Author Topic: Carb Mayday (Read 4556 times)

JT_Flash · « **on:** June 21, 2007, 11:09:45 PM »

Ok so; I have a 1989 Bandit 400. Had an RG250 for a couple of months but tested the 400 and fell for it straight away. Heavier but puts out the same power in a nice linear progression (with a bit of high rev howl for good measure). As I told the bloke I bought it from, "I like my bikes like I like my women... about 18 years old and naked..."

I want to admit up front that I'm basically a mechanical retard but I love the bike and am having huge troubles sourcing parts for it.

I recently had the needles replaced using the Factory Pro Stage One Carb Kit. The old ones were worn to a point that the mechanics involved in the switch were almost speechless (my bad, kinda left that one for a long while). They've told me the emulsion tubes are worn too. Is there somewhere I can source those or is that one of those "cut your losses and get new carbs" type of issues. And I've been told the valves need a good clean.

The bike is running rich at the moment. The idle is around 2300rpm (cos it loses revs and stalls when idling lower than that), and when taking off at the lights I've got to feather the clutch and rev to the realm or 5500-6000 before it gets up the guts to go. There is also a sort of hesitation when accelerating below 6000, almost like the bike loses revs and then engages again.

Was wondering if anyone had any good theory's as to the main causes and any suggestions as to good places to source parts or whether it's just best trying to get all necessary parts to replace the carbs completely?

I've been looking posts by gsxr400 racer and BrianM, but I've gotta be honest, when they get technical I can't follow it.

I get that the carbs are Mikuni BST32's.

I looked at www.carbparts.com and I checked out https://www.carbkitscapital.com/carb_kit_list_part.php?make=Suzuki&cat=Carb_Kit

At Carbkitscapital the GSXR1100 (89-90) Carb Rebuild Kit. Includes the following, Float Bowl Gasket, O-Rings, Float Needle & Seat Assembly. Doesn't mention emulsion tubes... I'm totally out my element here.

Any advice would be greatly appreciated.

BrianM · « **Reply #1 on:** June 22, 2007, 12:38:35 AM »

I think I've seen the emulsion tubes listed somewhere... but it was almost Certainly at the pointer from Jay.

Have you had all the rubber bits (2 o-rings and 1 rubber plug pert folat bowl, and then another o-ring in the diaphragm) replaced? Those are the Notorious issue with running rich. Also, how far above sea level are you there? More than ~3000' (what's that, just shy of 1000 meters?), you'll likely want to drop the pilot jet one size too. Last thing is what are the air/fuel mixture screws set on, if more than 3, they're way too rich aswell.

It takes time to work out carb issues if you're not using a dyno/EGA. I'm still fussing with mine (though I'm at least in the ball park). Looking at tearing into them again this weekend for some more fine tuning.

JT_Flash · « **Reply #2 on:** June 22, 2007, 01:25:40 AM »

thanks Brian, the highest point in Brisbane is 300m above sea level, so I doubt elevation is an issue.

I think I'll order that gsxr1100 carb kit and try doing all the rubber bits. (Thanks for dumbing it down too)

gsxr400 racer · « **Reply #3 on:** June 22, 2007, 06:40:14 PM »

www.bikebandit.com is where i get mine from. if they wont ship to you i will. email me for any needs
cheers
jay

turbofb · « **Reply #4 on:** June 23, 2007, 01:04:16 AM »

Couldnt hurt to give Factory Pro a shout to see if they can source the tubes.They have a fair bit of experience with tuning the B4, from what I could tell.
They are a common problem on older bikes,both my FZR's had moderate wear on the front edges of the tubes, from the needle rubbing.

duane · « **Reply #5 on:** June 23, 2007, 04:56:30 PM »

I think Jay's right. 28-2 on Bike Bandit's list is what you want. It says it's still available.

PitterB4 · « **Reply #6 on:** June 24, 2007, 12:15:49 AM »

Quote from: "duane"

I think Jay's right. 28-2 on Bike Bandit's list is what you want. It says it's still available.

They were still available a year or so ago when I got mine.

gsxr400 racer · « **Reply #7 on:** June 24, 2007, 10:51:52 AM »

still available from bike bandit as of a couple weeks ago

JT_Flash · « **Reply #8 on:** June 24, 2007, 11:50:51 PM »

Holy Crap! You guys are really helpful. Thanks guys I'll see how i make out with the info so far.
And thanks Jay, if i've got any shipping issues i'll email you.

JT_Flash · « **Reply #9 on:** August 07, 2007, 03:11:46 AM »

Rightio, so I've finally got my credit card ready, and waiting and want to order the parts (lots of delays thanks to a wedding).

It would appear however that I've missed my window...

Part 28-2 no longer appears on the list.

Are the emulsion tubes going by another code on the new list or am I sh*t out of luck?

If it's option two are there any other sites you can reccomend?

Banditmax · « **Reply #10 on:** August 07, 2007, 04:54:34 AM »

Go to the schemtaic for the 1992 model and 28-1 is still available.

gsxr400 racer · « **Reply #11 on:** August 07, 2007, 11:57:04 AM »

yes all still available
cheers
jay

JT_Flash · « **Reply #12 on:** August 11, 2007, 11:00:02 PM »

Thanks again guys, the parts are on the way.