what happens when they become worn enough. I don't know if it is bad material that the gears are made of, or the way they are engaging. This is the problem we are having. We put new gears in and within a month or sooner they are worn to the point that they pop out of gear. This has happened on both practice bikes and both race bikes so it is not characteristic to one bike. The dealer is not ignoring us, they are actually footing the bill for all of it. Suzuki corp. is not reimbersing them though. I am to the point that I am afraid to let my son and his team mate ride the bike. So they are not taking responsibility, fine. Give us a way to fix it! If it was not for the fact that we are sponsored by the local Suzuki shop, we would have traded for another brand along time ago. We race to win races, develope skills, and gain exposure. We can't even finish a race! Take note the 450 is holding up fine. it is now his practice bike and race bike. We keep two 250's to make it through a race day. No practice.

81 cr250,along with their bs radiators on the front plate they spit out of gear and blasted the trans.Honda paid for fixing this booboo and recommended undercutting the dogs.Did not have to retreat the gears.The blind female slots was interesting,and the trans lasted fine.1 to 1 1/2 degree undercut does nothing to change shifting loads between gears and as bad as it seems sneaking into gear is a little different than slamming it into gear.I do not believe a straight cut dog would stay in gear for very long in mx competition and sure as hell would NOT want to ride a bike that MAY pop out at a high stress period,like the face of a jump!These gears need to be undercut and done fairly precise,its not like filing your clutch basket,or maybe you will think about not filing that basket next time,its a nice setup on a milling machine and any automotive type shop should be able to fix them.Suzuki fess'in up is another story,Honda has always been pretty decent about mistakes on bikes with no warranty.See how long till the gears change part numbers all of a sudden!

 

[hot125mod]

i know that suzuki s really like a hinson basket because the stock one gets notched real quick. it is worth the money for a whole hinson clutch espically if your kids are A riders cause they are a lot harder on parts than anyone else out there.

 

[motometal]

I agree that a degree or two back cutting is the hot ticket. Even a dragrace cut of say, seven degrees does not nec. cause a problem with the case hardening, because out near the end of the dog (which is where it really counts) if done properly, you are removing minimal, or zero material. But, more than a degree or two and you may not like the way it shifts.

I'm wondering if it could be possible to regrind the dogs if they are rounded, and re-carburize them?

I'm also wondering if the stockers have too thin or too soft of a case. If someone wants to send me a failed one, I could analyze it and maybe draw a conclusion...pm me if interested.

"foxforks"...what about the blind, female windows and back cutting? Did they do it? How? These are forged or formed in, not machined (stock) I think....very tricky if they are square windows...i've seen it done on the ones with rounded, recessed windows.

 

[whenfoxforks-ruled]

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!

 

[SFO]

I feel compelled to chime in.
I wouldn't be quick to use undercutting as the solution until I had done a thorough mock up of the transmission. I have had to R&D quite a few solutions to problems the factory said did not exist. If this was a bike I was responsible to keep running properly I would start dissassembling the trans after every weekend and try to catch the failure in the early fault stages, before failure. There is no rule about bending shift forks to get the engagement clearance you want, reshimming radial clearances, shift detent spring mods, star wheel grinding, case clearancing, etc.etc.etc.
I haven't seen these transmissions in person otherwise I might have a concurrent opinion with any of the previous posters.
I have found that undercutting can create as many problems as it might solve. I wouldn't use it as a catch all solution.
I might find if there is other suzuki transmission components that are interchangeable.
The solution might not as easy as leaning on US suzuki for free stuff, but where there is a will there is a way.
I would suggest R&D transmissions in Clearwater Florida for assistance in fault reading.
I have little faith in the factory admitting guilt.
Wait til the part #'s change without any mention in '08.
Fiche research taught me how the factory evolves their designs. Most people don't get beyond 4/5/6 speeds.
Good luck !

 

[Rich Rohrich]

Y You should be able to shift them any way you want. It's a race bike and should be able to handle the abuse.

:rotfl: :rotfl: :rotfl:

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.