MX 250a - Clutch rebuild

[BJJ]

Anybody know if Yamaha still have metal clutch plates in stock,  or who would have a NOS or repro set for sale?
(not the friction plates)

Other thing I am after a loan of in Sydney is a clutch tool for the same model.  I know they exist.  It's a bendy metal rod thing that you put in place so you can get the nut off the clutch basket....

[jimg1au]

i have one you can borrow if you get stuck
pm me your no i will ring you back monday night

[Freakshow]

the cluth tool is a rag in the teeth.

the steel plates are available   

for a couple of bucks more buy the barnett clutch - see ebay theyll be some on there   

[jimg1au]

so freaky how do you stop the inside clutch hub from turning with just a rag in the teeth??

[vmxrider]

My method is to grip an old metal clutch plate with a pair of vice grips to lock the inner and outer basket then use some rolled up rag between the gears. Could also weld a tab to the old plate for the same effect. What area in Sydney are you?

[BJJ]

Hi VMXRider.  PM Sent.

[BJJ]

Hi Freakshow.  I am reluctant to buy another clutch,  becasue I already have the Friction plates and basket.

Yamaha want AUD$29.00 each for the plates./  arrgghh.  So,  still looking for a cheaper alternative if anyone knows of suppliers phone or email address??  part #  4H7-16325 .  Regards...

[Freakshow]

im a bit confused you just want to change the steel plates ? whats the deal then needing to use a tool to pull it apart ? isnt it just 6 screw and the pressure plate comes off and then you unload the plates out the basket ? 

IF the clutch is just not hitting in hard enough check the spring free length or ram in some with more ompf ( 35mm) also check that stupid last spacer steal is in the right way, im tempted to say what happens if you piss that spacer out and use another fiction plate ?

Any how IF you have warped or burnt steels as you say just replace them only, steel PLates are on ebay  $9.95 , the plates fit all the early stuff.  grab some of those even S/H chances are they will be still good.  try part number 168-16325-00-00 its the same part, but easier to track.

http://cgi.ebay.com/ebaymotors/BARNETT-CLUTCH-DRIVE-PLATE-STL-YAM-YZ-XS-DT-XJ-250-600_W0QQcmdZViewItemQQ_trksidZp3286Q2em63Q2el1177QQhashZitem3ca162809bQQitemZ260405624987QQptZMotorcyclesQ5fPartsQ5fAccessories

Part # = 4H7-16325-00-00

DT2 - DT3 1973
MX250A - 360A 1974
RT2 - RT3 1973 360 

TT350S 1986 - 87
TY250RD 1992
TY350N 1985 -86

XJ600SD 1992 - on  XJ600 SECA II 
XJ650G 1980- on 650 XJ650
XJ750RH 1981- on
XS650LK 1983 650 XS650L
 
XT350 1990 --97
XZ550RJ 1982 - 83
YFM350ERA 1990 - 97


YZ250A 1974 
YZ250 1983 - 1987 
YZ360A 1974
YZ490A 1990
YZ490L 1984 -89

IT465J 1982 - 84

[BJJ]

Hi Freakshow

Thanks for you detailed concern and extra information.  I'll answer your questions, and then leave anything in doubt to the end.

1.  I planned to change the steel plates, because the look a little worn.  Not sure what thickness they should be,  but if they are still within the limit,  then obv I would be happy to keep them in there.  Also,  someone told me last week,  that when you change the friction plates,  you should also change the steels.  With regards to the clutch tool.  The current basket has one of it's legs snapped off  (possibley due to someone previous not using a clutch tool ).  I have a NOS basket here ready to be snapped in.

2,  Certainly I had not thought much about the springs.  But thats something I can check with the verniers.  Partly the rush for this clutch rebuild was because last race meet clutch was slipping when selecting 5th gear.  Not sure if this is easy to diagnose (clutch plates or springs).  I'll need to check on the position of the last spacer to see if that is correct, but thanks for the heads up.

3.  Freakshow, thanks for the link to steel plates.  Certainly thats a lot cheaper than Genuine.

If anyone has the wear measurements for steels,  then good.  I am Guessing Yamaha would just replace them back in the day and in the situation of a service/reco.

Lastly, with that link to the Barnett drive plates.  In the photo,  there is 2 steels and one weird looking disc.  What is the weird looking disk for?.  Also, that ebay ad is very confusing.  The ad says you need 7 plates,  but the listing is only showing 2 available.

im a bit confused you just want to change the steel plates ? whats the deal then needing to use a tool to pull it apart ? isnt it just 6 screw and the pressure plate comes off and then you unload the plates out the basket ? 

IF the clutch is just not hitting in hard enough check the spring free length or ram in some with more ompf ( 35mm) also check that stupid last spacer steal is in the right way, im tempted to say what happens if you piss that spacer out and use another fiction plate ?

Any how IF you have warped or burnt steels as you say just replace them only, steel PLates are on ebay  $9.95 , the plates fit all the early stuff.  grab some of those even S/H chances are they will be still good.  try part number 168-16325-00-00 its the same part, but easier to track.

http://cgi.ebay.com/ebaymotors/BARNETT-CLUTCH-DRIVE-PLATE-STL-YAM-YZ-XS-DT-XJ-250-600_W0QQcmdZViewItemQQ_trksidZp3286Q2em63Q2el1177QQhashZitem3ca162809bQQitemZ260405624987QQptZMotorcyclesQ5fPartsQ5fAccessories

Part # = 4H7-16325-00-00

DT2 - DT3 1973
MX250A - 360A 1974
RT2 - RT3 1973 360 

TT350S 1986 - 87
TY250RD 1992
TY350N 1985 -86

XJ600SD 1992 - on  XJ600 SECA II 
XJ650G 1980- on 650 XJ650
XJ750RH 1981- on
XS650LK 1983 650 XS650L
 
XT350 1990 --97
XZ550RJ 1982 - 83
YFM350ERA 1990 - 97


YZ250A 1974 
YZ250 1983 - 1987 
YZ360A 1974
YZ490A 1990
YZ490L 1984 -89

IT465J 1982 - 84

[Freakshow]

Friction plates are supposed to be 3mm new so you'd replace if under that  2.5 -2.7 mm ( meh) and the steel plates well they shouldnt wear out so to speak, just distort or burn in but would be obvious.

Seams strange it slips in 5th ? why wouldnt it spinin higher ratio's like 1 -3 gears and spin like crazy ?

Some steel plates had assymetrical shapes and you have to lay them in like in 1/7th all the way round ( so its like 15min on the clock or 4-5 teeth from the last)  there is a outer bump  that tells you the referance point to keep moving the eccetric cut outs around.  Stops them being unbalanced.

the springs are supposed to be 33 or 35mm from memory but check

the 250 uses a thicker plate as the end spacer instead of the extra friction plate the 500 or 360 has.  Check you have a thicker spacer plate in the end, if not there a problem there and it has the rough face facing inwards.


250 have 7 friction plates
360/500 have 8 friction plates.

i only used that ebay ad as a referance, remember these guys often use generic photo, and also its there version of the original equipt.   maybe they have 2 sets of 7 ?  dont know but so long as the plates are the same thickness, there shouldnt be any real reason why you cant just put in the one you need to replace, the whole set thing is fine if you have the money and your racing for world domination, but if you just trying to get you bike running so you can enjoy it and race it, why not just keep putting in plates as you find them.

1. check you have all the 7 disks x 2 in the right places including the thicker one ( 15 plates)
2. check for warpage/burns on steels or undersize (less than 2.7mm corks )- replace any or all as you feel like
3. check those springs - unsprung are 33 or 35mm whatever they are supposed to be after 34 years they wouldnt have as much push as they dad year 1.

the slip may also be a result of the plates moving in the dead basket.

if put the new basket in, check the above and ride it and report.

[BJJ]

Thanks Freakshow,  you have been very, very helpful.  I know what I have to do,  and will report back following the road test.

[Freakshow]

thats what we do 

 im repaying the help vandy gave me in the thread where i lost a Ball bearing and he was the only one to figure it out, and now it works a treat, sometimes its just enough to get the ideas or at least ask the question, who knows what it might lead you to find, it might not be the right answer but it might lead you in the end to what is.   If not youll just go mad trying to figure it out by yourself   


or we can just confuse the shit out of ya 

luck with it.

[BJJ]

Hi Freakshow

how many friction plates do DT's have

250 have 7 friction plates
360/500 have 8 friction plates.

[yamaico]

Hi Billjackjane,
Try to avoid using longer springs - coil-bind may result in which case the clutch will drag.
If the spring free length is within tolerance it will be fine. Spring sag as a result of age will be reflected in the free length.
Clutch slip gets worse as the load increases i.e higher gears.
Ensure that the actuator has free-play, lack of which being the most common cause of clutch slip.
An old drive and driven plate screwed together is the best clutch holding tool.
Use a rattle gun (if you have one) to undo and tighten the centre nut. If you don't have one use a piece of aluminium sheet between the primary gears.
A broken finger on the clutch hub will not cause clutch slip, however wear in the fingers will cause unsmooth clutch operation and undue wear on the plate locating tabs.

[holeshot buddy]

ok you butchers dont make up some torturess tool
to remove centre hub
all you do is remove pressure plate
leave all the clutch pack intact
put socket with impact gun on
hold pressure down with your fingers on out side plate
pull trigger on gun (with finger)
it will spin off
reverse procedure to install
dont tell anyone about this method
or they will all be doing it