TOPIC:

Hi guys, new here. Recently picked up an immaculate barn find 77 kz400. After spending a little time getting it running I've been riding it for about 3 weeks now and just found the original owners manual under the seat under the daily maintenance plate. In this manual it states that this bike (s3) is indeed supposed to be a 5 speed. I found that interesting as it only shifts into 4 gears. I think the most interesting thing is that this bike runs as though it should have 4 gears. The gears seem more spread out and I can cruise at 75 in 4th gear. The s3 doesn't have a tach but I can tell the rpms are nowhere near redlining. They seem at about 5k. Did someone rebuild this gearbox? Is there a way I can find out? fix this? Easy fix?

Thanks!

shootanappleoffmyhead wrote: Hi guys, new here. Recently picked up an immaculate barn find 77 kz400. After spending a little time getting it running I've been riding it for about 3 weeks now and just found the original owners manual under the seat under the daily maintenance plate. In this manual it states that this bike (s3) is indeed supposed to be a 5 speed. I found that interesting as it only shifts into 4 gears. I think the most interesting thing is that this bike runs as though it should have 4 gears. The gears seem more spread out and I can cruise at 75 in 4th gear. The s3 doesn't have a tach but I can tell the rpms are nowhere near redlining. They seem at about 5k. Did someone rebuild this gearbox? Is there a way I can find out? fix this? Easy fix? Thanks!

Hello, shootanappleoffmyhead, and WELCOME to KZr!

Is neutral accessible as normal (perhaps indicated by a green light on the dashboard), with 1st gear becoming engaged by pressing downward on the foot shift lever?

Perhaps one of the gears is non-functional for whatever reason. But it would be unusual to discover a transmission alteration from 5 speeds to 4 speeds (at least in my experience).

The stock drive ratios may have been changed by installing non-stock sprocket size (counter-shaft and/or drive).

Does the shift lever seem being able to find more than one "neutral" position?

Has the counter-shaft sprocket nut become loose, or missing?

Good Fortune!

.

It sounds like you may be using gears 2 through 5 and never shifting into 1st gear. With the transmission in neutral (N) you should be able to push the shifter down 1 time to go into first gear. Gears 2 through 5 are engaged by lifting the shifter up from the neutral position. Is your transmission working like that or are you engaging 4 gears above neutral and none below or maybe engaging 1 gear below neutral and 3 above? Ed

Seem like it would be difficult to start off in second gear with Kawasaki's famous Positive Neutral Finder. You would have to use your feet to get the bike moving fast enough to get it in second gear.
Fun to watch but not so much fun to do.

77 KZ400S3 transmission. 5 input gears and 5 output gears equals five speed transmission.

I don't think the 1977 KZ400 has the Positive Neutral Finder. I know for certain that the 1977 KZ650 does not have it. On the KZ650 Kawasaki did not implement that feature until 1978. Ed

Patton wrote:
Hello, shootanappleoffmyhead, and WELCOME to KZr!

Is neutral accessible as normal (perhaps indicated by a green light on the dashboard), with 1st gear becoming engaged by pressing downward on the foot shift lever?

Perhaps one of the gears is non-functional for whatever reason. But it would be unusual to discover a transmission alteration from 5 speeds to 4 speeds (at least in my experience).

The stock drive ratios may have been changed by installing non-stock sprocket size (counter-shaft and/or drive).

Does the shift lever seem being able to find more than one "neutral" position?

Has the counter-shaft sprocket nut become loose, or missing?

Good Fortune!

.

HI Patton, Thanks for the response. Yes, neutral is accessible as normal. It's 1st N 2nd 3rd or(4th?) 4th or(5th?). The green light comes on when I find neutral. The shift lever doesn't normally find another neutral however if I'm shifting gears very fast it will sometimes drop out of gear completely after 2nd gear, but it just seems like a misshift due to too rapid of a shift. I'll check on the sprocket nut.

After thinking about it I'm thinking maybe it's missing a gear. Maybe 3rd or 4th?
Gonna ride today so i'll try to see if I can hear an unusual change in rpms from one gear to the next.

After taking a close look at the parts diagram, I see that there are no three ball bearings shown, so no Neutral Finder.
See #31 in the pic? That's the shift drum that moves the shift forks in response to the external shift lever and your foot. It is a linear shifter, which means it has to go through every gear in order. You can't shift from first directly to third, you have to shift through second. If you were missing any gear then you would have an additional neutral where that gear used to be.

It's not complicated, you just aren't shifting into high gear for some reason.

Hey Guys,
Thanks for your help on this. Eventually I came to realize that for some reason 5th gear was stuck, as in it wouldn't shift into 5th. Then one day I pushed it really really hard and it went into 5th gear and has gone into 5th normally since then.

Thanks again!

shootanappleoffmyhead wrote: Hey Guys,
Thanks for your help on this. Eventually I came to realize that for some reason 5th gear was stuck, as in it wouldn't shift into 5th. Then one day I pushed it really really hard and it went into 5th gear and has gone into 5th normally since then.

Thanks again!

Well, I hope it keeps working, but that's not very reassuring. Things don't really tend to fix themselves very often, at least not permanently.

Maybe your shift pedal is not in the right position for your foot, you can mark where the pedal is on the shaft, remove it, & replace it one notch down, to make it easier for your foot to up shift
Pete