Non start after ten minute ride

[Lenn0x84]

 :mbird Hi all  :mbird

Finally rebuilt my 1985 K100, started her up a few times while I finished the build (engine started and restarted half a dozen times without a problem) and took her out for the first time this morning. Went for a ten minute ride through my local streets hoping nothing would fall off, and thankfully all went well. Idled fine, pickup up and drop revs well for Donner engine that hadn't been started for 7 years. (My original engine blew so I got a Donner engine, replaced the torsion dampener with a later model and put on fresh hoses, plugs, oil, air filter and radiator.)

As the ride ended I parked out the front of my garage, with the bike happily idling, gandered at my beautiful baby with pride as she seemed to be running smoothly. Turned her off, opened my garage, went to turn her on again to drive her in....

Starter spins, lights are on, but no go. Fuel pump seems to be on when I hit the start button, but if I recall when you first turn the key the fuel pump turns on for a second, but that isn't happening, relays are clicking when the start button is pressed to.

I'm still a newbie but I can turn a wrench and have basic electrical knowledge, built a 100watt stereo amp once. So any help would be great and forgive me as I learn the proper words for things, as I noticed in these forums a lot of people know a lot more than I and all I've got as reference is the huge clymer manual that seems to confuse the names of parts in its own book. (i.e. Union bolt vs banjo bolt)??

The only thing that changed from when the bike was stationary is I topped up the fuel in tank with new fuel, could a blocked fuel filter really do this? Is the starter gone? (even though its spinning). I've tried to be as accurate as I can and am looking forward to see what you all suggest.

By the way this is my first post as I've been a long time reader but first time poster as I thought I should have a working/semi working bike before I can contribute. Cant wait to fix this and hopefully be able to helps others with their problems/projects on Motobrick.com.

Cheers
Lennox in Melbourne Australia 

[Scott_]

Well, I'll try my best to help you here. I'm not that well versed in the older "jetronic" control system that you should have on that bike.
The fuel pump doesn't prime with ign switch on with that type system. The pump only runs when the controller sees that the motor is actually turning.
Hence the next question, is the motor actually turning, or is just the starter spinning without turning the motor.
With the donor motor, did it come with the intermediate housing and gears? or did you have to put yours on it. Where I'm going here with that question is, I'm wondering if the sprag clutch gear is not engaging and thus not allowing the starter to turn the motor gears. These can gum up with age and dirty oil and not function properly.

It's a start, others hopefully will chime in eventually with other ideas.

[Lenn0x84]

Aha yes that crossed my mind because it only sounds like the starter is turning and nothing else... so no I don't think the sprag is engaging, but how do I nudge/force it too. I read that rocking the bike forward and backward while in first can trigger it but I tried with no luck. The weird thing was when I rock the bike forward the fuel pump seems to trigger for a second or so.

The donor engine was just the block and bell housing?? replaced alternater, gearbox and clutch with mine from the old engine.

Thanks for the fast reply
 

[mystic red]

Well, if the starter is turning but not engaging, you need to pull it to find out why. As long as you have it out, you need to do this. Sorry...

[lunchbox]

Try the rocking back and forth a few more times.

When I bought my one-owner '92 in '07 the owner described what might happen if the moto has sat for awhile. Sure enough when he went to start it, spinning starter and no start of the motor. 

He demonstrated the rocking back and forth (he did it in fifth gear) it fired right up. He said it would occasionally take a  few tries. He owned it fifteen years and only put 5000 miles on it so I think it would sit for few months at a time.

Hasn't happened since, though I ride it nearly every day.

If multiple rockings don't do it, then as mystic red said, time to clean the starter.

[Lenn0x84]

 :clap: :clap: Thank you all for your help!!

Scott you got me on the right trouble shooting track to fix the issue, Red the I pulled starter out & it was fine but as it was out I decided to follow the guide you linked to and that meant it must be the sprag. Unfortunately lunchbox I saw your post after I push started it, I did read about and tried the rocking method but didnt know what gear to use so I tried 1st & 2nd, no luck, then looked for what gear to push start in and didn't know. Old car knowledge of the past suggested 2nd gear and viola (dunno how to spell french words) she was alive.

Now I'm a happy man, running fuel injecter cleaner and radiator flush in my K to make her fighting fit. The new donor engine feels great and thank all you guys for helping me out
Cheers
 :riding: :2thumbup:
You were all a great help, now that I've got another question do I start another thread or continue in this one as its got to do with my bike?? Moderator what do I do?

[robleyd]

Might as well start another thread - it's a new problem so give it a new subject. That way, people will see a new problem to answer, and it helps for anyone searching for the same problem.

Hint - have a look in the Lieberry and try a search for the problem before you post; odds are the question has already been asked :-)

[Scott_]

Now that you can get it running, I'd try and run some extra(not an excessive amount) detergent in the oil to try and cleanup the sprag assembly as it is bathed with the motor oil. SeaFoam (if you can get it where you are at) does wonders for cleaning systems up, both oil based and fuel based.
Put a can in the oil and run it, get it good and hot to really work it in, then change the oil/filter(after it cools a bit..........)

BTW, I'd still consider staying with regular dino oil instead of synthetic, but that's another topic that you can research here with the search field. Sometimes older seals don't like synthetic oil and will leak.

[JamesInCA]

Well ... NOT to turn this into an oil thread -- I do remember a thread somewhere, in which the owner reported that synthetic oil kept his starter sprag clutch happy, while dino seemed to get it stuck after about 5000 miles. So it does seem that either some occasional detergent toward the end of your oil change interval, or some high-detergent oil, or synthetic, might help keep the problem at bay.

[Lenn0x84]

Cheers guys, well I'm running full synthetic at the moment Penrite 10/70 and the k seems to like it, started her up about half a dozen times with the traditional anthem of the K... "Starting up first kick". So the sprag seems to be cleaned up now. And I only had white smoke for the first 3-5mins when I first brought her to life so I'm guessing/hoping shes not burning any oil. Not smoke at all out the back.  :2thumbup:

I'll look into the oil threads to get some more info as I'll be doing an oil change in 50-100 km, the engines been sitting for 8 years before I got my grubby hands on it so I'll flush her out twice before I'll consider a country ride. I've read about these oil detergents, being down under I dont know which ones we have so I'll look into it and will happily use it as I've read it along with all documentation thats got to do with sprag, so I'll consider it a must do.

Cheers Scott & James
"To anyone reading this thread for help with their sprag I'll link some documents that helped me out along with the advice from Motobrick users. "

(Moderator, is there somewhere on the forum that I can upload and link to, like our own document liebrerry? Let me know it there is and I'll follow procedure. Otherwise I'll link to me own public dropbox, cheers)

[robleyd]

When you reply to a, or create a new, post you'll see under the text box, a link to "Attachments and other options" - click that and all will be revealed :-)

[mystic red]

LennOx86, What Roblyed said...

Try a search before asking but questions are always well received.

Put some kind of location in your profile so we at least know what part of the world you're in....helps with answering questions sometimes.

Put what bikes you have in your signature line. Also helps with questions.