Hi. I`ve got fuel leaking out one of the overflow pipes, I`ve tried tapping the float bowls with little or no effect. I`m going to remove, strip and clean the carbs but seeing as I`ve never done this on a 900ss it`s a voyage into the unknown for me. The bike ran perfect last time I used it so a carb clean should be all it needs. Any tips, advice or pictures would be very helpful. I already know the float bowl screws are not the best quality.
This is a job I've done many times. Most important things are cheak float heights, emoulsion tubes for ware, diaphrams split, floats split and I suggest replacining all the screws with SS bolts. I think if you go onto Allen Performance web site, I think there is an exploded diagram on there, and if you need any bits that's the place to go. float height is a grey area, not much info on it but I would say 12mm is a good starting place. Just hope your mixture screws aren't sized!!
Thanks for that. Do you know what model of Mikuni carbs would be fitted to a 93 900ss? BDST 38? I`m hoping because it was running ok before then all it will need is float bowls off and a blow out with compressed air and carb cleaner. We shall see. I haven`t lifted the tank yet but I know there`s quite a bit of stuff to remove to get to the carbs. I want to have a go at sorting this but I`ll admit I`m a bit fazed by it, I`m sure I`ll be ok when I get started. I suppose if I fack it up I can always van it to my Ducati mechanic and he can sort it.
Do it carefully and take photos of everything as you go, before you dismantle anything............that's even before you can get the airbox off......ie; starter solenoid and coils mounting bracket...........plus four bolts that hold the airbox down (two at the back next to the frame and two underneath at the front). Same applies to the carbs..and photograph the cable routes and any wiring that you will disturb. When you reassemble, it's best not to tighten the manifold rubbers until you have the airbox back on and bolted down. But before you do anything at all, try removing some of the petrol from the tank......the overflows can run if the tank is filled up particularly if the petrol tank breather isn't working properly......try removing the breather valve and see if the overflow stops running (also shove a bit of strimmer cable down the stub on the tank........paint and shitty old rubber can block it) I've had two faulty breather valves (one was new).....if it doesn't release the tank pressure, it can pressurise the whole fuel system and petrol will run from the overflows.......once it starts, a full tank can just about keep the float valves open with the head of fuel in the tank, thus a siphon starts.
On the same lines how easy is it to remove the carbs. I've got a dynojet kit to drop in can i do it over a weekend or would it take longer. Sorry if I'm hijacking the thread just thought it relevant.
It all depends on how quick you work, I guess........ If.......(and I mean 'if').........you get the airbox off, you might just be able to fiddle the tops off the carbs off, so you can fit the spring and the needle; and then, on your knees, you might just be able to get the float bowls off, so you can change the main jet........ .........but that would probably be more difficult than taking the carbs off........ .....if you aren't going to be stopping to clean everything as you go along, you could do it in a morning...... This could be what is ahead for you.........mine was filthy........
Once you've done it, you'll understand how much of an arse it is. I can do the lot now in about 2-3 hours, but this is because I've done it around 8 times as I had loads of problems whenI first got my 750 running. Every time I've though what the hell am I doing when I was half way through!!
There's a knack to the cables. With them off at the carbs and the throttle, start by refitting the hardest bit first. 1 fit the return cable at the carbs 2 fit the return cable at the throttle 3 fit the open cable at the throttle 4 fit the open cable at the carbs 5 adjust I reckon I could change the jets in about 1.5 hours now having done it so many times.
I never take them off the twistgrip.....I slacken the locknuts and adjusters off.........makes it easier to get the cables back on the carbs (with some long medical forceps)... Now that mine is (was....bloody brake dust!) clean, I reckon I could easily do a Dynojet install in a morning, because like Lumbux, I've had the carbs off about five times now.
EEEK! sounds like a right pita. What are the unions I`ve arrowed in your pic and do they have copper washers? I`ve been quoted £350-ish for this job, that`s to remove, strip, clean and replace the carbs, that`s the price if it all comes apart with no rounded bolts etc.
The banjos are for the carb heaters, you may or may not have these, they are the same fittings as the brake lines.
If the carbs need parts, the cost could push that £350 up by rather a lot. Float assemblies are about £19 each; diaphragms around £15 each etc etc....
I did a 100 mile run today, fast and hot......Got home and left the bike in the sun.......about 10 minutes later there was a puddle of petrol under the bike even though the tank is half full....... Sho nuff, undid the filler cap, released quite a lot of pressure and it stopped dripping. Closed the cap and it started to drip again after 10 minutes. IMO Hot sun and hot engine, plus the decidedly dodgy design of the breather valve = pressurised tank and fuel system. Breather valve is brand new and blowing through it can cause it to stick open both ways or very hard to blow through to release tank pressure.
Well........it's all I can think it is.......float assemblies are new and they seem to work OK as when I tested them, they can only be overcome by about 12psi. But that means the breather valve isn't releasing the pressure in the tank at 12psi either. Fortunately I can switch my fuel pump off, so I can drain the carbs by letting the engine run....that seems to work as well.
