Another broken tranny

[mydirtkids]

We broke our 4th tranny yesterday. We use the Wiley slipper sprocket, but don't think thats the problem. In the past we have broken teeth off the gears. Always replaced all the gears after a break.

This time, the gears were fine. The needle bearing failed again, and all the needles were floating around getting chewed up by the gears. The third time we broke the tranny, a couple teeth on the gears broke and put alot of stress on the needle bearing causing it to fail. This time we had to have the case welded and replaced all the gears and all the bearings. Lasted about 10 brutal races and a few practices.

When the case broke, there was a crack through the needle bearing seat. I wonder if the hole was ovaled or something causing it to lose support and integrity (probably why the bearing failed this time).

I know some people are using the Double Wide bearing that the shops are selling. I don't have time to send cases off, and completely rebuild the motor before the next race.

Anyone using the double wide needle bearing share info? I am sure I can get machining done locally if necessary, and ready to try something

Thanks

[qcitytile]

we use a wider bearing that does not require machining. You have to remove the snap ring behind the bearing. It also has a harder race. We been using for two years never had one fail, but I put all new bearings in every year. I will go look for part # and let you know if interested.

[mydirtkids]

Yeah if you come across it that would be great. Were you able to use the seal or did you have to use silicone? I cant remember off hand, does the snap ring hold the bearing in place or the seal? Thanks

[cik orange]

do you also use case saver will take some of the load off your bearings (sounds like time for new cases)

[Logan #34's Dad]

The bearing you want is a: Slovakia: INA NK 25/16.
More needles, stronger cage, little wider. No modifications needed.

[selbygirl]

if you do have a bad case send it to dave carter ours was craked and he put a sleeve in it with 2 sets of bearings and and a brass bushing i seen a kid athe track blow his trany and had a hole in the case you could almost stick your finger it and he fixed it and it was at a good price its worth it if your kid is leaping over tall buildings seeya tommy

[nastynotchback1]

Ours has a bushing in it.works great except when the cover bolts back out and it destroys the trans like we did this weekend.

[qcitytile]

we use the INA NK 25/20 just cant use the snap ring behind the bearing. I've also used the one logans dad recommends and never a problem I just came across this one and tried because its a little wider. I get mine from motion ind. I think around twenty bones

[mydirtkids]

I think I will try the bearings to get us through the last 3 races. The needles really gouged the heck out of the seat though. Almost sure it will fail again without either getting new cases or having these sleeved. I will order new cases and see Dave about having the work done for next season without a doubt, just no time to do it before the next race.

Gotta love it!!!

Anyone know how close the tolerances are on the cases? Probably should re-check the squish on new cases? Really hate taking the new crank back out and risk some silly goof up or oops. Guess gotta do whacha gotta do...

Thanks again everyone!

[selbygirl]

if you think your going to get a dnf you should just over night it to dave he's pretty fast you could blow a set of gears and tranny cover entry fee gas just thinking green take care tommy

[wrhracing]

Originally posted by mydirtkids
I think I will try the bearings to get us through the last 3 races. The needles really gouged the heck out of the seat though. Almost sure it will fail again without either getting new cases or having these sleeved. I will order new cases and see Dave about having the work done for next season without a doubt, just no time to do it before the next race.

Gotta love it!!!

Anyone know how close the tolerances are on the cases? Probably should re-check the squish on new cases? Really hate taking the new crank back out and risk some silly goof up or oops. Guess gotta do whacha gotta do...

Thanks again everyone!

Use bearing and stud loctite, usually green or the red loctite.
Get your feeler gauges put the bearing in the hole measure the slack with a feeler gauge.
Then cut the feeler gauge and install around the outside of the bearing taking up the "Slack" between the cases and bearing.
Same thing works for RH LH main Bearings on cases worn out.

[mydirtkids]

Use bearing and stud loctite, usually green or the red loctite. Get your feeler gauges put the bearing in the hole measure the slack with a feeler gauge.
Then cut the feeler gauge and install around the outside of the bearing taking up the "Slack" between the cases and bearing.
Same thing works for RH LH main Bearings on cases worn out.


Nice idea... you must know colby :D

Going to the bearing shop tomorrow to try to get a 25/20 and a 25/16.

I have another set of good 90 cases in the practice bike, just did not want to rip both motors apart for 3 races.

I guess if anyone has a SMOKIN deal on some cases then I might consider it. I really prefer to support guys at the shops. They got overhead and alot of risk involved. For a few extra bucks, am glad to have guys like Marc and Gary around. (plus peace of mind on a purchase).

[nastynotchback1]

Originally posted by mydirtkids
Use bearing and stud loctite, usually green or the red loctite. Get your feeler gauges put the bearing in the hole measure the slack with a feeler gauge.
Then cut the feeler gauge and install around the outside of the bearing taking up the "Slack" between the cases and bearing.
Same thing works for RH LH main Bearings on cases worn out.


Nice idea... you must know colby :D

Going to the bearing shop tomorrow to try to get a 25/20 and a 25/16.

I have another set of good 90 cases in the practice bike, just did not want to rip both motors apart for 3 races.

I guess if anyone has a SMOKIN deal on some cases then I might consider it. I really prefer to support guys at the shops. They got overhead and alot of risk involved. For a few extra bucks, am glad to have guys like Marc and Gary around. (plus peace of mind on a purchase).

I have a set of 90cc cases if thats what you need.150.00 for them.

[quadracrdad]

any body got number for Dave Carter

[BradLoomis]

(501) 679 - 5780