SOLVED! Fixed a no start issue.
Thread Starter
Joined: Jan 2008
Posts: 9
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SOLVED! Fixed a no start issue.
Yet another no start post!
Trying to get a bike I bought running, and afterthoroughly cleaning the carbs (ensured passages and jets were clean), it still wouldn't fire. Checked the plugs and they weren't great soI installed new plugsand it struggled but did fire and run for about 4 min under it's own. (closed garage late at night so I couldn't run it longer.)
Thought I had it figured but the bike won't fire now unless it's primed through the carbs, and it will only burn up what was sprayed in. Fuel is getting to the carbs - but they don't seem to be feeding the motor under any circumstance. (Choke, idle, high rpm, etc) The FSM doesn't indicate anything about fuel pressure, just volume from the fuel pump. (I've just checked the bowls for fuel, and cracked lines to make sure there was fuel there.)
I'm going to try bypassing the pump just in case - but wanted to see if anyone can say if these carbs need fuel pressure to run.
If the bike should run with full fuel bowls - can anyone familiar with these things point me in another direction? I'm stumped as I've had the carbs off again and they are quite clean, just don't know why the damn thing won't run!
Thanks!
Rabin
Trying to get a bike I bought running, and afterthoroughly cleaning the carbs (ensured passages and jets were clean), it still wouldn't fire. Checked the plugs and they weren't great soI installed new plugsand it struggled but did fire and run for about 4 min under it's own. (closed garage late at night so I couldn't run it longer.)
Thought I had it figured but the bike won't fire now unless it's primed through the carbs, and it will only burn up what was sprayed in. Fuel is getting to the carbs - but they don't seem to be feeding the motor under any circumstance. (Choke, idle, high rpm, etc) The FSM doesn't indicate anything about fuel pressure, just volume from the fuel pump. (I've just checked the bowls for fuel, and cracked lines to make sure there was fuel there.)
I'm going to try bypassing the pump just in case - but wanted to see if anyone can say if these carbs need fuel pressure to run.
If the bike should run with full fuel bowls - can anyone familiar with these things point me in another direction? I'm stumped as I've had the carbs off again and they are quite clean, just don't know why the damn thing won't run!
Thanks!
Rabin
Joined: Sep 2007
Posts: 72
Likes: 0
From:
RE: Do these carbs need fuel pressure to run?
Well if your sure you got fuel in the carbs and its not running and you just cleaned the carbs. But the only thing thats limiting the fuel in the bowls from getting into the cylinders would be the needles in the carbs have to be plugged. And no you don't need fuel pressure for the bike to run. Just as long as you have fuel in the bowls. Maybe I'm wrong and another senior dude can answer this. Ohh and one more thought is you have a serious air leak around the carbs to where its not sucking air from the carbs but from a seal around the carb.
Thread Starter
Joined: Jan 2008
Posts: 9
Likes: 0
RE: Do these carbs need fuel pressure to run?
Nope - needle passages are clear, and there's definitely fuel in the bowls. My buddy sprayed fuel into the carbs and was able to keep it running that way, but the bike wouldn't continue to run on it's own.
Normally if it's a plugged jet it won't run in that range (IE idle get plugged it won't idle but it'll rev) - but this bike won't run in choke, idle or at higher RPM - but it did run for a good 3-4 minutes when I first replaced the plugs. Ran a bit rough, but revved freely to 9-10K, and had the idle turned up to about 2K and it was still fine.
Checked for air leaks and made sure all the carb to head clamps were tight and the boots themselves are in good shape.
Definitely got me stumped...
Rabin
Normally if it's a plugged jet it won't run in that range (IE idle get plugged it won't idle but it'll rev) - but this bike won't run in choke, idle or at higher RPM - but it did run for a good 3-4 minutes when I first replaced the plugs. Ran a bit rough, but revved freely to 9-10K, and had the idle turned up to about 2K and it was still fine.
Checked for air leaks and made sure all the carb to head clamps were tight and the boots themselves are in good shape.
Definitely got me stumped...
Rabin
Thread Starter
Joined: Jan 2008
Posts: 9
Likes: 0
RE: Do these carbs need fuel pressure to run?
SUCCESS!
Spent another 3 hours on the bike trying to figure out why it won't run, but finally got the bike to fire and run! Got it up to nice operating temp, and after shutting down it fires right up. Reassembled the bike, and it still fires up. Cold start tomorrow is the final test!
What I found:
[ul][*]1 of the new NGK plugs wasn't sparking. Grabbed on of the old ones from the garbage, confirmed it was sparking and put it in.[*]Carbs were getting fuel and the plugs were getting wet - but it firing when primed was just a wild goose chase.[*]These bikes foul their plugs REALLY easily - had to pull them out and dry with compressed air 4 times.[*]Once plugs are fouled - they need to be pulled - waiting over night doesn't cut it.[/ul]
Solution: The starting procedure itself! I went through every system to ensure it was working and confirmed everything was good. (Air, fuel, spark) During testing I'd pull the plugs after every attempt and find wet plugs. So I dried them and tried the starting procedure I found here that said full choke and don't touch the throttle. Sure enough it fired and ran! (Fuel pump was bypassed at this point). Put the fuel lines back together to use the pump and it still ran! Brought it up to temp and the bike sounds great! Revs nice and it starts super quick once warm.
Just wanted to note that the bike does run fine without the air box on, and that once fouled, the bike will crank and crank then backfire. No idea why it'll sometimes fire when primed, then die while the plugs are fouled - but it did - and that sent me on a wild goose chase into the carbs.
I'll comfirm it's a total success tomorrow with a cold start - but I think it should be good!
Rabin
Spent another 3 hours on the bike trying to figure out why it won't run, but finally got the bike to fire and run! Got it up to nice operating temp, and after shutting down it fires right up. Reassembled the bike, and it still fires up. Cold start tomorrow is the final test!
What I found:
[ul][*]1 of the new NGK plugs wasn't sparking. Grabbed on of the old ones from the garbage, confirmed it was sparking and put it in.[*]Carbs were getting fuel and the plugs were getting wet - but it firing when primed was just a wild goose chase.[*]These bikes foul their plugs REALLY easily - had to pull them out and dry with compressed air 4 times.[*]Once plugs are fouled - they need to be pulled - waiting over night doesn't cut it.[/ul]
Solution: The starting procedure itself! I went through every system to ensure it was working and confirmed everything was good. (Air, fuel, spark) During testing I'd pull the plugs after every attempt and find wet plugs. So I dried them and tried the starting procedure I found here that said full choke and don't touch the throttle. Sure enough it fired and ran! (Fuel pump was bypassed at this point). Put the fuel lines back together to use the pump and it still ran! Brought it up to temp and the bike sounds great! Revs nice and it starts super quick once warm.
Just wanted to note that the bike does run fine without the air box on, and that once fouled, the bike will crank and crank then backfire. No idea why it'll sometimes fire when primed, then die while the plugs are fouled - but it did - and that sent me on a wild goose chase into the carbs.
I'll comfirm it's a total success tomorrow with a cold start - but I think it should be good!
Rabin
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