Changing from 1st to 2nd gear doesn't really work

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Catalin24
Posts: 24
Joined: Sat Oct 07, 2017 7:36 pm
My Bike: ZXR 400 L5

Changing from 1st to 2nd gear doesn't really work

Post by Catalin24 » Sat Sep 29, 2018 4:00 pm

Hello friends! please help me because this drives me crazy.
The problem is as follow:
Trying to shift from 1st gear to 2nd gear at low rpm's (below 5-6k) works perfectly. Nice clunk, nice pull forward.
But trying to shift from 1st gear to 2nd gear above 6-7k results in a horrible noise, like a grinding noise, and a bit of pulsation from the shift lever. And gets just to neutral. It's like get trough neutral, almost into the 2nd gear but it can't engage.
If I shift in this way: 1st -> NEUTRAL -> 2nd it works fine. In other words I need to shift to neutral first, I can't jump over it from 1st to 2nd.

The problem was pretty much every time I owned the bike but now it's really bad. Before i could've shift from 1st to 2nd without the clutch and it worked perfectly, now if I try to clutchless shift the bikes goes only into neutral and if I force the shift lever a bit harder does that grinding noise. Clutchless shifting from 2nd-3rd, 3rd-4th, etc works perfectly . (the bike also shifts perfectly in any other gear except 1st to 2nd)

Thinked of possible cooperates for this:
-Clutch cable was loose, I thought it won't disengage properly. (I've changed it and adjusted it. No improvement, maybe just a tiny bit. But no real improvement.)
-RPM too high. It idles around 2-3k rpm. I suspect the carbs, they are not sync'ed. (Gonna do it this weak with some help from a friend)
-Chain, Rear wheel sprocket damper too loose? (Read in some topic here that these little toys are really moody about the chain tension)
-The shifting linkage is really worn out, those black pivots(idk how call them) are really loose, and the mounting of the foot thingy where you press are really worn out and loose. A lot of play from left-right and a bit from up-down. I thought this is the problem because I played a lot with the adjustments and sometimes works a bit better. I looked on the web how it should look stock, now it's in the stock position. The problem still persist.
-Clutch assembly? Springs, plates
-Oil? its 10W-40 Motul 5100 Semi-Synthetic (done just 1-2000km on it, but it was stored over winter with that oil, almost 1 year old)
-And at last... the dreaded gearbox it self (shift forks, gear dogs, gear drum, the shift lever witch pulls on the gear drum, etc)

I'm not a mechanic but I'm no fool either, I've rebuilt this bike from the ground up. The only thing that intimidates me it's the actual gearbox. :excited
Help is much appreciated!

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banner001
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Re: Changing from 1st to 2nd gear doesn't really work

Post by banner001 » Sat Sep 29, 2018 7:54 pm

My thoughts would be worn selector forks as opposed to the actual gearbox...how many miles has the bike done, also clutch less shifting is not really advisable unless you really hate your gearbox :D
UK ZXR400 L3 (1993) - Fully restored and on the roads, my green beast!
JPN ZXR250 A2 (1990) - Revs to 19,200rpm... 'nuff said :smt003

Catalin24
Posts: 24
Joined: Sat Oct 07, 2017 7:36 pm
My Bike: ZXR 400 L5

Re: Changing from 1st to 2nd gear doesn't really work

Post by Catalin24 » Sat Sep 29, 2018 9:37 pm

@banner001 The bike has ~62000 km or ~38500 miles. Do I need to split the cases to change the selector forks? Can you show me the actual part you are talking about?(I want to be sure 100% we are thinking about the same deal)

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banner001
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Re: Changing from 1st to 2nd gear doesn't really work

Post by banner001 » Sun Sep 30, 2018 7:57 am

Gearbox on the left, forks in the middle, drum on the right
Https://goo.gl/images/ye8eo1

The oil pan needs to come off, the cases need to be split, but you can do this and leave the crank in place, i.e. you don't need to touch the top end of the motor at all.
UK ZXR400 L3 (1993) - Fully restored and on the roads, my green beast!
JPN ZXR250 A2 (1990) - Revs to 19,200rpm... 'nuff said :smt003

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banner001
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Re: Changing from 1st to 2nd gear doesn't really work

Post by banner001 » Sun Sep 30, 2018 8:02 am

I would be thinking it's worn selector forks, possibly a worn drum, and I would think it unlikely that it's the gearbox dogs or another transmission issue.

If you need transmission parts, buy new from Kawasaki...
UK ZXR400 L3 (1993) - Fully restored and on the roads, my green beast!
JPN ZXR250 A2 (1990) - Revs to 19,200rpm... 'nuff said :smt003

Catalin24
Posts: 24
Joined: Sat Oct 07, 2017 7:36 pm
My Bike: ZXR 400 L5

Re: Changing from 1st to 2nd gear doesn't really work

Post by Catalin24 » Sun Sep 30, 2018 2:20 pm

Banner I'm a bit confused, what do you mean by "you don't need to touch the top end at all" ? :smt017 How can I split the cases without taking the head and the cylinder block out? I can get enough access from the bottom of it(i.e oil pan ) Or from the clutch cover?
To be honest I would really love not fiddle with the top end again. It had a leaking head gasket and a really badly warped head. Skimmed the head, changed the base and cylinder head gasket, new timing chain. And after the rebuilt the bloody thing still contaminated the oil with water(antifreeze), I washed(with break cleaner) the engine while it was opened. I got really frustrated and left her sit over the winter (~about 5 months) and when I started it. No problems at all since then.

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banner001
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Re: Changing from 1st to 2nd gear doesn't really work

Post by banner001 » Sun Sep 30, 2018 4:29 pm

the bikes cases can be split with the engine flipped upside down, the crank will be held in place, you dont need to remove the clutch or timing chain.

there are no internal bolts between the cylinders like in some bigger bikes, so there is nothing stopping you, when i snapped a tooth of my gearbox roger middleton who did it for me didnt need to take the whole engine apart, just split the cases and removed the gearbox...
viewtopic.php?t=13653#p101484

all of the bolts that hold the case together are on the outside of the cases, so you just remove them all and then split the cases, just make sure that the cam cover is at the bottom and that the gearbox is pointing towards the sky...
UK ZXR400 L3 (1993) - Fully restored and on the roads, my green beast!
JPN ZXR250 A2 (1990) - Revs to 19,200rpm... 'nuff said :smt003

Catalin24
Posts: 24
Joined: Sat Oct 07, 2017 7:36 pm
My Bike: ZXR 400 L5

Re: Changing from 1st to 2nd gear doesn't really work

Post by Catalin24 » Mon Oct 01, 2018 5:59 pm

Thanks a lot banner! Never thought of that! You are a real time saver. Any idea how to turn the engine upside down and secure it in place without an engine crane ? Also as you wrote in that topic from 6 years ago, would the crankshaft move/twist from it's place (i.e bearings).
Should a loose the tension on the timing chain or not?
In my mind, If I don't loose it maybe the chain will pull too hard on the crankshaft and move the crank or put unwanted pressure on the rods, pistons, piston rings, etc
But If I loose the tension, maybe the chain would skip a tooth or two? Being that is upside down.

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banner001
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Re: Changing from 1st to 2nd gear doesn't really work

Post by banner001 » Tue Oct 02, 2018 7:03 am

Remove the chain tensioner should be all that's needed.

You can always check that it's still alligned afterwards, now might also be a good time to check/replace the chain and check your valve clearances.

I would knock up a small wooden holder for the engine with some 2" X 2" wooden blocks...will easily do the job as a quick engine stand
UK ZXR400 L3 (1993) - Fully restored and on the roads, my green beast!
JPN ZXR250 A2 (1990) - Revs to 19,200rpm... 'nuff said :smt003

Van223
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Joined: Tue Nov 29, 2016 8:27 am

Re: Changing from 1st to 2nd gear doesn't really work

Post by Van223 » Sat Jul 18, 2020 9:26 am

hey,
I've got the same problem, did you ever find out what the cause was??

Cheers.

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