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Discussion Starter · #1 · (Edited)
Hey all!

I just got into a Gen 1 (2004) ZX10R, I traded my big turbo MK4 GTI away for it, and quickly learned there was a lot of work to be done on it. I've already replaced the clutches, clutch cable, throttle cables, fairings, wiring for the turn signals, exhaust+exhaust mounts, and BOY did the bike get a lot faster after the clutches.

However, I noticed a surging/bucking in first gear under WOT, which makes the dreaded headshake even worse. I'll be tearing the bike down to get into the transmission and drop all new items in, as well as do a general refresh to the bike so it's ready for the warm days again, do you guys have any recommendations on items to pre-emptively replace/upgrade while I have the engine that far down?

Thanks!
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Welcome! Another Gen 1 here is sweet!

And that's a hell of a winter project for sure. You are aware that the get to the transmission parts on the earlier bikes, you have to remove the entire motor and split the engine cases apart. It's not really hard to do, but it is time consuming. If you're going to go to that level and inspect all the parts in the transmission, the only things I'd recommend changing out just for the sake of it would be the shift forks themselves. I can't think of anything more general than the usual things as you inspect it all during the teardown. If you find something, then you can replace it. But usually that's just things like gaskets and things.
 
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Discussion Starter · #3 ·
Welcome! Another Gen 1 here is sweet!

And that's a hell of a winter project for sure. You are aware that the get to the transmission parts on the earlier bikes, you have to remove the entire motor and split the engine cases apart. It's not really hard to do, but it is time consuming. If you're going to go to that level and inspect all the parts in the transmission, the only things I'd recommend changing out just for the sake of it would be the shift forks themselves. I can't think of anything more general than the usual things as you inspect it all during the teardown. If you find something, then you can replace it. But usually that's just things like gaskets and things.
Yeah, I've built quite a few of the 1.8T 20v engines from VW, around 11 of them with crankshafts out of the engine so the only thing new to me about this is going to be the transmission work itself.

I'm aware of needing to split the case, not super sure what that entails but I'm hoping I won't need to take the conrods out to do that as the bottom end is noise-free but if I have to drop new bearings in oh well.

I expect the forks to be jacked up, and I expect some stripping on the first gear, but we'll see what happens!
 

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Discussion Starter · #4 ·
I forgot to mention I'll also be replacing the clutch hub and the pads again while the engine is out, as the hub was VERY wavy, but I just wanted to ride it again 😅
 

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Yeah, I've built quite a few of the 1.8T 20v engines from VW, around 11 of them with crankshafts out of the engine so the only thing new to me about this is going to be the transmission work itself.

I'm aware of needing to split the case, not super sure what that entails but I'm hoping I won't need to take the conrods out to do that as the bottom end is noise-free but if I have to drop new bearings in oh well.

I expect the forks to be jacked up, and I expect some stripping on the first gear, but we'll see what happens!
OK, good to know the details.

No, you don't have to touch the crankshaft at all. You don't have to touch anything in the top-end of the motor. You just need to pull the motor, turn it over, and take the bottom half of the case off and all the transmission parts are right there. You don't touch the conrods and you don't need new crank bearings unless you notice a problem with them in the bottom half. Otherwise, you leave them alone and just put the case back together with them after the transmission work.

It uses a sequential, constant mesh transmission and the gear pairs slide along the input and output shafts. They engage each other with a dog ears and slots on them. If they are significantly worn down and not locking in properly, they will slide apart and move the next set. That would feel like what you describe. That typically happens from a worn shift fork or shift drum that doesn't move the gear pairs enough. The forks wear down over time since they don't move like the gears rotating next to them. Too much force on the shift pedal and they can bend as well. Most likely you need 3 new forks in there, but inspect the gear dogs and slots for any rounded corners, and make sure the shift drum slots aren't rounded off either. Then just bolt it all back together and ride off into the sunset.
 

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Discussion Starter · #6 ·
OK, good to know the details.

No, you don't have to touch the crankshaft at all. You don't have to touch anything in the top-end of the motor. You just need to pull the motor, turn it over, and take the bottom half of the case off and all the transmission parts are right there. You don't touch the conrods and you don't need new crank bearings unless you notice a problem with them in the bottom half. Otherwise, you leave them alone and just put the case back together with them after the transmission work.

It uses a sequential, constant mesh transmission and the gear pairs slide along the input and output shafts. They engage each other with a dog ears and slots on them. If they are significantly worn down and not locking in properly, they will slide apart and move the next set. That would feel like what you describe. That typically happens from a worn shift fork or shift drum that doesn't move the gear pairs enough. The forks wear down over time since they don't move like the gears rotating next to them. Too much force on the shift pedal and they can bend as well. Most likely you need 3 new forks in there, but inspect the gear dogs and slots for any rounded corners, and make sure the shift drum slots aren't rounded off either. Then just bolt it all back together and ride off into the sunset.
Awesome! Thank you for the information!

I'll probably be posting pictures of it all in here when I get it apart, to make sure that I replace what I need to replace and don't mess with the stuff I don't need to.

Thanks for the help!
 

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Discussion Starter · #7 ·
Was running late at work yesterday so didn't get as much done as I would've wanted, however, I still got the motor ready to come out (I think)

I still have to figure out how to get these throttle cables out, I need to remove the clutch cable, and I need to remove the shift shaft.

Picking up some large allen bits on my way home today, and hopefully I'll have the engine out and case split after work but I suppose we'll see how much I'm overestimating my abilities 😛

When the engine is out I'll also be checking the frame for cracks.

Figured out how to get the bike's rear tire up in the air without a bike stand, can't remember if I saw this here or a different forum, but if it was here, THANKS for the idea!

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The throttle cables need loosing out the twist grip first, then you have enough slack to remove them off the throttle body once it is out the boots and then you can lift it clear. Clutch needs backing right off on the case, then screw the adjuster on the lever all ways in, from there free the cable out the lever and you will have enough slack on case end to disconnect from actuator arm.
 

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^^^^ What he said on the cables.

The jackstands need to be moved inward as close to the frame mount to support the bike like that. With them that far out on the ends, there is too much moment arm and the pegs will likely bend.

Aside from your allen keys for the motor mounts, you also need to release and unscrew the locking collar from them first or they won't budge. You likely don't have that as it's a typical Kawasaki special tool. That is needed to loosen the lock nut on the mounts and to retorque it afterwards. It's just a special castellated socket for it.

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Discussion Starter · #10 ·
The throttle cables need loosing out the twist grip first, then you have enough slack to remove them off the throttle body once it is out the boots and then you can lift it clear. Clutch needs backing right off on the case, then screw the adjuster on the lever all ways in, from there free the cable out the lever and you will have enough slack on case end to disconnect from actuator arm.
Awesome I'll give that a shot when I get home! May be a little early today as I have to get poked..

As for the clutch stuff I'm super familiar with how all that works, as I had to replace the cable before I could ever ride the bike, then I had to replace the clutch disks.
 

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Discussion Starter · #11 ·
^^^^ What he said on the cables.

The jackstands need to be moved inward as close to the frame mount to support the bike like that. With them that far out on the ends, there is too much moment arm and the pegs will likely bend.

Aside from your allen keys for the motor mounts, you also need to release and unscrew the locking collar from them first or they won't budge. You likely don't have that as it's a typical Kawasaki special tool. That is needed to loosen the lock nut on the mounts and to retorque it afterwards. It's just a special castellated socket for it.

View attachment 449376
I've got a friend with that specialty tool!

Good info on moving the jackstands in further on the pegs, I'll get that done when I get home as well. I also need to un-lower this bike, I absolutely loathe how literbikes feel when they're lowered, I've scraped up my work shoes from leaning and hitting them on the concrete 😕
 

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I've got a friend with that specialty tool!

Good info on moving the jackstands in further on the pegs, I'll get that done when I get home as well. I also need to un-lower this bike, I absolutely loathe how literbikes feel when they're lowered, I've scraped up my work shoes from leaning and hitting them on the concrete 😕
OK, that's great! Yes, please, please, PLEASE raise that bike back up to it's stock height! We all loathe that lowering craze if it's not at a drag strip. Make sure you replace the kickstand before you do that though. The one that is bent right now for it being lowered looks weird and the bike will fall over since it's too short now for the bike to be raised with it. Previous owner bent it to make it work. It should not have that curve in it.

From the pics, it isn't obvious it's been lowered. It must be done on the rear only. The forks usually stick up through the triple-tree more and the rear tailsection closes the gap to the tire. I don't see much of that in the pics other than the sidestand that needs a dose of viagra.
 

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OK, that's great! Yes, please, please, PLEASE raise that bike back up to it's stock height! We all loathe that lowering craze if it's not at a drag strip. Make sure you replace the kickstand before you do that though. The one that is bent right now for it being lowered looks weird and the bike will fall over since it's too short now for the bike to be raised with it. Previous owner bent it to make it work. It should not have that curve in it.

From the pics, it isn't obvious it's been lowered. It must be done on the rear only. The forks usually stick up through the triple-tree more and the rear tailsection closes the gap to the tire. I don't see much of that in the pics other than the sidestand that needs a dose of viagra.
Yeah, local girl around here explained the front lowering thing to me, It's just got some lowering link in the back with "ZX-10R" laser etched in it, looks super cool but it just handles terribly when it's lowered like this.

I mean, it handles GREAT, but compared to how it should handle it's abysmal.

I'll have to find something for a kickstand, I also need to figure out what I can do about the intake plenum thing, where all those allen bolts go in, one of the captive nuts has been broken out for god knows how long
 

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Discussion Starter · #14 ·
So my poor widowmaker has been laid over at some point in her life, as evident by the one un-original fairing on the right side of the bike, as well as the clutch cover being all scraped up, also found motor mount bolts that were shaved clean down from sliding, luckily a task my harbor freight welder was up to. Way easier than taking a car engine out.

Already found quite a few things on the engine I'm going to fix while it's out, and I'll be doing the spark plugs as well, as they seem like they'd be rather difficult to do in the bike.

Definitely had the "what have I done" thought after dropping the engine out of the bike, but I suppose either I did it or I pay someone to do it, who knows how much more damage could've been done if I kept riding it like that.


Now to find a guide on splitting the case so I can get the transmission apart.

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The hard part is done at least. Cool. You need to replace that K&N oil filter as well.

The case splitting procedure is step-by-step in chapter 9 of the manual. It's on page 313 for how to do it. Once the case is split, then you can move onto the tranny section (that's not a porn reference if that's what you're into).

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The hard part is done at least. Cool. You need to replace that K&N oil filter as well.

The case splitting procedure is step-by-step in chapter 9 of the manual. It's on page 313 for how to do it. Once the case is split, then you can move onto the tranny section (that's not a porn reference if that's what you're into).

View attachment 449381
Cool, I'll find a copy of the manual online somewhere.

Good to know on the K&N oil filter... The guy that put it on there must have just picked the only thing in stock when he was trying to figure out if an oil change would help with the bucking..

It was me 😔
 

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Cool, I'll find a copy of the manual online somewhere.

Good to know on the K&N oil filter... The guy that put it on there must have just picked the only thing in stock when he was trying to figure out if an oil change would help with the bucking..

It was me 😔
Geezus dude. Do I have to hold your hand for this whole process? :unsure::geek:

 

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Discussion Starter · #18 ·
Geezus dude. Do I have to hold your hand for this whole process? :unsure::geek:

Someone's gotta...

I'd love to say I didn't need anymore help, but I'll probably have a few more questions. For one, the lowering link thing on this bike was set to the middle groove, so I'm not sure which way to move it to lower or raise, I moved it up, picture attached. Is this right or is it lower now? Can't tell since the engine isn't in the frame anymore lol
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Someone's gotta...

I'd love to say I didn't need anymore help, but I'll probably have a few more questions. For one, the lowering link thing on this bike was set to the middle groove, so I'm not sure which way to move it to lower or raise, I moved it up, picture attached. Is this right or is it lower now? Can't tell since the engine isn't in the frame anymore lol
You should be able to just look at the rear wheel moving as you adjust the link. I'm not sure if that hole is considered the "stock height" or not, but that upper hole should be the highest it will go. The middle hole and the bottom hole would be lower in height. So you got it better than it was at least!
 

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Discussion Starter · #20 ·
You should be able to just look at the rear wheel moving as you adjust the link. I'm not sure if that hole is considered the "stock height" or not, but that upper hole should be the highest it will go. The middle hole and the bottom hole would be lower in height. So you got it better than it was at least!
Excellent, thank you! Drying up the coolant on my floor now then will begin case splitting
 
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