MOTOBRICK.COM
TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: tr33houseman on August 21, 2016, 11:07:24 PM
-
Hey, everyone, first time poster on this forum. I’ve been reading on here for a while and this site has definitely helped with solving an electrical issue before. Thank you! I have a 1987 K75 with 10,000 miles on it. Let’s see what you guys think.
Today I was riding to work and coming to a red light. I started decelerating by braking normally as well as down shifting to 3rd gear and engine braking. I noticed as I held in the clutch the rpm dropped unusually low. (The bike was already warm by the way. I’d been riding for about 10 minutes already and its 65 degrees out.) Anyway the rpm dropped to around 700 and the engine sounded like it was gonna stall until I let out the clutch for minute. I’m still braking as usual and I shift down to 2nd gear to assist with engine braking. Again the rpms drop low and the engine sounds like it’s gonna stall. I let the clutch out and finish braking to a stop. Once I stop (still in second gear with the clutch pulled back in now) the engine dies. While Im waiting for the left turn arrow I switched it into neutral and started the bike up again. It wouldn’t hold so I flipped the “choke” switch to its half way position to raise the idle. Seemed to run alright with the choke half way causing the idle to raise. I proceed onto the last stretch of road before work. Everything’s running great, I get up to 70mph in 5th gear and start to slow down because my turn is coming on the left. As I was driving I put the “choke” switch back into its normal “off” position. I start to slow down in the same way as before using engine braking to assist me. I shift down to 4th, all good, engine braking. I shift down to the 3rd to continue engine braking all good, but this time as I’m COMING to a stop, not even stopped yet, the engine dies as I pull in the clutch before I drop into second gear. Now while I’m coasting with the engine off, I shift down to neutral, start the bike, flip the “choke” switch back to half way and proceed to make my left turn into my work parking lot. I park the bike and now when I go to start it the bike will turn over and the starter will turn but as soon as the engine catches and runs on its own the idle drops and it dies.
I've tried starting it a couple times since i've been at work and as i switch between neutral, 1st, and 2nd with the engine OFF, the tach starts to jump around for about 30 seconds. The engine is not running and the tach jumped up to 3,000 and bounced back down. I have drained the battery trying to start it so i guess im stuck here for a little while.
I have almost a full tank of gas.
As I was accelerating and riding along, even after the first time it stalled out, the acceleration was smooth and even. No misfires or roughness at any point during acceleration.
Thank you very much for any suggestions or advice.
-
My money is on "bad gas". I'd pour in a bottle of HEET and slosh it around. Charge your battery.
-
Fuel filter maybe.
I never ride without a spare
-
The only time my k75 dies on me is when the Z tube is getting cracked and unmetered air is going in. Then it will die on idle sometimes, or idle roughly in a loping/pulsing fashion. It'll ride fine, but when I clutch in and drop the throttle it'll want to die at the red light instead of coming to an idle. So maybe see if your z tube is still 1 piece.
Crankcase breather hose is the legit name, i believe...
-
+1 on Hershey
-
+1 herseyb
Connects from engine to air box.
-
Thank you very much for the ideas. I checked my crankcase breather hose and its in good condition. Its slightly pliable with no cracks and not hard or breakable even though it does look original. I dont really know whats happened but after i towed my bike back to my house, put in on a charger for a day and then went to try to recreate the issue to see if i could gain anymore clues, the bike worked fine. Riding great... I was hesitant to post back saying it was good to everyone because sure enough now that i said it... Its gonna fail again. I guess we'll see. Thanks for the help and ideas!
-
Probably some water under the fuel in the tank that gets push into the pump inlet area under braking and sucked up in there.
Might want to drain and inspect, look for onset of pinholes in the tank in the left hand seam.
-
I was hesitant to post back saying it was good to everyone because sure enough now that i said it... Its gonna fail again.
Thanks for the update despite the sizable risk. :giggles It's helpful to those following a thread to learn of the resolution, no matter how it came about. You also now have a chance inspect electrical connections, air supply connections and the condition of your fuel tank without desperation being part of the equation. :2thumbup:
-
True indeed! Thank you all again!