Topic: Give me quick and easy thoughts on this

[Hush]

OK I'm working on this bike (generic bike not SOHC4) and it has an annoying problem, when I fire it up it starts first time but will not accelerate no matter how much you twist the throttle, activating the choke has no effect at all on this.
It's either a fuel delivery problem or a coil/plug issue.
I'm at the stage of just sitting and running a few scenarios before ripping it apart again.
I tore the carbs down when the motor was out, they shouldn't (operative word) be the problem, it ran perfect without air filters when I first got it, now it has the correct airbox.
I have used new gas since the rebuild, yeah I know I'm being extremely lazy asking for advice before going to far ahead but I have this niggling feeling that the answer is something simple I should know, sometimes we are too close to the problem.

[onepieceatatime]

Throttle cable is properly connected on both ends (connection points, or cable itself not broken)?
If not that, I would check the carbs again.
Good luck solving the problem.

[Retro Rocket]

Are you sure its getting any fuel above idle.? If its running and you twist the throttle and nothing happens sounds like only the idle circuit is working, if thats even possible.... If it was electrical or timing then it should just flood if it is getting fuel. Broken cable..? is the throttle cable connected at the bar end and carbs properly .? I know some of those may appear obvious but its happened to me and probably most guys here at some time..... .

[heffay]

by "accelerate", do you mean it won't rev up or it will not accelerate under load.
if it ran perfectly with no filters and you added the stock box, it would be too rich.
i fought a similar problem with jetting on my wife's ex500, just had to find the right jetting combo.
if a bike is too rich, it just won't accelerate.
now, if it won't rev out, period... i think your linkage is screwy... accidentally flip flop your throttle cables?

[grcamna2]

If it has CV carbs check you're vacuum slide for correct operation.

[heffay]

If it has CV carbs check you're vacuum slide for correct operation.

good point, i also had to get new diaphragms for that same ex500.

[Hush]

Hm yeah I had that same problem on a CB360 with CV diaphrams split but no this is an intermittent problem, if the bike is left for a while it will rev OK for a while which kinda tells me it is only getting enough gas to run the idle cicuits and I'm going to be going back into them carbs.
It could also have picked up some crud in the supply line as the tank was away getting painted for some time and may have injested some filth.

[grcamna2]

Motorcycles are Very sensitive to ANY bit of crud in the tank..,you know ? Imagine how many auto's would be in the repair shops if they had gravity feed fuel lines from the bottom lowest point in their tanks ??   It's easy enough for us to remove our M/C fuel tanks to clean them..thank God. 

[Hush]

OK had the carb rack off and tore them down, only thing of interest I could find was one float valve seems to have dislodged it's tiny keeper spring/pin thing that keeps it attached to the float tongue. Not sure if this happened during my dissasembly or whether it was in there like that.
Refitted them and after some coertion finally got the bike to fire up minus the airfilters, I wanted to see if it ran any better without the stock airbox, runs OK too so I'm thinking some bright spark has played with the air screws to compensate, now I'll need to go find the correct adjustments.

Found it, as per usual 2 turns out is initial factory setting.

[grcamna2]

Hush,
    What type of M/C are you working on ? I may have missed it if you already mentioned it.

[Hush]

Little 4 cylinder Suzi GSXR250R, think I got it cured but needed some level heads to bounce my ideas off, and you thought this site only worked for SOHC4 bikes lol.

[grcamna2]

lol..yeah those little engines w/ their little wee carbs are sensitive.

[Hush]

Damn, worked all day on this bike and got the airfilters on correctly for once, then it started playing up again.
My son came to give me a hand and we hooked up a clear tube full of gas so we could see what happened to the flow, well it scoffed it big time, we couldn't believe that any carb could keep up with that flow. Obviously this was what was happening, the carbs were being overloaded with gas and the motor couldn't keep up with it so was running at idle only, when my boy put his finger over the tube end the gas stopped flowing and after a few moments the engine picked up and ran well.
Tore it all apart again, benched the carbs and found the small "O" rings that surround the copper carb valve casings had perished, guess 14 years against a shed wall didn't help them, they snapped as I removed them, brittle as. I had a swag of new ones I bought for my partner's bike so all good there.
So now I'm too tired to go back out to the shed to put it all back together but tomorrow is another day (and last day of my holidays)

[heffay]

copper carb valve casings?

[Hush]

Um yeah best way I could describe it and my hands were covered in gas so the camera wasn't an option. I've struck this quite often esp on Suzukis from the 80's, where the float valve goes up inside the carb to shut off the flow of gas from the tank the actual float valve holder is a copper tube with a rubber "O" ring half way up to help it seal, these invariably (and I should have known better) go hard and fail after being left for a decade.
There Heffay, did that help?

[grcamna2]

Is it a slip fit float needle seat that has the parts you describe up inside the carb body and held in w/ a clip ?

[Hush]

Sort of, fiddley little sucker!

[heffay]

There Heffay, did that help?

Why yes, yes it did.   

[Hush]

New float valves arrive Monday.

[grcamna2]

Now....what did the old ones look like  ?

[Hush]

Picture Angelina Jolie braless in a tee shirt with ice water being tipped over her!
I really need to have my glasses on when I examine float valves, they were seriously malformed after sitting for 12 years in the stored bike.
Bike has only done a genuine 27000 k's since new!!!!

[grcamna2]

   LOL Yeah ! & they didn't even need a twist to get'em like that ? I like my old solid ones w/o the viton tips for that reason..especially w/ this stuff they're putting in the fuel now. She should run Sweet once you do that & adj./synch. them up !