High Idle Problems

[ActiveRusty]

Thanks FOG

Could possibly look into one of theese carbs as they look pretty good and are very tunable to the looks of it thanks for your help

Possibly one of theese be good https://www.gasbike.net/collections...0-reed-valve-keihin-carburetor-clone-assembly

Or even better this https://www.bikeberry.com/engine-ki...ce-carburetor.html#product_tabs_review_tabbed

 

[FOG]

Both of those look like what I'd call a normal carb.

FWIW, Keihn carbs came on Honda's for just about forever so a decent clone should be fine. A wrinkle on that one tho is it also has a reed valve which would normally need a window in the piston? I wish the more directly experienced guys would check in. It might work fine without the window.

The CNS looks straightforward and I think I see an air screw back near the air filter. That's not the "usual" location but if it works who cares? Good reviews.

You might also look for Dellorto clones. Indian22 is a well respected builder around here and I believe he uses them on a regular basis.

And if the regular guys don't show up soon I'm gonna start sending PM's.

 

[indian22]

Rusty I read through all the posts and good advice given, but still idling fast with choke off and the slide completely closed. Is this correct? Will the engine eventually stall out with the choke closed?

Rick C.

 

[indian22]

The carb you have is a Dellorto clone. I'm not familiar with the brand though. I've had success with some of the clones and others just don't work out of the box. The real deals are well over a hundred bucks. The clones only external adjustment is simple idle that the screw raises the slide. Jet change inside the bowl and no float level to adjust. Very simple as carbs go,

If the bike idles with choke closed and slide completely closed and doesn't die air is entering in enough volume to pick up fuel with venturi effect and run the motor...no fuel pump just air flow principle. The only point of entry that hasn't been mentioned is the carb slide cap. It should have an O ring and seal tight the other spot is the throttle cable hole on top of the carb slide cap. The cable should have a tight fitting boot that seals air from being pulled into the carb from around the cable and the cable should seat firmly in place. Poor throttle cable tie downs can pull the boot out of place.

Air is entering the fuel system from somewhere or the motor wouldn't run.

I typically have several kit carbs on hand that I use to check that a replacement works. If you have one or can get one with a kit manifold you can quickly check if a new carb changes things. I'd stay away from a reed modification until after you figure this problem out....one thing at a time.

 

[indian22]

Either of those carbs should work, when setup correctly. Avoid using the reed for now, though the carb by itself is fine. Just understand that if there is an air leak other than at the carb the new carb won't help. Also when using WD-40 for air leaks do so with the choke closed so the motor is idling slow, then any change in speed is readily noticed. At run away engine speeds leaks are harder to detect.

Rick C.

 

[ActiveRusty]

HI indian22

The engine with the choke will idle fine for as long as it can but when i would put full throttle on it, it would die and like to stall out and this is with the choke on. The cap on the carb is made out of platsic and has a gasket in place. The throttle cable nice and tight. so yeah possibly getting air through another place like you said I can send photos of the entire carb to

Thanks

 

[ActiveRusty]

Photos

 

[indian22]

Good photos, the area I referred to is above the plastic top cap, where the throttle cable enters the carb. I would suggest wrapping the cable and fitting at that point to temporarily seal that area of the carb to see if that works.

Also did you actually fit an O ring at the manifold to carb connection as was suggested? This is the most common area for a leak. Also when tightening the carb to manifold be cautious not to over tighten or you will break the carb alloy housing and then you've no option other than a new carb. Also did you spray WD40 with the choke closed and idling? It's hard to know these things & eliminate the possibilities without some feedback.

Rick C.

 

[ActiveRusty]

Will try to wrap the cable with some tape so it fits snug in haven't done the o ring as Ii thought it wasn't need as the carb sliding onto the manifold is a pretty tight fit. I also did spray WD:40 with the choke on sprayed everything no change in rpms
Thanks

 

[indian22]

Thanks. Are you leaking any oil from the crankcase or cylinder? With the choke on and engine idling block off all air ,using the palm of your hand, from entering the carb. The engine should stall quickly. Do the same thing with choke off. This also should kill the engine.

Rick C.

 

[ActiveRusty]

No oil near in the magneto or clutch or head gasket as well exhaust gasket everything looks to be in shape just fine, besides a little oil dropping out of the exhaust as I'm still breaking in the motor I've done about 230km out 500km

 

[indian22]

Good that eliminates some more possibilities.

 

[ActiveRusty]

Aprreciate the help so far

 

[ActiveRusty]

@indian22 I also notice that when its hotter outside like it was 25 degrees today and it was idleing highing than like on a 15 degrees day

 

[indian22]

Rusty does the bike cruise well at various speeds and pull well through the whole range except for the fast idle?

Rick C.

 

[ActiveRusty]

yeah she runs like a champ I can just let the clutch out and it will just go and with atiny bit of throttle im doing about 30 and pulls good to nice and smooth and no it will stay at the same rpm crusing

 

[indian22]

I'll admit that trouble shooting problems long distance is a challenge, that said and if you've attended to each point mentioned including placing a proper O ring in the carb at the intake manifold juncture and sealed off the throttle cable connection at the top of the carb. I'd have to say the carb has a factory defect since some brands of these Dellorto clones are known to have very spotty reputations when it comes to quality especially noted over the last couple of years. It is a $20. carb, though some vendors such as Dax seem to be selling the good ones. I really like the simplicity of the real deal Italian Dellorto carbs that feature external jet change and high quality & high price, they too don't have much adjustability compared to Mikuni or Kehin carbs or even the various carbs which come with the kits.

Your carb is feeding plenty of fuel to the engine and plug chop you reported sounds good as well, you changed jet with no improvement which brings us back to air at idle. You never replied to my question about choking off all air to the carb at idle with your hand and that was important information! I'm not there to make sure these things have been checked properly so I'd suggest a different carb.

Rick C.

 

[ActiveRusty]

Sorry I must've missed it silly me lol I'll try covering it with my hand tommorow on the intake to see if that kills it and if does then it probably just a carb issue but I appreciate you taking the time to help me

 

[indian22]

No problem, but if blocking air into the carb kills the engine, with both the choke on and when it's off that shows what would happen normally with a good running engine. If it tries to keep running but eventually dies or if it just keeps running with the hand blocking the carb & pressed tight, that would indicate an external leak or leaks, in the carb most likely, or the engine itself. Since the bike and engine start and run fine other than at idle, my guess is the engine will try to keep running a bit with the carb blocked, but that's just a guess. There is a major air leak and I feel, another guess, it's the carb. Let me know one way or the other Rusty.

Rick C.

 

[ActiveRusty]

@indian22 It does die when I put my hand at the intake of the carb after about 2 seconds with choke and about 4 seconds with choke off

So what do you think?