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· Registered
31 Posts
Discussion Starter · #1 ·
could a broken petcock vacuum be the reason my bike constantly floods... after 15 minutes the thing bogs and wont go past 2k?

gone through floats, jets, o rings, clean tank.. all fuel related things. I know I shouldn't expect a 1998 to run like a 2020 but it always seems like right after you fix one thing... boom there goes another. let me know what you guys think and what I can expand on.

just last night I did the floats 8mm and it ran great! idles for 20 mins and then i'm pretty sure it floods and can't start it.
THIS morning started up but couldnt rev past 2k bogging, smoke (grey) not water vapor...

couple days ago I hydrolocked it.. got it free by taking plugs and cranking gas out.. maybe some coolant or gas got past the piston rings and thats a problem. I should change the oil out because theres a chance some gas is mixing with it.

MY SUSPICION is that after I adjusted the floats, i looked at the needle seats and they looks pretty ragged.. like something that the needle may get stuck on. Does this seem like an explanation for the excessive flooding? It's really hard to tell whats wrong with this thing.

Have at it see what ideas y'all got.
appreciate you all,


· Likes to race old junk.
3,047 Posts
It will be difficult to pull the bowls off the carbs, while still on the bike.

Pull the carbs off and test them on a bench.
You need to remove the bowls and supply fuel to the carbs.
Place a drain pan underneath, it's going to get messy.

This is no different than the magic that occurs in your toilet tank.
You should be able to observe, that by moving the float upwards, the needle will seat and fuel will stop flowing.

Welcome to working on old bikes.

· Premium Member
8,256 Posts
again, needles must be NEW, same for seats, find titanium needles, good bronze alloy seats, good chemical resistant o'rings or this will be back, I already know, the rubber tipped are junk, a waste...

also what are you measuring float height with and HOW, what position? the spring on the needle is just depressed then you measure height from the 2 spots the manual describes, carbs at the angle the manual describes, IMPORTANT..

my 600 runs better than new bikes so these bikes can run very very good... no jokes

however ethanol is hard on carbs, some chemical they put in it is destroying rubber and corroding hard parts, avoid ethanol if at all possible, Efree is way better, otherwise you are going to go through this every 8 months or so, first time you let it sit for a few months its all over unless you perform the steps I told you..

I've been wrangling it for 10 years now and I just got it under control, getting into my FI bikes like I said my Busa gas went sour in 4 months, 4 fookin months! I had to dump it bike would hardly run, I have a FI 750 where the gas is gel and tank rusty, fun fun fun shoulda kept the Tbird..

post up some pics of the ruler on the carb at the angle you are measuring, be sure to level out the lens so we can tell whats what, usually you can rest the carb(s) on a flat surface and they are perfectly at the 45 degree angle then its just a matter of putting the stick in the right spot and taking the reading, if its off bend the tang till they are all the same and nutted, start with 7 this time, you did get the petcock sorted right? pics of all that, the entire fuel system.. did you overhaul the pump or is it stock? you might want to take a PSI reading to make sure the pump isn't pumping too much pressure.

service manual has that spec.. its a low pressure system

pics of the assembly

pics of the needle and seats, macro

this can be done this bike can run like a champ I already know, took me 8 years but it is possible..

pics pics pics
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