Transmission trouble

My xj750 motor is having an issue where i'll pull up to the corner, stop ect... and it'll decide to jump outta gear or something it won't have any power going anywhere then i have to jump on the shifter and mess with it a little for it to get back to putting power down then when i shift into second it makes a knocking noise which i guess it's just not engaging properly kinda like when you shift into gear with to low of rpms. So what do you think the issue is and what would it take to fix it.

 

Remove the shifter cover and inspect the springs.

Gary H.

 

you may want to check this link out , incase your chain guide if breaking apart
http://www.xjcd.org/emergency_guidectomy

 

Well ok so I don't see anything in there the looks like anything that article describes, and why would my first gear not be grabbing if I come to a complete stop then it wants to not catch and go.

 

I don't see anything that looks like the cam chain guide

 

If the guide has disenigrated it could be jamming the forks.

Gary H.

 

So what should I be looking for then if that's the case?

 

The hyvo chain guide is the one we're talking about not the cam chain.


You'll have to drop the sump and look for pieces of the guide in the oil pump screen.

Gary H.

 

Ok it shifts fine out of first second tends to chug third is fine and everything past it is fine it tends to not put power out in first then will jump

 

Have you rebuilt the clutch?

Gary H.

 

No haven't touched the clutch that was a thought for the current issue but I have no clue for the 2nd gear issue just seems like it's not fully engaged so I tend to shift past into third

 

This very much sounds like a weak or broken shifter spring. Pull the cover like mentioned earlier (drain the oil first).
Which year XJ750? The early ones had a weaker shift spring that would cause the sort of trouble that you are describing (shift dogs not fully engaging due to the shift drum not being held into position by the shift mechanism).

 

I have an 82

 

OK. Still worth taking a look at the shift mechanism. There are two springs. One big one that wraps around the shift-shaft, and one smaller one that is on the shift pawl. Either one could be the source of the problem. You cak put the shift lever back on once the cover is off and work the mechanisim to see if it's moving correctly and keeping the shift drum in place. There is a wheel at the end of the linkage that sets into a divot for each gear position. The roller should seat positively in every divot, and resist rolling out. You should not be able to easily turn the shift drum by hand with the linkage in place, but it will turn fairly easily with the linkage removed (that is if the gears are aligned to mesh; you may need to turn the rear wheel to help the gears align).

 

would this also Make it a pain to find neutral?

 

this is the springs

 

Alright, figured those were it when someone mentioned them earlier

 

Not exactly...it is a photo of the shift mechanism(s), and the springs are included in it (numbers 4 & 6 to be exact). Lets help this guy out by being as clear as possible.

Mr. Thrash metal silver guy, the parts @k-moe were describing are numbers 3 and 4; #3 being the roller that fits into the divots on the shift drum, and 4 being the spring that should be holding it there firmly.

 

Alright thanks I also understood that as well I knew what kmoe ment when he said it as well as the springs they were talking about. The only thing I was wrong with the name was the hyvo chain guide but their is no evidence that that is the case theirs no plastic/rubber bits hanging out in the shift drum as per what the article mentions. If it's not the springs that's the issue then I feel that there might be an actual issue with the shifting guides(Dogs) in the transmission. Maybe not a common problem but if I end up tearing it apart to get down in there to check to see if that's the case I'd rather be surprised to see that it's the chain guide over the actual transmission components themselves.

 

I can move the drum by hand with the shifter assembly still in so then I'd think itd be the spring. Agree/Disagree

 

It sounds to me like the roller/detente mechanism is weak. That roller should be held into the "divots" so tightly by its' spring that you cannot just rotate the drum. Can you move the roller/arm with your hand? Is the spring broken, mis-installed or just sacked(worn out)?

 

It's installed properly I'd just say it's to week I can grab onto the end of the drum and shift it with my fingers the actual parts look to be in good shape so I'd attribute it to a worn out spring

 

#1 on a weak spring. Chacal has new ones in stock.

 

Thanks for all the Help Gents, once i get the part ordered and on i'll give an update

 

There are two springs. They are inexpensive enough that ordering both would not hurt.

 

So lost 2nd completely and now 5th isn't engaging and when you shift into where fifth should be it the rooms just climb up but it doesn't grab or anything just acts like neutral

 

Go back in, look through the holes near the shift drum and shift mechanism with a flashlight, and check for bits of black plastic in the transmission.

http://xjcd.org/emergency_guidectomy

It may also be that you have work gear dogs, or bent shift forks.

 

Did you replace the springs or not?

 

Welp looked into it and I'm tearing it apart right now the gear was definitely ground down I'm tearing into the bottom end have the transmission shafts on order and am going to either have to straighten the shifter forks

 

Photos please.

 

Welp I was right found ton of metal shavings in the oil and a couple teeth in the oil pan filter

 

Oh dear not good...Id say k moe and chacal will need to help .

 

Full teardown time. Check every bearing for scoring. Flush the works with solvent to get all the metal out.
I'd like to see pics of the broken gear.

 

I'll show you I have the bottom end off I just need to get the pictures out of the camera first

 

It's ground down pretty flush sadly

 

thats what it's supposed to look like

 

Did you post pics? I do not see any.

 

What it actually looked like

 

Ya. not good, but could be worse. Gearsets usually go for pretty cheap on Ebay, and I've seen several listed lately.

 

already got it hence why i had the new ones in it already but i need to figure out what caused it to get so f'ed up in the first place the gear selectors all look to be in good shape

 

What likely caused it is that somewhere somebody was HBFL power shifting through the gears and missed the shift. But instead of grabbing clutch it was forced into gear chipping/cracking a tooth. These trannies are pretty stout and it would take a long time for that type of damage to develop to that point..

While you have the cases open. I highly recommend taking the time to replace the springs, caps, and rollers in the starter clutch. You can use the XJ900R pieces to upgrade it with better springs. Also check the chain guides for cracks. Any cracking will eventually lead to guide failure.

~Ghost

 

Just go ahead and replace the starter chain guide. It will fail eventually and you don't want to have to open the cases again just for that.

 

Can Someone remind me of what the names for the half ring that are on the bearings are called i can't remember and i can't order them if i don't know what they're called

 

Yamaha calls them circlips. Some other places call them bearing locating clips or locating shims. Yours should not be missing, and they do not normally need to be replaced.
There is only one per bearing, and it only covers 1/2 of the diameter of the bearing.

 

Are you sure about that? Is the entire 900 starter clutch hub interchangeable with the 650/750 (air-cooled) models?

 

I don't see the point anyway, seeing as how it's the same spring,
http://www.yamahapartsnation.com/oemparts/p/yamaha/90501-04503-00/-spring-compression

and roller,
http://www.yamahapartsnation.com/oemparts/p/yamaha/93615-12088-00/-pin-dowel

Same outer clutch assembly too.
http://www.yamahapartsnation.com/oemparts/p/yamaha/31a-15580-00-00/starter-clutch-outer-assy

 

For the 650/750 models the outer clutch assembly is 4H7-15580-10-00..............it may be that the roller SPRING is the only different component.

 

The starter wheel and idler gear are the common 4h7 pieces used in all XJ 650/700/700X/750/750X/900. I include the 750X as it will be the same as the 700X. This makes the 900 starter clutch assy 31A-15580-00-00 a bolt in replacement.

The difference is the compression spring 90501-04503-00. Based on the 78 up XS1100 it would be a higher rated spring.
A bullet proof starter clutch upgrade for the smaller engines!

~Ghost

 

Same spring. At least that's the only one Yamaha lists now for all the XJ series, and XS series, and...well look at the link for the whole list.

 

compression spring 90501-04503-00
Not seeing any xj650's, or xj750 maxim's in the list. 82 XJ750R is the only 650/750 listed.

Original 650/750 spring.
Compression Spring, 90501-04596-00
http://www.babbittsonline.com/oemparts/p/yamaha/90501-04596-00/-spring-compression
Note that other than the xj 650/750 this spring is not used in anything larger than a 250.
Perhaps a clue here?

~Ghost