Plug reading help
- dom2570
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Plug reading help
24 Oct 2014 12:27
I have an 82 750ltd that has been running fine, but I'm sure it could be better. I started to notice that full choke will initially help the bike start, but must be shut off right away or it will bogg and die. This is weird because in the past if left on the rpms would just shoot up. Is this normal?
I am worried bike is running lean. My headers are a little blue. I pulled the plugs, and they are all wearing pretty uniformly. Let me know what you guys think.
I am worried bike is running lean. My headers are a little blue. I pulled the plugs, and they are all wearing pretty uniformly. Let me know what you guys think.
Whip it like a mule!
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- dom2570
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Re: Re:Re: Plug reading help
24 Oct 2014 12:28
plugs from 1 and 4, 2 and 3 are almost identical.
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Re: Re:Plug reading help
24 Oct 2014 13:01
Took it for a short ride. Noticed a slight pop from the carbs while at ideal, seems to happen randomly. Also noticed the faint white smoke from the crankcase breather. I'm starting to think my oil got contaminated.
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- JR
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Re: Plug reading help
24 Oct 2014 13:04 - 24 Oct 2014 13:06dom2570 wrote: I have an 82 750ltd that has been running fine, but I'm sure it could be better. I started to notice that full choke will initially help the bike start, but must be shut off right away or it will bogg and die. This is weird because in the past if left on the rpms would just shoot up. Is this normal?
........
Sounds pretty much like mine. After a few seconds on full choke it will bog and I turn the choke lever down maybe a 1/4. It has done this since I bought the bike 11 years ago.
The plugs don't look to bad. Could be just right or a smidgen lean. Mine are a tad darker. I did notice though that there is oxidation and rust on the nut part of té plug so am thinking they have been in the motor for some time. Replacement plugs are inexpensive.
1980 kz750E1, Delkevic exhaust
Last edit: 24 Oct 2014 13:06 by JR.
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Re: Re:Plug reading help
24 Oct 2014 13:37 - 24 Oct 2014 13:38dom2570 wrote: Took it for a short ride. Noticed a slight pop from the carbs while at ideal, seems to happen randomly. Also noticed the faint white smoke from the crankcase breather. I'm starting to think my oil got contaminated.
Like a slight spit back through the carbs at idle or low speed ?
with me that was due to slight air leak at the carb boots / carb to engine rubbers. They should attach to the engine dry and without sealer but I found (with new ones) that I had to use a thin smear of Threebond 1194 on the engine side.
If in doubt about contamination sniff the oil for gas
A little white smoke from the breather shouldn't be a problem
1980 kz750E1, Delkevic exhaust
Last edit: 24 Oct 2014 13:38 by JR.
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Re: Re:Re: Re:Plug reading help
24 Oct 2014 15:49JR wrote:dom2570 wrote: Took it for a short ride. Noticed a slight pop from the carbs while at ideal, seems to happen randomly. Also noticed the faint white smoke from the crankcase breather. I'm starting to think my oil got contaminated.
Like a slight spit back through the carbs at idle or low speed ?
If in doubt about contamination sniff the oil for gas
A little white smoke from the breather shouldn't be a problem
Yeah, a slight spit back would probably be the best way to describe it.
I thought it might be from a leak in the emissions system, so I removed it and plugged everything. I'll check the boots with wd40.
The plugs were new in june, I just ride a lot in the rain lol.
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Re: Re:Re: Re:Plug reading help
24 Oct 2014 16:14
Ah, the emissions system. Maybe. We never had that stuff up here in Canada so not something I think about. 
good luck

good luck
1980 kz750E1, Delkevic exhaust
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Re: Re:Plug reading help
25 Oct 2014 07:45
Thanms, I think I'm going to change the oil again, better safe then sorry.
I think the popping might be a leaky vaccum cap on the carbs.
Here she is running. Crankcase smoke?:
I think the popping might be a leaky vaccum cap on the carbs.
Here she is running. Crankcase smoke?:
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Re: Re:Re: Plug reading help
25 Oct 2014 19:11
Sprayed the carb boots with wd40 no leaks, but I discovered one of the vaccum caps was cracked. No more poping, so far.
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Re: Re:Re: Plug reading help
25 Oct 2014 19:38
Cracked Vacuum cap - that's probably it
regarding the "crankcase smoke" could be just water vapor from condenation. If the bike is running well and not using oil then I don't think I'd worry about it. My crankcase vent is routed to the bottom of the air box so i never see anything but I'm sure there are vapors being expelled and making their way back through the carbs.
it would be interesting to hear other opinions
regarding the "crankcase smoke" could be just water vapor from condenation. If the bike is running well and not using oil then I don't think I'd worry about it. My crankcase vent is routed to the bottom of the air box so i never see anything but I'm sure there are vapors being expelled and making their way back through the carbs.
it would be interesting to hear other opinions
1980 kz750E1, Delkevic exhaust
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Re: Plug reading help
27 Oct 2014 16:53
carbs are out of sync by the sound of engine.
1984 750 Turbo
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