re: bike not starting, follow up from last week

[skram]

hey all.  thanks for your thoughts about my issue du jour, which is that the bike is almost entirely unwilling to start, almost all the time.  It's very, very fussy.  We talked about choke or not choke, how much throttle to give, etc. last time.  

Reality is, i don't think my bike likes to be choked very much--that seems to make it worse.  But I can't get it to reliably start almost ever these days.  It just cranks and cranks unitl the battery gives up.

So, remember that we did do a carb rebuild a couple of weeks ago, and I've got a new coil, wires and plugs.  By the way, I did remove my plugs during a recent episode and the left side one seems a bit 'wet' with i think gas.  I think this may be an important clue, but i'm not sure.    

Any thoughts. . . .?  

thanks.

[Bob_Roller]

Well, if the plug(s) are wet with fuel, first option is an ignition problem, with the plugs removed from the engine, and placed on the cylinder fins, when you crank the engine with the starter, what color spark do you have ?

Blue/white is what it should be, yellow/red/orange is not good .

If you have a multimeter, with the battery fully charged, place the leads from the multimeter onto the battery posts, crank the engine with the starter for about 45 seconds, and see what the battery voltage is while the starter is still turning .

If you have under 10.1 volts, or around that value, possibility exists, that the starter needs to be cleaned and lubricated internally, as it is drawing too much power, leaving the ignition not enough power to properly do it's job .

[montmil]

"...the left side one seems a bit 'wet' with i think gas."

First check for a spark at the plugs. Remove the plugs and secure them to the cylinder head. Insure good contact as you do not ever want to crank the engine with the plugs ungrounded. I use Irwin bar clamps; the ones with rubber feet on each clamp surface.

See if you're getting a nice spark when you crank the engine. If not, then begin checking all your recent ignition alterations. We need sparks to ignite that fuel.

Check back with the results...   Monte

[Bob_Roller]

I checked your previous posts, but you didn't mention what the replacement coil was, OEM, or aftermarket like Dyna .

[skram]

okay.  so after i recharged the bike, as recommended i checked the plugs, with them removed from the casing and the spark seemed white/yellow.

the new coil if aftermarket, a dynacoil i believe.

and what do you make of this:  after pulling the plugs to check the spark and then putting them back in, I started the bike, but forgot to turn the fuel petcock to on.  and the bike starts right up.  i've done it several times since--basically, not turning on the fuel until after the bike is running.  

In general, though, does it seem to you all that the bike might be runing very rich?  that i perhaps maladjusted something when redoing the carbs?  Problem with that though is that it was running remarkably well for a week after doing the carbs.  sorry. . .i'm rambling.  

[Bengt_Phorqs]

Just my two cents, but did you disconnect the choke cables when you rebuilt the carbs?  I presume you did.  The choke is really a "mini" carburetor and if either one is open just a wee bit it could be a problem.  Be very sure the cables are properly adjusted.  The Clymer manual has a detailed explanation.

[clouseau]

Do the plug wires have 1.5K ohm caps?
Is the old coil bad?  If not is it still around and maybe you should pop it back on and compare spark color?  Sounds to me like you're not getting a good spark.  Just had same problem...

One last thing.  Check that bean can. Mine went bye-bye along with the coil.  There is a procedure to test the bean can while it's on the bike.  The hall effect sensor in the bean can could be your culprit.

[weasel01]

okay.  so after i recharged the bike, as recommended i checked the plugs, with them removed from the casing and the spark seemed white/yellow.

the new coil if aftermarket, a dynacoil i believe.

and what do you make of this:  after pulling the plugs to check the spark and then putting them back in, I started the bike, but forgot to turn the fuel petcock to on.  and the bike starts right up.  i've done it several times since--basically, not turning on the fuel until after the bike is running.  

In general, though, does it seem to you all that the bike might be running very rich?  that i perhaps maladjusted something when redoing the carbs?  Problem with that though is that it was running remarkably well for a week after doing the carbs.  sorry. . .i'm rambling.  

 

Skram I feel your pain I just went though 2 weeks of carburetor hell after a rebuild ended up being an adjustment on the throttle plates.
the amount they were off was microscopic but it fixed my problem (Thanks to Montmil!!!!).

All I'm saying is you would be surprised how little (I mean teeny tiny) differences in adjustment or set up will catastrophically affect your engine.

I am a beginner at this bike wrench stuff but having spent 16 or so days in a row thinking about what could be wrong with my carbs.

I think your bike is flooded to the max.

When you removed your plugs the the flooded gas evaporated.

With the petcock off there was no pressure on your floats and so either the float valve(s) are malfunctioning or the enrichner (choke assembly) is either assembled upsidedown or the cables are adjusted wrong.

I had my choke cable off a few twists of the adjuster and it was very hard to start. readjusted so there is just a little (but equal) play in the cable and now it starts on the forst blip every time.