Seems I have a problem with idle.

Re: Seems I have a problem.

http://www.sparkplugs.co.uk/pages/techn ... g-code.htm

The P is a projected insulator type, not having it could potentially result in less effective ignition of fuel/air mixture, especially on our bikes with their "super powerful" spark lol

 

Re: Seems I have a problem.

Awrighty. So, I got new plugs, NGK BP7ES. They do protrude into the chamber quite a bit more than the ones I had before.

I tried to start, and it spun, but didn't fire. I put the charger on, and it fired almost right away. That kinda looks like my battery is too weak to provide decent spark.

 

Re: Seems I have a problem.

One more time...

New plugs, fully charged battery. Kept charger on, just in case.

Started. Synched at 1000 (maybe a little higher)
Ran just fine at 1000 for a few minutes with the choke completely off.

I gave it gas, it revved and came down. Three times.

On the fourth it revved to 4000 and stayed there.

Seriously, what the hell?

 

Re: Seems I have a problem.

Maybe it's the 550 next to it that's doing this. They made a deal over the winter and the 550 wants to get ridden first. Yeah. That's it. Or, it's haunted.

 

Is your bike by any chance named Christine? 8O

Sorry but I'm almost out of ideas if it was definitely firing on all 4 when you set the idle....

Have you tried turning the idle screw down when the revs jump up? Maybe be an idea, Does it have any effect?

 

Idle screw is all the way out. I unscrewed it till it was loose and then just got it to start, so it's in the threads.

I'm back to wondering if there isn't something wrong with the valve train...

This is where people typically talk about how much they hate carburetors, but I'm not wholly certain that's the problem. I know damn sure with the amount of work I've put into them they were done right.

 

I think you still have an airleak somewhere...see also:

http://www.xjbikes.com/Forums/viewtopic ... art=0.html

 

So it's still able to rev to 4000 with the idle screw backed all the way loose (so it's not touching the throttle at all)?

That, to me, suggests sync far out. As in, needing bench sync far:? Strange as you running sync'd it...

An air leak *is* a possibility, but this would cause the revving symptoms only if there was extra fuel available too...

 

And... I'm a moron.

I just realized I forgot to plug the YICS just now, so the sync isn't really a sync.

 

You got that syncing feeling? :roll: sorry couldn't help myself

 

You put your YICS tool in
You take your YICS tool out
Then you do the hokey pokey
And curse everything around


Re-did sync this time remembering the YICS.

Same damn thing. Climbs to 3000.

 

Can't remember if you said you tried to sync without the YICS tool or not, it would be interesting to see if it would make any difference.

 

Yes, that was just done not an hour ago quebecois (by accident, but didn't fix anything) That's the reason I brought out my best syncing pun

 

I understood that he sync'ed with the YICS tool in but the YICS chamber opened, it doesn't mean the same to me that with the chamber closed but without the YICS tool in. Do I miss something here?

 

Either you missed something or I did, I read "forgot to plug the YICS" as he forgot to use the YICS tool.... Could be either, but I'd think having the YICS passage open would be glaringly obvious in the way the bike ran...

 

That would be correct. I had the plugs in, and the tool out.


(Heh. "My tool was out". In some jurisdictions that's indecent exposure... )

 

Start over.

Re-do your bench sync, ensuring that you have enough adjustment left on the main idle adjuster knob to back it all the way off and then some.

Double-check all your intake manifolds while the carbs are off. Re-verify your float levels, wet. If they're good, re-checking won't take long.

BE SURE THE BIKE IS FULLY WARMED UP before doing the running vacuum sync.

And don't make the mistake I'm sure we've all made: DON'T OVER-ADJUST. Tweak, blip, allow to settle. Nudge, blip, allow to settle.

Tweak, nudge. Not "crank" on the screws. If you did a decent bench sync doing the vac sync will only involve some very SMALL adjustments. You can drive yourself right out of range if you're not careful; then all you can do is...

Start over.

 

Talked to a guy who suggested that the problem might be needle valves that are not sealing and letting too much gas in.

I haven't replaced the needles, they looked to be in good shape. Can looks be deceiving and this be the case?

 

what did you use to do your bench sync(s)? I though you mentioned a paperclip or wire? That would open up your butterflys too much. use a strip of business card paper.....

 

also, what's your plug color like?

 

No, that wasn't me. I used paper.

I'll check the plugs.

 

Well What happened?