06 yz 250 gearbox problems

dpgalvin said:

Hi, I am just wondering if anybody else has experienced gearbox failure on the 06 yz 250.

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Nope. I got our dealers first '06 last August; its been running strong since.

What kind of faliure?

dpgalvin said:

sounded like the sprokets slipping in second and third gear.

Will post what happened later

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First time I hear such a thing on a 2006 yz250. It sounds like some teeth are broken off the gears. Did you tri other gears to see if it is the same.

Please tell me your not using ATF?

dpgalvin said:

No, I use Castrol 10w40 synthetic and change after every ride.

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Though your oil selection may not be the cause of your problem, I personally wouldn't recommend using motor oil. Of the motor oils, API tests show that your selection has some of the best properties, but also has one of the lowest shear strengths which is most important in gear boxes.

If you suspect that you have a gearbox problem, don't abuse it more, dis-assemble it now.
If you do have a have a gear box problem, inspect it and determine the "cause" of the problem. If the cause of the problem seems to lubrication related, then back that out to see if the "source" is the type of lubrication.

There are many opinions and lots of data on this topic. Do your due diligence and make a selection afterwards.

BTW, when you re-assemble, new crank bearings and seals are a must.

Ride safe.

Ian

it is most likly ur sproket, i had the same prob on mine and i needed to get a new one and now it works perfet
-mike

dpgalvin said:

sounded like the sprokets slipping in second and third gear.

Will post what happened later

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Well, a little more info would help.

My tranny went out, takin it to the stealer when I get the cash. :bang:

LIttle under 30 hours on it too... :(

whats so bad about atf? is'nt that what they use in auto trannys that also uso wet type clutch discs and gear boxes?????

mxduner said:

whats so bad about atf? is'nt that what they use in auto trannys that also uso wet type clutch discs and gear boxes?????

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Do a search on ATF as there have been many debates for using and not using ATF; its all been covered before.

All I will say is your bike tranny is not an automatic car transmission in design or function.

All I will say is your bike tranny is not an automatic car transmission in design or function.[/QUOTE]

its not a car engine either and a bike tranny is much more similar to an auto trans than a car engine which motor oil is designed for

All I will say is your bike tranny is not an automatic car transmission in design or function.
its not a car engine either and a bike tranny is much more similar to an auto trans than a car engine which motor oil is designed for

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Well, we have beat this to death in numerous threads here, but to summarize my opinion (not necessarly the opinion of all memebers of course...)

An automatic transmission has planetary gearsets, your bike does not. It is a constant-mesh sequential transmission

http://auto.howstuffworks.com/autom...ransmission.htm

http://auto.howstuffworks.com/motorcycle3.htm


ATF will provide better clutch action and shifting (depending on bike)...

...at the price of increased wear and tear on the gears.

ATF has additives for clutch packs in automatic transmissions that do also help clutch action in dirt bikes.

Its is thinner than any gear lube I know so it can help a notchy bike shift better.

It DOES NOT have the gear cushion additives that gear lube does (because an automatic transmission does NOT need them...). The design and action of our transmissions is different than an automotive automatic.

In the '70's a lot of racers used ATF to help with shifting and clutch action but also knew they were going to get increased wear and tear on the gears. This was an acceptable tradeoff.

So the answer to which is better soley depends on how you ask it. Whats better for the gears? Gear lube hands down. Which provides the better clutch action (and possibly shifting depending on the bike), the answer is ATF.

I don't use ATF because I expect the longest life out of the bike and don't care about the miniscule difference in clutch feel. I also would not buy a used bike if I know its been run on ATF (but thats just my opinion).

However; if you are racing and need that extra bit of performance, change it very often, and won't be keeping the bike long term then its likely a good trade off.