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Discussion Starter #1 (Edited)
^^^add to that timing and the advancer unit operation. and if you're running a bit rich, heat range 9 plugs isn't helping either. you should be running B8ES to start with and could run B7ES if a bit rich, but getting the jetting closer couldn't hurt either
Hey AncientDad, I saw this in the post on a CB350 that could not reach above 65 mph. I'm interested to know about changing spark plugs to help with a rich/ lean condition. My engine is currently apart for a rebuild due initially for a stripped spark plug hole that I was going to have TimeSerted, still am on both holes since the machinist says they are stronger then the original head but getting back on topic. On my bike I had the spark plugs both running nice in tan with the exhaust at the time. 2-2 with Vintage VW Exhaust Tips. The bike ran loud as expected and would not pull over 7,000 rpm's.

I finally built a 2-1 exhaust after looking for months for the elusive and probably out of my price range Hooker 2-1. Benjie's was also out of my price range. The 2-1 I built uses a 1.5, 1.5 to 1.75 collector. I'm currently using an old Harley Muffler but am considering switchhing to a Cone Engineering Reverse Cone. I do understand this may change my jetting again and this also may make this discussion irrelevant to my situation but in the interest of learning, I'm curious.

I had my right cylinder running nice and tan but my left was running a bit rich but the bike rode really nice with it pulling to 10,500 rpms, would reach and maintain 85mph on slightly hilly terrian, and I could feel the "power band" kick in from 7,000 to 9,000 rpms. Keep in mind my set up was Mikuni VM30's running Thunder Products UFO's with a 3.0 Slide per the UFO instructions( only issue with this is the bike would only idle around 1600 rpms, no lower with the idle screws all the way out).

With that on to my left slightly rich left cylinder. Can this issue be resolved with a slightly hotter plug such as the B7ES. I have no issue changing jets, just curious on the hotter plug on one side versus the other. Of Note: I may change out the slides after I put the bike back together. I am thinking of switching to the Paamco Ignition system and I understand its advance works best if idle is set to 1200 rpms. We'll see how the bike runs once I get it back together.

Cheers for any insite. Goat`
 

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I'd certainly try a change of slides to get the idle to an adjustable place. If one side is running that much richer than the other to be a noticeable difference in color (and if it's upper range, as in WOT plug chop), I'd try changing the main jet on that side to get it closer. If it's just a little bit richer than the other, I suppose you could run a hotter plug - I've never felt that a hotter plug was a permanent solution. That comment was made to someone who asked a similar question but about both sides IIRC, and I mentioned getting the jetting closer then as well. If it runs really well when you're done, I'm not sure I'd be too concerned with a small difference between sides since you are running typically-unequal scrambler pipes - and of your own creation as well. It's not like you're dealing with high compression pistons or higher performance cams where you'd have a more difficult time getting the last few percent of max performance out of it
 

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Discussion Starter #3
I'd certainly try a change of slides to get the idle to an adjustable place. If one side is running that much richer than the other to be a noticeable difference in color (and if it's upper range, as in WOT plug chop), I'd try changing the main jet on that side to get it closer. If it's just a little bit richer than the other, I suppose you could run a hotter plug - I've never felt that a hotter plug was a permanent solution. That comment was made to someone who asked a similar question but about both sides IIRC, and I mentioned getting the jetting closer then as well. If it runs really well when you're done, I'm not sure I'd be too concerned with a small difference between sides since you are running typically-unequal scrambler pipes - and of your own creation as well. It's not like you're dealing with high compression pistons or higher performance cams where you'd have a more difficult time getting the last few percent of max performance out of it
Thanks for the info Ancientdad. What you say makes sense. The left plug was just that side of Rich to where I was questioning the color difference. Otherwise the bike ran like a champ and after pulling the motor and discovering I had lots of wear on my right Cam lobe and rocker and my machinist said the right intake valve was slightly bent. I have the Cam and Rockers at Delta Cam and getting a new intake valve. machinist is also cleaning up the cases, installing timeserts, and tapping the oil plate on the lower case to install screws. Rebuilding the kickstarter to as it was worn. Otherwise new piston rings, Hone was good, all new gaskets and cam chain tensioner.
 

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I can't imagine having a "slightly" bent valve - if it ran great and had what you believe to be normal power, it couldn't have been bent at all. Small volume combustion chamber, 9.5:1 compression ratio, any bend in a valve would cause more than a little loss of compression and power as a result. Personally, I wouldn't have removed the windage tray, I'd have found a way to clean up the lower case without taking it off the original mounting from the factory. I took my crankcases to a speed shop and had them hot tanked and as gunky as mine were, they came out beautifully clean. Delta should do a good job on the cam and rockers. Are you replacing the cam chain as well, since you're all the way apart?
 

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Discussion Starter #5
I can't imagine having a "slightly" bent valve - if it ran great and had what you believe to be normal power, it couldn't have been bent at all. Small volume combustion chamber, 9.5:1 compression ratio, any bend in a valve would cause more than a little loss of compression and power as a result. Personally, I wouldn't have removed the windage tray, I'd have found a way to clean up the lower case without taking it off the original mounting from the factory. I took my crankcases to a speed shop and had them hot tanked and as gunky as mine were, they came out beautifully clean. Delta should do a good job on the cam and rockers. Are you replacing the cam chain as well, since you're all the way apart?
The machinist showed me the valve and where it didn’t lap like the rest. It definitely looked different. Maybe that’s what he meant? New cam chain and metal rollers are soaking in oil right now. Delta cam just received the Cam and rockers Friday so waiting to hear on the estimate after his review. I found a new intake valve for $30. Should be here Thursday. 2 motorcycle shops I trust recommended this machinist and he’s been straight about the rest so replacing it per his recommendation.
 

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I've had an ongoing problem with my CL350 running too rich. I've tried about everything but lowering the float level more than the manual calls for (but I think I'm going to try that next). The B8ES plugs would eventually foul, especially after a lot of slower in-town riding, so I bought a pair of B7ES plugs and they don't foul any more...in fact, they now have a little brown on them instead of being black. I've ridden it that way for about 2 years now with no problems. That said, I have the original 1968/69 owner's manual and it calls for B7ES plugs, not the B8ES plugs that are the norm.

IMG_2139.jpg
 

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Hey AncientDad, I saw this in the post on a CB350 that could not reach above 65 mph. I'm interested to know about changing spark plugs to help with a rich/ lean condition. My engine is currently apart for a rebuild due initially for a stripped spark plug hole that I was going to have TimeSerted, still am on both holes since the machinist says they are stronger then the original head but getting back on topic. On my bike I had the spark plugs both running nice in tan with the exhaust at the time. 2-2 with Vintage VW Exhaust Tips. The bike ran loud as expected and would not pull over 7,000 rpm's.

I finally built a 2-1 exhaust after looking for months for the elusive and probably out of my price range Hooker 2-1. Benjie's was also out of my price range. The 2-1 I built uses a 1.5, 1.5 to 1.75 collector. I'm currently using an old Harley Muffler but am considering switchhing to a Cone Engineering Reverse Cone. I do understand this may change my jetting again and this also may make this discussion irrelevant to my situation but in the interest of learning, I'm curious.

I had my right cylinder running nice and tan but my left was running a bit rich but the bike rode really nice with it pulling to 10,500 rpms, would reach and maintain 85mph on slightly hilly terrian, and I could feel the "power band" kick in from 7,000 to 9,000 rpms. Keep in mind my set up was Mikuni VM30's running Thunder Products UFO's with a 3.0 Slide per the UFO instructions( only issue with this is the bike would only idle around 1600 rpms, no lower with the idle screws all the way out).

With that on to my left slightly rich left cylinder. Can this issue be resolved with a slightly hotter plug such as the B7ES. I have no issue changing jets, just curious on the hotter plug on one side versus the other. Of Note: I may change out the slides after I put the bike back together. I am thinking of switching to the Paamco Ignition system and I understand its advance works best if idle is set to 1200 rpms. We'll see how the bike runs once I get it back together.

Cheers for any insite. Goat`[/QUOTE
One other thing thing to possibly consider: the two into one exhaust system, coupled with the uneven spaced firing impulses of the 180° engine, one cylinder may be getting better scavenging(flow) than the other one.
 

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yeah Mike, that's what I was thinking with regard to the pipes he made... and really, all scrambler pipes that aren't matched length. Hey, if running one B7ES and one B8ES works, do it
 

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I've had an ongoing problem with my CL350 running too rich. I've tried about everything but lowering the float level more than the manual calls for (but I think I'm going to try that next). The B8ES plugs would eventually foul, especially after a lot of slower in-town riding, so I bought a pair of B7ES plugs and they don't foul any more...in fact, they now have a little brown on them instead of being black. I've ridden it that way for about 2 years now with no problems. That said, I have the original 1968/69 owner's manual and it calls for B7ES plugs, not the B8ES plugs that are the norm.
Never saw that in a 350 owner's manual, but I never owned a CB or CL either - only the SL350K1. Interesting
 
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