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2nd Gear Help (again)

4K views 49 replies 7 participants last post by  Brandon35 
#1 ·
Hey guys. My bike is back together and she was riding just fine for a little while but today when I went into 2nd gear I started getting very obvious clicking noises. Pull the clutch and it goes away, let it out and it’s back, definitely speeds up or slows down with wheel speed. Every other gear is fine (except needing a clutch replacement now... god why). Hoping it’s something related to the gear shift - seemed to have to increase my foot up-shift distance after it happened. Any clues?
 
#2 ·
So you did something wrong or used old parts and they seemed to work for a bit and now dont?

Does that about sum this up, looks like you get more practice at taking things apart and "fixing" them................
 
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#4 ·
Transmission is from a bike with half the miles of my engine, everything but the throwout bearing was fine and functioned properly, I’ve replaced all the races and such. Not sure why used parts are a problem but either way I’m feeling like it’s a shifter/shift drum problem and not the trans itself. Pulling the pan this morning to investigate.
 
#8 ·
I have the original transmission - i found out after i bough this one that i simply had a loose sprocket nut that was causing a skip but put this trans in anyway. I don't really trust the trans in it now so I'm going back to the original. I’ll swap over any parts that look better. I’m not paying $120-$160 PER GEAR to build a new trans.
 
#13 ·
Will probably call a tranny place tomorrow and see if they can at least inspect the one I have that I want to put back in. I wonder if the gears could be heat treated to strengthen them up a bit.
 
#14 ·
I wouldn’t bother. Is this bike that old? Kind of a lot of work for such an old one. 2009 or newer is a cassette. Easy and fast transmission swaps. Relatively
 
#15 ·
As you found, the only way to split the cases is with the engine out of the chassis............. so you should be getting good at that by now- what is this 5th time or more???

Using old (used) parts is always a crapshoot.......... $70-$120 per gear is pretty standard pricing

And I would certainly go out and spend the $100 or so on all new gaskets your orange silicone shit slathered everywhere is disgusting, and it certainly is not the proper method to seal the case halves............. be the best $100 you could spend on the bike IMO!

So you think you are going to find a transmission specialist for a motorcycle transmission?????????
or are you talking about going to some car shop and have one of those knuckleheads tell you about your motorcycle transmission???
I mean they should be able to look at it and look for wear and they should know how it operates to know where to look- but beyond that they are likely clueless and even this may be giving them far too much credit for too many of them........... Always the pessimist!!! People are lazy fucking idiots- proven fact!

So what does the mating gear look like? - guess it does not matter if you throwing in your old trans that the c/s spun around and around on the output shaft........... (where is the picture of that damage?)

You did get very lucky in that, that piece of the gear tooth fell seemingly harmlessly into the oil pan rather than get caught up wedged between the input and ouput shaft gears and gernade your cases and engine......

cryo treating may make them brittle, heat treating, they already are......... you would be far better served to undercut atleast the upshift side and then ISF treatment to polish it all......... likely to run in the $500 range total for an entire trans (plus shipping to and from)

if all you are doing is riding it around on the street until the next thing breaks on your 20+ year old bike, and don't have a huge personal connection to the bike, just install oe parts and ride the bike.........
if on the other hand you don't mind spending the monies and actually having something, then spend the monies and hand someone will skills the entire engine and let them work the magic and then with a smile happily hand them a few thousand dollars for thier time and efforts and Thank them! (but yes, this would be more than the entire is worth now or ever)
 
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#18 ·
As you found, the only way to split the cases is with the engine out of the chassis............. so you should be getting good at that by now- what is this 5th time or more<img src="http://zx6r.com/images/smilies/rock.gif" border="0" alt="" title="Eh?" class="inlineimg" />

Using old (used) parts is always a crapshoot.......... $70-$120 per gear is pretty standard pricing

And I would certainly go out and spend the $100 or so on all new gaskets your orange silicone shit slathered everywhere is disgusting, and it certainly is not the proper method to seal the case halves............. be the best $100 you could spend on the bike IMO!

So you think you are going to find a transmission specialist for a motorcycle transmission<img src="http://zx6r.com/images/smilies/rock.gif" border="0" alt="" title="Eh?" class="inlineimg" /><img src="http://zx6r.com/images/smilies/rock.gif" border="0" alt="" title="Eh?" class="inlineimg" /><img src="http://zx6r.com/images/smilies/rock.gif" border="0" alt="" title="Eh?" class="inlineimg" />
or are you talking about going to some car shop and have one of those knuckleheads tell you about your motorcycle transmission<img src="http://zx6r.com/images/smilies/rock.gif" border="0" alt="" title="Eh?" class="inlineimg" />
I mean they should be able to look at it and look for wear and they should know how it operates to know where to look- but beyond that they are likely clueless and even this may be giving them far too much credit for too many of them........... Always the pessimist!!! People are lazy fucking idiots- proven fact!

So what does the mating gear look like? - guess it does not matter if you throwing in your old trans that the c/s spun around and around on the output shaft........... (where is the picture of that damage?)

You did get very lucky in that, that piece of the gear tooth fell seemingly harmlessly into the oil pan rather than get caught up wedged between the input and ouput shaft gears and gernade your cases and engine......

cryo treating may make them brittle, heat treating, they already are......... you would be far better served to undercut atleast the upshift side and then ISF treatment to polish it all......... likely to run in the $500 range total for an entire trans (plus shipping to and from)

if all you are doing is riding it around on the street until the next thing breaks on your 20+ year old bike, and don't have a huge personal connection to the bike, just install oe parts and ride the bike.........
if on the other hand you don't mind spending the monies and actually having something, then spend the monies and hand someone will skills the entire engine and let them work the magic and then with a smile happily hand them a few thousand dollars for thier time and efforts and Thank them! (but yes, this would be more than the entire is worth now or ever)
Trying to figure out what you mean by “C/S spun around” paragraph, but I'm looking at the APE website and may call tomorrow. I’m guessing I could send both sets of gears minus the broken one and they could use the best looking bits for the undercut. Their sight doesn't say anything about ISF treatment (idk what that is but sounds nifty). I think it’s worth the money if it’s solid stuff. Also here’s another pic of the damage; just a missing tooth making my clunking sound. Kinda weird.
 

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#16 ·
I guess I’m just figuring out now which route I want to go. Engine is apart again so i’ll take my time but we’ll see.

There is no “crankcase gasket” or anything, so what should I be looking for to use to seal the crankcase? I mean, they’re machined together right?

Only reason I say heat treating is that this is a 23 year old bike and probably same on the trans so with constant heat cycles the metal could be fatigued. And I believe the trans shop near me does some bikes but there is also a bike shop so either way I want to get mine looked at.

The sentimental value is all there. Honestly I could nuke this engine and I’d rather buy a used engine on eBay. Call it crazy but I love the way this bike rides and feels (when it does!).

We’ll see about undercutting.
 
#19 ·
THREEBOND which is also yamabond, hondabond, kawibond, suzibond.......is what you need for the crankcase mating surface.......... and excellent choice on all new gaskets for the oil pan, clutch cover, stator cover and ignition cover- although I would have went OEM

The transmission... as long as you never ran it out of oil......... will never get hot enough to effect the original heat treating of the gears, regardless of age or miles, especially not on a street engine


I’ve got cometic gaskets on the way for everything else case wise
Trying to figure out what you mean by “C/S spun around” paragraph, but I'm looking at the APE website and may call tomorrow. I’m guessing I could send both sets of gears minus the broken one and they could use the best looking bits for the undercut. Their sight doesn't say anything about ISF treatment (idk what that is but sounds nifty). I think it’s worth the money if it’s solid stuff. Also here’s another pic of the damage; just a missing tooth making my clunking sound. Kinda weird.
You said the original transmission was replaced with this unti becasue the c/s sprocket nut was loose/missing so the c/s sprocket was spinning on the shaft???


ISF treatment for the transmission.....................

There are several places that do quality undercutting, there are also a handful of very good ISF treatment centers, some also do undercutting so do not........
 
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#21 ·
Alright I ordered some Threebond - we’ll see how much better that works but everything else will be cometic gaskets. Never thought rtv was a problem but I did see a small amount in the oil screen this time around.

I guess I just don't understand how a tooth would just pop off like this so I’m curious.
 
#23 ·
The original trans was replaced because I thought second gear was having an issue, but I found that I had a severely loose sprocket nut - like I could turn it by hand. Although... I never confirmed that there wasn’t still an issue with second gear on that trans... idk yet.
 
#27 ·
Pictures of the engagement dogs !!!!!!!!!!!!

Show the pictures....

Do they look anything like these???

While you are at it, may as well inspect closely the shift forks and the shift drum!
 

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#25 ·
Your shifting problem may well be a worn shifter dog, or selector drum, or both. Only way I can see a tooth breaking like that is if it had already been stressed from having a chunk of steel get jammed in there from something else breaking. Like, a con rod or piston getting shattered. Without knowing the history of the engine that second transmission came from you have no way to know why.

If you did not change out the shif components when you went from one tranny to the other, you probably never addressed the initial issue.
 
#26 ·
The new trans came with the drum and shift forks, they all looked better wear wise (forks had little to no wear). I put them all in at the same time and will keep the drum I have in it and double check my forks. Maybe I’ll replace those too, we’ll see. I need to call around and get my options.
 
#29 ·
Transmission that was put in (worn dogs) vs. my OE trans (not worn). I guess this confirms that I didn’t have an issue with my original trans and that it really was a loose sprocket nut/clutch problem.

Anyways, if it’s not crazy super expensive I’ll be sending most of the trans parts out to Mike at Stonebridge Cryoscience for cryo treatment and REM ISF. If his and my other options quotes are just crazy, I’ll save treatment and such for another time. The good news is that I’m confident that the problem was the transmission I got from ebay. Learn from me people, garbage in, garbage out. The nice thing here is I’m getting really comfortable with how this engine/trans works.

- New bearings and oil seal for the trans inbound
- New Crank rod bolts/nuts inbound
- New SBK street racer clutch kit with heavier springs here

Will update as I go.
 

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#30 ·
So just a quick question for anyone with lots if trans experience. I remember this from when I broke it down, but why do the 3rd gear dogs on the input shaft not seem to make full contact? What I mean is, the 4th gear dogs contact completely, whereas there is about a 1/16in gap on 3rd. This is the proper assembly per the manual, all oil holes lined up.
 

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#40 ·
There are tons of motorcycle transmissions out there with this or a very similar scenario.......

You can rearrange/buy new shims to shim the transmission for optimal engagement.....

you would need to fully assembly the complete trans with shift forks, drum, shifter shaft and both input/output shafts in the (lower case in this scenario) and then shift through the gears measuring contact and throw........


Have you measured your clearance between the sides of the shift forks and the sides of the machined surface in the cluster gears they ride in?
 
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#31 ·
I also dont understand why the last two gears on the input shaft have freeplay between them and the roller bearing, whereas everything else is a tight fit. I have all the pieces in correctly both checking the manual AND an exploded view on partzilla.
 

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#41 ·
When that race is over the top of the roller bearing and installed in the cases (pins located properly) how much gap is there then between the washer and gear?
 
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#33 ·
It’s the same, but I can’t imagine why this is the only set of dogs that don’t make full face contact. It’s strange but I’m leaning towards correct seeing as I’ve triple checked. I am still confused about the free play though - why would there be so much room for these gears to move near the roller bearing?
 
#35 ·
Well, I got done cleaning each gear, shaft, etc. and put everything back together. All new bearings and seal as well. Waiting on my roller bearings, and two backordered crankshaft bolts before I seal up the engine. Will be my first time using Three-bond sealant for the case halves and as an addition to all the cometic engine gaskets i have. Inspecting and measuring the transmission gears/dogs, forks, drum, making sure all the components are in the proper position and having all new bearings and brand new friction/steel plates and heavier springs, there is just no way there can be a problem. I triple checked everything and even tore half of the output shaft off again to check an oil passage was lined up. I’m confident. Sorry Rivers, no undercut or ISF treatment this time around. Weddings are expensive!
 
#43 ·
You only want to install the transmission in one side of the case halves, if you install in both and bolt the cases together how are you going to get in there to measure?????????

Assemble in the lower cases and measure!!!!!!!!!!!
 
#44 ·
You only want to install the transmission in one side of the case halves, if you install in both and bolt the cases together how are you going to get in there to measure<img src="http://zx6r.com/images/smilies/rock.gif" border="0" alt="" title="Eh?" class="inlineimg" /><img src="http://zx6r.com/images/smilies/rock.gif" border="0" alt="" title="Eh?" class="inlineimg" /><img src="http://zx6r.com/images/smilies/rock.gif" border="0" alt="" title="Eh?" class="inlineimg" />

Assemble in the lower cases and measure!!!!!!!!!!!
Yeah I know, I just want to have my new roller bearings so i can measure with those in. I should have been more clear.
 
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