rm shifting probs split cases

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02stampede

Member

Jan 5, 2009

76

0

• Jun 18, 2009

• #1

Here is the problem I was having before I tore it down. In 2nd gear, it falls to neutral when it "hits" under throttle. When putting at low rpm in 2nd it will hold it just fine.

I tore it all apart and split the cases because the oil would turn black very quickly and had a bit more metal shavings than I liked to see. I noticed right off the clutch basket is very worn and notched. The plates have a little lip on them too. Also, the shift forks look decent but might be a bit under spec thickness wise but dont look too bad. The shift drum is okay. All the cogs are in great shape as well.

Should I replace the shift forks or could the clutch assembly cause my problem? I know it needs replaced. Is there anything else I should pay attention to while its apart?

Sorry for the long post and thanks in advance.

The bike is an 2000 rm 125

 

IndyMX

Crash Test Dummy

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Jul 18, 2006

5,548

2

Amo, IN

• Jun 18, 2009

• #2

Well obviously you need to replace the clutch basket and clutch plates. You may also need to replace the clutch hub.

As for it dropping into neutral, I'd guess that is probably caused by the detent on the shift drum being worn, or the spring on the stopper.. Look at the bikebandit fiche, it's part #24 on Transmissions / Gear Shifting page.

And for those, you don't need to split the cases.

 

M

m4i2k2e2

Member

Oct 8, 2007

344

0

• Jun 18, 2009

• #3

good call indy. thats what i was thinking. make sure to take pictures, on the cr's the drum of some other part has a line and goes on a certain way. i cant remember, its been a little while since my rebuild.

-mike.

 

R

RM85rider123

Member

Oct 28, 2007

681

0

• Jun 18, 2009

• #4

I was always told that false neutrals were from bent shift forks, but I am not sure. I would still check the drum.

 

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02stampede

Member

Jan 5, 2009

76

0

• Jun 18, 2009

• Thread starter
• #5

Thanks for the replies guys. I will get pics of those components up tomorrow when I get back to the shop. Maybe you can see something I dont. I probably shouldn't have split the cases just yet but I did it more out of curiosity. There is a lot going on in there! I'm starting to understand it though. Thanks again.

 

whenfoxforks-ruled

Old MX Racer

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Oct 19, 2006

8,129

2

Merrillville,Indiana

• Jun 18, 2009

• #6

Look at the gear dogs for second gear. Chances are good they are rounded over. They are supposed to have a slight under cut to hold it in gear.

 

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02stampede

Member

Jan 5, 2009

76

0

• Jun 19, 2009

• Thread starter
• #7

Here are some pics of the parts in question. I did notice some scoring on the inside of the forks and indents on the detent pawls. I think the gears and dogs are okay. What do you guys think?

http://img7.imageshack.us/img7/7599/drumdetentass.jpg
http://img7.imageshack.us/img7/663/forksclose.jpg
http://img7.imageshack.us/img7/3589/drumk.jpg
http://img7.imageshack.us/img7/5035/detenthousing.jpg
http://img7.imageshack.us/img7/8205/cmshafts.jpg
http://img7.imageshack.us/img7/9563/shiftforks.jpg
http://img7.imageshack.us/img7/5485/2ndgear.jpg

 

whenfoxforks-ruled

Old MX Racer

~SPONSOR~

Oct 19, 2006

8,129

2

Merrillville,Indiana

• Jun 19, 2009

• #8

You have to check the forks with a micrometer. I would replace the gear that has any burnt forks rubbing away on it. There is a second gear on each shaft, and any gears they mate with. Where each one mates, its either a slot or another square looking edge, it should not be rounded. Even a little, new that should be a slight under cut. Take both gears off and lets see the gear dogs. Without the under cut, under power it will kick into a false neutral. All that other stuff combined can not hold it in gear. Them dents in the shifter pawls is unreal! The springs and pins can not be much better? Near 10 year old race bike, and a Suzuki, you are lucky it did not scatter in a million pieces.

 

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02stampede

Member

Jan 5, 2009

76

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• Jun 19, 2009

• Thread starter
• #9

Alright thanks. I will get some pics of the 2nd gear dogs up. I did check the forks with a micrometer and they are all slighly under spec by about .03 inches. You can see in the pics that 2 of them have material removed from the valley as well. Kind of like a spun bearing.. I will definitely get new pawls, springs and pins as well. I am lucky this bike didnt blow up for sure! I got it cheap last year when I got back into riding. Now I know why. Tranny's are expensive to fix!

 

whenfoxforks-ruled

Old MX Racer

~SPONSOR~

Oct 19, 2006

8,129

2

Merrillville,Indiana

• Jun 19, 2009

• #10

35 bucks a gear? In theory, when you put a new gear in, its mate should be new also. A garage theory about when the old gear breaks in the new gear, the old gear can not hold up. They shear, fall apart like they were made of clay. Thats on the gear teeth. For the inside radius of the fork to rub? Trans bearings and shift drum bearings. That much movement, check the bearing bores for being oval. 2nd gear dogs may be good looking at all the other issues! But, forcing itself out of gear, there is a rounded dog in there also.

 

0

02stampede

Member

Jan 5, 2009

76

0

• Jun 19, 2009

• Thread starter
• #11

Thanks fox. That makes perfect sense. I bet I have worn bearings on my hands as well. I will check them and post better pics of the dogs. Hopefully they are okay still. I just meant that pricing out trans parts is pricey when compared to a lot of other 2 stroke parts. I paid $800 for the bike and I see why. I'm learning from the best and all your help is much appreciated.

 

whenfoxforks-ruled

Old MX Racer

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Oct 19, 2006

8,129

2

Merrillville,Indiana

• Jun 20, 2009

• #12

Best no, just been there done that! The best are lurking in the shadows? Get on it, I get to replace a 1 ton trucks front brakes, I hate working on cars!

 

R

RM85rider123

Member

Oct 28, 2007

681

0

• Jun 20, 2009

• #13

whenfoxforks-ruled said:

Best no, just been there done that! The best are lurking in the shadows? Get on it, I get to replace a 1 ton trucks front brakes, I hate working on cars!

Click to expand...

I do to, there just not as fun as working on bikes.

 

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02stampede

Member

Jan 5, 2009

76

0

• Jun 23, 2009

• Thread starter
• #14

Im the opposite! I have had a few mustangs that I did all my own work on. Bikes seem much easier. I just need to learn more about them. Anyways, I have a few gears with bad dogs so those will be replaced along with bearings and shift forks. Thanks for your help guys. Hopefully I get her back together after I get the parts...