Topic: Splitting the cases on my CB750...first of many ?'s

[ron.cieri.313]

Well...more waiting...wtf?...I send the seller a note that i still haven't received the replacement transmission...oops, his helper never sent it out and he was out of the country...man that blows.

In the meatime, cleaning up the rear wheel...freak, the new brake shoes I ordered last week will beat the transmission to my house...anyways, will have a new rear sprocket on, new tire, all corroded parts cleaned.

Also, on the exhaust...I tried painting myself but the cold and the chrome were seriously working against me...took it to a painter who said..."sandblast it or your wasting your time and money"...so, found a sandblaster who did a great job for $50 and his painting it with very high temp matte black furnace paint for another $50.  He called a powder coater for me but he buddy said powder coating is no good for exhaust as it will discolor from the heat.

Will take the swingarm off tomorrow as I am going to paint (or have it painted) and replace the bushings...I have bronze bushings which worked great on my 450...there another post on this subject but I'm going to wait and see if they fit before anymore posts on that...

...sorry for making this a project log...believe me, I'm chomping at the bit to get back to the transmission...l8r, ron.

[ekpent]

Ron-Eric in Kazoo. No matter what happens with that seller-I will cover your back. Hope it works out with them. I know you may have a kid over here in school,WMU,have a couple of lower ends around if needed in a pinch we could dig into.Good Holiday to all.

[ron.cieri.313]

thx Eric...I think he will send but just screwed up...but...nice to know I got an alternative!...ttyl.

[nobody]

The appearance of the clutch plates won't tell you very much, except about wear of the cork or burnt spots.

You must measure the warpage of the plates. If they are more than 0.010" warped, the clutch will barely disengage when pulled. I use a thick piece of glass as a poor-man's "Flat Plate", laying the clutch plates down one at a time and sliding feeler gages under the edges to see what the max warp is. New ones are usually under 0.003", used ones often around 0.006". Beyond that 0.006" figure, they start dragging a little when disengaged, which will make for hard shifting. Honda says "replace at 0.012" warp", but by then, the tranny usually won't shift unless you're rolling.

So it's 11 degrees and snowing in Denver and I just spent the last hour in the garage. My hands are so cold they hurt and I can't feel my toes. I wouldn't recommend this.

I finally got a feeler gauge. I went around every plate (both sides) and the .005 plate went into quite a few spots. The .006 made it into a couple more. The .008 just barely fit into a few spots. So it looks like I MAY have found my hard shift problem, right? Can anybody recommend a quality clutch and where to get it from?

Just to be sure I removed the forks and drum, they look good to me. What do you think? Should I be concerned about the minor wear on the middle fork? What about that wear around where the neutral switch contacts the drum?

[MCRider]

As to the shift forks, they look fine. When one is bent, it pushes in its gear slot at an angle and the slot in the gear wears a very noticable arc in the pad of the fork. YOurs are smooth.

The dogs on the gears are harder to see.

[nobody]

I didn't see anything that stuck out at me on the dogs, I believe they're fine. I can take some close ups if you'd like to see them, if you think they may be the root of my problem

[HondaMan]

A couple of things:
1. Stack those clutch plates, friction plate on friction plate, and see how much they gap between each other. Rotate them around a bit, one at a time. This is another good way to check: if you see gaps, they are warped. Repeat with the steel plates as well. When reinstalling the steel plates, the "sharp" edge goes toward the engine.
2. The fork receiving grooves on the countersprocket gears appear curiously worn: is that just a trick of the camera? Remove the gear, clean the holes in the shaft and each gear where the oil is distributed from inside the shaft. Even the tiniest amount of blockage in those holes will slow down the small amounts of oil that must reach the area.
3. There is a small O-ring under the countershaft's bearing retainer: you probably noticed it when you took of the retainer to get the countershaft out. Make 100% sure it is there, and replace with a new one. They get cooked and brittle and then they leak, because they get hot oil from the crankcase all the time. If it is split, extra hard, or missing, there would be low oil pressure to the countershaft and mainshaft. I have seen these be accidentally removed (or lost) when the bearing retainer is removed, and engines reassembled without them. It makes for worn shift forks and real stiff shifting.

Where in Denver do you live? I'm in Lakewood...it's 3 degrees here... 

[nobody]

A couple of things:
1. Stack those clutch plates, friction plate on friction plate, and see how much they gap between each other. Rotate them around a bit, one at a time. This is another good way to check: if you see gaps, they are warped. Repeat with the steel plates as well. When reinstalling the steel plates, the "sharp" edge goes toward the engine.

I can do that. I didn't know that the plates had to be facing a certain direction either, I'll pay special attention to that.

2. The fork receiving grooves on the countersprocket gears appear curiously worn: is that just a trick of the camera? Remove the gear, clean the holes in the shaft and each gear where the oil is distributed from inside the shaft. Even the tiniest amount of blockage in those holes will slow down the small amounts of oil that must reach the area.

You're referring to this picture right? The groove on the far right? To me it's just a mess of gears, they all look the same. I actually hadn't noticed that little bit of wear last night. I'll have to look closer at that. I'll go ahead an pull the gears for cleaning too.

3. There is a small O-ring under the countershaft's bearing retainer: you probably noticed it when you took of the retainer to get the countershaft out. Make 100% sure it is there, and replace with a new one. They get cooked and brittle and then they leak, because they get hot oil from the crankcase all the time. If it is split, extra hard, or missing, there would be low oil pressure to the countershaft and mainshaft. I have seen these be accidentally removed (or lost) when the bearing retainer is removed, and engines reassembled without them. It makes for worn shift forks and real stiff shifting.

You're talking about the shift pattern drum right? I don't recall seeing any Orings last night when I pulled any of those bits out.

Where in Denver do you live? I'm in Lakewood...it's 3 degrees here... 

I'm over near Lowry, twelfth and Quebec. I thought eleven degrees last night was cold, the low tonight is three below. Not sure I'll be too keen on spending time in the garage tonight, maybe I just need to crank up the propane heater and try to get it to a balmy forty degrees or so, haha.

[ron.cieri.313]

I agree, that at least in the picture, your C4 gear (furthest to the right in your picture but left side of the bike) looks worn...correct me if I'm wrong but isn't that the dreaded C4 gear that can't keep dogs on their leash?

[torchmonkey]

Great topic, I just split my cases this weekend and have been reading this for quite a while. I'll definitely be checking in from time to time.

[ekpent]

I am sure Ron will be very happy when this thread is DEAD 

[HondaMan]

You're referring to this picture right? The groove on the far right? To me it's just a mess of gears, they all look the same. I actually hadn't noticed that little bit of wear last night. I'll have to look closer at that. I'll go ahead an pull the gears for cleaning too.

3. There is a small O-ring under the countershaft's bearing retainer: you probably noticed it when you took of the retainer to get the countershaft out. Make 100% sure it is there, and replace with a new one. They get cooked and brittle and then they leak, because they get hot oil from the crankcase all the time. If it is split, extra hard, or missing, there would be low oil pressure to the countershaft and mainshaft. I have seen these be accidentally removed (or lost) when the bearing retainer is removed, and engines reassembled without them. It makes for worn shift forks and real stiff shifting.

You're talking about the shift pattern drum right? I don't recall seeing any Orings last night when I pulled any of those bits out.

Where in Denver do you live? I'm in Lakewood...it's 3 degrees here... 

I'm over near Lowry, twelfth and Quebec. I thought eleven degrees last night was cold, the low tonight is three below. Not sure I'll be too keen on spending time in the garage tonight, maybe I just need to crank up the propane heater and try to get it to a balmy forty degrees or so, haha.

If it gets warm enough to go somewhere, maybe I can go over and look at your box...I spent the day lying on a shop floor in coveralls, wiring someone's machinery, today (part-time day job...). Brr!

BTW: what is that round thing lying on the engine case near those gears? It looks like a bushing out of something. 

Attached is the O-ring I'm talking about...near the center of the picture, just above the big hole...

[nobody]

If it gets warm enough to go somewhere, maybe I can go over and look at your box...I spent the day lying on a shop floor in coveralls, wiring someone's machinery, today (part-time day job...). Brr!

Oh man, gotta stay off the floor on days like this, that concrete will suck the heat right out of you. I played hooky today and have no plans to go anywhere. If you decide to come by give me a call at 303.261.5351 and I'll start up the heater to try to get it warm enough to be tolerable in there. The name is Matt.

BTW: what is that round thing lying on the engine case near those gears? It looks like a bushing out of something. 

If you and I are looking at the same thing it's the hole where the neutral switch goes.

Attached is the O-ring I'm talking about...near the center of the picture, just above the big hole...

I just ran outside and checked, no O-ring on either the rebuild or the donor transmission.

[HondaMan]

If it gets warm enough to go somewhere, maybe I can go over and look at your box...I spent the day lying on a shop floor in coveralls, wiring someone's machinery, today (part-time day job...). Brr!

Oh man, gotta stay off the floor on days like this, that concrete will suck the heat right out of you. I played hooky today and have no plans to go anywhere. If you decide to come by give me a call at 303.261.5351 and I'll start up the heater to try to get it warm enough to be tolerable in there. The name is Matt.

BTW: what is that round thing lying on the engine case near those gears? It looks like a bushing out of something. 

If you and I are looking at the same thing it's the hole where the neutral switch goes.

Attached is the O-ring I'm talking about...near the center of the picture, just above the big hole...

I just ran outside and checked, no O-ring on either the rebuild or the donor transmission.

I was thinking of this picture.
http://img694.imageshack.us/img694/1861/img3659.jpg

On the right side, near the bottom: it looks like someone's wedding ring. or something... 

This cold is miserable. I've only seen this once here, in 1984. We're about to break that record, too.

Find the O-ring in your gasket kit: if that is missing, then the mainshaft will have been startved for oil on the insides of the gears. So, pull the gears off the mainshaft and look for scoring or galling on the inner surfaces, with the shaft. This will make the sideways movement of the gears on the mainshaft quite difficult, which then results in hard shifting. This little O-ring is one of those parts that novice wrenches lose when they pull of the countershaft bearing housing, and never reinstall because it isn't mentioned in most manuals. But, it can cost you a mainshaft and eventually, shift forks and drums, from the drag it causes.

The backlash measurement is the only way to determine if the gears are worn out. I need a picture of a setup to measure this, for my book, to complete the Inspection chapter. I would have to spend half a day just setting up the picture here: if yours is already apart I could just bring the tools over and set it up there...I'll try to call you over this weekend.

[nobody]

I was thinking of this picture.
http://img694.imageshack.us/img694/1861/img3659.jpg

On the right side, near the bottom: it looks like someone's wedding ring. or something... 

That's the neutral switch hole

This cold is miserable. I've only seen this once here, in 1984. We're about to break that record, too.

I was still adjusting to life outside of the womb then so I don't remember it. I keep telling my girlfriend how crazy and abnormal this is. It's a little odd to get excited about a forty degree day in the forecast...

Find the O-ring in your gasket kit: if that is missing, then the mainshaft will have been startved for oil on the insides of the gears. So, pull the gears off the mainshaft and look for scoring or galling on the inner surfaces, with the shaft. This will make the sideways movement of the gears on the mainshaft quite difficult, which then results in hard shifting. This little O-ring is one of those parts that novice wrenches lose when they pull of the countershaft bearing housing, and never reinstall because it isn't mentioned in most manuals. But, it can cost you a mainshaft and eventually, shift forks and drums, from the drag it causes.

The backlash measurement is the only way to determine if the gears are worn out. I need a picture of a setup to measure this, for my book, to complete the Inspection chapter. I would have to spend half a day just setting up the picture here: if yours is already apart I could just bring the tools over and set it up there...I'll try to call you over this weekend.

Alright, I'll try to get those gears and such out either tonight or tomorrow night. Saturday would probably be the better day for me, I'll be doing my girlfriend's brakes at a friend's shop midday on Sunday. Let me know what works for you and we'll go from there.

I'll check my Athena kit to see if it has that O-ring. I need to order a Vesrah kit before reassembly, I've heard too much negative feedback about Athena.

Thanks for offering your help, it means a lot to me.

[HondaMan]

I was thinking of this picture.
http://img694.imageshack.us/img694/1861/img3659.jpg

On the right side, near the bottom: it looks like someone's wedding ring. or something... 

That's the neutral switch hole

This cold is miserable. I've only seen this once here, in 1984. We're about to break that record, too.

I was still adjusting to life outside of the womb then so I don't remember it. I keep telling my girlfriend how crazy and abnormal this is. It's a little odd to get excited about a forty degree day in the forecast...

Find the O-ring in your gasket kit: if that is missing, then the mainshaft will have been startved for oil on the insides of the gears. So, pull the gears off the mainshaft and look for scoring or galling on the inner surfaces, with the shaft. This will make the sideways movement of the gears on the mainshaft quite difficult, which then results in hard shifting. This little O-ring is one of those parts that novice wrenches lose when they pull of the countershaft bearing housing, and never reinstall because it isn't mentioned in most manuals. But, it can cost you a mainshaft and eventually, shift forks and drums, from the drag it causes.

The backlash measurement is the only way to determine if the gears are worn out. I need a picture of a setup to measure this, for my book, to complete the Inspection chapter. I would have to spend half a day just setting up the picture here: if yours is already apart I could just bring the tools over and set it up there...I'll try to call you over this weekend.

Alright, I'll try to get those gears and such out either tonight or tomorrow night. Saturday would probably be the better day for me, I'll be doing my girlfriend's brakes at a friend's shop midday on Sunday. Let me know what works for you and we'll go from there.

I'll check my Athena kit to see if it has that O-ring. I need to order a Vesrah kit before reassembly, I've heard too much negative feedback about Athena.

Thanks for offering your help, it means a lot to me.

If you don't find that O-ring, let me know and I'll bring one with me.

[nobody]

Will do, thanks again.

[ron.cieri.313]

Ah last, a thing of beauty to behold fer sure...my new old tranny arrived in the mail and put it where it needs to be.  No clattering sound at all between the final drive gear and countershaft gear....sweet lubricated silence.

I think it time for re-assembly?...was going to work on the shift mechanism (so many damn little pieces) and do dry run with the two halves before closing the patient up...any thoughts???

Also picked up my recently sandblasted, and matte black exhaust...hmmm, if I actually get this thing to run, she might look pretty nice.

Oh, yes!...does anybody recognize this???...it drop out from the cylinder head when i was cleaning external side for painting

[nobody]

With a little help from Hondaman last night it seems that I, too, may be ready to reassemble my bike. There were two gears that had rough spots in their rotations, something I didn't notice until Mark pointed it out. Swapped those gears with ones from my donor transmission and took some sandpaper to a spot that is notorious for dragging (I can take a picture of that spot later if anybody wants to see it). After those changes all the gears slide and rotate very smoothly.

Mark believes that the root of my hard shift may have been from several things:
1) Abuse, probably much of it on my part.
2) Wrong oil. I was using 10w-40 car oil. I guess the high detergent in car oil causes it to foam at higher rpms and it ceases to lubricate effectively. I had no idea, I'll definitely be getting motorcycle specific oil.
3) The combination of those and my missed shift must have caused a small bit of one of the bronze bushings to seperate and create unwanted rough spots. These rough spots caused the gears to drag ever so slightly, creating unwanted friction between all gears and causing a hard shift.

I'll be swapping out the final drive bearing with one from the donor transmission, supposedly a K1 (how he can tell that by looking just at the guts of it, impressive). This change should add one or two HP, one row of bearings on the K1 instead of two on the K4, can't turn down free power. I think he said that the K2 and on had the two row bearings. I need to get a Vesrah gasket set before I can go any further. Then to replace a few clutch plates and slap it all back together.

[Henning]

Ron,

the rubber bit looks like it's from one of the spark plug caps; it's from the bottom, seals against the spark plug itself.

- Henning

[ron.cieri.313]

Eureka!...thx H

[ron.cieri.313]

Question...when I apply the gasket goo (in my case i got Yamahabond instead of Hondabond as they were out of the latter)...do I apply it to all mating surfaces on the Lower crankcase including the weird type of spots circled in red below?..thx, ron.

[MCRider]

I just follow the periphery, skip anything that is inside the boundary. That's just me see what others say.

You've got bigger problems, that Yamahabond has been known to interact with Honda aluminum and the whole thing will just melt into a pile of goo like the wicked witch of the East (West?).  JK 

[HondaMan]

I just follow the periphery, skip anything that is inside the boundary. That's just me see what others say.

You've got bigger problems, that Yamahabond has been known to interact with Honda aluminum and the whole thing will just melt into a pile of goo like the wicked witch of the East (West?).  JK 

Ah, so THAT's what went wrong with my last Kawasaki job... 

[ron.cieri.313]

No worries here, I will be putting the halves back together on opposite day