my tranny held for about a month... is this my fault?


13 replies to this topic
  • tool

Posted October 25, 2004 - 01:53 PM

#1

can you go through a transmission in 4 weeks?

about a month ago i lost 3rd gear. i had to replace a bent shift fork and the 3rd/5th gears that it actuates.
after fixing it, and riding it hard for about a month, the shift to third is loose again and the shifter is making a grinding feeling when i pull the lever all the way up. :cry: it has done all of this before, but this time it happened really fast, maybe 25 hrs of riding. everything was tight after the rebuild.
there have been some sketchy shifts since and i ride it really hard, but to tear up a tranny so quickly and regularly - it seems its either the bikes fault or mine.
anyone know what i can do about this?
maybe i should learn how to shift correctly, but come on... its a race bike. :cry: and i dont even race it.

  • ncmountainman

Posted October 25, 2004 - 03:13 PM

#2

i think the z start if used with the tc balls and the light spring puts undue stress on the drivetrain,i was running this setup and after switching to the heavier spring it stopped clanging so much(on and off the gas). may or may not be it but i'm glad i caught mine when i did! :cry: if you go to ten tc balls i'd put in the heavy spring for sure :cry:

  • tool

Posted October 26, 2004 - 12:24 AM

#3

i think the z start if used with the tc balls and the light spring puts undue stress on the drivetrain...


that could be entirely possible, as ive rebuild my tranny twice since i put in the z start. absolutely no transmission problems before the auto, now i cant keep it together.
but i have a different theory... i think the undue stress on the drivetrain comes from shifting (or trying to) without the clutch lever. i was thinking when i got the auto, that maybe im pushing the clutch/trans on this bike as far as possible. then i get on the track and ride it as hard as possible. obviously this is the weak link.
but what im wondering is, how can the auto clutch put more stress on the drivetrain then a manual clutch? the manual makes the chain slap like somethings wrong. :cry:

  • sirthumpalot

Posted October 26, 2004 - 02:28 AM

#4

Seeing that the auto doesn't disengage when you shift, do you at least let off the gas? If not then that could be the problem. I would not expect any gear box to hold up to full throttle clutchless shifts for very long. I was watching a tape the other day of a MX start and they zoomed in on Ricky. Guess what, he clutches when he shifts on the holeshot.

  • Indy_WR450

Posted October 26, 2004 - 03:59 AM

#5

Agreed. You must back off the gas completely to shift and save the gear box. I up shift without the clutch and down shift with it except at very low revs but I always back off the gas. :cry:

  • beezer

Posted October 26, 2004 - 05:12 AM

#6

A buddy and his son had 2 YZ426's that they out auto clutchs in. They had transmission troubles with both. They would land off a jump with the gas on and boom, no 3rd gear. They were told by the clutch mfger that you had to let off on the gas especially with Yamaha transmissions.

  • tool

Posted October 26, 2004 - 03:47 PM

#7

...do you at least let off the gas?



well, i let off slightly. i always know which shift is doing the damage, but i just screw it up. its this one hill at the track where i shift from 3rd to 4th, but its always 3rd gear that goes loose and eventually disappears altogether.

im thinking about the only thing i can do is gear my bike so i go from 4th to 5th on that hill, and use a little clutch on that particular shift every lap. im thinking that 3rd is the weakest gear and should be avoided.

the bike should hold up fine, but i break it. its my fault. :cry:

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  • markvan

Posted October 31, 2004 - 09:52 PM

#8

I've been considering getting the zstart, but after reading this thread, I'm starting to get second thoughts. Will the autoclutch cause more wear on my tranny, causing it to constantly blow out like that? The autoclutch sounds great but, not if it's going to dammage the drivetrain....

What do you guys with the zstart clutch think of this? Is this a common problem?

  • tool

Posted November 01, 2004 - 01:41 AM

#9

What do you guys with the zstart clutch think of this? Is this a common problem?


its a common problem for me because i beat on my bike. im very hard on the gears. its not that im some blazing fast pro, i just dont shift the smoothest and that causes my trans problems.
its you shift normally, you shouldnt have a problem. i dont use the clutch for shifting. ever. if that takes its toll on the tranny, so be it.

  • ncmountainman

Posted November 01, 2004 - 09:25 AM

#10

my problem was with 5 tc balls and the soft spring it was getting too much engagement too fast and causing undo stress to the drivetrain(with the tc balls and soft spring the rekluse will have much more clamping force on the clutch than the stock unit,therefore not allowing that little bit of slip that buffers the drivetrain)so by using the stiffer spring it allowed the buffer zone to come back. if that makes any sense,anyhoo the rekluse is totally adjustable and you will know if its set up wrong if your in tune with your bike. its a great product,and any failures associated with it are more likely from not understanding it! :cry:

  • tool

Posted November 01, 2004 - 04:11 PM

#11

(with the tc balls and soft spring the rekluse will have much more clamping force on the clutch than the stock unit,therefore not allowing that little bit of slip that buffers the drivetrain)


now i see what your talking about. the clamping force. my installed gap is around 1 mm, which is close to being too large. maybe this is part of the reason i dont feel the "undue stress" on my drivetrain.
maybe the wide gap allows the balls to have thier full travel, but not clamp the plates too hard? what kind of gap are you running nc?

  • ncmountainman

Posted November 01, 2004 - 06:18 PM

#12

now that i've got it stabilized(its been the same last two times)its at .033" and seems to be working quite well. 1 mm !! what is that in thousandths? max is .039" and mine went as far as .047" and started acting funny. maybe thats one other reason why you can't get the engagement you desire? :cry:

  • tool

Posted November 02, 2004 - 02:39 AM

#13

see, im using mm and your using inches. my range in MM is something like .70 - 1.07 mm. so im still within range, the clutch doesnt act funny at all. i run the large gap to reduce the drag a bit.
i was running all types of gaps when i first put the clutch in. its very easy to tell if your gap is too large, because it wont fully engage. or too small, because it will have a terrible drag.

so if:

max is .039" and mine went as far as .047" and started acting funny.



and your at .33", then it seems we are using about the same gap. :cry: man, the primary ratios must be way different to cause such different results with the same clutch. i had no idea about this when i recommended you use the TC balls. :cry: i need 15, and five is almost too much for you. have you tried using only 3?

  • ncmountainman

Posted November 02, 2004 - 08:07 AM

#14

the five works perfectly with the heavy spring,if i kept up with the light one i'd of been rebuilding transmissions too :cry: way too much engagement. perfect now! :cry: :cry:





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