Carb mixture adjust

[finmac]

So I've finally got some action getting my bike running as it should. A neighbour put me in touch with a couple of motorcycle gurus. Took the carbs to them, opened em right up there and cleaned them out. Couple of interesting things- first that the carbs werent syncd, second a small bit of aluminum was blocking one sides' jet, third and much to my surprise, the brass plugs over the mixture adjust had already been drilled out! The mechanic set them to three turns out...is that about right for stock jetting?

Also, are the mixture adjust screws accessible once the bike is all back together??


Fin

[Jarrett]

So I've finally got some action getting my bike running as it should. A neighbour put me in touch with a couple of motorcycle gurus. Took the carbs to them, opened em right up there and cleaned them out. Couple of interesting things- first that the carbs werent syncd, second a small bit of aluminum was blocking one sides' jet, third and much to my surprise, the brass plugs over the mixture adjust had already been drilled out! The mechanic set them to three turns out...is that about right for stock jetting?

Also, are the mixture adjust screws accessible once the bike is all back together??


Fin

Yes they are accessible with the carbs on the bike.  3 turns out might do it, it might not.  It's something you have to play with to get right.  And you probably want to consider a rejet.  Do you know what size jets you have in right now?

Edit:  Give us a little more info as to how the bike was running before the carbs were cleaned, and the number of miles on the bike.  You could need more than just a rejet.

[finmac]

Well, a couple things were happening before I put the bike away for the winter.

1) Cold starting took many many cranks. I would try leaving the petcock in the prime position for a bit, but that didnt help. It just took a whole lot of cranking and throttle twisting

2) Once it began to start, it'd die pretty quickly. I could keep it from dying for about 10 seconds with throttle. Itd have to start and die a few times before it would respond to continuous throttle input.

3) Once warmed up, bike would not idle. Would have to keep some throttle on when stopped. Idle adjust screw (once warmed up) set to 1500rpm, throttle hangs or races bigtime (I attribute this to carbs not being syncd?)

I will be putting in one sized up jets before I re-install as I have a K&N stock replacement filter

-Fin

[NiceGuysFinishLast]

Uhh.. it's HARDER to start a cold bike with throttle.. that's what your choke is for

[finmac]

whats a choke? you mean like choking the chicken??

[The Buddha]

No more like ... sprinking the chicken with more gas in order to wake it up.
Cool.
Srinath.

[NiceGuysFinishLast]

whats a choke? you mean like choking the chicken??

[finmac]

So what you guys are saying is maybe that my choke isnt functioning properly? Could it be clogged or something? I'm hoping now that the carbs have been cleaned, that the choke will be more effective.

I think I was dealing with a set of interrelated problems- that it wouldnt idle properly and that JUST using the choke to start wasnt enough to get it started. If its not going to idle with or without the choke....its not going to idle.

Does that sound reasonable?

Fin

[NiceGuysFinishLast]

You should also rejet.. stock jetting is lean, which makes it harder to start on a cold day.

As for whether or not the choke is stuck.. look at the carbs, and pull the choke.. does the little slider move back and forth?

[Jarrett]

Sounds like a jetting issue.  It could also be a valve issue.  Tight valves are a nightmare.  The bike wont start quickly, and it wont stay running without full choke.  Check your valve clearances.  Hold off on the K&N till you get the bike running well.  It will not help.  It will add another variable in an equation that has a result of bike running like crap.

Your diagnosis should look something like this:
Tackle the carbs first.  Clean them, clean jets, synch them.
If you still have probs, then tackle the valves.  Get them all within spec.  Your bike should be running well at that point.

After you're done with all that, then play with jetting and air flow.