View Full Version : Carb question

03-08-2007, 09:38 AM
First off, let me say I have not yet had the pleasure of riding this particular bike, so it's quirks are a mystery to me.

I need to pull the carbs again and see if I can get any more gunk out of the wee passages. It won't start without a shot of starter fluid but will idle by itself after that. It also bogs and tries to die if you crack the throttle more than a sliver, but it will rev if you coax it up. I figure I just didn't clean it good enough. I also need to double check the floats.

When I had it open the first time, I noted that it's sporting 130 main jets. The bike has an aftermarket 4-1 with a yoshi can, stock airbox with a k&n.
130 seems a bit rich to me (especially since I live above 6000 feet) It looks like it has a stock needle (only a single groove) and no additional spacers.

So the question (finally) is whether I should bother dropping in smaller jets while I have it apart again.

I'm hoping one of the pros here can toss it on the mind dyno and get me close :)

03-09-2007, 03:15 AM
Not sure on the jets . 600's seem to use larger than 750's stock , and I tinker with 750's :lol: . But , I'd check to make SURE there are no air leaks , all rubber bits fit nice & snug , and the synch is done after . If it'll run and get warm , you can synch it . I'd BET though that if it'll only start with starting fluid , it's either the pilots ain't set right , or there's still crap in the lil holes in there (leaning towards "crap") .
How do the plugs look with those jets in there :-s ?

03-09-2007, 09:52 AM
The old plugs were pretty fouled, but I don't know if it was fouling at idle or mid or high.
The new plugs haven't been in long enough to show anything other than wetness, which is probably floats.
I gave it the wd-40 test and it didn't change rpm so I'm pretty sure everything was buttoned up tight.
I also did an "eyeball" sync, and all the pipes seemed to be at about the same temp.. (I didn't want to leave my fingers on too long :) should be close enough to start up.
I set the mixture screws 2.5 turns out.

I'm going to give them another cleaning this weekend and see if anymore gunk comes out

03-09-2007, 12:02 PM
I don't know what year you have but it's worth pulling the mixture screws all the way out and checking the orings.. Shooting carb cleaner up there is a good idea too

03-09-2007, 12:18 PM
check your slide boots, could be torn!!

I find that to be the problem with what you explained.

Special K
03-09-2007, 09:40 PM

I know its a long read, but it will walk you through things:

Should help a bunch.

Tear them apart, clean everything with more than a fine tooth comb, then be meticulous about putting them back together with everythign set just right.

There are LOTS of helpful hints in my write up.

05-13-2007, 12:02 AM
Just some closure and some info for those who may be in the same boat as me.

After tearing into the carbs so many times I got quick at it, :) I got the bike to the point where it would fire right up with a little choke and would for the most part idle by itself.
However, I ran into the nasty idle problem where the idle would increase by itself and rpms dropped very slowly.
I took this to mean a lean condition, so I ordered a Motion Pro 90deg screwdriver. My intention was to attempt an idle drop mixture adjustment. Sadly, either my tool was a POS or I'm just a 'tard but I couldn't get the screwdriver blade to engage for anything.
I got tired of futzing around with it, so I just started to richen the mix up a 1/2 turn at a time. (Pull the carbs off, turn the screws, put 'em back on)

My final adjustment was 4.5 turns out! The throttle is snappy and responsive and there is gobs of power 3k+ (Enough that my '06 gixR 6 friend was pleased with it)

The plugs show a very slight rich mix, but no fouling, so I'm going to leave it alone with the 130 jets and just ride :) (I've since replaced fork seals, chain/sprockets, and flushed the brakes)

Now I need to chase down a clutch/tranny problem... :P

05-13-2007, 06:46 AM
That motion pro tool is not all tea and biscuits..

I ground off the step in the flange thingie.
Then drilled a hole in the tip and inserted a pin.
The flange was supposed to lock onto the collar of the FA screw hole, but it won't work with the Kat..

The pin keeps the head from disappearing down the tube.

05-13-2007, 03:54 PM
I tried grinding the flange off, but didn't even consider pinning the screwdriver blade. lol I was just so pissed about the wasted $20.

I'll try pinning the blade.. maybe I can dial the idle mix in a little tighter


05-13-2007, 04:35 PM
Yeah the tip is not hardened.. I pinned it with a piece of copper wire (so it would slide ok)