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SL350 K1 - initial start up and carb adjustments

The_Rooster

Veteran Member
Joined
Jul 11, 2020
Total Posts
184
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Location
Zeeland, MI, USA
It was a long winter but things are warming up and I have the electrical done on my bike. Fired it up yesterday but need some advice.

I have addressed this a bit before but still am unsure of what the next steps are. At this point I can can start the engine on the second kick and get a good idea but it is obvious that I am running primarily on one cylinder. The left gets hot quick and the exhaust is warm while the right is much colder. Infrared thermometer reads pipe on left very hot at 300+ degrees and the right hovering around half that. Both exhausts feel the same pressure wise at the tailpipe.

I have to have the left idle adjustment about all the way in, or one turn from being all the way in to get to this point. Any adjustment on the right idle doesn’t seem to have any impact on getting the right side to join in consistently. Fuel mixture screws are both about a turn and an half from fully closed.

Checked the plugs on both sides and swapped them even. Both are good. Good spark on each. Rechecked the timing as well.

Any suggestions?


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Update…

I tried starting the engine on the one cylinder that isn’t firing consistently and was able to get it to run but had to crack the throttle a bit to do so. Idle screw was turned all the way in and I couldn’t get it to start with just that. Mixture screws are the same on both sides.

All you gurus out there, what does that tell you if anything?

Sprint - I will give you a call Friday or this weekend if that’s ok. Thanks!


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I haven't messed with these carbs other than rebuilding. One thing I did notice is that the idle screw can be turned in without raising the piston which is the purpose. I had to slightly raise the piston, turn the screw and release the piston to get an effective measurable change.
Have you verified that your ignition system is 100%, resistances of the plug caps and coils, timing set correctly on both cylinders, correct B8ES plugs? If you're using the BR8ES plugs with resisted plug caps then your spark is weakened, can't run both.
 
LongDistanceRider said:
I haven't messed with these carbs other than rebuilding. One thing I did notice is that the idle screw can be turned in without raising the piston which is the purpose. I had to slightly raise the piston, turn the screw and release the piston to get an effective measurable change.
Have you verified that your ignition system is 100%, resistances of the plug caps and coils, timing set correctly on both cylinders, correct B8ES plugs? If you're using the BR8ES plugs with resisted plug caps then your spark is weakened, can't run both.
Click to expand...

I did put BR8ES plugs in! I had no idea that might be a problem! Rookie mistake!

Timing is good and battery has a good solid charge. I will have to look into the resistance of the plug caps and coils though and how to check that. They are new so hopefully no issue there. I will start with new correct plugs and see what happens from there.

Thanks!


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The_Rooster said:
I did put BR8ES plugs in! I had no idea that might be a problem! Rookie mistake!
Click to expand...
Not really a rookie mistake there. NGK stopped producing the B8ES plugs, replacing them with the BR8ES. It's only something those intimately familiar with ignition systems would know about and even there it leads to some disagreements.
You can run the newer plugs if you change the plug end caps to NGK LBZ or source some LBF caps from Europe. LBF's aren't sold in the US. The stock replacement caps are LB05F, the 05 meaning 5K ohm resistance.
Don't bother trying another brand sparkplug, they never last if they even work correctly.

You still want to talk to Steve!
 
I will be interested to see what solves the problem. Seems I have the same issue as you are describing though mine is on the left. It will run on one cylinder (right lead pulled) but only with the throttle advanced, but still not a punchy exhaust like the right. Granted, I am saying this without having dug in and performed the cam chain tension adjustment and working up from there to valve spacing and points timing and points gap . But my carbs are rebuilt!
 
The_Rooster said:
I did put BR8ES plugs in! I had no idea that might be a problem! Rookie mistake!
Click to expand...

I made the same mistake. Didn't know better.

I found some B8ES, but that's getting harder and more expensive. I ended up ordering the non-resistor plug caps that LongDistanceRider suggested. They come from Europe so it takes a bit if you're in the US. Advantage is the resistored spark plugs are easier to find and cheaper.

For a short time, until my B8ES arrived, I used a NGK B8EG and didn't experience problems. They were available locally. But didn't use them that long. There are two versions, so watch out. You need the terminal type version.
 
wentwest said:
I feel your pain. Mine is the right side that fails.
Click to expand...

My son had a weak firing cylinder on his lower mileage '71 CB350 and followed all the video advice on CMC. I would mention to him from time to time "have you checked the point's gap setting" and he would look at me like that wasn't a thing! After he took the top end apart, honed the barrels, installed new rings and ended up with the same result, he finally decided to check the point's gap (that Dad had mentioned many weeks prior). Low and behold, with point gap's adjusted correctly weak cylinder exhaust was punching like the other.

Takes me back to my Mazda rotary engine days, twin dizzy and single dizzy memories.
 
LongDistanceRider said:
Not really a rookie mistake there. NGK stopped producing the B8ES plugs, replacing them with the BR8ES. It's only something those intimately familiar with ignition systems would know about and even there it leads to some disagreements.
You can run the newer plugs if you change the plug end caps to NGK LBZ or source some LBF caps from Europe. LBF's aren't sold in the US. The stock replacement caps are LB05F, the 05 meaning 5K ohm resistance.
Don't bother trying another brand sparkplug, they never last if they even work correctly.

You still want to talk to Steve!
Click to expand...

Ok so I just want to be sure I understand this correctly.

If I opt to replace my plug end caps to LBZ caps I can run the BR8ES plugs, correct? I found these online. So strange to have to source these from Europe…

https://ducati-gowanloch.com/shop/service-items/ngk-lbf-plug-cap/

Or…

I keep the end caps I have and order the harder to find B8ES plugs.

Is that correct?


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The_Rooster said:
Ok so I just want to be sure I understand this correctly.

If I opt to replace my plug end caps to LBZ caps I can run the BR8ES plugs, correct? I found these online. So strange to have to source these from Europe…

https://ducati-gowanloch.com/shop/service-items/ngk-lbf-plug-cap/

Or…

I keep the end caps I have and order the harder to find B8ES plugs.

Is that correct?


Sent from my iPhone using Tapatalk
Click to expand...

That is correct, but B8ES aren't just harder to find, they're discontinued by NGK so eventually they will be impossible to find like they pretty much already are in my area. You want a total of 5k ohms resistance, whether from the 5k ohm resistor plug or from the 5k resistor cap - but not both which would total 10k ohms and reduce your firing strength.
 
Currently, there is still a plentiful supply of NGK B8ES plugs on eBay.
 
ausman1000 said:
Currently, there is still a plentiful supply of NGK B8ES plugs on eBay.
Click to expand...

What made me make the leap to unresistored caps is the increase in chatter over fake B8ES plugs. The decreasing supply has driven the price up which increases the incentive to provide bogus plugs. Since I can't tell the difference based on a picture, I don't see the B8ES as a sustainable route.

Besides... BR8ES are cheaper. Iridium plugs are just better. Non-resistored caps allow for that. It my case, I could tell a difference. I was running slightly rich, and I think the better spark help compensate for that. That's my theory at least.
 
ausman1000 said:
I did not know there were Chinese fakes, is anything sacred?
Click to expand...

Not anymore apparently. If a scammer thinks he can make a few bucks he'll do it. I've always been more suspicious of things and people in my life than my parents were, I watched them get screwed enough times while trusting someone that it convinced me to be a lot more skeptical.
 
ancientdad said:
Not anymore apparently. If a scammer thinks he can make a few bucks he'll do it. I've always been more suspicious of things and people in my life than my parents were, I watched them get screwed enough times while trusting someone that it convinced me to be a lot more skeptical.
Click to expand...

It's just so much easier and risk free now for this type stuff. No one is going to go kicking doors in way over in China for some spark plugs.

It really doesn't matter much. At some point, B8ES just won't exist anymore. Unless someone finds a large stash, non-resistor caps are in their future. Even then, it'll be top dollar for those. From a purely monetary standpoint, I paid $20 for the caps. Given the prices of plugs, that is made up for in a couple plug changes. Heck, I ruined a newish set of B8ES in about 5 seconds during one ride. That was a $15 oops.
 
teebo said:
It's just so much easier and risk free now for this type stuff. No one is going to go kicking doors in way over in China for some spark plugs.

It really doesn't matter much. At some point, B8ES just won't exist anymore. Unless someone finds a large stash, non-resistor caps are in their future. Even then, it'll be top dollar for those. From a purely monetary standpoint, I paid $20 for the caps. Given the prices of plugs, that is made up for in a couple plug changes. Heck, I ruined a newish set of B8ES in about 5 seconds during one ride. That was a $15 oops.
Click to expand...

Heard someone mention Alan Millyard throws em on the the barbie to clean em.
 
Yeah, and I wonder how long that lasts. Back when I was getting started with Hondas my father and I tried a lot of ways to clean plugs, even the little cloth-bag-wall-mount plug sandblaster, and they never lasted very long afterward. A guy we went camping with used to pack dirt into the plug around the insulator in an attempt to dry out some of the fuel soaked into the porcelain while we were on a camping weekend and believe it or not it actually worked on some plugs but again, not for very long.
 
ancientdad said:
Yeah, and I wonder how long that lasts. Back when I was getting started with Hondas my father and I tried a lot of ways to clean plugs, even the little cloth-bag-wall-mount plug sandblaster, and they never lasted very long afterward. A guy we went camping with used to pack dirt into the plug around the insulator in an attempt to dry out some of the fuel soaked into the porcelain while we were on a camping weekend and believe it or not it actually worked on some plugs but again, not for very long.
Click to expand...

I'd like to try a vapor blaster
 
ancientdad said:
Yeah, and I wonder how long that lasts. Back when I was getting started with Hondas my father and I tried a lot of ways to clean plugs, even the little cloth-bag-wall-mount plug sandblaster, and they never lasted very long afterward. A guy we went camping with used to pack dirt into the plug around the insulator in an attempt to dry out some of the fuel soaked into the porcelain while we were on a camping weekend and believe it or not it actually worked on some plugs but again, not for very long.
Click to expand...

Anyone tried rice? It works for getting moisture out of salt and sugar. And if some where left in the plug it would then be a.... (drum roll please)... RICE BURNER.

I crack myself up.
 
teebo said:
Anyone tried rice? It works for getting moisture out of salt and sugar. And if some where left in the plug it would then be a.... (drum roll please)... RICE BURNER.

I crack myself up.
Click to expand...

And for accidently submerged cell phones.
 
ausman1000 said:
Thanks for those links and thanks for allowing me to discover that my last purchase were fakes, I kid you not!
Click to expand...

Sorry brother, wish you'd seen those links when they were up originally. That's why I always (well, in my case it's my job) go to "What's New", you see every new post that way and sometimes there's a cross-reference to your situation, like B8ES being used by both the 350/360s and 450/500Ts.
 
They will work. The H designation is "compact" which means the plug wire end is shorter than normal.
LB-F are the direct replacement but only available from Europe and Australia.
LZ-F is a multi plug replacement fitting 10, 12 and 14mm plugs
 
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