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Plug fouling and idle issues

amc49

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I gave there, no need to get the last stab. Where's all your talk of getting along with people now? Thanks only and I would have been gone.
 

dirtdigger

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No ones making you come back all the time. You have no idea how many complain about you on this forum to the moderators. I'm tired of talking people into staying and contributing to the forum because of something you said to them. No matter how much I preach you dont get it. Your the only one that people have a problem with, maybe that should tell you something. Just sayin.
 

wkong

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Update: relay has been installed so I’ve got battery voltage at the coils. Float valves will arrive today so I’ll set those first and see how it runs, then check the lift with the dial indicator.
 

wkong

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And I’ll just say, it’s true amc your responses weren’t exactly inviting for a first time poster. The “you’re wrong and if you don’t listen to me you’re also stupid” sort of stuff isn’t what people are looking for when they’re inexperienced with these bikes and need help.
 

wkong

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Alright, it’ll hold a steady idle and sounds good at 1100. Still can’t use the choke to start or warm it up or it sounds like it’s flooding, all four plugs are a very light tan so bumping the idle jets down to 38s and trying the choke doesn’t seem like a great idea.

Did the clear tube fuel level check and got 3mm below the mating surface in 3&4 and 7mm in 1&2. I triple checked all the float heights before installing and they’re the same, seems unlikely that it’s a float height problem innthat the carbs on the same fuel inlet are the same level but I can adjust the heights on 1&2 if no one has a different recommendation.

Ideas?
 

dirtdigger

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Ive never used the clear tube, I always just use my honda float gauge. If you do indeed have different levels then that is a problem. You are checking on the center stand not the side stand correct? To me your numbers sound really high.
 

wkong

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Ive never used the clear tube, I always just use my honda float gauge. If you do indeed have different levels then that is a problem. You are checking on the center stand not the side stand correct? To me your numbers sound really high.

Sorry, it wasn’t a float height problem. The fuel line to 1&2 went uphill. Once I routed it correctly I see all fuel levels even and at the correct height. Dealing with carb boot leaks at the head now. New boots, 46 and 44mm clamps don’t seal it well enough. I can’t even crank the 44mm all the way down so I’m at a loss. No leaks previously so the spigots on the heads are sealed.
 

wkong

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Just got 0.355” on the inlet side and 0.311” on the outlet. Getting the dial indicator set perfectly in line is harder than I thought and the slot for a flathead screwdriver on the top of the tappet makes it worse.
 

wkong

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Okay tried a flat tip (duh.), got 0.315 inlet and 0.312 outlet. I don’t know if the rocker arm geometry ends up reducing the lift at the tappets or increasing them, but these look really close to stock
 

wkong

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So keeping in mind the fact that they don’t move in a straight line, adding a curve to that measurement would increase it just slightly, but the fact that I’m using a flat edge to measure something that starts with one angle and ends with another (then barely reducing the movement), it should be real close to the numbers I have. Sound about right?
 

wkong

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Plugs all look good and it idles great! Choke still doesn’t help but it warms up quickly. I’m not worried about the tappet adjustment after seeing those numbers. Thanks everyone.
 

dirtdigger

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I still dont get why your choke does work....putting the choke on once the engine is running should literally kill the engine....unless you have a huge vacuum leak. Maybe post some pictures of the choke plates open and closed, maybe can see something you are missing.
 

wkong

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It does kill the engine if the engine is warm and I put the choke on. My problem is it doesn’t act like a more modern choke in that it won’t start or idle choked when cold, but that seems to be a common problem with very early carbs. I verified no light was getting through at all when they’re closed and they were raising in sync.
 

dirtdigger

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If these are the correct round top carbs for the 71 then there is not a fast warmup idle system on these. You have to increase the throttle setting manually to keep it running when cold. These are old school, the choke is just that a choke, all it does is restrict airflow to make the mixture rich it doesnt do anything to throttle position. More modern carbs open the throttle just a bit as the choke is put on to raise the rpm to compensate for the cold engine etc.
 

wkong

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Yup, exactly what I’ve learned. Why I chose an early 70s bike with four carbs to be my first to try to rebuild I’ll never know. Probably should have had a running one next to it to see how it worked first. Oh well! It’s all good now
 
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