Topic: Partners Suzuki 400 WTF?

[Hush]

OK so we got all togged up for a ride today, me on the old 650 Honda and Jaffa on the GSX400L.
Last time we tried to go riding mine spewed petrol (all fixed) and hers died from battery drain (all fixed), this time we got around the block and she called out she was taking it home.
The bike was spluttering and the gears were hard to engage?
Anyhow we get home and the 400 spills gas on the drive, no big deal my Honda used to do that all the time, but after getting out of our riding gear the gas is still there, it should have evapourated.
So I get a closer look and it's mainly oil?!
When we bought this bike last year it had a sump full of petrol/oil mixed, we blamed the PO for leaving the gas in the "prime" position and changed oil and filters.
Today again we have a sump full of oil/gas mixed, does anyone know why this would happen???
My best guess is the petrol tap which is the vacuum type and has only "prime, on and reserve" is leaking in some way and allowing gas to flow 24/7 filling the carbs then over flowing into the air box (which was full of gas/oil too) then running past the valves and into the cylinders and down into the sump.....does that theory hold water???

[crazypj]

Did you check the vacuum diaphragm in tap?
 There is a plunger attached to it with an 'O' ring.
 Seats get corrosion and don't seal, diaphragms wear and leak (which makes life fun as you get rich mixture and lean mixture left/right at low/mid which may just go lean at mid/upper rpm)
 You'll have to pull tap apart to check, also make sure the pressure sring is in correct place, should be between outer cover and diaphragm.
 I'm pretty sure you can get new diaphragm/tap repair kit.
 There are two types, early was single diaphragm, later had dual diaphragms and a 'sandwich plate'
If you have early type, just look for 'new' tap

PJ
 

[Hush]

Cheers Crazypj, have had this tap apart a few times and cannot find any faults, I'm thinking why don't the floats seal up and stop the gas going any further?
Also wierd is that these carbs don't have over-flows?
I mean if they over fill it has no where to go but either backwards into the air filter or forwards into the combustion chambers?

[Hush]

I have had so many bikes through my shed lately I honestly can't remember if I removed and cleaned the carbs or not?
Anyhow they are about to come off so I can figure this puzzle out, can only be really badly set floats or leaking float valves I'm guessing.

[scunny]

ahhhhhhhhhhhh, carb heaven. have a good day Hush 

[Hush]

Hi Scunny, yeah well quite a productive day in the end, I'm having to start thinking Suzuki again which is kinda wierd after working on Hondas' for so long.
The carbs came off easy as (Suzuki have that over Honda) the airbox slides waaaay back to allow the carbs to just drop out, I cleaned them up and reset the floats (one was way out) and thought I'd done a good job but just to be sure I popped down to the local Suzuki dealers for a chat with an old friend who is pretty much God when it comes to bikes.
He said same as I guessed that it had to be either the gas tap allowing the gas to flow down or the float valves failing, he aslo warned that Suzuki have "O" rings around the float valves and they go hard over time.
I went straight home and pulled the suckers apart again and sure enough the float valves had tiny "O" rings that looked OK but when I tried to remove them they flew apart, so they weren't doing much!
I replaced them (box of assorted "O" rings from Supercheap $5) and the one on the gas tap diaphram.
Ran out of time tonight as I had visitors over but will know tomorrow if I've worked a cure.

[manjisann]

What I can't figure out is how you've already forgotten the most important lesson you learned while working on your bike.... Let Jaffa fix carbs!! 

Good luck Hush, hope they are fixed so you can all enjoy a nice ride!

Brandon

[Hush]

Bike fired right up sweet as, still hates to be weened off the prime on the gas tap but took it for a spin, nearly lost it on a corner when the gas (I'd turned the tap to off by mistake) ran out and she got into a nice sideways slide any speedway rider would have been proud of.
Damn I hate that Cheng Shin rear tire? It's just bloody dangerous I reckon, it's gotta go, can't have Jaffa sliding off like that, she hasn't got the experience these days to recover the bike.
In the mean time I'll see if I can adjust the rear brake to be less severe when it gets stood on.
Those "O" rings seemed to have cured everything else so fingers crossed I don't end up with a sump full of gas again.