carb adjustments

Odin · Post by **Odin** » Mon May 18, 2009 3:03 pm

ok so every things back together and running well, now I would like to set the carb's up properly.
the bike idles well and the carbs are sync'ed my problem is this,
how am I supposed to do a plug chop? I can't pull the clutch turn the key and hold the throttle open at the same time ( unless I grow a third arm

)
and locally I can't get the bike to 4th 5th gear and ride long enough to do it (live in the city)
does the bike have to be in gear and pulling load?
can I just leave it in neutral on the center stand and open up the throttle then kill the motor?
any help is appreciated thanks.

tz375 · Post by **tz375** » Mon May 18, 2009 3:47 pm

The motor has to be under load and pulling hard. The motor has to be up to operating temperature at that load level which is usually about 1/4 mile or more WFO.

The trick is to flip the kill switch as you pull the clutch in and as you close the throttle. That assumes you have a kill switch on the bars.

Revving it up on the stand doesn't get the bike under load and it's not hot enough. The plug must be up to peak temperature and that takes time and load.

An easier way is to measure time from say 40 to 60 (or 60 to 90) in top gear at WFO. Start rich and go down one jet size at a time until the time stops decresaing and then go back up two steps on the mains so it is a smidge rich. Check the plugs each time to confirm what is happening.

Throttle must be wide open though. if it's partially closed the results tell you more about needle and jet

You need a very quiet road with no traffic where its safe to measure elapsed times - and no cops or neighbors to complain.

parksie · Post by **parksie** » Tue May 19, 2009 2:23 am

Thats OK if you have a kill switch

Coyote · Post by **Coyote** » Tue May 19, 2009 7:36 am

Can be done easily on a dyno, but dyno time is costly.

Odin · Post by **Odin** » Tue May 19, 2009 8:50 am

No kill switch and the closest dino to me is in Vancouver (off the island) so that's ever more costly.
any other options?

H2RICK · Post by **H2RICK** » Tue May 19, 2009 8:56 am

How about rigging up a temporary kill switch ?? Aftermarket switches are only $8-$10 at your local small dealer....or maybe even cheaper at your local wreckers. Wire it in series with the main hot wire to your coils. There should be a double female bullet connector coming from the key to single male bullets, one to each coil. With some low rent standard bullet connectors you should be able to rig up something quite easily/cheaply.

Odin · Post by **Odin** » Tue May 19, 2009 8:46 pm

will look into that thanks for the idea Rick.

tz375 · Post by **tz375** » Tue May 19, 2009 8:52 pm

I should perhaps have made myself a little clearer. If you do the timed run from X mph to Y mph, you don't need a plug chop and you don't need a lot of expensive instrumentation. Just a stop watch on the bars where you can get to it.

Stop. Record the time and look at the plugs. they will be close enough to tell if they are miles off. That way you use the times to tell you what the motor needs rather than trying to read plugs

Odin · Post by **Odin** » Sun May 24, 2009 7:31 pm

Well here's where it stands, after yet another dismantle of the carbs and another cleaning, reset the float height and reassemble, this is what i dicovered. The left carb won't bottom out if i turn the air screw all the way in also it doesn't get as hot as the right side, which leads me to beleive this is why the left always looks rich its just not as hot.

what would cause one side to not bottom out yet not run as hot as the other side?

tz375 · Post by **tz375** » Sun May 24, 2009 9:51 pm

I'm confused by that last post.

The air screw adjusts the amount of air allowed to pass the pilot jet. Screwing it all the way in makes it rich (less air)

Slide adjustment is usually a screw on the side of the carb which when it's screwed in raises the slide and screw it out to allow the slide to drop.

Sometimes a cable is adjusted at the top of the carb so that there's insufficient slack and the slide cannot drop fully.

Which screw did you adjust - the air screw or the idle speed (slide) screw?

Odin · Post by **Odin** » Sun May 24, 2009 10:13 pm

both.
my bike is a T200 and the idle screw is actually at the top of the carb next to the cable.
according to the manual I have it says that if I turn the air screw (on the side of the carb) all the way in the cylinder will choke it's self out, then back the screw out 1 1/2 turns.

so I've done that, and on the left it bottoms/chokes out, then I back the screw out 1 1/2 turns.
on the right when I do it she keeps on running.

checked both cables and there is slack. the throttle valve's are synced and rise at the same time when I twist the thottle. also from wide open the valve's drop at the same time.

what symptoms would a bad neoprene seal on the starter plunger cause?

Post by **Suzsmokeyallan** » Sun May 24, 2009 10:28 pm

A bad seal on the choke plunger will cause the choke circuit on that carb to partially operate. If the spring is weak the same thing will happen, so make sure the seals on the base of those plungers are good and the springs are nice and strong.

H2RICK · Post by **H2RICK** » Mon May 25, 2009 8:06 am

A bad seal on the choke plunger will cause the choke circuit on that carb to partially operate.

To clarify Allan's comment a little: This means that that particular cylinder will run rich at idle thus fouling the plug when the engine is hot. This condition will also add a little fuel to the mix at part throttle.
Your problem with the one slide not dropping down properly has me perplexed. Maybe a bent idle adjusting rod ?? Or maybe the rod is from another carb of some sort and is too short ??

on the right when I do it she keeps on running.

You are definitely getting fuel and/or air at idle if this is the case. Start checking for air leaks. Check that starter plunger.

Odin · Post by **Odin** » Mon May 25, 2009 8:49 am

Thanks for clarifying that Rick. I will check the starter plunger first.
(after work tonight) and let you guy's know.

without a kill switch I've been adjusting by ride and feel, I know I'm close cause she preforms better then ever. I pulled the carbs to increase the main jet size cause at a steady speed the engine surges. (this was after raising the needle).

Odin · Post by **Odin** » Mon May 25, 2009 8:43 pm

It was the plunger!
now both plugs have a tan color.
now on Wednesday when I have the chance to ride I'll see if the larger main jet solved the surging engine when I try to maintain a constant speed.

thanks again guy's I will keep you posted.