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Fist Time Rider - Issues with Idel and Throttle
Throttle slide
House, the slide"should" rest fairly close to the bottom, or carb floor. Make sure the cut-away faces the rear of the carb. See how well it works disconnected from the throttle itself(try it with just the cable) good luck....................D
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e3steve
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That's a symptom indicative of fuel starvation or the carb float bowl just about to become empty; when the 14:1 air/fuel mix gets weak/lean (less fuel/more air) the idle speed will increase. Like when you're sat at a traffic light, for example, if the idle starts to rise then it's usually a good moment to switch to reserve!........I got the bike to idle at a more reasonable level but after about 10 seconds of purring it'd suddenly and without any influence on my part surge and roar then stall out.
With the correct slide in the correct carb (CB / CL carb slides can be incorrectly transposed and installed into the "wrong" carb!) you should see a gap of about 1mm or so at the base of the slide's cutaway.Try as I might I can't find any pics that show where the slide is supposed to sit when the throttle is not being engaged.
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toastyhamster
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LOUD MOUSE
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My experience is that the engine when warm/up to temp can idle nicely at 900/1000 and not heat up.
Of course I make certain that I timed it perfect and adjust the carb/carbs to get there. ..................lm
Of course I make certain that I timed it perfect and adjust the carb/carbs to get there. ..................lm
toastyhamster wrote:What should a good idle speed be? And how long after starting from cold should the bike reliably stay at this speed?
I can get mine to idle just under 2k after about 5 minutes warming up in the garage.
Patrick, there are all manner of possibilities as to the problem and you seem to have dealt with most of them with all the good suggestions.
Sticky Throttle
The throttle should close completely when you snap the grip back to idle and you should be able to hear a slight click as the throttle slide closes. You have already dealt with the grip and the cable, but it's possible that the way the cable is touted is creating a tight spot. Are all the bends in the cable smooth and free flowing or did it have to go through any really tight turns?
Rising idle
An idle that rises suddenly is probably as someone already pointed out a lack of fuel. That could be a blockage in the tiny breather hole in the filler cap, or it could be the float valve is sticking and the carb runs dry.
Next time it does that, slip a small container under the carb and whip the float bowl off and see if it's empty or close to empty. Then open the filler cap and if fuels tarts to flow, it's the breather hole. If the floats are hung up, it's probably the gasket out of place and if the float is down, and it's still not flowing it could be dirt jamming the float valve.
Carb rebuilding
The guys have already mentioned not overtightening the bolts on the carb. The reason for that is that the flange bows when it's done up too tightly.
It wod be smart to take the carb off and gently and carefully lap that flange face flat. Just take a sheet of 400 grit wet and dry, and lay it on a perfectly smooth surface. Wet it with wd40 and slowly "sand" the flange face. Try not to let it rock, but keep it flat. After say 30 seconds, check the face. It will probably be shiny on the outer edges by the bolt holes and dull in teh middle. Continue unto the whole surface looks the same and when you lift it off the wet and dry, it will have a uniform layer of dirty WD40 across the face.
If there is a tufnol/phenolic spacer between the head and the carb, repeat on that and then replace the face O ring(s).
With carb beside the bike and not bolted in, slip the slide back in and see if it opens and closes smoothly and closes down to almost closed (small gap on the filter side and 1/2mm gap or less on the engine side).
Adjustment
There are two screws on the side of the carb. The one in line with the slide is the throttle stop or idle speed adjuster or whatever Honda calls it. Screw that out so the slide is all the way down. If the slide is hanging up, find out why. It may be a problem with the cable freeplay. Screw it back in until it just starts to lift the slide. It only has to be raised a "poofteenth" as a buddy of mine used to say.
The other screw adjusts the amount of fuel going into the slow running circuit. Screw it all the way in (not too hard) and then back out to the required number of turns. I don't know about your bike, but they are typically 1 1/4 turns out.
Refit the carbs and with clean points and plugs, you are ready to fine tune it.
Loud Mouse has a procedure which sets this all out clearly somewhere on this site. It's a good process to follow.
Air filter
Is it safe to assume that the stock Honda air filter is still fitted and in good condition? lack of a filter or a torn or clogged filter will make carb adjustment next to impossible.
Ignition
Clean and set the points. Throw in a new set of plugs and check the timing. If you do not know how, get a manual. Seriously. you will be amazed what you can learn.
Good luck
Sticky Throttle
The throttle should close completely when you snap the grip back to idle and you should be able to hear a slight click as the throttle slide closes. You have already dealt with the grip and the cable, but it's possible that the way the cable is touted is creating a tight spot. Are all the bends in the cable smooth and free flowing or did it have to go through any really tight turns?
Rising idle
An idle that rises suddenly is probably as someone already pointed out a lack of fuel. That could be a blockage in the tiny breather hole in the filler cap, or it could be the float valve is sticking and the carb runs dry.
Next time it does that, slip a small container under the carb and whip the float bowl off and see if it's empty or close to empty. Then open the filler cap and if fuels tarts to flow, it's the breather hole. If the floats are hung up, it's probably the gasket out of place and if the float is down, and it's still not flowing it could be dirt jamming the float valve.
Carb rebuilding
The guys have already mentioned not overtightening the bolts on the carb. The reason for that is that the flange bows when it's done up too tightly.
It wod be smart to take the carb off and gently and carefully lap that flange face flat. Just take a sheet of 400 grit wet and dry, and lay it on a perfectly smooth surface. Wet it with wd40 and slowly "sand" the flange face. Try not to let it rock, but keep it flat. After say 30 seconds, check the face. It will probably be shiny on the outer edges by the bolt holes and dull in teh middle. Continue unto the whole surface looks the same and when you lift it off the wet and dry, it will have a uniform layer of dirty WD40 across the face.
If there is a tufnol/phenolic spacer between the head and the carb, repeat on that and then replace the face O ring(s).
With carb beside the bike and not bolted in, slip the slide back in and see if it opens and closes smoothly and closes down to almost closed (small gap on the filter side and 1/2mm gap or less on the engine side).
Adjustment
There are two screws on the side of the carb. The one in line with the slide is the throttle stop or idle speed adjuster or whatever Honda calls it. Screw that out so the slide is all the way down. If the slide is hanging up, find out why. It may be a problem with the cable freeplay. Screw it back in until it just starts to lift the slide. It only has to be raised a "poofteenth" as a buddy of mine used to say.
The other screw adjusts the amount of fuel going into the slow running circuit. Screw it all the way in (not too hard) and then back out to the required number of turns. I don't know about your bike, but they are typically 1 1/4 turns out.
Refit the carbs and with clean points and plugs, you are ready to fine tune it.
Loud Mouse has a procedure which sets this all out clearly somewhere on this site. It's a good process to follow.
Air filter
Is it safe to assume that the stock Honda air filter is still fitted and in good condition? lack of a filter or a torn or clogged filter will make carb adjustment next to impossible.
Ignition
Clean and set the points. Throw in a new set of plugs and check the timing. If you do not know how, get a manual. Seriously. you will be amazed what you can learn.
Good luck