Boxerworks.com

melville wrote: ↑Thu Sep 29, 2022 9:45 am What's your final drive ratio?

GS's are geared lower than most (if not all) airheads.
Stock OE gearing 3.09:1 (34/11)
Stock OE size rear tire 130/80-17

Yeah, my R100/7 has the same final drive but probably a taller tire at 26 1/2" for a 4.00-18. On the open road, cruising is at 4K to 5K rpm with 4K being mostly legal and 5K being distinctly illegal but I've yet to be stopped.

I put almost 1000km on my new 5th gear this week.
I LOVE IT!
I've really been letting 'er rip, so I don't have a really conclusive fuel consumption improvement number but preliminary observations seem to point in the right direction.
The new speed vs. rpm ratio takes a bit of getting used to, especially at highly illegal speeds.
It's running about 400rpm lower at 100mph (160kmh) than with the stock 5th gear.
And it feels more relaxed than before at legal(er) speeds.

The one question I've been asking myself is "Why the hell did I wait so long to do this?"

Just spotted a oil drip at the rear paralever boot.
My new output shaft seal is leaking oil into my paralever.
Caught it in time, trans didn't run dry, just low.

Jody at EME is sending me a new seal on warranty.

My old seal hadn't leaked in years, but I tossed it in the garbage.
In retrospect, I should have re-used it instead of replacing it.
I've been reading all kinds of stories about these seals being problematic.

I installed it the conventional direction, lip facing in, as instructed on the packaging.
preformed the seal, sealed the notch, etc.
I'm wondering if installing it backwards as BMW initially did is a better idea?

The new seal arrived today at 4pm, less than 24 hours from when it was ordered.
I inspected the flange meticulously, installed it meticulously, cleaned out all traces of oil in the boots and paralever.
Put everything back together and went for a 20 km test ride.
Guess what?
I pulled the front clamp off to check inside the boot and about 2 tablespoons of oil came out.
I'm really peeved.

I'm gonna pull the tranny out tomorrow and stand it with the flange facing downwards overnight to see exactly where the oil is leaking from. I'm the guy who first discovered the V notch leak thing and initiated the service bulletins related to it back in the '90's and that's how I found it.

I also noticed when cleaning stuff up that my driveshaft was a bit out of phase from the rubber damper being a bit distorted. I was gonna replace it this winter, but I guess I'll do it now. Possibly this out of phase issue is causing a bit of vibration at the flange and causing it to leak? I doubt it, but it is possible. I don't feel any vibration from it when riding and it wasn't leaking before the seal was replaced.

I might try one of these: It's a Polaris ATV transmission seal.
I might be able to get one locally tomorrow.
Same exact dimensions, triple lip w/spring, Viton for high temperatures.
What have I got to lose?
All the knowledgeable people are gone from my local BMW dealers.
Now they're mostly newbies without a clue.
They have only the latest model fast moving parts in stock,
anything else takes a month to get.

I installed this Polaris seal for the output shaft flange
I left the front boot off and went for a 50km test beat.
NO LEAKS!! Whoopie!! totally dry as a bone, not even a hint of a sweat.
The seal is a triple lip seal,
it's designed to keep oil in and water out of their ATV differentials.
Viton for high temps.
Exact same size as BMW.
I'm going for a 3-400km ride tomorrow, that'll be a more definitive test.
Now, just have to see how long it lasts.
Looks promising for now.

gspd wrote: ↑Mon Oct 03, 2022 1:59 pm Just spotted a oil drip at the rear paralever boot.
My new output shaft seal is leaking oil into my paralever.
Caught it in time, trans didn't run dry, just low.

Jody at EME is sending me a new seal on warranty.

My old seal hadn't leaked in years, but I tossed it in the garbage.
In retrospect, I should have re-used it instead of replacing it.
I've been reading all kinds of stories about these seals being problematic.

I installed it the conventional direction, lip facing in, as instructed on the packaging.
preformed the seal, sealed the notch, etc.
I'm wondering if installing it backwards as BMW initially did is a better idea?

Hi, interesting problem you had there and just wondered if as you said BMW installed it backward for a reason and that being shaft rotation direction, I have seen this issue previously on Honda cars and the last one was only last year on a Honda Civic, we had someone come in to the workshop after he replaced the cam belt and had oil all over the new belt and plastered all through the timing cover, we asked what else he replaced and it was the cam shaft seal, now here is the thing he purchased the seal from an engineering supply shop not from Honda or an automotive supplier, these engines run anticlockwise from the timing end and thus Honda had special seals with the tiny scrolls on the lips cut in a direction to suit L/H rotation the genuine seal has a letter L stamped on it to indicate the direction.
Maybe that's why BMW put the seal in reverse to what you would think as the correct way.

jackonz wrote: ↑Thu Oct 06, 2022 4:06 am

gspd wrote: ↑Mon Oct 03, 2022 1:59 pm Just spotted a oil drip at the rear paralever boot.
My new output shaft seal is leaking oil into my paralever.
Caught it in time, trans didn't run dry, just low.

Jody at EME is sending me a new seal on warranty.

My old seal hadn't leaked in years, but I tossed it in the garbage.
In retrospect, I should have re-used it instead of replacing it.
I've been reading all kinds of stories about these seals being problematic.

I installed it the conventional direction, lip facing in, as instructed on the packaging.
preformed the seal, sealed the notch, etc.
I'm wondering if installing it backwards as BMW initially did is a better idea?

Hi, interesting problem you had there and just wondered if as you said BMW installed it backward for a reason and that being shaft rotation direction, I have seen this issue previously on Honda cars and the last one was only last year on a Honda Civic, we had someone come in to the workshop after he replaced the cam belt and had oil all over the new belt and plastered all through the timing cover, we asked what else he replaced and it was the cam shaft seal, now here is the thing he purchased the seal from an engineering supply shop not from Honda or an automotive supplier, these engines run anticlockwise from the timing end and thus Honda had special seals with the tiny scrolls on the lips cut in a direction to suit L/H rotation the genuine seal has a letter L stamped on it to indicate the direction.
Maybe that's why BMW put the seal in reverse to what you would think as the correct way.

My understanding is that the seal orientation was reversed due to the change, with the introduction of the paralever, from a wet to a dry drive shaft. Originally, the seal was to stop oil migrating from the shaft to the gearbox as pressure changed in the shaft housing due to movement and temperature change. With the introduction of a dry shaft, this was no longer required so the seal was reversed (and the breather sealed) to avoid oil migrating in the other direction. From memory, I don't think this was an immediate change but was introduced as a result of experience with the first 'paralever' rear suspensions. I don't recall seeing any authoritative information that BMW ever changed that recommendation.

Rob

jackonz wrote: ↑Thu Oct 06, 2022 4:06 am Hi, interesting problem you had there and just wondered if as you said BMW installed it backward for a reason and that being shaft rotation direction, I have seen this issue previously on Honda cars and the last one was only last year on a Honda Civic, we had someone come in to the workshop after he replaced the cam belt and had oil all over the new belt and plastered all through the timing cover, we asked what else he replaced and it was the cam shaft seal, now here is the thing he purchased the seal from an engineering supply shop not from Honda or an automotive supplier, these engines run anticlockwise from the timing end and thus Honda had special seals with the tiny scrolls on the lips cut in a direction to suit L/H rotation the genuine seal has a letter L stamped on it to indicate the direction.
Maybe that's why BMW put the seal in reverse to what you would think as the correct way.

Small world, I've encountered that exact same issue. Some earlier Hondas had the timing belt on the left, now they're all on the right side. The engines always spin the same direction as the drive wheels (when going forwards). Their seals had different direction spraling inside. The EME seals that are leaking and the OE BMW seals (for this particular application) do not have directional spiraling, just parallel grooves. I was thinking of reversing it so the lip would be farther away from the speedometer drive gear. The package specifically says to install with the lip inwards. My old one was that way and never leaked. I think it's simply a material issue with the EME seals; The inside flexible lip is too rigid, it doesn't have enough elasticity to keep it snugly on the flange. If you bend it out a bit with your fingers, it just stays there instead of slowly returning to it's original shape as it should.

Rob Frankham wrote: ↑Thu Oct 06, 2022 4:17 am My understanding is that the seal orientation was reversed due to the change, with the introduction of the paralever, from a wet to a dry drive shaft. Originally, the seal was to stop oil migrating from the shaft to the gearbox as pressure changed in the shaft housing due to movement and temperature change. With the introduction of a dry shaft, this was no longer required so the seal was reversed (and the breather sealed) to avoid oil migrating in the other direction. From memory, I don't think this was an immediate change but was introduced as a result of experience with the first 'paralever' rear suspensions. I don't recall seeing any authoritative information that BMW ever changed that recommendation.

The small quantity of swingarm oil (on pre-paralever bikes) was never significant enough to migrate upwards into the transmission however a bad output shaft seal could let transmission oil migrate to the shaft. The swingarm pressure and transmission pressure were always the same. The swingarm vented through the V notch to the trans, the trans vented through the speedo cable hollow bolt. Trans oil going into the swingarm was less consequential on earlier bikes, but with the paralever setup it started ruining the rubber cush drive in the shaft and filling the lower boot and dripping on the tire. The paralever shafts were designed to run dry, that's why venting (v notch) was no longer necessary. The seals for the pre-paralever bikes are the same size but different part numbers. I'm not sure about the different orientations and physical differences, how they came about, and how they changed over the years and models, but the later paralever bikes had the seal with the lip inwards. I believe many output shaft forward bearing failures were caused by low transmission fluid and not the lack of 'the circlip'. Many bikes that were brought in for transmission noises and failures had oil filled paralevers.