OzVMX Forum
Marque Remarks => Yamaha => Topic started by: Freakshow on January 19, 2011, 06:31:59 pm
-
Davey you might know ? i bought a YZ 125A and the motor is a piece of snot, cut a long story short one main issue, is the gear change has about a 5 mm+ movement in it, so much so that it has made the little outer cover oval, which in turn has made the actual case side the rod sits in the same ( oval) can you buy shims to pick up the slack in the cases or a drill out press in sleeve ?
I dont really want to have to get the case welded and then try to get the shaft hole bored back in, its too fiddly to get it back to spec that way and would be hit or mess to get it stright too.
Any ideas
-
freaky
that part is on sale on ebay all the time ask nathan but i think all 125 175 have them.
it just bolts on /off not part off the crankcase
jim
-
YEp the covers forked i can see that, but where the shaft sits inside the case doesnt seem to be bushed it looks like it just sits in the alloy case itself, and that bits flogged out too, thats the side im taking about, it moves arond n there so it transferrs that slop up the shaft and then floggs out the cover as well or vise versa.
-
Davey Crocket can do rebushed covers, on an exchange basis. They're a longer bush, so they provide some support even if the hole in the case is like yo mamma.
The cases themselves, would have to be bushed seperately. Its not too hard a job, so shouldn't cost a million dollars from your local machine shop.
-
Sounds very like the problem ty175s get, tytrials in the uk sell brand new covers that have been bushed to get around it
http://www.tytrials.co.uk/trailandtrialsuk/prod_215437--1617-amp-19-Shifter-Repair-Kit-TY125-amp-TY175.html
-
yep NAt..........its like to mumma's either side, not sure how they where able to ever change gears with it like this............
do you know the correct stator number for these A/B or what else is the same ? the one in it has been made to fit and the air gap on one side is about 1mm rubbing on the Rotor and the other side 5mm or more, you cant move the stator as its been cut in to fit so no adjustment, i have an old points stator but prefer to go to a normal yam one that fits properly. Are they smaller than the MX250- M100 ? as i notice the box and rotor appear to be from the 250s
-
I assume the gear mechanism is the same as a YZ125C?
I've repaired a few C gear linkages, one by boring the case and bushing it and one by boring the case and building up the shaft.
Take off the clutch cover and the motor can be set up on parallel blocks on a milling machine table. If possible use a new outer gear mechanism cover and set up the mill spindle to the centre of the hole. Remove the cover and you are dead centre on the bore in the inner case.
I bored one and bushed it, but there's not much meat to bore into, and bored another to 90-95% clean up. I built up the shaft with Nickel Bronze and remachined the shaft to size.
I've also bored and bushed a couple of outer housings.
It's not a big job it's just a matter having access to the equipment.
Brent
-
I assume the gear mechanism is the same as a YZ125C?
Yes.
-
Send me your cover and those bolts for Gally and I'll put one of my bushes in it for you....it's the same set up as the pommy one. I got a heap of bushes made up out of phosfer bronze which is self lubricating whereas the pommy one is stainless....I dont know why they chose stainless...has no lubricating properties at all. You can still buy the cover new from Yamaha but even that has alot of excess movement in it (its about $85? new). Make sure you send it in a waterproof package...its abit wet up here.