r5 transmission issues (six speed swap)

[mewherman]

So I made a previous thread about this when I was putting the engine together, but didn't really get to the bottom of it. I decided to just put the thing together and see if it would work, since it was so hard to determine if it was working while the engine is on the bench. I have the bike all together now, and it only has two gears, it will go into first with difficulty and then into second again with difficulty, it makes a noise when I pull the clutch, I think the clutch must be rubbing on the inside of the case. I cannot get any gears beyond second even while riding the bike.

This mirrors my issues I had on the bench, obviously this is a disappointment since the engine runs great and this setback will most certainly mean the bike is not going to be finished before the snow falls this year.

The bikes looks nice at least?



Here are my photos of the transmission internals from before. Yes I did correct the star wheel before I assembled it. I used all the parts from a 1975 rd250 which was a working transmission.

[Striker1423]

I think you might have either a shift fork in wrong, or one of the dog's is backwards. When my bike wouldn't shift past second it was one of the gears in backwards. 

[mewherman]

I think you might have either a shift fork in wrong, or one of the dog's is backwards. When my bike wouldn't shift past second it was one of the gears in backwards.

I guess I'll just have to take it all apart and mess around with the forks again and try them in all the positions possible, I doubt it's a gear issue because I never disassembled the gears from the shafts, I directly swapped them from the case they were in. My main mistake was not taking photos of the rd transmission fork/drum assembly and how it was assembled. Had I known how hard it would be to find any info photos or documentation for how it's supposed to go back together, I would have.

[m in sc]

did you swap the shift shaft as well? they are different.
my trick is always set the drum to neutral, then drop the trans in. it should spin free. if not, then its wrong.

[mewherman]

did you swap the shift shaft as well? they are different.
my trick is always set the drum to neutral, then drop the trans in. it should spin free. if not, then its wrong.

Yes, all the parts were from the RD, the R5 only has three forks. It did spin free but it doesn't shift past 2nd.

Where the drum is in neutral, that kinda cut out area of the detent wheel should be on the detent right? Because that's what I did.

[mewherman]

Well, I took the engine completly apart again, I found quite a bit of metal shavings which looked like aluminum in the case, I have read somewhere that Rd clutches can hit the r5 case and you need to grind down areas of the case but I can't find any damage anywhere to indicate where the shavings have come from, there is no damage to the inside of the case or the clutch, although there was a noise when the clutch was disengaged which is what made me think it was hitting in the first place. As far as a shifting issue goes, I didn't see anything interesting, and it's now bare cases again.

I'm really at a loss here and have no clue what the issue could be. I've looked at as many photos diagrams and videos of rd internals as I can find and I don't see anything out of place.

  I will likely be putting the 5 speed trans back in it with all the r5 parts and hoping that it works, since there were no issues with the transmission before. Maybe this r5 just wasn't meant to have six speeds.

I took some photos of the parts.

I never took any of these gears off and so it's impossible that they are somehow wrong, these came from a working rd250 trans.






No damage in here at all and yet it was chattering when I pulled the clutch.

[pidjones]

I've only had my RD400c apart, but uppon reassembly I could shift it through all gears (turning the input to help mesh of the dogs). Your photo of the assembled trans seems to show two gears with dogs meshed with each other. That doesn't seem right. I suggest you get an RD250 manual (Yamaha, not Haynes or Chilton/Clymer) and assemble the gears as it shows as well as the dogs. If the manual is any good, you should be able to get it together properly. Illustrated parts diagrams can help, too. I just finished assembling an XR100R trans for a friend from a jumble of two sets. Manual and parts diagrams were invaluable.

[85RZwade]

  I see it, too. On the mainshaft, there appears to be two gears facing each other, their dogs engaged. It's that way in the assembled-in-the-case picture, too.

[m in sc]

the clutch basket spacer washers behind the clutch are different thicknesses between rd and r5. make sure you have proper clearnce there. the primary gear and clutch gear should be flush to each other. but, before that, you can put the trans in the lower part of the case and turn the drum to check gear engagement & operation before fully assembling. like said, put in N, drop gears in (yes its the part at 6 o'clock in the pic). if it doesnt work, check the shift forks arent swapped, common issue. you'll get it.

[1976RD400C]

You say that it will only go into 1st and 2nd yet in your assemble picture it is shifted into 4th. I have a 250 case and trans apart that I could take pics but yours looks like everything is assembled right.

[Striker1423]

the clutch basket spacer washers behind the clutch are different thicknesses between rd and r5. make sure you have proper clearnce there. the primary gear and clutch gear should be flush to each other. but, before that, you can put the trans in the lower part of the case and turn the drum to check gear engagement & operation before fully assembling. like said, put in N, drop gears in (yes its the part at 6 o'clock in the pic). if it doesnt work, check the shift forks arent swapped, common issue. you'll get it.

This^
Shift forks are confusing on these as I have found. They WILL go together wrong. Most likely culprit. I didn't see anything wrong in the trans. As you stated, it was never taken apart by you, so...

[mewherman]

You say that it will only go into 1st and 2nd yet in your assemble picture it is shifted into 4th. I have a 250 case and trans apart that I could take pics but yours looks like everything is assembled right.

Yeah, i took that photo before I realized i had installed the shift drum not in neutral. 

[mewherman]

the clutch basket spacer washers behind the clutch are different thicknesses between rd and r5. make sure you have proper clearnce there. the primary gear and clutch gear should be flush to each other. but, before that, you can put the trans in the lower part of the case and turn the drum to check gear engagement & operation before fully assembling. like said, put in N, drop gears in (yes its the part at 6 o'clock in the pic). if it doesnt work, check the shift forks arent swapped, common issue. you'll get it.

This^
Shift forks are confusing on these as I have found. They WILL go together wrong. Most likely culprit. I didn't see anything wrong in the trans. As you stated, it was never taken apart by you, so...

Hmm, when you say swapped do you mean the set of forks are on the wrong shaft or do you mean the forks are in the wrong order on the same shaft. It's confusing because all four forks look the same.

[m in sc]

they look the same.. but the offsets ARE slightly different. Id bet wrong order on the shafts. this is why i assemble in neutral. if any forks are out, this will be immediately noticeable. you should be able to spin the input shaft and the output shaft independent of each other when in neutral just set in the case. if not, you have the forks in wrong.

[1976RD400C]

Here's what m in sc is talking about. There are 2 different forks. There should be a number 1 or 2 on the side of them. 1 has less offset than 2. This is their position.