Best Spark Plug?

I ran a B9HS with an .020 gap for about 15km today, engine liked it well enough as the idle was smooth and it would pull under load without missing a beat. Plug temp was consistently 400-425 at the base and CHT was hovering around 220-240 1\2" away from the plug. A plug chop indicates richness but that's fine with me for now until I get a few hours on this engine.
 
I added another 20km to the odometer and here's what the B9HS looks like now after 35km or so. Temps are good but the thing is running way rich still and I doubt it'll ever not be rich with the factory jet. I could drop the needle another notch to it's last position but I fear it'll then be too lean on the over run...which is the bugger with all cheap single jet carbs that have no pilot jet and or low speed circuitry.
 
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I doubt that you can run it too lean I do not think that you are going to burn a piston in these bikes I run very lean and have had no problems other than I have to start with the choke 1/2 on even when warm.
 
just thought i would mention a ran all these spark plug #'s and for a application that they all fit is aircoold volkswagens. say 60-s through 78 beetle or late
78-79's renoult le car that way when you go to a parts store the can tell you all the brands they have available.
 
Rockenstein said:
I added another 20km to the odometer and here's what the B9HS looks like now after 35km or so. Temps are good but the thing is running way rich still and I doubt it'll ever not be rich with the factory jet. I could drop the needle another notch to it's last position but I fear it'll then be too lean on the over run...which is the bugger with all cheap single jet carbs that have no pilot jet and or low speed circuitry.
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What altitude are you at?

I'm at 643 Ft. above sea level and I'm running 32:1 with NGK 6s and 7s @ .025" gap. My jet needle has 5 positions and is set to the second one from the top. I use the stock jet. I've seen replacement jets at moped places like 1977 mopeds and the like. Bikerguy Joe and Norman have some good ideas too, they helped me out alot.
 
tnanks to all. i think i'll go to parts store and see what i can dind to replace the orignal. either ngk or the bosch.

mybike
 
I took the stock one out hoping to gain something and put in a NGK B7HS; I liked the performance of the stock one better. It had more top end and ran all around better. I will try the B6 when I get around to it and post what I find.

CCC
 
Zack01GC said:
I just got a B5HS... are these things pre-gapped so I can just put it in and go? Or does it need gapped?
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You should check/set the gap on any spark plug you buy.
Gapping tools are cheap and they even give them away sometimes when you buy a set of six or eight plugs.
Tom
 
I used to be an NGK devotee but I've had better service from the Champion 811 (L82C) plug.
One of my engines always was a little sketchy about idleing. I like my engines to idle very slow and that one would just not do it. I switched to the Champion and it will idle like I want it too. It also showed some top end speed increase as well as hill climbing ability. Just to compare I went back to the NGK, a new one by the way, and the engine acted as it did before; no slow idle and a decrease in top end. Changed back to the Champion and the performance followed the plug. Made a believer out of me.
Tom
 
2door said:
I used to be an NGK devotee but I've had better service from the Champion 811 (L82C) plug.
One of my engines always was a little sketchy about idleing. I like my engines to idle very slow and that one would just not do it. I switched to the Champion and it will idle like I want it too. It also showed some top end speed increase as well as hill climbing ability. Just to compare I went back to the NGK, a new one by the way, and the engine acted as it did before; no slow idle and a decrease in top end. Changed back to the Champion and the performance followed the plug. Made a believer out of me.
Tom
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Have you ever tried an extended tip plug? Champion 811 (L82C) plug looks more like a NGK B6HS regular tip plug in pictures.
 
biknut said:
Have you ever tried an extended tip plug? Champion 811 (L82C) plug looks more like a NGK B6HS regular tip plug in pictures.
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No, I've never tried the extended tip plug. Is there an advantage with our 2 stroke engines?
Tom
 
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