Swapped Transmissions.... Now Intermittent Clunking Noise

I have an 83 Venture (68,000 miles) with the classic second gear failure.

I found a used transmission on ebay removed from a 2001 (12,000 miles).

I figured this was a good way to go as it came with transmission, all shift forks, and the new style shift cam.

I swapped my middle gear pinion onto the transmission output shaft to keep my middle gear matched gear set together.

Everything appeared to fit in the case perfectly.

Just got the bike running the other day with the new transmission in the case.

On the center stand it make no noise.

On the side stand (Leaning left) it makes a clunking noise while it sits there idling.

The noise is very frequent (once or twice per second), but random.....

Not like the same two parts contacting every revolution.....

If I lean the bike to the right, the noise stops.

Pulling the clutch lever in seems to have no effect.

Having the bike in neutral vs. in first gear seems to have no effect.

The bike drives and shifts normally.

At higher speeds (60 to 80) I can hear an occasional clunk.

This is very concerning as I don't want to have a failure that locks up the rear wheel.

(or locks up and shoves part of the transmission out the side of the case).

I've scoured the parts diagrams for spacers or shims I may have omitted, but, everything I see is to space the two middle drive pinions together.... all of those shims are installed.

Can anyone give me some insight as to what I'm looking for when I split the case again?

Did you check that the lash for the middle drive output shaft was correct?

There are shims between case and middle drive output shaft to set this. This shim may have needed changed due to output shaft being in a different case.

Just a guess, I don't know if this would cause random clunking though.

Gary

My wife's Shadow does a similar thing in neutral, but will stop when in 1st gear.

What I think it is is one of her shift forks is either bent or worn, and in neutral either the 1st or 2nd gear dogs are rattling against their mates.

It might be interesting to try yours in all gears and see if the noise goes away in any gear.

I pulled the oil drain plug with the magnetic chip detector..... found a few small slivers of metal (And I've only logged 18 miles since transmission swap), so I decided to pull the motor back out and see what's going on.

It's on the bench now.

When I put all the transmission shafts in the lower case half and put it in neutral, it makes no noise if the case is level.

If I tilt the Clutch side of the case up (simulating the bike being on the side stand) the first gear wheel (Item 21 in the transmission parts list) has just enough freedom to barely touch the dogs on the fourth gear wheel (item 20 in the transmission parts list). Both of these gears are on the drive axle (item 12 in the transmission parts list).

The looseness of the first gear wheel relative to the drive axle initially bothered me.....

Then I compared the fit of the first gear wheel in my original transmission (which had the skipping second gear syndrome, but absolutely no clunking going on.) That first gear wheel fits very much the same.

So, I put the old transmission shafts back in the case.

After I removed my middle gear from the original transmission, I did not install the other middle gear/damper spring/cam ect. from the other transmission onto the old shaft.

As such, I am able to slide the drive axle left and right in the case.

If I slide the shaft to the right, I can minimize the freedom allowed to the first gear wheel.

In that position, I get no clunking between the first gear wheel and fourth wheel dogs.

If I slide the shaft 0.05 to the left, I get exactly the same clunking noise caused by contact between first and fourth.

When I swapped the middle drive pinion off of the original transmission, I measured the thickness of the washer under the two halves of the infamous split washers (Items 5 and 6 respectively in the middle drive gear parts list). I found one measured 0.015 thicker than the other. The parts list just list this as a washer... not a shim.... there are no different thicknesses offered in the list. I see nothing in the manual that addresses shimming the shaft position relative to the transmission position in the case.

When the split washers wear (causing the classic second gear failure), the damper spring takes all the slack out by moving the shaft to the right which progressively diminishes second gear dog engagement as the washer wear more and more.

Based on this, I surmised that I would be better off to use the thicker washer which I assumed buy me an additional 0.015 inch engagement in the second gear dogs.

I believe my noise is the result of too much play between first gear wheel and the shaft.

Further, I believe I made this play on the shaft worse with my selection of the thicker washer.

Tomorrow, I will swap the thick washer under the split washer for the thin one I did not use.

Hopefully, this will tighten the first gear wheel up and my noise will go away.

If not, I believe I can decrease the thickness of that washer until my problem does go away.

I do not think changing that washer thickness will have any effect on the middle gear set lash as that is controlled through separate shims.

Would really like to hear opinions before I proceed...... my help is growing weary of removing and installing the motor from this beast!!!

Attached is a PDF from 83 service manual detailing setting middle drive lash.

There are 6 different shims sizes listed.

Gary

Just out of curiosity, did you use a 2001 Venture or RSTD trans? I ask this because they have different ratios.

I have an 83 engine that I put a 02 Venture trans in and with the new style shift drum, it appears that everything lines up nicely. Before I used the new drum, I had some gears that were touching at times they were not supposed to touch.

As far as matching up the gears at the middle gear/output gear, I have used the complete setup that came together and I have used mix and match and as far as quietness, the mix and match worked best. I just made sure I had adequate mesh on the output gear.

Now, I have not installed this engine in my bike yet, so I can not tell you that I don't have the same problem.

Please keep us posted as I feel the later trans may be a good fit for the early 1st gen.

RandyA

RandyA was right-on with his information about the shift cam.

My problem had nothing to do with the thickness of the washer under the split washers as I originally thought.

Even though I had received the shift cam out of the same bike that my new transmission came out of (2001 Bike)...... I elected not to use it because it had a nick in the bearing journal on the end opposite the shift sequencer.

That was a bad decision.

After pulling the engine and splitting the case halves, I could see that the first gear wheel was touching the fourth gear wheel when the case was tilted.

Acting on RandyA's input, I removed the shift cam (Original from my 83) and compared it to the shift cam for the 2001 transmission.

To compare the two cams; I measured from the base of the ball bearing under the shift sequencer (Right side of case) to the edge of the channel for each shift fork.

The shift cam channels for the left fork and center fork are identical on the two cams.

The cam channel for the right shift fork (the fork that controls the Fourth gear wheel that was intermittently touching the first gear wheel) is 0.075 inch different between the two cams.

(The channel in the newer cam is 0.075 farther to the left... farther away from the shift sequencer.... farther away from the first gear wheel.)

The right shift fork moves the fourth gear wheel, thus, when the fork moved to the left 0.075 inch, the first gear wheel could no longer touch intermittently.

So, I've swapped the 1983 shift cam for the 2001 shift cam and I cannot make the transmission gears touch in any position where they are not supposed to be touching.

I believe this has solved my intermittent clunking issue.

Engine is back together, but, I'm working out of town this week, so it will be next week before we get it installed and test drive.

And Randy asked which model bike the doner transmission came from...

so I counted teeth;

1st Gear: 43/17

2nd Gear: 31/19

3rd Gear: 30/25

4th Gear: 24/25

5th Gear: 22/28

I currently have the original 83 Venture Final Drive gears installed, but, I've already got a set of VMax Final Drive gears on hand.

I'll report back in this thread re: the final results of changing this shift cam to the 2001 cam.

/and/

I'll start another thread re: how my engine RPMs vs. speedometer change using this transmission and the two different final drive sets.

And of course, Thanks to everyone for the input/advice to help me solve this issue!

Wow, I got one right for a change.

It looks like what you have is an RSV trans with the gear ratios you noted. I think you will be more happy with this setup than if you had used the RSTD setup. These ratios are a bit closer together. This is a comparison of the three different gear sets.

I just need to get off my butt and get the engine in my bike with the RSV trans after I have been running the V-Max rear for a while now.

RandyA

Very Interesting.... I am thinking I got a lot of work to do.