Rich or Lean - I am confused

e3steve · Post by **e3steve** » Sun Sep 28, 2008 4:54 am

I am going to try a new set of points. I noticed that with the pts cover off, while I was turning it over, that they sparked quite a bit.

Hey Bryan, points' sparking is either the condenser breaking down or the contacts' faces are contaminated. First, clean them up & reface them with a flat needle file (equalising file) or Emery cloth/Wet or Dry to get rid of any 'peaks'; then try grounding the coils' bodies with a temporary piece of wire; byrdman had a similar problem http://www.honda305.com/forums/viewtopic.php?t=3274 a while back; this was his remedy.

If this doesn't stop the arcing, change the condenser.

G'luck.

PS: you might find this topic helpful: http://www.honda305.com/forums/viewtopic.php?t=3336

bj · Post by bj » Thu Oct 02, 2008 2:56 pm

Sweet!

I put in a brand new set of points and condensor. Now the bike runs better than ever. Fires right up, runs smooth though the whole throttle range. But, it still is running rich. After a 5 min ride, the plugs are already black and sooty. The exhaust looked ok. Started from cold with no choke.

I am not complaining though. It feels great to finally get it running descent. Good enough to put into my rebuild and see if I want to go through a complete rebuild on my other engine. I'd take it for a few good rides on my parts bike, to see how it holds up, but I don't trust that bike. I haven't gone through it yet.

Now if I could get rid of the richness issue. I guess I will fiddle with the carb again. I think most of my problems before were ignition related.

Thanks,

Bryan.

e3steve · Post by **e3steve** » Thu Oct 02, 2008 5:16 pm

Hey Bryan, a step in the right direction with the ignition parts! Cool!

I just re-read your original post; the 26mm carb on the 77 requires a float level of 22.5mm, not 26.5mm -- that's the level for the 22mm carb, á la CA72.

Give it a try?

Steve

bj · Post by bj » Thu Oct 02, 2008 8:59 pm

Thanks,

I have it set at 26.5 now. I moved the needle down (clip up) today also, one notch to 4th position. I didn't really notice much of a change. It still ran good, but is fouling the plugs. I suppose I could move it down to the last notch.

As far as start up, moving the needle doesn't have much effect. Is that correct?. For start up and idle it is the slow jet, right?

I have read many times that these motors shouldn't start when cold without choke. What would be the remedy? Smaller slow jet and main jet?

Bryan

e3steve · Post by **e3steve** » Fri Oct 03, 2008 2:22 am

Did you read Bill's scribe that I posted for you http://www.honda305.com/forums/download.php?id=1489 earlier in this topic? I'd say your carb is shagged. Follow Ed's or Bill's setup advice to the letter: 22.5mm float height http://www.honda305.com/forums/download.php?id=1494 (measure from the lip, not from the recess indicated by the red line), air screw 1⅛-turns out, needle clip in the middle groove. Start again from there. Clean the plugs, idle the motor for 5-10 mins with no filter & see what the outcome is with the plugs then.

Then clean the plugs once more and take the bike out for a 15-min ride, avoiding allowing it to idle; inspect the plugs again. If they're still fouling, then I'd say that the needle jet is ovalled or too large.

Also, have you checked the floats for pinholes? If the float isn't floating properly then the fuel level in the bowl will never be correct.

If it still starts from cold with no choke and runs fine, it's too rich; drop the needle a notch at a time, but bear in mind that the idle jet is what predominantly sets the mixture at idle. I think I recall that the position of the needle doesn't have overriding control of the fuel/air ratio until around ¼-thottle and above. If the plugs only foul up on idle, turn the air screw out to weaken the mixture. If they only foul up after a ride, drop the needle a step.

If I was tuning that bike, I'd: clean the carb out with an air nozzle> clean & gap the plugs> check that the floats float> set the float level> start at 1¼-turns out on the air screw (in view of the fact that it's known to run rich)> run the motor to 'warm', adjust the idle screw (not the air screw) to attain a fast idle (around 1500rpm) then turn the air screw in (richer) until the rpm decays; then turn it out (weaker), ¼-turn at a time, until the rpm restores and then starts to falter. Note the ¼-turn (or ⅛-turn for more accurate results) counts between these two points and turn the screw back in by half that count. Clean the plugs again then idle the motor for 5-10 before inspecting the colour once more. If the colour is good (sandy), then ride for a few miles and inspect yet again to see if the mixture is enriching via the needle jet. It is long-winded but it's the only way to eventually get it right. You can't short-cut vital adjustments.

Ed should chime in with specifics regarding the single carb motor. I can get a CB running sweet, pretty much, standing on my head, but the C/CA needs somewhat different, if less, attention.

bj · Post by bj » Fri Oct 03, 2008 12:22 pm

e3steve,

Thanks for reposting the technuckle article. After re reading the part about the needle jet, it seems like it describes my problem.

Is it possible to replace the needle jet? How? Or do I need to find a new carb body?

Thanks again,

I wouldn't be able to do this without your guys help.

Bryan

e3steve · Post by **e3steve** » Fri Oct 03, 2008 12:55 pm

Bryan, get a genuine Honda C/CA77 carb service kit -- other guys here will be able to point you in the right direction as to from where. Take the carb off the bike and strip it, getting to know it intimately -- where various jets and orifices are, the jets' metering numbers etc. Unless your carb had been stood with crappy or gooey old fuel, or moisture, for a long time, then the body may be redeemable. Re-jet and re-needle it as per the book. Someone on this forum must have the correct jet/needle metering numbers from a Honda or Silver publication or from experience, for sure.

If you need a carb, Ed, or another forum benefactor, may have a PW26 for sale.

G'luck!

Steve