Author Topic: First ride and only got 500ft (Read 36718 times)

danpalooza · « **on:** May 22, 2016, 02:13:26 AM »

I just bought a '92 K75 RT today and was so excited to take her out on her first little ride. I pulled out of my place, gaining speed with a smile on my face, when suddenly my elation was halted after I shifted into second gear. An alarming CLUNK sound, followed by the rear wheel locking up, sent me in a panic. I squeezed the clutch in to stop the skidding and to try preventing from highsiding. Luckily I wasn't going very fast. I coasted into a nearby parking lot confused and frustrated. I test rode the bike earlier that day and it shifted smooth 1-5, no problems at all. The guy I bought the bike from was a mechanic and apparently he maintained it regularly (I'm not putting it past me that he could be lying). Anyway, only getting 500ft from my house wasn't a good way to start the relationship with my bike. Although I'm thankful I wasn't on the freeway when it happened. I will be taking her apart soon and let you know what I find. But in the meantime, anyone have ideas on what could have caused the transmission to fail like that?

-Danner

rbm · « **Reply #1 on:** May 22, 2016, 07:39:50 AM »

Welcome. Your experience is very much unlike a K-bike. These beasts are usually robust and bulletproof.

In the absence of any evidence, it's hard to say what went wrong, whether it is a failure of the transmission or the driveshaft or final drive, or something else. My first guess is probably the U-joint on the driveshaft may have failed. If the transmission or final drive had locked up for some reason, you would not have been able to coast. It's known to have driveshaft U-joint failures, and to have the grub screw on the shift lever inside the transmission loosen and fall out. But, this would be a first for me to hear of the transmission locking up.

Scott_ · « **Reply #2 on:** May 22, 2016, 08:10:28 AM »

My 1st vote would also lean towards a u-joint failure.
Though I have heard more of them happening with the paralever(2-joints) than the monolever(1-joint)

The Mighty Gryphon · « **Reply #3 on:** May 22, 2016, 09:08:18 AM »

You mention pulling the clutch to be able to coast. That would indicate a problem with the engine.

Can you move the bike with the clutch out and the transmission in gear? That would put the problem downstream of the clutch. Probably in the drive shaft. Most likely the universal joint as mentioned by others.

Is the wheel locked up or free turning?

Does it free wheel when in gear and the clutch pulled in?

Does the engine run? Does it stall when the clutch is let out in gear when the bike is up on the center stand? That would make me think the problem is in the transmission or final drive.

Can you shift gears with the engine running? If you can, I would think the transmission is probably ok.

Do you hear any noises from the drive shaft when you turn the rear wheel? That would point to the universal joint.

danpalooza · « **Reply #4 on:** May 22, 2016, 01:46:45 PM »

Gryphon,

I cannot move the bike with the clutch out and transmission in gear.

The wheel frees when in gear and the clutch is pulled in.

The engine won't start.

I can shift gears with the engine off.

No noises from the drive shaft when I turn the rear wheel.

I'm beginning to suspect the problem is in the engine now. I wondering if it has seized up and that is the reason why it won't turn over now.

danpalooza · « **Reply #5 on:** May 22, 2016, 02:00:18 PM »

UPDATE:
I couldn't see this from last night when it happened but just inspecting the bike again this morning I saw it is leaking oil badly from the oil sump. Definitely an engine problem not transmission. I'll be tearing it down this week...

Laitch · « **Reply #6 on:** May 22, 2016, 02:10:15 PM »

Quote from: danpalooza on May 22, 2016, 01:46:45 PM

The engine won't start.

Thanks to Gryph for providing a well-considered check list, and to danpalooza for a timely followup with it.

danpalooza · « **Reply #7 on:** May 22, 2016, 02:12:38 PM »

Quote from: Laitch on May 22, 2016, 02:10:15 PM

Quote from: danpalooza on May 22, 2016, 01:46:45 PM
The engine won't start.
Thanks to Gryph for providing a well-considered check list, and to danpalooza for a timely followup with it.

Yes, thank you Gryph. Very much appreciated.

mystic red · « **Reply #8 on:** May 22, 2016, 02:13:53 PM »

Wow, it's hardly ever the engine! How many miles?

danpalooza · « **Reply #9 on:** May 22, 2016, 02:15:52 PM »

Mystic,

55k, not that much for those engines. The previous owner must of really not taken care of it. What a shame.

Chaos · « **Reply #10 on:** May 22, 2016, 02:38:42 PM »

mystic red · « **Reply #11 on:** May 22, 2016, 02:50:49 PM »

Quote from: danpalooza on May 22, 2016, 02:15:52 PM

Mystic,

55k, not that much for those engines. The previous owner must of really not taken care of it. What a shame.

No shit, he must have been a hell of a mechanic. 55K is about when mine needed a slight valve adjustment.
Be interested to see what the problem turns out to be. If it turns out to need a rebuild, I'd call him up and ask him what he ran for oil. Used, unstrained chainsaw oil?

danpalooza · « **Reply #12 on:** May 22, 2016, 03:34:44 PM »

I'll keep you guys posted.

The Mighty Gryphon · « **Reply #13 on:** May 22, 2016, 05:19:25 PM »

Does the oil light come on when you turn on the ignition? If not, is the wire connected to the sensor on the front of the engine? I am suspecting an oil pressure problem leading to a thrown rod. OUCH!!! If the wire is disconnected, the seller might have known there was a problem and figured he could hide it long enough to sell the bike. Have you contacted him yet? I would consider small claims court if he doesn't offer some sorrt of compensation.

If there is a bright side to this, it might be that a decent short block can be had fairly reasonably as these engines seem to usually outlive the rest of the bike, and there are a fair number of them out there.

johnny · « **Reply #14 on:** May 22, 2016, 05:22:28 PM »

i have never heard of a motobricker with a donkey avatar throw a rod on a 750 motobrick...

coincidence... i dont believe in coincidence...

j o

Elipten · « **Reply #15 on:** May 23, 2016, 10:16:15 PM »

TrueAce · « **Reply #16 on:** May 23, 2016, 10:32:32 PM »

Before we leave this as an engine tear-down................Could you have had a sloppy shift which jumped higher, loading the engine, causing the stall? Do you have a strong battery? I would test the electrics, starter,etc. to be sure there is a good starter system. Does the transmission give you 1-N-2-3-4-5? The oil could be an unrelated issue. Check the battery and starter relay before dropping the engine.

Scott_ · « **Reply #17 on:** May 23, 2016, 10:50:17 PM »

Should be able to remove the crank cover from the right side for inspection without too much difficulty. (other than draining some coolant and removing the coolant hose)

Laitch · « **Reply #18 on:** May 23, 2016, 11:00:50 PM »

Quote from: johnny on May 22, 2016, 05:22:28 PM

i have never heard of a motobricker with a donkey avatar throw a rod on a 750 motobrick...

I believe scripture indicates the donkey avatar motobrickers wring driveshafts into scrap metal using the 1100 motobrick.

The Dude · « **Reply #19 on:** May 24, 2016, 01:12:54 AM »

Quote from: danpalooza on May 22, 2016, 02:15:52 PM

Mystic,

55k, not that much for those engines. The previous owner must of really not taken care of it. What a shame.

The least reliable part of my brick was the odometer- speedo actually...I'm on my third,two gone under warranties.I have to add 50,000 km to my third which stopped at 175,000 odd' bout 30 k ago...

Quote from: danpalooza on May 22, 2016, 01:46:45 PM

Gryphon

I'm beginning to suspect the problem is in the engine now. I wondering if it has seized up and that is the reason why it won't turn over now.

Yep ,but it will be because of something stupid,I'll bet.2nd gear....you were lucky,but...

I bought a T150.in the seventies,cheap..completely rebuilt with Norman Hyde big bore and crank.No oil pressure.....He told me he'd run it about five miles and then laid it up.He said it was ok when he did.I didn't run it ,just took it apart.The "mechanic"left the oil plugs on the brand new crank out...
Blue big end journals,effed con rods.reground 10thou under,new rods.Made the mechanic pay for it ,on threatening his reputation.kept it ten years,50kmiles,two top end rebuilds.
I'm over it ....now.
'Hope yours works out OK....

danpalooza · « **Reply #20 on:** May 24, 2016, 02:04:36 AM »

Had a long day at work and finally had a chance to get a better look at the damage. I got the fairings off and my heart dropped when I saw this. Here's a couple of pics of the crank case cover.

danpalooza · « **Reply #21 on:** May 24, 2016, 02:05:30 AM »

The pictures got turned upside down for some reason.

Martin · « **Reply #22 on:** May 24, 2016, 02:09:48 AM »

Sorry, looks like something has let go. Should be able to pick up a short engine at a reasonable price with a bit of luck.
Best of luck Martin.

67charger · « **Reply #23 on:** May 24, 2016, 02:33:22 AM »

There are a couple of engines on ebay for around 200 bucks. These motors aren't worth much because they rarely blow up. Sorry for your experience, very disheartening I'm sure.

The Dude · « **Reply #24 on:** May 24, 2016, 02:39:33 AM »

Yeh,new motor,for nix....well worth it...but what the Fifi?...oil light???loose oil filter?conrod cap bolt?
These bricks are bullet proof...so, please post pics of inside.
All,the best.

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Author Topic: First ride and only got 500ft (Read 36718 times)