second gear slippage question - 90 k75

[allisonmo2]

So I am looking at a k bike that is advertised as having a second gear "slippage issue". I get that it is super hard to diagnose a bike that you have never seen, nor have I, but I am a bit curious about the response i received after asking about it. I did search here first and found a second gear slipping post, but that author just replaced his tranny for resolution. Wondering if this reply is hogwash, or if he is on to something.
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i specifically asked about the slipping habits, ie. under power, when coasting, any other gears indicating a spline issue, etc....


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I only have the issue in second gear. I've not tried slow, steady acceleration, but it is only in lower revs (betw 3000 and 4500 rpm) that it slips. There is no clunking.

An acquaintance (not a professional mechanic) diagnosed the issue as: "most likely thrust adapter. It limits the torque in the transmission to limit stress on gears. Means removal and opening tranny. Its on one of the shafts kind of like a large slotted screwdriver into a slot and held in place by a heavy spring. The spring gets weak and then as it slips begins to wear the two interfacing components down."

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Thanks Ya'll! :2thumbup:

[allisonmo2]

not that i doubt you blue, but do you care to expand on your assumption?

[The Dude]

Second gear is superflous.I hardly ever use it.

[Motorhobo]

Well, for lack of helpful responses here on what the cause of the slippage might be, I guess I can only say your best bet might be to look on eBay or other sources for transmissions and offer the seller a price that compensates for the replacement. I don't use 2nd gear much either but having it slip if I do need it isn't acceptable.

If you want the bike and are comfortable swapping out the trans, buy it. There are a lot of voices here who say 'Don't buy a K-bike unless it's perfect!' I'm not one of them. These are older machines and at some point something's going to fail and you're going to have to fix it, so for me it makes little difference if I fix it after buying it or six months down the road. You're going to want to pull the transmission first thing on any k-bike you buy to check out and lube the splines anyway, so if you can get a good price and you want the bike, buy it, put in a replacement tranny and ride.

[allisonmo2]

thank you hobo. that was basically what i thought as well. plan 300$ for used transmission, 200 for what i don't plan on,  then double that to get an accurate depreciation. i was hoping that there was some known widget for .50 cents that commonly fails and is a 5 minute replacement

[Chaos]

I'm wondering if the owner is confusing slipping with jumping out of gear, not unusual with older K's,  worn shift drum and/or bent shift fork.  Whatever, plenty of transmissions out there http://www.ebay.com/itm/BMW-K75-K100-transmission-20k-miles-/282136166459?fits=Make%3ABMW%7CModel%3AK100&hash=item41b0a0403b:g:rZoAAOSw-itXsMb0&vxp=mtr

[allisonmo2]

true enough, i have found them as low as 100 bucks on there too, but i still plan on worst case scenario, or over estimate. i'm not going to run out of cash here, but i do have a budget i would like to stick to. he's asking 1800 with the issues, i just feel with the probable need for a new tranny right off the bat it's a 1000$ bike at best. has some fairing rash as well, and one of the bags looks like the bottom of the clamshell is open a bit. maybe 1/3-1/4" gap. rear tire about done, and who knows what else i can't see at the moment.

[Motorhobo]

one of the bags looks like the bottom of the clamshell is open a bit. maybe 1/3-1/4" gap. rear tire about done, and who knows what else i can't see at the moment.

That's probably just one of the plastic hinges holding the two halves together at the bottom is shot, they're just plastic and and tend to split in half after a while. Easy enough to check that out, but if that's the case, it's not something that would depreciate the value, those hinges are $5.50 at the dealer.

If the bike runs, I think $1000 is low. List value on the bike is about $2450 without ABS, about $2750 with. You'll find threads here where people seem to agree that $800 is a reasonable price for a non-runner in good visual condition, so using that as a benchmark, if he's asking $1800 and told you about the transmission issues, I think he's pretty in the reasonable range wrt his asking price. Offering him $1000 might just piss him off -- he sounds like his tried to be upfront and fair with you so far.

I'm sure someone will disagree and recommend the low-ball route -- but I personally don't think asking $1800 for a running K75 is unreasonable.

[The Mighty Gryphon]

I agree with Motorhobo's sentiments.  These bikes are going on 30 years old and there aren't that many in showroom fresh condition anymore, and those bikes are getting a lot more than $1800. 

I would shop for a used transmission under $200.  Doing the swap along with the splines, rear brake  pads and bleed, fluid change, and a good detailing from the clutch back is easily a weekend job or even a long day. 

You didn't mention the miles.  Is it an S or an RT?   A lot of miles might mean more issues.  As far as price, if the miles are in the 50's or 60's and the fairing rash is just scratches and not cracks or busted off pieces I would think $1000 might be a bit low, you're getting into the parts bike price range.  If it was an otherwise running bike and me selling it I would hold out for $1200-1300 minimum. 

[allisonmo2]

both very valid points.
the bike is a 1990 k75s with 148k miles, seat has a tear, front fairing has enough rash to expose the fiberglass, about 8-10" long and about 1" high.
i didn't offer the 1000, as yes, i'm sure that would be an insult. that was just what i would be willing to spend on that particular bike. i would rather wait, find a bit more of what i am looking for and spend more. i don't mind tearing it apart and replacing a tranny, and i plan on investigating the splines about right away no matter what bike i find, but i don't want to have to do all of this before i ride mile #1.

[Motorhobo]

Well then -- 148k miles -- different ball game completely.

At 148k miles you might be getting to the end of the valve adjustment threshold and need a new top end. No way of knowing that without taking the valve cover off and doing the measurements.

Go ahead and lowball him and if it doesn't like it, look for another, lower mileage k-bike!

My $0.02...

[allisonmo2]

yeah, my target was about 50k or of course lower. i originally started this hoping that it w was likely something super cheap and easy. didn't think it would be, but you never know. this has been a great site for learning about these bikes and has gotten me really excited about owning and working on a brick. and the fact that i am brickurious makes me giggle every time i see it.

[The Mighty Gryphon]

Wow!  148k is a lot, even for a brick.

Splines, steering head bearings, valve shims, wheel bearings, seals etc. could all be issues, if not now, but in the near future.   I would pass on this bike and keep looking.  There are a lot of them out there with 60k or less for not much more(or maybe less) than you will have in this one when you finally have it all sorted.

[The Mighty Gryphon]

You are getting close to the end of the season.  In a month or two you should be able to get a decent deal on a lower mileage brick from an eager owner anxious to get their bike out of the garage before the snow flies.

[Motorhobo]

Wow!  148k is a lot, even for a brick.

Heeey...the K75 on currently on my lift has 175k and I (hope to) see it turn 250k. Having said that, it's been on that lift for over a month now.

If it runs, odds are good you'll get another 20k out of it without too much worry. After that...it's a science project.

[The Mighty Gryphon]

Motorhobo, I know these bikes will run for a lot of miles, but looking at buying one with that many miles with an unknown service history is not what I would recommend for a first time brick owner.  Especially, when there are so many nicer bricks around for not much more.

IMO The bike in question is more of a project bike for someone who already has a running brick and is looking for something to tinker with over the winter(and maybe the summer, too).

[allisonmo2]

Motorhobo, I know these bikes will run for a lot of miles, but looking at buying one with that many miles with an unknown service history is not what I would recommend for a first time brick owner.  Especially, when there are so many nicer bricks around for not much more.

IMO The bike in question is more of a project bike for someone who already has a running brick and is looking for something to tinker with over the winter(and maybe the summer, too).

couldn't agree more. 80% of my wrenching experience are on a variety of singles, from my little xr75 when i was a wee lad, to my dr350s i have now and an ascot in-between. also run through in no particular order, v30 magna, zx-6, pc-800, ex-500, and a pile of 4 wheelers and 3 wheelers. most wrenching was done on dirt equipment. been lucky in life or purchase decisions to not really have any big issues with the street bikes. just tires, exhausts, brakes, chains etc.... normal wear and tear. i saw a vid here recently where a guy removed his engine completely in about 10 minutes or so. some ridiculous easy time.  that's what started the appeal. i have also been in love from a distance with bmw's since i started being able to afford better machinery in the late 80's and early 90's. a bunch of the love, admiration, and mystique is peter egans fault too. once i feel comfy, tearing a multi cyl bike down to the frame, and get better with electrical diagnosis, i may start looking for an old commando or similar brit bike. old tech makes me happy. the sounds of old tech make me drool.

[Laitch]

i saw a vid here recently where a guy removed his engine completely in about 10 minutes or so. some ridiculous easy time.  that's what started the appeal.

That's kind of slow. This guy does it in less than 6 minutes. With your mechanical experience, taking down a Commando in that time should be a piece of cake.

[Motorhobo]

Sorry -- misunderstanding. I wasn't recommending he buy it if he wants a right-away rider. I thought that was pretty clear from me using words like 'science project' and 'it's been on my lift for a month'...if he's got the money he should be looking for a lower-miles bike, clearly.

But hey, allisonmo2, if you're looking for a great deal, I have a 95 K75 I can give you a great deal on. Plus, I'm not too far from you!

Some assembly required.

[allisonmo2]

hey, at least checking the splines would be super easy!

[kennybobby]

Carefully inspect the left hand seam area at the forward bottom of the fuel tank for signs of an imminent leak. 

i bought a k75 recently that seemed to be a good running machine with a few nits, but turns out the tank was holding fuel only by a thin layer of paint--the tank had oxidized from the inside at the point where water collects in that lh seam.  As soon as i touched that area with a fingernail to see what that bump was, it let loose the fuel.

Put it on the side stand and you can get a visual of where the crud would collect.

[Elipten]

Walk away!  Too Many miles.  You can do better.

[allisonmo2]

I didn't walk away. I ran! Actually i offerred a probably lowish, but respectful 1450. He declined. I moved on. Search continues

[Elipten]

Smart move


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[Chaos]

I didn't walk away. I ran! Actually i offerred a probably lowish, but respectful 1450. He declined. I moved on. Search continues

Seller should have taken you up.  Nobody is going to pay that much when lower mileage bikes are abundant.  Actually, 150K means the bike has been taken care of and could be less of a headache than a 30K bike that's been sitting.  Mine is pushing 200K now and just keeps going and going and going.