[Ward501]

I just joined the forum because I am looking at purchasing a bike. Its a 1985 K100 (looks to be the 100LT because of the saddle bags). The guy offered it to me for $300. It is not in bad shape as far as appearance but it does not run according to him.

He told me he concentrated on cleaning the fuel system and had a problem with blowing fuses. He tracked it to a coolant sensor and fixed it. If he pushes the start button the fuel pump comes on but starter does not engage. He said he check the regular things you would check when the engine doesn't start but those did not fix the problem. He also threw in a comment that it "needs a new set of eyes on it" and I am assuming he means someone else to look at it but did not know if that was a part I was not recognizing.

What are yalls thoughts on this for $300? What do you think the things to check to try and find a solution are?

Thank you for your time,
Spencer

 

[cmonSTART]

What's your goal with this bike?

The price seems right for a non-running bike if it's not too bad off, but it will be a gamble. Those K bikes have a somewhat complicated electrical system - it can be fixed if you have a manual and can do basic troubleshooting, but it might take some effort. It might just be the relay too, located under the fuel tank.

Are you OK with working on the bike and getting it running? Is that something you think you will enjoy?

Are you prepared to work through more problems after getting the engine to turn?

Out of curiosity, is the engine seized?

 

[Ward501]

My goal is to take my time and turn it into a cafe racer style bike. I am currently in law school and love to mess with this kind of stuff. I am no expert in any way but love to try and work on my vehicles and make them personal. I would absolutely love working on it so thats no problem.

I do not know if the engine is seized. I have not gone to see it in person, but I will touch base with the seller to see what he says.

I'd really like to buy the bike and spend a while working on it and tweaking it but having a bike that doesn't run could turn into a headache both with frustration and financially if I have to take it to a shop to find a solution (working on a law school budget lol). I am in no rush to get it completed aesthetically or performance but I do want it to run so I can use it.

 

[cmonSTART]

Ya, that's the unpredictable thing. It might be a simple fix like the starter relay, but it might not also. If you don't have the desire/time/money to work out the issues with it you might just want to scrape a bit more together and get something that you can hear run.

What makes me nervous with this one is that you can't hear it turn over - so a basic assessment of engine health isn't possible. You can't hear it crank, do a compression test, etc.

I'd be willing to bet it needs a valve adjustment, too, which isn't the cheapest thing to do on that bike.

 

[Oz]

Welcome to the forum.

Law school budget! LOL. I remember when my ex-brother in law was in law school. He struck a deal with a local farmer to buy his leftover pumpkins. The poor guy ate pumpkin soup, roasted pumpkin, pumpkin curry, and various pumpkin recipes almost every day for months.

If you buy that bike, keep in mind it's 33 years old. Even if it was properly maintained, which it obviously wasn't, replacing parts could get expensive.

When the current owner says "it needs a new set of eyes on it", what he means is it needs a competent mechanic to sort it out.

If that doesn't scare you off, I recommend you check out the Beemer Boneyard for all your replacement parts. Here's the link: https://www.beemerboneyard.com

Best of luck with the bike. And good luck with law school.

 

[Ward501]

Thanks for the feedback. I’m going to go tomorrow afternoon and see the bike in person.

What questions do y’all recommend asking him about the bike? What are the list of things I should check while looking at a bike this old? Is there an order of trouble shooting I should use for trying to get the engine running?

Any feedback on how to go about checking out the bike would be appreciated and I will likely come back with more questions post purchase.

The law school budget is tight, but the working soon-to-be wife of mine is cool with me taking on our project! So that’s a blessing hahah but thank you for the well wishes.

 

[cmonSTART]

When evaluating a project bike I start with the bones of the bike - is the frame solid and straight? Any serious rust issues? How many miles? Does the engine turn over and sound somewhat even? Can I get a compression test done? (Compression likely won't be perfect as the bike has sat for a while, but it should have something there.) Are there any things about the bike that will hurt my wallet? (Shredded seat, missing or defective exhaust?) Does the bike appear to be taken care of somewhat? (Is the wiring hacked and taped back together, are the fluids reasonably topped off, etc.) How complete is it?

In your specific case I would want to know when (if?) the valves were ever adjusted. That bike uses a shim and bucket type adjustment which can be a bit pricey to do - and it's pretty important to have them in spec.

How many miles are on it? BMW's generally will last a long time if taken care of, so I wouldn't necessarily walk away if it has high mileage, but it should be considered.

Lastly (and maybe the most important issue) is what's with the start issue? If the wiring harness looks cut, hacked, and bubble-gummed back together that would be a big issue for me. It can take a lot of time to sort through someone's hackiness to figure out why the starter won't turn.

I have a K-series manual here - I'll thumb through it a bit later and see if I can come up with any ideas to check aside from the relay or starter itself.