running funny shifting in 2nd

[DocDrop]

This is my sisters busa, its an 03. I got on it to see what she was talking about. You start out in first not problem you shift into second no problem till you hit around 35 mph, then the bike starts to buck/surge if you keep throttling up it starts to buck/surge more then you get tired of that and you shift up and the rest of the gears all run out fine. What do you think it is.

 

[SnapAttack]

What RPM are you spinning in second when this happens? Are you running a PC3 or yoshi box? If it's the engine side I would say it's a bad ecm or program. Install the magical TRE and see if it corrects. If it has one take it off. If it's on the tranny side I have no idea.

GL

 

[Gunnybusa]

35 is WAY too slow to be in 2nd gear. Check the chain for proper adjustment, if it's loose it will increase the bucking sensation. But like I said 35 is too low of a speed for that gear.

 

[Professor]

This is my sisters busa, its an 03. I got on it to see what she was talking about. You start out in first not problem you shift into second no problem till you hit around 35 mph, then the bike starts to buck/surge if you keep throttling up it starts to buck/surge more then you get tired of that and you shift up and the rest of the gears all run out fine. What do you think it is.

Doc,

Sounds like the Shift fork/Shift shaft 2nd gear issue. The dreaded 2nd gear issue. Likely at this point the dogs are rounded on the gear.

Check this thread

https://www.hayabusa.org/forums/?act=ST;f=10;t=58267;hl=


Actually there are several. Partial list of threads some of which have good info.

https://www.hayabusa.org/forums....end=&p=

Fix is going to be splitting the case and taking a look. You can just about count on two gears (they may be able to be saved by backcutting) 1-2 forks shift shafts and possible drum damage.

I rode a bike with the issue and is sounds/feels just like that.... only in second.

 

[DocDrop]

AM -->

1299612[/ATTACH] AM]
This is my sisters busa, its an 03. I got on it to see what she was talking about. You start out in first not problem you shift into second no problem till you hit around 35 mph, then the bike starts to buck/surge if you keep throttling up it starts to buck/surge more then you get tired of that and you shift up and the rest of the gears all run out fine. What do you think it is.

Doc,

Sounds like the Shift fork/Shift shaft 2nd gear issue. The dreaded 2nd gear issue. Likely at this point the dogs are rounded on the gear.

Check this thread  

https://www.hayabusa.org/forums/?act=ST;f=10;t=58267;hl=


Actually there are several. Partial list of threads some of which have good info.

https://www.hayabusa.org/forums....end=&p=

Fix is going to be splitting the case and taking a look. You can just about count on two gears (they may be able to be saved by backcutting) 1-2 forks  shift shafts  and possible drum damage.

I rode a bike with the issue and is sounds/feels just like that.... only in second.

Professor,
Yup it only does it in 2nd. She had been quoted a price of like $1200 to replace the tranny it think she said, or maybe it was just the gear set and labor. I was hoping maybe it could have been a little quicker fix but sounds like not this time.

 

[Revolution]

could be a map, or air filter also...?

it was happening to me when i installed a BMC "race" filter. switched back to stock and all is fine.

 

[99'busa]

It kinda sounds like the emfamous surging. being in 2nd gear at only 35mph. you are barely in the throttle does it still do it if you wait till 45-50 before you shift. This is just a cheap idea to start w/ but professor is probably right.

 

[djorgensen3]

I agree with the Professor. I went through the same thing and am in the middle of a tranny R&R fpr a fellow busa rider here in Phoenix. Good luck on your repair. It's not difficult but it is extensive.

 

[Gunnybusa]

I had the 2nd gear issue with my 02 and it didnt feel like bucking and it only did it under heavy load. If you have a loose chain and are in to high of a gear for your speed you will get a surge in the lowwer RPM band. If it feels like the chain is slipping or the tire is spinning under heavy load and ONLY in 2nd then you have the dog bone issue. Rule out the easy stuff first.

 

[GMbusa]

You need to repair the trans. That requires removing the engine and splitting the cases. 2nd gear might have some rounded dogs. Contact FastByGast and get them to check it out. They will inspect the shift shafts, shift forks and all. Get the standard undercut and a set of hardened shift shafts and you'll have a bulletproof trans.

That is, make sure it aint another problem first.