Author Topic: 86 k75 with sprag clutch issue, need to start it to fix it. Suggestions request (Read 25770 times)

filmhog · « **on:** October 25, 2019, 09:46:58 PM »

Hello to the group. Long time lurker but just signed up. Really like k bikes as they are so smooth. I need input and assistance in workflow starting of a k75 that I purchased for virtually nothing that has a sprag clutch issue. Owner just gave up on it so its a project for me. But the bike won't start when push starting. Please follow my saga:
86 k75 52,000, series is in my profile. Made 4/86.
First off I have read virtually everything to fix the sprag clutch problem and am ready to do it. BUT I need to start the bike to get the proper oil and solvent working. That failing I will pull the cover and look for the 3 oiling holes and pickle them with carb cleaner. I'm confident about the process...........That is one job.
I read here how to bump start the bike. 3rd gear, run the starter to prime the FI and watch for flooding. Then how to not use the starter and open the throttle completely to burn any residual fuel.
Lo and behold the k75 started and ran perfectly for about 3-4 minutes. Had it on high idle then medium and then no idle advance. Running great. Then it stopped. didn't should like it ran out of gas, just stopped. Could not get it started again. Have not yet started it after repeated attempts. I checked the fuel pump for vibration and noise indicating operation. I also checked the flow of gas to the fuel rail and it was positive. Plugs were wet indicating something was getting through the injectors. But the bike had run!!! so something was working right. Checked plug to brain (I have an extra brain also), inserted new plugs, installed new injectors (the 4 hole kind, old ones were that ball configuration.) The injectors were looking like originals albeit the electrical plugs had damage at the clips so I know someone had monkeyed with in the life of the bike.
If I have to check spark, how can one do that when your push starting a bike? Where can I check for the reason its not firing. (yes I tried some starter fluid to on the air cleaner and it did not help put I feel the application of the fluid was not optimal. Any thoughts on things to check? Again, it ran perfect for a few minutes. My first bike was a k75 and I put some miles on it so I know when the engine is sounding right and this one was. Thanks to this forum for any help. This should be a fun project.

Chaos · « **Reply #1 on:** October 25, 2019, 10:11:19 PM »

I've never tried it but others have had success drilling a hole in the case and lubing the sprag clutch directly. Might be worth a try, just be careful of getting chips in the crankcase though a little bit of soft aluminum probably wouldn't hurt anything

filmhog · « **Reply #2 on:** October 25, 2019, 10:33:08 PM »

That fix is in the mix for sure. Im confident about the sprag problem. Its getting this thing started to do the minimal oil treatment that I need help with.
Thanks for the input.

filmhog · « **Reply #3 on:** October 25, 2019, 10:35:23 PM »

I did not mention that my project k75 has not run in at least 5 years when I acquired it. that why I thought maybe the injectors got clogged. But the darn thing ran perfect for a few minutes!

Chaos · « **Reply #4 on:** October 25, 2019, 10:53:03 PM »

bump starting a K can be tricky at best. I was thinking if you got the sprag working you could use the E starter and get it running as der faterland intended.

Laitch · « **Reply #5 on:** October 25, 2019, 11:01:27 PM »

Welcome to MOTOBRICK.COM.

Have you cleaned interior of the fuel tank, replaced the fuel filter, checked the condition of all the submersible hoses in the tank, tightened all the hose connections within the tank, cleaned the inside of the coil terminals with a wire brush and the HT wire terminals with emery cloth or a wire brush? Have you disconnected the four-pin fuel pump electrical connector, cleaned it then tightly connected it? Has the air filter been cleaned and the muffler outlet checked for obstructions. Have you checked the plug of the electronic fuel injection control under the seat to be certain it is tightly connected? What is the battery voltage output?

There is a laundry list of procedures to perform on a neglected Brick to insure there are optimal conditions for starting it. Spraying starter fluid on the air filter isn't one of them.

If the engine was running then stalled, a perfectly performing starter won't help keep it running; it'll just help it stall more frequently with less effort on your part. :-)

Please tell us everything you have done to the engine so far.

volador · « **Reply #6 on:** October 25, 2019, 11:30:26 PM »

If you overhaul it this might help
http://www.k100-forum.com/t4116-sprag-clutch-cleaning-the-sprag-clutch-and-bearing-replacement

filmhog · « **Reply #7 on:** October 26, 2019, 01:04:58 PM »

Laitch, Good list and I'll do those items today. I noticed corrosion on the FI electric connectors from age and will clean the coil connections too. I tested the fuel pump by disconnecting the fuel line to rail connection and hit the starter button, Fuel flowed very well. Removed the rail and cleaned it, installed new 4 nozzle FI's, new plugs. So electrics to the tank seems fine as well as flow through fuel filter and pump.

1ockdown · « **Reply #8 on:** October 26, 2019, 01:16:22 PM »

To tag onto Laitch, Is the battery brand new or perfectly charged? For your kind of situation I'd consider it smart to have a 100% perfect power source to accurately diagnose the tedious electrical issues. Check that tedious crankcase breather hose. You had it running but could've been leaking air in places causing it to stall out, or battery voltage could've been too low to support the system staying running. Make sure the alternator is connected to the battery and the system.

filmhog · « **Reply #9 on:** October 26, 2019, 01:20:18 PM »

Lockdown, thanks for info. Yes the battery is new and fully charged. That vacuum port on the front of the engine just below the radiator is capped with a proper cap. Good list. Thank you.

1ockdown · « **Reply #10 on:** October 26, 2019, 01:24:41 PM »

No not that vent port. The Breather Hose. Here :) It's an unlikely culprit in this situation, but considering you got it running and it died out, that hose is a usual place to start.

Inkedk75-M_LI.jpg (626.67 kB . 599x444 - viewed 698 times)

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filmhog · « **Reply #11 on:** October 26, 2019, 01:32:56 PM »

Im on it today. Thanks

filmhog · « **Reply #12 on:** October 26, 2019, 04:16:31 PM »

Lockdown, the hose was flared, fraid anddisconnected at the airbox. Im working on it now. That can contribute to an issue certainly. Thanks for the heads up on it.

1ockdown · « **Reply #13 on:** October 26, 2019, 04:19:06 PM »

Definitely get a replacement. You need to order it because you won't get the proper fit from your local auto store. Teflon tape, gasket sealer or whatever creativeness you can come up with is your best friend to seal that hose until you get the replacement so you can keep testing.

SDCR john · « **Reply #14 on:** October 27, 2019, 01:20:53 PM »

not trying to hi jack this thread, but what are the symptoms/ issues that would be exhibited from a bad Breather hose?

Quote from: 1ockdown on October 26, 2019, 01:24:41 PM

No not that vent port. The Breather Hose. Here :) It's an unlikely culprit in this situation, but considering you got it running and it died out, that hose is a usual place to start.

Inkedk75-M_LI.jpg (626.67 kB . 599x444 - viewed 698 times)

Inkedphoto165_LI.jpg (183.3 kB . 350x272 - viewed 698 times)

filmhog · « **Reply #15 on:** October 27, 2019, 01:23:16 PM »

I sleeved the breather hose tank connection for the time being. My local bmw has to order it.
Question, What are the two unused plugs under the seat? White 4 pin female and what appears to be a black 5 pin male. Id post a photo but please tell me where a good fee sight is for photos to park. I figure in this resto I'll be posing pics.
Thanks

1ockdown · « **Reply #16 on:** October 27, 2019, 01:29:55 PM »

filmhog, upload the pics to your computer via sending them to yourself from your phone to your email or some other fashion. then attach photots with the attachments and other options. Theres a lot of connectors on the bike.

The breather hose symptoms are hair loss, explosive anxiety and social discomfort if you aren't aware of the hose. It cracks over time just like any other rubber, but seems to wear faster. It causes a decent sized air leak into your system, as it vents the crankcase to the air plenum. It normally will crack where the hose clamps are connected. It's easy to remove, if in doubt, take it out and check it.

P.S. u can edit and modify your existing posts after you have posted 10 times i believe.

filmhog · « **Reply #17 on:** October 27, 2019, 01:30:10 PM »

Never mind the photo question. I read the thread here that tells me about Gallery.

filmhog · « **Reply #18 on:** October 27, 2019, 01:41:44 PM »

Here is the photo of the connectors in question. Thanks for any help

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1ockdown · « **Reply #19 on:** October 27, 2019, 01:45:29 PM »

If I'm not mistaken, I have similar wires hanging around in my fuse box as well. I think the bike may have come wired for additional accessories such as an alarm. Might just be an unused plug.

volador · « **Reply #20 on:** October 27, 2019, 01:50:07 PM »

Accessory connectors
Anti-theft Alarm
Radio, or Police related acc. lights, siren, etc...

filmhog · « **Reply #21 on:** October 27, 2019, 02:03:30 PM »

Volador, thanks. I was going to install a radio so I'll try to figure out which is what.
As I am asking these questions, I though I'd share what Im working on. This 86 was on Craigslist. 52k miles It was stupid cheap....the former owner just gave up when he heard sprag clutch and the BMW dealer hit him with a quote $$$.
I was going to cafe racer it, but when I did the accounting of parts it was basically all there. 25 years ago, I remember those Pichler Uni 4 fairing were very expensive. It needs some body work, but that's easy and have the proper paint waiting to be sprayed. Great paint shop here in Reno. I was going to pull the package rack but I remember those being expensive in the day. Anyway thought you guys would like a photo.

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I'll put a brake question in the next post.

filmhog · « **Reply #22 on:** October 27, 2019, 02:04:31 PM »

The original City Bags are cool too.

filmhog · « **Reply #23 on:** October 27, 2019, 02:07:14 PM »

Working on the brakes too. Front master has a leak at the seam line of the two cast blocks. On Harley and my triumphs, when I had a piston brake leak it came out the back by the lever actuator. This is leaking at the seam. Seeking comments on what I will find when I get in there. should I order a piston or is this an obscure gasket or ?
Thanks

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Laitch · « **Reply #24 on:** October 27, 2019, 02:18:27 PM »

The fuel cap is 180º out of rotation. In its correct position, it allows water accumulating around the cap to drain to pavement via a port beneath the right side of the tank that is connect to a port in the cap's flange.

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Author Topic: 86 k75 with sprag clutch issue, need to start it to fix it. Suggestions request (Read 25770 times)