Rebuilt a bike: gears in wrong order. shifts into third not first =(.

Ok, I rebuilt a bike (Yamaha JX 750) and everything is (was) going dandy. Just did a carb rebuild and was ready to take it around the block, but the shift pattern is totally wrong. It shifts into neutral just fine but when I shift down one gear from neutral it seems like it goes into something like third not first . Its not easy to shift from neutral to whatever is in the location of first(gears grind every time). The bike isn't as much fun without first ,just not as satisfying to ride the clutch until an appropriate speed is reached.

Has anyone heard of this? I didn't take apart the shafts for the transmission they were left alone. I know there is component that the petal uses to shift gears with removable shafts in it could I have assembled this wrong? How messed up am I is this going to be something where I have to pull the motor to fix my transmission I sure hope not.

I tired finding a form that spoke of this but have not found one. It seems like I cannot be the only person with the mad skills to jumble up the transmission this good.

 

you have the short shift lever that goes on the splined engine shaft upside down

 

I agree with polock.....your foot
shift lever is upside down....reverse it

 

no room to push the pedal down if its reversed but got it to work just to hope it would work. I imagine that that was fourth gear I tried starting in. I was really hoping that that was it.

 

Could the orientation of this guy cause my problem?

 

those only go together one way

 

My bike has essentially two gears right now what feels like third and forth? It can only shift up once and down once. I have a feeling this motor is going to come out again.

 

that cam looking thing that's circled, fits with a roller on the shaft pictured to the right. take that cover off and lift the back wheel , as you rock the wheel, work the shifter shaft and see that the roller goes in all the lobes on the cam. you could have a broken piece of chain guide jamming the shift drum, the cam thing could be loose, their could be a broken spring in there. look at a parts diagram and see if all your springs are there. your sure the little lever isn't upside down, that makes first up and fifth all the way down

 

yea positive, shifting up or shifting down does not put me in first either way. Ill dig around in there looking for an answer. it shifts up into a gear that is even higher than if i shift down. I have to really ride the clutch to go forward in either gear and it wont shift higher or lower than either of those two gears.

 

Are you certain the central selector engaged the groove in the 2/3 gear pinion when the case halves were joined?

Gary H.

 

All three selectors were engaged when the halves were put together.

 

But were they engaged into the correct slots? This is one of the parts of putting the case halves together that can be done wrong, and can result in the problems that you are having.

Give us a pic of the shift lever as you have it on the bike now, just for clarity's sake.

 

Unfortunately the shifter lever is already off again and don't believe it was the issue. If that was the only issue I would still have more than two gears. I have found the issue.




this guy exists on the end of the selector drum like on the other image I posted and and has pins that determine where neutral is, how high and how low you can shift.
the removable pins are essential to be in the right location. The longer pin needs to be in the right hole and the right two holes need to be left empty. I have in my reassembly mismatched everything with this. I do not however know the right location for the pins although i now know this is the issue. does anyone know where I can find a picture that has the pins in the right locations? I have looked for one and cannot find one that offers me any clarity on the issue. Thank you guys for your input.

Edit: The transmission cycles through all of its gears which indicates all the selector arms are correctly located. I remember now I cycled the transmission before I put the pistons on to make sure I didn't mess up but have been second guessing my work. Its always worst case with me.

 

For clarity's sake, was the shift drum disassembled before? I ask because unless you or a previous owner had the shift drum apart the pins were already in the correct position.

This thread may help.
http://xjbikes.com/forums/threads/xj650-1981-shifter-drum-star-segment-default-position.40759/

 

Yes the end of the drum was removed and I put it back on shortly after when I realized it didn't need to come off. So I totally skrewed that up. Its called the star segment? Thankyou kindly hopefully this helps.

There is a three demensional model someone put together on that thread that really cleared up my questions with configuration. Many thanks.

 

Glad you found the problem.

Gary H.

 

Put it all back together and it was the first time I have ridden the bike since a year and a half when I tore it apart. thanks gents! although I sill messed something up because the gear pattern goes 3, 4,1,N,2(or something like that). At the lest they are all there now right? Time to move pins around again.

 

The pins just index the star with the drum. The arrangement of the pins does matter, but I don't think that is all that is happening to get the gear order you describe.
Once again, pic of your shift lever please.

 

You are totally correct. For some reason I thought that the drum could rotate in a full 360 degrees pattern which would let it go from 1st to forth but it was going from second to third like it was supposed to. But I have managed to confuse myself to no end trying to figure out the right pin locations that would make sense and after all kinds of lever movements. I either the pedal is on backwards or I was shifting the wrong way. Basically I think I have made myself the idiot again. Ill get you a picture of this pedal when I can take one. Thanks k-moe.

 

If you can take a pic of the shifter/where it hooks to the shift shaft splines. I recently screwed up one on my honda. I put the adjuster on the bottom of the shift shaft in stead of the side my shift pattern was completely backwards 1 up 4 down. Thought i blew up the trans took 5 min to fix. Not sure if it is your problem but you never know

 

Interesting, learn something new here each day.

 

Here is the pedal attached to the splined shaft that comes out of the side of the block.
it seems to be all working right now. Thanks guys. The gears still grind a little going into first but I think that can be fixed with a clutch adjustment. but for the first time in a little bit it can be taken around the block. Now just need to figure out something for a rear seat and change out my grips and put some mufflers on and i'm good to go.

 

Looks right to me

 

The linkage is correct.

 

Is the bolt missing that holds the linkage to the splined shaft?

 

Good eye. It is missing in the picture.

 

Yea this I know but I think it is the least of my issues. My starter clutch makes the whole coffy can full of rocks noise some times. It engages every time but will disengage sometimes for reasons unknow. So all this work is wasted. I think I am going to go out back and shoot myselft for not thinking about rebuilding this a few months back when the case was still open

Thanks Obama.

 

Then you'd miss out on all the great things life has to offer. "We only get one shot to rock, here's your chance to flow". Learning is living.

Gary H.

 

Yea your right. Realistically rebuilding the old gal isn't time effective. But it's doing something that counts. Just wish I had more time with school coming up.

The hope is that when I get the bike to actually start ok then it will be less of an issue.

 

If you do go back in there, did you replace the primary chain guide when you had the cases split? If not, make sure that gets done along with the starter clutch rebuild. There are some good posts on here describing the process and things to look out for.

Starter clutches can be affected by type of oil, battery condition, and starter condition. Always best to evaluate those items first before blaming the clutch. I was experiencing the box of rocks intermittently. I switched from full synthetic Amsoil motorcycle oil to Castrol dino motorcycle oil and at the same time reconditioned the starter. Not sure which one took care of it, but I have not had a singe issue since then.

You are just like many of us, if we had found this site earlier and asked a few questions life would have been easier.

 

I did replace the chain guide, the old one was starting to crack. They are getting hard to find. Got a new battery today with some extra cash I was able to get together and the bike starts right up every time now. But it didn't help the clutch. Ill try the oil that you used and see if that helps. Maybe it just has some junk in it or something.

 

They shouldn't be. Yamaha still makes them and the same part is still in use in current machines (the still-not-available-here XJR1300 for example).