1st gear problem

Greg

Greg

XS650 Enthusiast
Messages
76
Reaction score
2
Points
6
Location
Depew NY
what would cause my 1st gear to slip out under load all other gears are fine i can get it to move in 2nd but in 1st it slips out half way or somthing and makes a bad clank grind noise that wont stop till i put it back in nutral

i checked the bike on center stand and it shifts fine through all gears ,i also checked and adjusted the shift drum but did not help ,i am getting a little clutch drag but the clutch seems to be good

anyone got any ideas before i have to spilt the case because im not sure if i am up for that kind of project
 
You'll find the pic below under the right case cover. There are also some small springs like you see in the upper left that may be broken. Remove the cover carefully and chances are you can reuse the gasket. Keep the kick start shaft pushed in while you remove the cover.
 

Attachments

  • gear slector.JPG
    gear slector.JPG
    60.3 KB · Views: 1,099
should there be 5 pins i only seen 4 and if so can these pins be replaced by just removeing the star wheel it will shift into gear just wont stay
 
I don't know the answer to those questions. But I know that when it won't stay in gear it is sometimes one of those springs broken.
 
looks like i found the problem to my 1st gear. shift fork very worn also the dogs on the 4th gear were rounded off i am going to replace the whole thing with 1 i got from xscris anything i should do while i have bottom opened up

downsize.jpg
 
I have/had this mysterious jumping 1st gear and managed to find this with Thanks to the guys on here:

http://www.xs650.com/forum/showthread.php?t=1411

If you read it through you realise the worn 4th selector fork is in fact a symptom and not the cause of the problem.

The problem is actually wear to the edges of the 3 engaging dogs on 4th gear that engage with holes in 1st gear. On initial inspection it doesn't look bad however under the torque of pulling away in 1st the dogs are sliding out of 1st gear and jumping round to the next hole and repeating this motion therefore causing the bike to constantly jump out of 1st gear.

The dogs on 4th gear are flat where they engage and bite into 1st gear unlike the other 2 sets of gears that have undercut / angled dogs that actually pull the gears together under load and this is something that might have to be remedied though I guess 30yrs isn't bad on a set of gears.

I sourced another set of gears only for it to be the same, Doh!
So I have had the dogs precision machined to remove the wear as trying this myself I failed miserably, still a way to get it going but think this is the cure.
 
I meant to say above (being a lazy cut and pasting type) that the worn selector fork is happening when the gear dogs jump out. There's a lot of pressure and the fork bears the brunt of it but isn't the cause.

I ended up with two sets of worn gears - can't blame the guy who sold me his set of gears as the wear doesn't look like it'd cause all this hassle as its hard to spot but I wasn't willing to rebuild an engine knowing it could still jump out of gear or do so in the very near future. Spent quite a while before working this out .

*This was of course after trying the gear change adjustment already mentioned.

In the end I found a engineering company who specialise in wire erosion just down the road who was willing to machine my gears for about £40 for both sets of gears and you can't beat wire erosion for accuracy - might even be over the top for this - but at least I got it done cheap.
 
sorry to resurrect an old post but it seems there are a lot of people that post on the web with this problem and everyone seems to have a different answer. I would think that with as many people who have had this problem that there would be a sure fix?? I too have the clanking and jumping out of first when shifted to from neutral. I split the case and found the shift fork to be worn and grooved just as others who have posted. is grinding a bevel in the 4th gear dogs really the best solution? obviously need a shift fork but id hate to build this thing and then still have tranny problems down the road. just wondering if there is any new information regarding this issue?

Posted via Mobile
 
I've rebuilt many Honda transmissions that had the typical "rounded dog corners" and "bent shift fork" scenario. Usually caused by missed shifts while street racing. In the dealership environment, the fix is "replace parts".

Interestingly, I've not seen/heard anywhere near the number of similar tranny issues with the XS650 on this forum. Many involve the shifter/starwheel area, but the tranny seems to tolerate abuse much better than the Hondas.

A couple of scenarios I can think of with the XS650 first gear would be:

Damaged/jammed neutral detent, forcing the rider to get aggressive to get into first, possibly getting only partial engagement, leading to rounded dog corners and bent shift fork.

The insidious stuck/draggy/misadjusted clutch. On initial startup, the rider may pull-in the clutch (but the clutch is still stuck/engaged), select first gear (with that typical clunk), and this would be mechanically similar to a missed shift. The dog corners are carrying the brunt of the shock, get rounded, try to jump out of the slots, while the shiftdrum is trying to continue to shove the shiftfork over, hence bending it. Once rounded with bent shiftfork, the problem only gets worse.

One solution/prevention procedure some of us use is to free-up the clutch before starting. Hold the clutch lever in while kickstarting, continue until the clutch breaks free...

Edit: Warning, the above dialog comes from my '70s shop experience. Can't make the same claims for bikes built after 1978...
 
Not common maybe but I have seen this; Namby pamby riders that don't hit/ firmly (ok kind of stomp) the shift lever all the way to the stop, instead gently try to "ease" it into gear, letting the dogs hammer against each otherly trying to slowly match shaft speeds. Apparently in the mistaken belief this is "better" for the transmission. The gear shift is an in/out thing, the faster you get the job done the better it is. When you know your tranny and or you are moving, the trans shifts easily with little effort but like 2many says if the clutch is dragging or gear speeds aren't well matched the shift needs to be crisp and firm NOT prolonged. I had a driver take the first gear syncho out of my truck one time, he would ssssllloowwllyy push the shifter at first at stop signs. It just made the synchro rings try to match the gear speeds for freakin ever and wore them out. When you are going to shift; shift dag nab it! MC don't have synchros, just thoose widely spaced square "dogs" that must slide fully into square slots to engage the next gear. This is where most of the driveline slop you feel when rolling the bike back and forth in gear with the engine off comes from; the space between the dogs and slots is a fine compromise between enough room to let the dogs in and so much room the tranny is "clunky". Street word is that Honda engineered more space than needed into the Shadow trannys to act more like that 'merikan V twin's clunky box!

On our poor suffering 650's I'll guess a common cause of "beaten dog syndrome"; some PO had the broken shift spring and just kept riding and putting up with clunking and dropping out of gear until the dogs are so beat up they won't stay in even when the spring is replaced. I can just imagine them trying to "hold the bike in gear" by keeping their foot on the shift lever.
I have done some odd "repairs" to keep an ancient truck, car, forklift tranny in gear after the dogs were well rounded.
 
I think tomanyxs is on to something with the sticky clutch if I don't free my clutch before I start I get the nasty clunk the first time time I shift I always remember to free it before I srart, btw I have had no problems with the transmission after replacement .
thanks for all of the advice and information
 
Thanks for the input fellas...I just bought the bike, got it running, and heard the bouncing in and out of first. Once it falls in its good but it will bounce around for a min or two and then fall in. The dogs do have some wear but nothing like what I was expecting to see. Most of the wear is to the shift fork which from my understanding is just a symptom of the real problem which would be the slight wear on the dogs. I'm hesitant to by used tranny because I don't want any issues once the build is done. Is there anywhere to purchase new or reman trannys for the xs? Without spending a fortune of course.
 
I looked around for a new one but no luck
I got mine from a member here and it was in perfect condition
 
When you look at the first gear it doesn't engage very far so rounds both the dogs and the gear it locates into,
 

Similar threads

bosco659
Inconsistent shifting
2
Replies
21
Views
2K
bosco659
bosco659
J
Hard shift/no shift
Replies
6
Views
939
Jusblowit
J
thrilla
I fell off my XS650 'Fat Cast Brat' and I'd like your opinion.
Replies
19
Views
2K
Splodge
Splodge
J
Carb Jetting
Replies
2
Views
725
jgimar
J
C
Gear Shifting Issues, Case cleaning Question, Non Running 75
Replies
4
Views
1K
David Toll
David Toll
Back
Top