SRX250 won't start [Archive] - Kiwi Biker forums

jleahy23

14th January 2009, 00:47

Hey All,

I bought my SRX250, and opposed to what I was told it doesnt start. (Although I got it $100 cheaper than what I was originally told.)

Now, I haven't gone digging very deep yet, but basically wanted to get a basic troubleshooting list. Here's the back story.

The bike has been sitting for around 2yrs, now when I arrived there the guy had a can of "Start Ya Bastard" and we sprayed it into the air box and cranked it. Broooom... It started then died. So the engine isnt ceased and ignition etc is working.

One thing I couldn't make sense of is the fuel tap with the three settings ON, RES, PRI. I'm assuming the following RES = Reserve, ON = Main Fuel On, PRI = Prime. I had it set to ON when I was attempting to start it. I'm guessing this is correct.

Thing's I've tried.
Emptied fuel and put fresh stuff in.
Checked fuel filter - OK
Checked air filter - OK

Where should I go from here?
I was going to pull the carb off and clean it all, but if there's anything simple please let me know. Especially if there are common errors with the SRX that I'm not aware of.

Any help is appreciated.

Cheers
Jono

LBD

14th January 2009, 03:02

Mate it sounds like a fuel problem, but first check that there spark. I assume there is because it ran on a can...

Loosen the drain screw in bottom of Carby...Fuel come out?

When cranking but no start, can you smell gas from exhaust? If you cannot smell gas but you have a spark, remove and clean the carb. Check float and valve working, check jets are clear then try again.

NinjaNanna

14th January 2009, 08:17

Try starting it in the Prime position, also check that the fuel filter is full (my wife's little ZR250 is a bitch if it isn't and then suffers from vapour lock)

FYI: ON and RESERVE require vacumn pressure from the engine to allow fuel to flow (basically the vacumn sucks on a little diaphram in the fuel tap.

The Prime position allows the fuel to flow straight through (which with everything being equal then fills the Float Bowls of the Carb)

PS where abouts in Canberra are you (Bruce's Motorcycles in Mitchell were good when I lived there)

Ixion

14th January 2009, 09:23

I would drain ALL the fuel out and throw it away. Also drain the float bowl as above. Add new fuel and put the fuel tap to 'P' (prime). Leave the carb drain plug open. Let about a cupfull of fuel run out the carb drain, then close it.

Check the old fuel for muck, if there is any you'll need to clean the fuel tap and maybe the carb.

Connect a car battery across the bike battery (like a jump start). The SRX is very sensitive to low battery voltage, and a battery that is slightly down will turn the engine happily but not start - the car battery gives you a lot more crankability.

If it won't start after a few minutes cranking you'll need to strip the carb. But I think it should be OK.

jleahy23

14th January 2009, 18:00

OK...

This is what i've done.
I've emptied fuel tank (fuel seemed OK - not dirty). Filled it up with fresh stuff. Also just made sure that the fuelcock was working (which it is - my leg likes petrol on it... :P) I took the little brass screw off the bottom of the carby - no fuel came out. Anyway, put it on PRI and started cranking away, still no fuel coming out of bottom of carby. Put the screw back in, started cranking away again. Took the screw out again and guess what... NO FUEL.

So where to now guys? Carby off and clean??
- If this is the case, whats the easiest way to get the carb off??

Cheers
Tubbs

Ixion

14th January 2009, 19:28

Assuming you got the right screw (it's the recessed horizontal one on the left, not the big round vertical one on the right, I had to go and look myself on that) , the inlet filter may be blocked , I have a vague memory they have a mesh filter at the carb inlet. Or the float valve may be stuck or the float may be jammed. Anyway, you're going to need to take the carb off.

Straight forward. Remove fuel lines, removes throttle cable, undo clip thingies and wriggle twist and pry . The carb is jammed into a rubbe rmanifold that is bolted to the head, you'll probably find it easier to undo the manifold bolts and remove the complete assembly.

As carbs go, there's reasonable working space.

jleahy23

14th January 2009, 19:48

Thanks Les,

I got the carb off, will start pulling it down and cleaning it all out now.
- Will keep you all posted with my progress.

Cheers
Jono

jleahy23

14th January 2009, 23:57

NinjaNanna

15th January 2009, 07:52

OK...
Success - Kind of...
Well it started, BUT... after about a minute of running she stopped and I couldnt get it started again.

I started it on PRI, with full choke. And left it on prime. I think it might've put too much fuel in and flooded it maybe.

Anyone got any ideas? or do you think try tomorrow.

Cheers
Jono

So did you release the choke??? It's pretty warm at the moment so its possible that it died simply because you left the choke on after getting it started.

Also technically you can leave your fuel tap on PRI the whole time (so long as the float valve is working correctly) but it is best to use the other positions otherwise you'll ride straight through RES and run out of fuel. If the float valve isn't working you could lose a tank of fuel through the overflow or worse through the cyclinder into your engine oil (depending on the design of the bike)

Also my first impression before considering the choke was that its run out of fuel again (ie you haven't properly sorted your original problem which was preventing fuel getting to your carbs in the first place)

jleahy23

15th January 2009, 18:37

OK, have had another attempt to start it, with no luck.
I took it out the front and tried to push start it, it sounds like its half running then nothing.

Also, Have checked that there is spark at the plug.

Carb off again?

Ixion

15th January 2009, 21:34

Yes. Fraid so. Remove, strip, clean, blow everything out with compressed air (I actually use the canned air from computer shops, it's easier and cleaner than the compressor - but pricey ) . Check the diaphragm on the right hand half too. If it's any consolation , you won't be the first to pull a carb off many and time again. I had to pull the carbs off my arzhole about 97 times before I finally got them clean.

If it started, that would to me probably rule out electrics. Unless you have a dodgy connection which is intermittent, but if you are seeing a spark that's unlikely. I would try a new plug though the one you have may be pretty munted. What does the plug look like ?

Have you tried ether spray again , sometimes with these situations the trick is just to get it running anyhow and let it work itself clean.

jleahy23

15th January 2009, 22:52

Tried spray again - Nothing.

Plug is brand new, I replaced it last night just to rule it out.

Will play around with it tomorrow arvo/weekend and let you all know.

jleahy23

17th January 2009, 18:44

OK...

Pulled the carby apart and cleaned everything, soaked it in fuel for a while as well.

Put it all back on, now its leaking fuel from the drain plug. I've checked that the O ring is still on the drain plug and everything.

Oh and by the way - still not kicking over!
Getting sick of this thing already!

Ixion

17th January 2009, 18:57

OK. Ti me to dig deeper. Bikes been parked up for 2 years you said. Now, maybe there is just something as a result of the 2 years idleness. Blocked carb jet (I know, you cleaned them , but sometimes you have to do it MANY times). Stuck inlet valve,whatever. Or maybe it was parked up because it wouldn't start two years ago? There's a big difference.

Bike requires to run: spark, at the right time; fuel, in correct air/fuel ratio; compression. Give it these three and it MUST start. So one of them is missing.

Leaking fuel from the drain plug. That's a smoking gun. Either the float/shut off needle is defective, or it's maladjusted or incorrectly assembled. Fix that. Bike won't start if the fuel level is that high. Either there was something wrong there to start with (maybe wrong two years ago?) or you did something wrong in your previous carb assembly.

Then check compression. Hard to get a gauge reading on those engines the plug is deeply recessed. But pull it forward in gear get a feel of whether there is compression. You should not be able to push it in first gear with the clutch engaged.

Spark is the easiest. Check for a spark. A good blue spark. Check that it is happening in about the right place, TDC on the compression stroke, or a bit before (your finger will tell you if it's the compression stroke, mine is calibrated to +/- 1 psi , but you don't need accuracy here )

FROSTY

17th January 2009, 19:49

Im beting that the little seive is full of crude--the one in the carby

quickbuck

17th January 2009, 20:02

Im beting that the little seive is full of crude--the one in the carby

Yep. It can look like white sugar, and be as hard as caramel. This substance will not let petrol past it.

jleahy23

17th January 2009, 20:59

Yep. It can look like white sugar, and be as hard as caramel. This substance will not let petrol past it.

I have had the carby appart twice now and havent seen a seive in it.
Anyone know where i should be looking?

FROSTY

17th January 2009, 21:32

Have a look between the fuel line and the float valve
I'd be checking that the float valve is goin up n down like its sposed to -thats an area affected by varnish build up
Also whe ya say youve cleaned out "all" the jets you have removed the needle and the pipe it slides down havent ya?
Im also wondering if you should pull your fuel tap out of the tank--maybee its also crudded up
Hey Um silly question but you are blowing all the orifices of the carb out with high pressure air arent you?

Ixion

17th January 2009, 21:48

You said before that there was no fuel reaching the carb. Now, that fuel is overflowing out the overflow drain. That, to me, would point suspiciously tOWard a float or float valve that was jamming. Initially jammed in the closed position now jammed in the open position.

The SRX250 carb is a wierd and wonderful thing, basically a slide carb and a CV carb combined into one. It has many little passages. All must be claer. blwo them out with compressed air or canned air fROm a computer store

jleahy23

18th January 2009, 08:02

I'm thinking of going to the Yamaha dealer here and ordering new jets, needles and float valves.

Does anyone think this is a good idea, and if so, is there anything else i should be ordering?

xwhatsit

18th January 2009, 10:50

I'm thinking of going to the Yamaha dealer here and ordering new jets, needles and float valves.

Does anyone think this is a good idea, and if so, is there anything else i should be ordering?
Stuff like that is easy enough to clean and see that it's clean. Those are just small brass removable bits you can pull out anyway. I'd check float height and whether the float valve is actually sealing first -- you can do this with the carb stripped and the float bowl off -- just plug it into the fuel line and manually move the float upwards with your finger and see where/if the fuel flow stops out of the float valve.

The float's not leaking, is it? It'll be plastic and they don't generally leak but just check there's no fuel sloshing around inside it anyway.

Ixion

18th January 2009, 13:05

If the internal apssagewyas are blocked replacing the removeable bits won't help.

What you can do is find a dealer that has an ultrasonic cleaning bath. That'll clean all the bits that can't be reached .

jleahy23

19th January 2009, 22:21

NinjaNanna

20th January 2009, 07:37

OK Guys,
I took it apart, and there was a bit of rubber in the float valve .....

When its running, warm and no choke it kinda pulses, as in it'll sit around 1500-2000rpm for a while then go up to 3-4000 revs, then back down.

Any Ideas?

Find out where that rubber came from and you'll probably answer your own question

Ixion

20th January 2009, 10:22

jleahy23

20th January 2009, 20:08

Had a look at the inlet manifolds and both look in good shape, no cracks or anything. I have bought new O rings for where they join onto the head, just incase it's leaking there, also bought new O rings for inside the carb to replace the one that seems perished. Could it be a fuel hose with a nic in it or something?

Also, when it is running with choke on it idles fine, but doesnt rev nicely, choke off it surges but revs nice.

Ixion

20th January 2009, 20:13

Fuel hose, no. Needs to be on the inlet side. Perished or torn diaphragm might. With the motor running , spray engine start carefully (carefully ! don't blow y'self up!) onto possible suspect points. A bit at a time and take it slowly. When the engine races, that's the spot.

It could be tight valves, but they don't tend to move much on those motors. Also try smearing some grease here and there, see if that stops it.

And also, sometimes the best fix for that sort of thing is to take it for a hard ride, cane it, then tighten everything up once it's cool again. It's sat round for years, it's all mucked up inside.

EDIT: Oh, and check the air filter.

jleahy23

20th January 2009, 20:20

Ixion

20th January 2009, 20:22

Yeah,
I have a new air filter on the way from yamaha, should arrive tomorrow. I'll chuck these new o rings on and see how it goes. Will also try that engine start trick. Could it possibly be the vacuum hose going from the secondary inlet to the fuel cock leaking?

Yes. that's a distinct possibility. Block it off , as near to source as possible, and run on the P tap setting, see if it fixes it. Any thing that lets air inot the engine without going through the carb.

jleahy23

20th January 2009, 22:14

Hey Guys,

One other thing I thought of, could it possibly be exhaust related?
Just while im testing things out...

Cheers
Jono

Ixion

21st January 2009, 10:30

Only if the exhaust valves are too tight.

jleahy23

21st January 2009, 23:15

thanks for that mate,
i replaced the air filter and it seems to have fixed it.
i've noticed if i dont leave the choke on long enough it stutters and farts when its off... but im guessing thats semi-normal..

wired00

28th January 2009, 16:31

OK Guys,
I took it apart, and there was a bit of rubber in the float valve preventing it from closing properly. I cleaned it out and put it all back on.

Guess what - IT STARTS!

Now, tuning...lol.

When its running, warm and no choke it kinda pulses, as in it'll sit around 1500-2000rpm for a while then go up to 3-4000 revs, then back down.

Any Ideas?

nice :) i was scrolling through the thread about to suggest double check the floats. You mentioned back in the thread there was no fuel in the float chamber really the only explaination is that the float is jamming closed and not allowing fuel to fill in when you have the tank on PRI :) Anyway glad you fixed that part

With the uneven revs maybe check these :

1\ check over the pilot fuel and air jet again(!) Make absolutely sure its clean. It could be the pilot is blocked and not letting correct air or fuel through when idling

2\ Check any holes going into the float chamber are clear and that the float mechanism isn't sticking. This would cause uneven flow of fuel when idling. If the vacuum port is blocked it might cause uneven fuel flow because not enough vacuum is created to suck fuel up into the venturi

just my 2 cents :)

Edit: Oops you've already solved with air filter. nice :)