View Full Version : srx250 valves and carb-like thing

Dangerous Dane
4th July 2006, 10:05
Hey there, after killing one of my head bolts and rocker cover gasket in the first couple of days of owning my bike I started pulling it apart.

First question: Can anyone give me the torque settings for the headbolts?
Second question: How the hell do I do valve clearances!? Its not like a car!

After putting new gasket and helicoils in I took a look at the carb. It was running rough as the rubber manifold thing had a couple of big holes in it.
I took it off and fixed that up but while looking at the carb it seems that one side has a butterfly valve and the other a piston type carb setup.
Now the clown who owned the bike before me had takne off the airbox and put two pod filters on "for looks" (you cant even see them...) By doing this he left alot of hoses disconnected etc.

Am I right to assume that the second carb is controlled by a vaccum hose that would usually go into the airbox? It seems like this carb hasn't been working.

I've now pissed around with it, taken the jets out and cleaned everything up etc. I put it back on the bike and tried to start it but now it just sprays petrol everywhere! Can anyone tell my why?

Cheers in advance!

4th July 2006, 10:22
One carb is a standard slide type,the other is a CV.They work well when properly set up,trouble no one knows how they work and so fuck them up.Set yourself the task of figuring them out and you'll be one of the few who knows how to get their SRX moving.The tappets use over bucket shims...easy peasy.Go back to a standard filter,the pods will kill it.

Dangerous Dane
4th July 2006, 10:33
Yeah I'm trying my best. Is it right that the piston type carb runs off the other carbs vaccum though?

Yeah I'm trying to track down the airbox. Easier said than done.

I didnt pay the last owner enough for him to want to go out of his way for me..

4th July 2006, 10:37
No,it runs on engine vacuum - study it Grasshopper,with frustration comes enlightenment....

Dangerous Dane
4th July 2006, 10:51
Trying my bestest. Its proving quite a task to find a manual and no one at the yamaha dealer has a clue about them Cheers though!

4th July 2006, 11:54
Here's a copy of the carb manual for an SRX600. It should help you identify the parts and hose connections even if the settings are not the same.

Ixion also runs an SRX250 and may be able to help.

Good luck!

Dangerous Dane
4th July 2006, 12:26
Yeah that should be a help. Thanks!

4th July 2006, 14:05
The vacuum (CV) carb should not kick in until about one third throttle. I've found it best to tune by ear to avoid a flat spot. Set the little adjusterscrew between the "carbs" so that it kicks in with the twistgrip about one third round. Pilot jet about 2.5 turns out I find, but it seems to vary from bike to bike. You'll definately need to fix the holes in the diaphragm. And yeah, stick the air box back, or make form from a biscuit tin.

I'll PM you the torque settings when I get home tonight.

Sprays petrol everywhere? You've put something back wrong, or left it out.

(Valve clearances are straight forward , normal bike style. What Mr Motu said. Timing marks on the rotor (through the little hole in the left hand cover) and a mark on each cam, on the nearside boss, that lines up with a casting mark on the cam bearing )

EDIT: Oops. LEFT hand cover, not right, silly

5th July 2006, 18:43
Valve clearances = 3 - 5 thou inlet, 4 - 6 thou exhaust (cold)

Cylinder head bolts = 29 ft lb
6mm ditto 7 ft lb
Cylinder head nuts 14 ft lb

Head cover bolts 7 ft lb
Oil drain plug 31 ft lb

Mental Trousers
5th July 2006, 19:41
I didnt pay the last owner enough for him to want to go out of his way for me..

Sounds like you already paid him too much bud.

Dangerous Dane
6th July 2006, 08:31
Yeah cheers for that, I couldnt find anything on the net for it.

$760 for running with reg and wof? He was after far more than that.
Doubt its had much maintainence but its my fault it blew up...

Need a faster bike.