MOTOBRICK.COM
TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: punchesdfw on August 06, 2018, 06:36:09 PM
-
New battery. Humming noise in tank. Fuel. Spark, umm don't do that with the plugs out! YIKES! Hot-foot! Side Stand up. In Neutral. Pull the plugs and they are wet. Any other ideas?
-
How long have you owned this bike? How many miles are on the odometer? Has it ever run well since you took possession of it? How many trouble-free miles have you ridden it? Have there been any modifications to the moto? How old is the fuel in the tank? How many miles on the plugs? What do their gaps measure? Do the plug wires fit tightly on the plugs or do they wiggle? Do the headlights operate? Do the turn signals operate? How about posting a few photos? Hot enough for you?
On a K75, the side stand position doesn't control starting; the moto can be started when the clutch lever is pulled in regardless of the gear position.
-
It could be flooded. Once the plugs get wet enough to not fire, the injectors will just keep pumping fuel into the engine.
I unplug the tank connector behind the right side battery cover and crank the engine for 10-15 seconds with the throttle wide open to blow the gas out of the cylinders. With any luck, once most of the fuel is blown out the engine will fire a couple times and die.
Plug the tank connector in again and try to start again. Make sure the throttle and "choke" are closed. If no start, put the choke in the first position and try again. If the problem was a flooded engine, it should now start.
-
Thanks to the Mighty Gryphon. Did as suggested and it ran for a bit and shot fuel about 15-feet across my shop! I'll let it sit for a bit and try it again. Thanks!
-
Never open the throttle when starting a brick engine. The only thing it might need on a cold morning is the "choke". Giving the engine any throttle when cranking will flood the engine. If you have a throttle lock "cruise control" you might want to make sure the throttle is fully closed before cranking.
No need to get into the details of how I learned this.
-
Here's the crazy thing it's been running smoothly at 3000 rpm for 20-minutes with the fuel pump unplugged! WTF? When I plug it back in, it won't run at all. Argh!
-
Here's the crazy thing it's been running smoothly at 3000 rpm for 20-minutes with the fuel pump unplugged! WTF? When I plug it back in, it won't run at all. Argh!
????????!!
-
That's what I said! I have absolutely no idea what's up.
-
Are you sure the fuel pump is not running when you unplug the tank connector?
-
Is the bike a cafe racer? Has it been modified? How long have you owned it? Has it run properly before today?
-
Now that's a good question. Completely stock. Maybe the previous owner did some hotwiring. I'll check under the tank in the Morning. Thanks!
-
I've only had it 2-days. Needed a battery, so I bought a new one. Heard it run when I bought it
-
When you say it shot fuel 15 feet across your shop, I assume the fuel was shot out of the exhaust. Am I correct?
-
Yep! Raw gas!
-
So the engine ran for 20 minutes with the fuel tank unplugged? Was the fuel pump running during this time? Can you see fuel returning inside the tank when the engine is running?
Can you post a photo of the connector you unplugged to get the engine to run?
-
Past my bedtime. I'll get it in the Morning. Thanks for your help. I really appreciate it!
-
Here's the crazy thing it's been running smoothly at 3000 rpm for 20-minutes with the fuel pump unplugged! WTF? When I plug it back in, it won't run at all. Argh!
A photo of the connector you're manipulating would be helpful.
-
Here's the connection.
-
And when it's unplugged the pump and the engine run. Is that correct?
-
Yes! Crazy huh?
-
I would be pulling that tank and trying to find what the heck is going on. Is there another fuel pump somewhere?
-
Don't know. I just got home from work. So, I'll take a look in the morning. Thank you so much.
-
There are 2 4-pin connectors under the seat. Make sure you have disconnected the correct one, not the one to the gear position indicator.
-
There are 2 4-pin connectors under the seat. Make sure you have disconnected the correct one, not the one to the gear position indicator.
Good point, especially if the tag that says "tank" is missing.
-
OK. Now I'm pissed! Pushed the starter button and it fired right up. After a minute or 2, it died like it had been switched off. Now it won't start!
UPDATE! Here's the CRAZY ting. I removed and reinstalled the tank. Pushed the starter and it ran for 15-minutes before I turned it off. I Pushed the button and turned it off several times and it runs perfectly?
Seems to be OK now. I have No Idea what just happened!
-
Here's the CRAZY ting. I removed and reinstalled the tank. Pushed the starter and it ran for 15-minutes before I turned it off. I Pushed the button and turned it off several times and it runs perfectly?
Seems to be OK now. I have No Idea what just happened!
-
?
-
4 pin
nuff said
Not nuff for me. What do you mean? Thanks!
-
Not nuff for me. What do you mean? Thanks!
the 4 pin tank fuel pump connector.
-
It was not the tank (pump) connector. I plugged it in and out probably 20-times. But.... We don't know what it was. Something was wiggled when I removed the tank. But it works for now.
-
Connectors not connecting because of rust / long stay outside ?
Not only your tank connector, but switches too.
-
No rust. No corrosion. If you read all the posts, it has been crazy. Either way, it works now.
-
I would strongly suggest that you pursue the cause of this whack you are experiencing. It appears to be intermittent and quite possibly could return, usually at the most inopportune time and location. Finding the cause will allow you to make a permanent fix and/or give you the knowledge to quickly get running again should the problem return.
Intermittent problems are the worst to troubleshoot because they can be difficult to make happen and it's hard to be sure you have actually fixed them.
Having said that, I think you should spend a little time reading up on the four pin fuel tank connector. It is the cause of a significant amount of whack on these bikes. It would be good to see how others have been able to improve the reliability of it's connection.
Along with that, it will be time well spent to remove the tank and do a good cleaning of the wiring under it. There are a number of ground and other critical electrical connections under there that need to be nice and clean to have a reliable well running machine. It is one of the first things I do when I add a bike to my fleet.
-
Thank you for the advice! I think I'll ignore it and wait until I'm all alone on a dirt road in the middle of the Chihuahuan desert until I consider it! lol
-
i have a k100 that had a similar problem
it would run at revs with the fuel pump disconnected, but stall when i connected the pump
it turned out that the fuel relay was stuck in the on position, causing overfueling
from memory when u turn key to ignition u should hear fuel pump for about 3 seconds and then turn off
if pump runs continuously possibly relay stuck
im guessing vacuum from cylinders at revs draws fuel in even though pump disconnected
i was surprised too that i could ride the bike even with the pump disconnected as long as the revs were high enough
-
It was not the tank (pump) connector. I plugged it in and out probably 20-times. But.... We don't know what it was. Something was wiggled when I removed the tank.I would strongly suggest that you pursue the cause of this whack you are experiencing.Thank you for the advice! I think I'll ignore it and wait until I'm all alone on a dirt road in the middle of the Chihuahuan desert until I consider it! lol
The fault could lie beyond the immediate pin-to-socket connections of the plug. The fault could be among the wire connections within each plug to the pins and sockets. The fault could also be among the wire connections to the fuel sender within the tank, from the fuel sender to the pump or the connections at the pump itself. Moving the tank might be re-establishing connection. The disconnection will occur when riding jostles the wiring enough to cause it.
Take extra water and sunscreen to Chihuahua—not that I want to interfere with natural selection. :giggles
from memory when u turn key to ignition u should hear fuel pump for about 3 seconds and then turn off
if pump runs continuously possibly relay stuck
it would run at revs with the fuel pump disconnected, but stall when i connected the pump
it turned out that the fuel relay was stuck in the on position, causing overfueling
i was surprised too that i could ride the bike even with the pump disconnected as long as the revs were high enough
That all seems a little whacky.
With 2V K-motos like punche's K75 and your K100, turning the ignition switch to On does not activate the fuel pump for 3 seconds. That happens on 4V motos.
On your motos, pressing the starter button enables activation of the fuel pump. Closing the contacts in the fuel injection relay ("the on position") is part of that activation. The fuel pump then runs continuously during engine operation to supply pressure to the fuel system as long as the fuel injection relay contacts are closed. One of the ways for depressurizing the fuel system to disconnect hoses is to remove fuse #6—the fuel pump fuse—then start the engine. The engine will run then stall from fuel starvation regardless of the throttle's position. These engines won't run for very long without fuel pumps in operation.
Your engine's overfueling was caused by some other condition.
-
"Take extra water and sunscreen to Chihuahua—not that I want to interfere with natural selection. :giggles"
I'll also take a gun with one bullet :hehehe!
-
I'll also take a gun with one bullet :hehehe !
Be certain the calibers match. Disappointment has its limits.
-
thats my memory of it, maybe im wrong, maybe the pump started with a quick jab of the start button but then remained on
fuel was leaking out from the header muffler joint, when fuel rail removed the injectors had a constant spray
after replacing the fuel relay the bike ran normally, so i assumed the relay was stuck open
-
meant stuck on
anyway i definitely remember the bike running and even going for a ride on it with the fuel pump disconnected
i too thought thats crazy, how can i ride it with the pump disconnected, i assume the fuel was sucked in by the vacuum
-
meant stuck on
anyway i definitely remember the bike running and even going for a ride on it with the fuel pump disconnected
i too thought thats crazy, how can i ride it with the pump disconnected, i assume the fuel was sucked in by the vacuum
:tinhat2
-
Relays are cheap. I nay just buy one and keep it in the tail section just in case