Shifting issues...

[eran_k]

I have started to ride my bike after the big rebuild project.
i didn't split cases but have done many things
new clutch friction plates, new clutch springs
mew oil and oil filter, clutch pushrod oild seal,shifter oil seal
new clutch cable
everything is suzuki OEM (except clutch springs)
carbs were stripped and rebuilt with new o-rings
new sprockets and chain
first i'll say that i didn't ride it before the rebuild, it's my first motorcycle so i have zero experience or any base for comparison how it should be.
been riding only scooters before .

motor seem to work fine.
when i start riding it pulls strong and up shifting is fine,it seem tough i'm "missing" a gear, i didn't mange to count yet but i feels like i could use another gear, like i'm not getting to 6th (i don't have the gear position light, just neutral)
also, after it gets worm - like 10 minutes of riding at least,it's hard to up shift from 1st to 2nd,i need to kick it hard to upshift,
upshifting to 3rd and up is fine and so is down shift.
any ideas?

Eran

[Guest]

Before getting too concerned, take a good look at your shift linkages; especially the hiem joints.

The whole reason I tore my engine down was because I believed I had a gearbox issue as it would regularly pop out of 5th and 6th unless I gave it a good solid shove into gear.

Turns out I didn't need the tear down

The hiem joints were worn really badly and, in addition, the part of the linkage that clamps onto the shifting shaft splines had a dodgy bolt that prevented it tightening correctly, so it was loose on the splines.

I picked up some hiem joints from a hobby shop to replace the originals and it is much improved now and I no longer have that issue.



The originals are peened on and I used a dremel to grind enough off to remove them.

The new ones had an M6 thread to bolt them on with, and they're a matched pair so one has a right hand M6 thread insert and the other has a left hand M6 thread insert, so I could just reuse the stock adjuster link.

In addition to all that, I discovered the footpeg bracket had a stress crack in it around the shift lever bolt that allowed it to flex as I changed gears, making it worse.

Some dodgy welding fixed that up.

[tkent02]

i need to kick it hard to upshift,

Please don'e ever kick it hard. Once you see how small the pieces inside that you are kicking are, you won't want to.

[Gorminrider]

i have zero experience or any base for comparison how it should be.

like 10 minutes of riding at least,it's hard to up shift from 1st to 2nd,i need to kick it hard to upshift,

It should not be hard but 1-2 is the shift that gets the most punishment, I think, especially from all the unknowably nasty habits of previous owners that handed the bike down to you. I have a couple of ideas to try before freaking out...

If the bike shifts ok when the oil is cold, I wouldn't guess the gearbox is at fault but I haven't been in there myself either. You were told: Don't force it!
Check your clutch adjustment when the bike is warm.The clutch runs in oil and the oil changes temperature...warm is the temperature where the clutch must work....a little variation cold oil ->warm oil is not uncommon but it shouldn't be wildly different... you've got new clutchplates and springs etc. too so maybe there's a little grace period to acclimatize these to their new home but not much.

This following is a "faint hope" to try after what Pete is saying but you are shifting through neutral on the way up 1-(N)-2 and there is a spring loaded device on the top of the crankcase that helps find neutral.You should feel the shift very gently kind of bump as it goes past neutral-so gentle that neutral is hard to find when you want it, until you get used to it....There's a "tower" cast into the crankcase under the carbs with a big bolt on it.Under the bolt is a spring thing...If you are getting stuck at neutral before getting to 2nd...any chance somebody has put a stronger spring in there?

[eran_k]

I also replaced the heim joints with more sturdy rod ends joints.
but the arm itself is a little loose on the shaft,i will try to tighten it some more (maybe put a nut on the bolt)
Also could the geometry of the linkage have an effect on smoothness\difficulty of shifting?
how should it look like when installed correctly?



Eran

Edit: there is also some slack at the shifter pivot,i have a new bolt shaft thing in there but there is still some play, mostly side to side inside the mount.

[Guest]

Forgot to add I also found an issue with the pivot itself.

I got a new pivot bolt as I figured the original had worn down given how much free play there was.

That was true, and it was probably half a mm smaller diameter than the new one, but what that resulted in was the pivot hole on the pedal had actually gone out of round, preventing the new bolt going through.

I had to get a large drill bit (can't remember the size) and round the hole out enough that I could get the new bolt in. There's still left/right free play which I'm thinking is fairly normal, but it doesn't flop around on the pivot bolt any more.

[eran_k]

it's weird that the lever is metal on metal, thinking on maybe sleeving it with an igus bearing. should solve the slack and provide smooth operation.
what about linkage geometry? any pics of how it should look?

Eran

[Guest]

Yeah metal on metal isn't great, so I just slather a bunch of marine grease in there which seems to go well. You need to remove it to do anything under the clutch cover so it gets removed and re-greased regularly.

As for geometry, there's really only one way it will all sit together neatly on the splines and still give you adjustment, which means around 90 degrees at both the lever and shifter shaft end.

[eran_k]

I have some findings that might be the reason (or not)
the rod link that i made from two rod ends (picture above) is 1 cm and a bit longer then the original rod with the heim joints, this made the shift arm not to be in 90 degrees with the shift lever and i think it may have effect on shifting.
the bad news is that i dont have the parts needed to make a shorter link rod, so i improvized something with the old heim joints - iv'e put a screw thru the haim "cup" and used a nylock self locking nut to secure it on the other side of the link arm\shift lever. i hope it will hold util i figure out a proper solution. either get new parts with the original heim, or get shorter rod ends or a shorter link rod.
Pete, do you have a link to where you got your rod ends, can you measure their length and the total length of the link rod? (mine should be 7 cm centrer to centrer) at least from the picture you posted it looks longer

Eran

[Guest]

Ah ok, that may not be helping... although I would think the geometry would have to be way off to make that much difference.

Here's where I got mine:

http://www.smallparts.com.au/store/partslist/jointsballandsocketrightanglelightduty/jointsballandsocketrightanglelightduty/Q/1/

All the spec's are on the page there, pretty sure I got the "JBS-M06.0Lx32.50-CS" and "JBS-M06.0Rx32.50-CS".

If I get some time tonight I'll try to measure the stock rod or at least the non-threaded part in the centre.

Worst case for you I guess would be to get two M6 bolts, one left and right hand thread and get them butt welded together... might not be pretty but if your welding is better than mine it should serve the purpose.

[eran_k]

never mind, saw the correct ones too

[Guest]

Bugger, completely forgot to measure it last night! Will endeavour to do so tonight...

[Guest]

Ok, I took a photo (attached) of how mine is sitting, but the lighting where I park my bike is terrible... you see though that lever is almost parallel to the linkage and both joints are pretty much 90 degrees.

You can also just make out that my initial photo had the front linkage onto the splines around the wrong way. It should be oriented so the bolt threads in from the front, not the rear.

Centre to centre of the hiem joints measures almost exactly 90mm on mine.

Hope that helps!

[eran_k]

Strange that 90mm works for you, maybe three's a difference in the frame between the 450 and the GSX400
my workaround link rod at 70mm work better then the 80mm one,shifting is easier, i found the 6th and finding neutral was also better.
still need to get a decent part though.

[Guest]

Yeah ok, definitely must be a difference! Glad that it looks like it's solved your issue though, that's the main thing