MX 250a - Clutch rebuild

[jimg1au]

so how do you do it with out the aid of air driven tools ie just a socket spanner
cheers
jim

[oldfart]

weld a steel rod to an old plate, make sure it fits between clutch fingers .

[BJJ]

frig  mine only looks like it has 6??

[jimg1au]

the 250s have less plates than the 360s i have both at home if you want to have a look.6 is the right no.
check out

cheersjim


http://www.yamaha-motor.com/sport/parts/home.aspx

[BJJ]

Thaks Jim.  I am pulling apart and using UR tool this weekend.  Cant  help but read that Freak said 7.
Have 3 new plates,  have another 3 ariving fron USA this week.  Yeah.  Thanks for your help.
Whats your opinion on engine oil?
I read some time back on this forum or the past that any oil will do.   That motorcycle shop stuff is expensive...

[BJJ]

OK,  so pulled the basket apart.

Seem to agree with Jim,  that 73mxa does have 6 friction plates according to my parts pdf.  (not 7 or



Not sure if you can see in this photo,  but there is 3 plates on the inside,  of which there should be. 

• the much talked abour spacer 214-16324
• Spacer Clutch Spr  214-16332.  I mean what the heck is this.
• 1st Steel  4H7-16325

Spacer Clutch Spr  214-16332 in my case has been replaced with another steel.  Not sure if that is a serious no.no?    Otherwise all looks normal.  Springs are about 34.5mm  (withing acceptable range).  and there is one Friction plate  (3rd from left in photo)  that doesn't have metal tabs and is not as wide,  that is broken.

So,  my plan,  unless I hear different, is to replace 6 friction plates,  the new basket,  and replace with 4T oil and see how she goes in 5th gear.  Feedback and comments welcome.

Regards

[Freakshow]

The 3rd cork is wrong piss it off, its out of somthing else.

Last 250mx I had apart, i saw had that steel (on the far left) in between the other 2 with the teeth. like a fictionless plate, check thats in the right spot.

Still think it had 7 corks , but cant say i was counting, butit might say that in my book, cause i also know it say 36mm springs  and yet a 74 book says 35mm, so its seems there are variable in there.

[BJJ]

Hi Guys,

Have a small issue that I need some advice on.  I received all the friction plates  (6) and placed everything back in the new basket,  as per microfiche (parts diagram).

in the meantime the clutch pushrod seems to have lost it's placing on the other side of the motor..

so,  when I put the clutch all back together,  and pull lever,  there is nothing.

I have layed the bike over on it's side an there is no resistance on the clutch push lever.
I think I have had this scenario before.  The push rod is definately in there,  I think it has just lost it's placing on the gear change side.

Any idea how this can be resolved?

Regards

[Freakshow]

if you have tiped the bike over the spring on the gear shaft liftsoff too and that shift selector comes out and you need to line them back up again, other wise you wont be able to select gears properly when you do get thwrod bac in its spot.

[BJJ]

Hi Freakshow.  Thanks for your reply. Unfortunately,  I do not understand fully what you are suggesting for the clutch or gear selector spring to be rectified.  Is yourself or any others able to explain to me in more detail?

I desperately want to have the bike fixed and running for a meet next week.

[yamaico]

Not sure about the MX250 but a lot of bikes run a steel ball between the two pushrods which you may have misplaced, which would fit the symptoms you describe. Alternatively, ensure that the clutch pack is in correctly and that the pressure (outer) plate is hard up against the first clutch plate. You should be able to tell if the clutch is together correctly by making sure it is engaged when turning the back wheel over in gear.

[BJJ]

Thanks Yamaico

[BJJ]

Everything appears to be working well in the clutch department.  I won't know for another week until I can test out top gear,  to see if it is still slipping.  Thanks to all who have contributed of the past many weeks.  Thanks to one forum member for lending me his "factory"  and "non factory"  clutch holding tools.

Recap.

• Clutch was slipping at CRC,  but only in top gear,  but was able to keep racing
• Replaced 6 x Yamaha Part # Friction Plates
• Replaced #1 Pri Drvn Gear  (outer Clutch basket)  with NOS unit
• apart from a spacer that was not in place,  all was relatively easy
• Replaced oil,  with 1L Castrol Activ 4T 15W-50
• Aproximate parts cost = AUD$120.00

[Motoman]

I thought I'd tap on to this topic with a question which someone may be able to help me with. The MX250A I bought 6 months ago has had clutch slip since I've had it. The seller told me this was the case. I have tried changing the springs, using ATF and working on the adjustment screw but with no success. I had an issue with what spring length is correct and am still not sure what's up there, but this is a minor issue I now believe.

Today I opened the clutch and checked the arrangements of plates against the US Yamaha web site parts breakdown and am again confused. You guys here touched on the number of plates but I have a question to ask which might finally solve my problem.

The web site has a choice of either 6 or 7 plates (not friction plates but item 6):
http://parts.yamaha-motor.com/partbody.aspx?ls=sport&c=4,174529,175271&i=10504,2

When I removed the plates I find mine has 6 plates.

Question(s)

1) Why is there a choice? Could it be a previous owner re built the clutch with 6 instead of 7 and never got it right? I have severe clutch slip from the start and through all gears. Eventually it stops but only just.

2) The first plate, closest to the engine,bottom of the clutch basket seemed to be the same as the other plates. maybe item 3 is the one that is missing?

3) What is the difference in plate number 1 (item 3 on the breakdown) compared to the others? In other words, rather than plate-spacer-plate-friction plate....what I found was plate-spacer-friction plate. That has to be wrong doesn't it?


Anyone have these plates they'd like to sell?

[jimg1au]

the 360 and 250 have similer but not the same clutches
the usa site is incorperating both 250and 360 in the parts lists
also the aust parts list i have is the same but 1 col is for the 250 and the other is for the 360
cheers
jim