#4 spark plug smokes !
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#4 spark plug smokes !
I am suspecting there may be an issue with plug seat.
The spark plug sits in nicely and no cross thread issues. I torque it down to 13 NM and all good.
Once bike heats up , I see smoke come from somewhere near #4 plug. The speed of smoke rises and falls with throttle. No visual sign of any oil leak from cam cover either.
Any ideas ? I am suspecting the seat on the head where plug threads may have some uneven surface ?
The spark plug sits in nicely and no cross thread issues. I torque it down to 13 NM and all good.
Once bike heats up , I see smoke come from somewhere near #4 plug. The speed of smoke rises and falls with throttle. No visual sign of any oil leak from cam cover either.
Any ideas ? I am suspecting the seat on the head where plug threads may have some uneven surface ?
1979 CBX (faster Red)
1981 CBX Streetfighter
2017 Aprilia Tuono.
Past rides : FZ1, BMWS100rr,S1000r,k1300S,YAMA RD350,Enfield 350
1981 CBX Streetfighter
2017 Aprilia Tuono.
Past rides : FZ1, BMWS100rr,S1000r,k1300S,YAMA RD350,Enfield 350
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Re: #4 spark plug smokes !
Here is video
https://m.youtube.com/watch?v=s2R1NHrSrJY
https://m.youtube.com/watch?v=s2R1NHrSrJY
1979 CBX (faster Red)
1981 CBX Streetfighter
2017 Aprilia Tuono.
Past rides : FZ1, BMWS100rr,S1000r,k1300S,YAMA RD350,Enfield 350
1981 CBX Streetfighter
2017 Aprilia Tuono.
Past rides : FZ1, BMWS100rr,S1000r,k1300S,YAMA RD350,Enfield 350
- SteveG
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Re: #4 spark plug smokes !
I say it is leftover oil / remnants cooking off. How far have you ridden the bike since putting it back together? If all of the plugs are tight, then ride it a good bit (100 miles at one stretch) and see if it still smokes.
My .02$
Nice bike!
Steve
My .02$
Nice bike!
Steve
82 CBX, 82 CB900F Project, 81 CB900(985)F, 79 CB750(810)F, 06 Wee-Strom
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Re: #4 spark plug smokes !
Steve
Bike has been going through a customization. Motor was not run in last 3 years . I did valve adjustment, carb rebuild, oil pan cleaning , filter oil changes new plugs . Where would this leftover be burning ? Outside on valve cover ? Not sure why it would smoke only at near #4 cylinder
Bike has been going through a customization. Motor was not run in last 3 years . I did valve adjustment, carb rebuild, oil pan cleaning , filter oil changes new plugs . Where would this leftover be burning ? Outside on valve cover ? Not sure why it would smoke only at near #4 cylinder
1979 CBX (faster Red)
1981 CBX Streetfighter
2017 Aprilia Tuono.
Past rides : FZ1, BMWS100rr,S1000r,k1300S,YAMA RD350,Enfield 350
1981 CBX Streetfighter
2017 Aprilia Tuono.
Past rides : FZ1, BMWS100rr,S1000r,k1300S,YAMA RD350,Enfield 350
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Re: #4 spark plug smokes !
Are you sure you don't have a loose exhaust collar that blowing exhaust back through the head fins? That's what it looks like to me.
Dave
Dave
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Re: #4 spark plug smokes !
Dave
I will check that . These are new pipes with new copper round shape gaskets and I had tightened them fairly good while aligning.
I will check that . These are new pipes with new copper round shape gaskets and I had tightened them fairly good while aligning.
1979 CBX (faster Red)
1981 CBX Streetfighter
2017 Aprilia Tuono.
Past rides : FZ1, BMWS100rr,S1000r,k1300S,YAMA RD350,Enfield 350
1981 CBX Streetfighter
2017 Aprilia Tuono.
Past rides : FZ1, BMWS100rr,S1000r,k1300S,YAMA RD350,Enfield 350
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Re: #4 spark plug smokes !
Will try again. Collars are retightened as per manual. In the process, found that one of the stud On cyl #1 was turning free. Luckily I had a 6mm helicoil kit that took care of it .
1979 CBX (faster Red)
1981 CBX Streetfighter
2017 Aprilia Tuono.
Past rides : FZ1, BMWS100rr,S1000r,k1300S,YAMA RD350,Enfield 350
1981 CBX Streetfighter
2017 Aprilia Tuono.
Past rides : FZ1, BMWS100rr,S1000r,k1300S,YAMA RD350,Enfield 350
- SteveG
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Re: #4 spark plug smokes !
Since you had the valve cover off to do the valve adjustment, some oil could have oozed/seeped/ran..... down into the #4 plug well/area while you were working.AshishNJ wrote: ↑Thu Jun 25, 2020 8:56 pmSteve
Bike has been going through a customization. Motor was not run in last 3 years . I did valve adjustment, carb rebuild, oil pan cleaning , filter oil changes new plugs . Where would this leftover be burning ? Outside on valve cover ? Not sure why it would smoke only at near #4 cylinder
Is it still smoking after checking the exhaust crush washers as Dave suggested?
Steve
82 CBX, 82 CB900F Project, 81 CB900(985)F, 79 CB750(810)F, 06 Wee-Strom
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Re: #4 spark plug smokes !
Steve. Haven’t had a chance to try due to rain. I hope it does not but we will see. I will setup an slr to take better video this time
1979 CBX (faster Red)
1981 CBX Streetfighter
2017 Aprilia Tuono.
Past rides : FZ1, BMWS100rr,S1000r,k1300S,YAMA RD350,Enfield 350
1981 CBX Streetfighter
2017 Aprilia Tuono.
Past rides : FZ1, BMWS100rr,S1000r,k1300S,YAMA RD350,Enfield 350
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Re: #4 spark plug smokes !
I tested it out today and once engine heats up after 5 minutes or so, there is smoke from around spark plugs. No leaky exhaust. What I suspect is the inside of the valve cover gasket is seeping oil when it is him and hot and burns up. I touch around the gasket and I could see the oil ! I am guessing when I give it a throttle pump builds more oil pressure and immediately that leak also increases. Does my theory has a leg ?
1979 CBX (faster Red)
1981 CBX Streetfighter
2017 Aprilia Tuono.
Past rides : FZ1, BMWS100rr,S1000r,k1300S,YAMA RD350,Enfield 350
1981 CBX Streetfighter
2017 Aprilia Tuono.
Past rides : FZ1, BMWS100rr,S1000r,k1300S,YAMA RD350,Enfield 350
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Re: #4 spark plug smokes !
Shouldn't be noticeable pressure build-up in the top end. Your valve cover gasket should not be seeping hardly any oil even if a cursory bit of care was taken during installation. Both cover and gasket should be thoroughly cleaned, then the gasket glued into the cover. Then just a dab of sealant around the 4 half-moons on the gasket and that should seal everything. I would suspect a pinched gasket somewhere causing the cover to not tighten down properly. Or else you have a very warped valve cover.
Dave
Dave
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Re: #4 spark plug smokes !
Dave. You have a point. The original valve cover I had was black color and was peeling off. I figured the engine should win beauty contest and decided to use another silver cover . It is possible the 2nd cover may have been warped, though it did not appear so. On a glass table it sat straight but at this point I will go back to older cover with new gasket. Those gaskets are not cheap ! Thanks for the advice.
1979 CBX (faster Red)
1981 CBX Streetfighter
2017 Aprilia Tuono.
Past rides : FZ1, BMWS100rr,S1000r,k1300S,YAMA RD350,Enfield 350
1981 CBX Streetfighter
2017 Aprilia Tuono.
Past rides : FZ1, BMWS100rr,S1000r,k1300S,YAMA RD350,Enfield 350
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Re: #4 spark plug smokes !
While you have the cover off, be certain that the head surface is OK. A little nick, a scrape, etc. to cause a leak.
Larry Zimmer
cbxlarry@sbcglobal.net
cbxlarry@sbcglobal.net
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Re: #4 spark plug smokes !
I will. Thanks
1979 CBX (faster Red)
1981 CBX Streetfighter
2017 Aprilia Tuono.
Past rides : FZ1, BMWS100rr,S1000r,k1300S,YAMA RD350,Enfield 350
1981 CBX Streetfighter
2017 Aprilia Tuono.
Past rides : FZ1, BMWS100rr,S1000r,k1300S,YAMA RD350,Enfield 350