1996 R1100RT Transmission clunk, WHY?

[oldcarman]

I have owned two R1100RT's, three K100RT's and many other Harley and Japanese motorcycles. All the metric bikes, from the 60's on, have super smooth shifting transmissions. My R1100's and K100's all have clunky shifting transmissions, mostly between 1-2 and 2-3, just like the Harley's. I love my R1100 but hate the transmission clunk.

My experience is, at the start of a ride, when they are cold, the transmission shifts somewhat smoother, but once fully warmed it clunks. Also, I feel a 75w - 140 gear oil shifts smoother than a 80-90 gear oil. What is your experiences?

Second, is the R1150RT, six speed transmission smoother?

Thanks, oldcarman Jim

 

[weschmann]

I have owned two R1100RT's, three K100RT's and many other Harley and Japanese motorcycles. All the metric bikes, from the 60's on, have super smooth shifting transmissions. My R1100's and K100's all have clunky shifting transmissions, mostly between 1-2 and 2-3, just like the Harley's. I love my R1100 but hate the transmission clunk.

My experience is, at the start of a ride, when they are cold, the transmission shifts somewhat smoother, but once fully warmed it clunks. Also, I feel a 75w - 140 gear oil shifts smoother than a 80-90 gear oil. What is your experiences?

Second, is the R1150RT, six speed transmission smoother?

Thanks, oldcarman Jim

Hi Jim, I just acquired a 94 1100 RS and I certainly agree with the 1st to 2nd shift clunk and down shifting from third on down. Just got it and changed the transmission to the 70/140 full synthetic. As bad as it clunk from first to second with 140 I can't imagine how bad it is with 70/90. And yes it does get worse once it warms up, but I guess it's normal for this model. I also get just a little slip when in 2nd gear, mostly when I've downshifts when initially torquing the engine when letting out the clutch. Not sure if that's a hint to future service needs or again, just a quirk og the old bike. Having a blast riding her though.....

 

[BC1100S]

Preload the shift lever and half-pull the clutch lever going up and rev match coming down. Should address some, not all, of the issue.

 

[pglaves]

I have posted this anecdote before but since the topic came up:

In 1977 we bought an R60/5 for Voni -her/our first BMW. The first time I rode it, the first shift from 1st to 2nd, I stopped and looked back to see what just broke/fell off the bike. It took a little getting used to. I was riding a Yamaha XS7502D with a snick-snick transmission and she was riding an RD250 with an equally quiet 6 speed.

 

[weschmann]

I have posted this anecdote before but since the topic came up:

In 1977 we bought an R60/5 for Voni -her/our first BMW. The first time I rode it, the first shift from 1st to 2nd, I stopped and looked back to see what just broke/fell off the bike. It took a little getting used to. I was riding a Yamaha XS7502D with a snick-snick transmission and she was riding an RD250 with an equally quiet 6 speed.

I can imagine. I was hoping you would comment. I kind of remember you speaking out about this issue in the past. I also remember you mentioning to use an additive of a couple (ounces?) of (again a question mark, TS 90 Moly Gear Concentrate) which I bought last year but never used. Am I remembering correctly or am I confusing some of the very valuable tidbits you have published over the years? Thanks in advance.......

 

[weschmann]

Preload the shift lever and half-pull the clutch lever going up and rev match coming down. Should address some, not all, of the issue.

. I give it a try. Going up, for the most part, I have been following your process. It's the down shift where I find issue. Not exactly sure what Rev match is on down shifting though. Maybe a dumb question but should I be blimping the throttle before releasing the clutch lever or doing a steady higher Rev with the throttle when letting out the clutch? Forgive me for the dumb question, but my previous motorcycles have all been no brainers when up or down shifting well over 100,000 miles between the different models.

 

[senseamidmadness]

Everyone I've ever heard talk about BMW motorcycle shifting says that the clunking and agricultural feel is simply characteristic of BMW's. It was an intentional design choice for a long time just like Harley-Davidson transmissions.

More modern Motorrads, 2013-forward, have supposedly completely eliminated the clunking because they have unified crankcases and multiplate wet clutches, so they share basically nothing with our older bikes.

On my particular bike, a 97 R850R, I found that changing my shifting technique helped. Pre-loading the shift lever and then pulling the clutch in sharply helps it shift more smooth. Trying to shift it like every other bike I've owned results in clunks so bad that it seems like the transmission is going to either kick me at the lever or fly apart. It still clunks more than the Japanese bikes I've owned but it's not grinding teeth and the shifts work. It's just how they are. They're different. How you treat the clutch and how you shift just have to be different from other bikes.

 

[pglaves]

I can imagine. I was hoping you would comment. I kind of remember you speaking out about this issue in the past. I also remember you mentioning to use an additive of a couple (ounces?) of (again a question mark, TS 90 Moly Gear Concentrate) which I bought last year but never used. Am I remembering correctly or am I confusing some of the very valuable tidbits you have published over the years? Thanks in advance.......

I have used a moly additive in all our gear oil lubricated transmissions and final drives upon the advice of Oak Okleshen since 1985. Originally I used Dow Corning Gear Guard. When it became available I began using Guardog Moly Lubricants gear oil additive. The owner closed the business but TS Moly is still packaging and selling some of the Guarddog formulations. Yes, I recommend it. Just follow the directions for the amount to add. It is 10% by volume if I recall correctly. Shake well.

 

[BC1100S]

Maybe a dumb question but should I be blimping the throttle before releasing the clutch lever....

Not a dumb question and yes - sorta. Pull clutch, blip the throttle while downshifting the lever and immediately let out the clutch upon doing the former. Practise makes perfect!

 

[BC1100S]

It was an intentional design choice for a long time just like Harley-Davidson transmissions.

Intentional? I'm thinking not. Can you imagine the engineers' conversation - "No Fritz, you have done too good a job designing that transmission. We need it to clunk like a Harley. Back to the drawing table! And while you're at it, add some weight to the crank throws so the engine vibrates more."

BMW transmissions have gotten progressively smoother from the airhead to the oilhead through the hexhead and finally to the wethead.

 

[weschmann]

I have used a moly additive in all our gear oil lubricated transmissions and final drives upon the advice of Oak Okleshen since 1985. Originally I used Dow Corning Gear Guard. When it became available I began using Guardog Moly Lubricants gear oil additive. The owner closed the business but TS Moly is still packaging and selling some of the Guarddog formulations. Yes, I recommend it. Just follow the directions for the amount to add. It is 10% by volume if I recall correctly. Shake well.

Thanks!

 

[cam_on_van_isle]

I quietly judge every single shift, up or down, and celebrate when it gets a "5" or above rating.....

 

[senseamidmadness]

Intentional? I'm thinking not. Can you imagine the engineers' conversation - "No Fritz, you have done too good a job designing that transmission. We need it to clunk like a Harley. Back to the drawing table! And while you're at it, add some weight to the crank throws so the engine vibrates more."

BMW transmissions have gotten progressively smoother from the airhead to the oilhead through the hexhead and finally to the wethead.

By "intentional" I mean they chose to do nothing about it for a long time. Had the engineers wanted to, they absolutely could've made their transmissions silky smooth as the Japanese makers did decades ago.

My 1993 Suzuki GS500E shifted smoother than the 1997 Oilhead I own now, and had a sixth gear, and it was designed in 1988, and sold for less than half the price of the Beemer new.

They always clunked and the customers didn't complain, so BMW saw no need to fix it.

 

[pauls1150]

Jim doesn't mention the actual mileage on his bike.

Some of the earlier transmissions did actually have "issues"; mine ('97 1100RT) was replaced under warranty when the shop (Marty's) was easily able to confirm my "customer states..." complaints; this was after we tried different oils and after allowing for some break-in mileage. My biggest issue was that it had started becoming "vague" to shift between 2nd and 3rd, going either up or down, and this finally became a false neutral slot and hang-up, sometimes rejecting the shift completely.

See also http://largiader.com/tech/oiltrans/ and http://largiader.com/articles/oilspline/ .

Other things to check would be the wear of the external shift mechanism; there are a few pieces that do wear, and closing up the tolerance with new parts can help.

Another issue may be the wear, and/or lack of grease, on the clutch center/trans input splines; as these wear (as they are known to), the rotational slop here will make shifting sloppy. I had to R&R the input shaft (and clutch) at about 80K miles on my '04 RT. At disassembly, they were pretty dry, almost like the assemblers forgot a step. The new shaft (with proper grease) and clutch made shifting MUCH better... maybe even better than when I first got the bike.

btw, I also add about a heaping tablespoon of Dow-Corning Gear-Guard to my trans' oil.

 

[oldcarman]

1996 R1100RT Transmission Clunk

My 96 has 25,000 miles, so very little use. One thing that was mentioned was the gearshift lever bushing. I did replace this last year and was surprised how much slop there was in it. So new bushings and grease did make the shifting mechanism work better but the internal clunk wasn't improved much. I also mentioned that on on my previous K's, and possibly on my previous R1100, I tried 75w140 gear oil and I felt the clunk was reduced. So, even though I changed gear oil last year, I decided to change gear oil again. This time I tried Royal Purple 80w140 full synthetic. The reason I tried this brand was it was the only one I found that had an 80w140. There are many 75w140 synthetic offerings. Initially I felt there was an immediate and definite reduction in clunk. So I thought I better give it a couple hundred miles and some really warm weather rides, 90 degree days, to see if I still felt the same. And yes it still feels significantly improved. Better than I recall from my earlier experiences with 75w140, on my other bikes. More time and miles will tell but so far I'm impressed. It isn't a metric bike quality shift but definitely not the Harley / ( older ) BMW clunk.