Srx440 roundslide carbs

Ok, we'll who ever installed the 38mm carbs must be blind. Here's what it currently has for jetting, try not to laugh.

1 carb had a 200 main, the other side had a 150. Huh?
The pilots are 350 on both
The needles are set at the middle position spacer on top and bottom
The air screws are 2 turns out.

They are definatly 38mm carbs, I measured. So can some one get me started on a base line jetting. Cause clearly this ain't even close. We are at sea level and average -10 degree celcious or 14 degrees farenheight for my south of the border friends.
 

i would start with turning the airscrews in a little at a time til it is willing to stay running without the idle having to be way up or in need of choke to start even when warm which is what it did the day i looked at it.if you end up turning them in to less than a turn out i would probably go up on the pilots.i would then raise the needle 1 positon until you get a feel for what it wants for fuel.it will let you know.i would also go up to a 220 or so maybe more on the mains to be safe and start backing it down after it does the big girgle.this is just my 2 cents and i'm sure others will have different ideas.i hope this helps,good luck!
 
Any suggestions for pilots, these carbs have the jets in the float bowl is that normal for 38mm
 
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Here are some pics of the jets.
 

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you need to come up with a starting point.look up a 78 srx 440 @ yamaha-motor .com to see about where to start with mains and pilots.i believe they had round slides.needles,set rich.you can make these work.i'm sure of it.
 
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The two mains are the 150 and 200. The 350s are the pilots il assume, they look alot like main jets, they are shaped nothing like the newer style long skinny pilots I am used to.
 
maybe you should get a set of 38's from a 90's polaris on ebay.that's what i'm going to use on mine.no funky carb heat or weird half size jetting like yamaha likes to use.
 
That 350 Is The Main Jet. The 150 Is A Power Jet. Thats Why Their In Bowls. You Can Start There. I Would Put Needles In 2 Nd Clip. Go With 40 Pilots. 3:16 (yammie Tony)
 
Ok now we are starting to make sense of it all I must have missed the pilot jet some where. Should the power jets be the same as one is 200 and the other bowl is 150
 
It has 42.5 pilots, picked up some 40s today, thanks to betheviper. We looked into the cylinder and it appears like there was some porting done to one side and not the other. May explain why it was jetted different on one side then the Other
 
In the photo (too small btw) they look like VM36s to me
Where did you measure?
Not much measures 36mm on a VM36
For instance on the 78-79 SRX the inside diameter of the VM36 outlet (engine side) measures just under 38mm (37.6mm)

BUT

When pushed to peak power your jetting will always be different side to side
No 2 cylinders are identical for a myriad of reasons
On the SRX the cluch side seems to run a bit hotter requiring more fuel
(mag side on an old-school Rotax SnoPro engine)
Not unusual
HTH
WOT
 
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it wouldn't idle and it took choke to keep it idling even after it was warm.seems to me depending on the airscrew settings,i would think it needed more pilot.
 
vmax carbs

I have an 87 vmax 540 L/C and it has the stock 38mm power jet roundslide carbs
I can take a pic of how they are set up for ya as far as the hoses go

your sled (I beleive) has throttle blade carbs stock...

here are the specs for a 87vmax and some side to side variance is normal as per yamaha service manuals...

Also check for a right and left stamping on them if looking at the opening it will be on the right side of the carbs one should have a R and one a L

-Dan
 

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