650/X-2 87 650sx upgraded carb now issues start help

[gdrum]

87 650sx had fuel pump and 28mm

Upgraded to 44keihin got from guy said had stock 750cc jets in it from a super sport

Complete PAIN to start and once i get started it runs like raped ape. Ski feels twice as fast as before.

Suggestions...figured fuel delivery would be approximately the same for my 650 maybe need new jets? It's like I have full choke or use starting fluid and then it'll fire. When i shut it off same thing doesn't matter if warmed up or not.

Suggestions?

 

[WFO Speedracer]

Jetting specs are as follows or close 140-145 main,115-120 low speed 2.0 needle and seat with a black spring. you are looking for around 20lbs popoff.

 

[gdrum]

Not sure what that means learning all of this...does the jet settings sound like my issue or something else....start over turn in and out 1.5 each?

 

[WFO Speedracer]

Forget where the adjustment screws are at for now,it is not important, find out what jets are in the carb, until you know this you are going nowhere fast.

 

[gdrum]

^awesome thanks....and it will say when I pull them out?

 

[gdrum]

Big jet said k155 and little said k75. Could this be my nightmare to get it started issue? Where do I go from here?

 

[gdrum]

1.6 spring on big carb.....pulled jets from the 28mm it was 125 and 48 with 1.6. Could I use either of those?

 

[WFO Speedracer]

The kehin jets don't fit the mikuni carb and yes that is your nightmare , you pilot is way too small and the main is too big

 

[gdrum]

so then just order the jets you advised were needed above ? those are the same thats needed for a bigger carb? What do you suggest I order...and any places to order from?

 

[WFO Speedracer]

The jetting specs I gave you are for a 44 carb , you also need the correct needle and seat and spring for it to work correctly, it is a 44 right ?

 

[gdrum]

Its a keihin...i searched and found most people on this forum run a 42mm keihin .havnt found any 44s...not sure on size exactly. I am now starting to wonder if its a 42 as thats more common... I will see if i can find out. If it is a 42 what size then? similiar?

The needle/seat combo that is a 1.6 needs to be a 2.0 as well right?

 

[WFO Speedracer]

No totally different jetting on a Kehin, actually I would leave the 75 pilot jet and go down on the main to about a 140-145, springs for changing Kehin popoff are hard to come by but you can use Mikuni springs in them to fine tune the popoff pressure, you may want to seriously consider installing a primer kit.

 

[gdrum]

so just getting a 140-145 hi jet + tuning will solve my problem? its got a 1.6 size needle/spring in it now what route should I go with on that?

 

[WFO Speedracer]

so just getting a 140-145 hi jet + tuning will solve my problem? its got a 1.6 size needle/spring in it now what route should I go with on that?

You are stuck with the needle and seat size as it is only replaceable by replacing the whole piece that holds the jets, when you initially started this thread you said 44 kehin, its not a 44 its a 42, I thought maybe you had a 44 Mikuni, could have gone either way suppose.Did you enlarge the stock intake to the diameter of the new carb ?

 

[gdrum]

I got an aftermarket intake manifold. < no size adjusting needed as its just bigger

I can tune it and get it running good with the hood off, I Played with the jets yesterday..turned all the way in and turned each out 1 turn then adjusted acccordingly. With the hood off it runs superb!! Stick the hood on, throw in water and the nightmare begins..starts dies repeat repeat until finally can get it to slowly engage on the throttle and then it will finally hit high end and take off.

Your help is appreciated on this. Ive learned a ton thus far lol.

 

[WFO Speedracer]

Well of course the obvious is to check the hood to see if the air passages are blocked by dirtdobber nest etc, you can do this with a hose pipe, direct water into the air intakes in the hood and see if it come out where it is supposed to, the not so obvious is that you may have an exhaust leak, even a slight exhaust leak will wreak havoc on your tuning, with the ski on the trailer and the hood on, crank it up , let it warm up for a second and then rev the bejessus out of it, turn it off and quickly remove the hood, if there is any sign of smoke you have an exhaust leak and need to find out where its coming from.

 

[gdrum]

some oil was dripping from my oil injection hose, got in the water and lightly coated the bottom...when water gets in there i bet it hits the muffler and creates a air thats not what it should be...great catch..ill have to clean this

i switched and got blockoff plate

any suggestions on if i should order jets to better it or leave it and thats not my main issue?

 

[WFO Speedracer]

Check what I said in the above post first before rejetting anything.

 

[Vumad]

They always run better on the trailer because they don't have to do any work. Leave the ski strapped to the trailer, back in until the entire pump is under water, run hood off. If your problem is not present then it's more likely to be a hood blockage/exhaust leak. If the problem is the same as when you were trying to ride before then the problem is more likely to be a carb/compression issue.

If the latter, check your plugs and see if they a really dark or lighte. Dark is rich, light is lean. Squeeze the throttle, if it feel like it is trying to shut off it's lean, if it sputters it's rich. Best test is to ride around at 1/3 throttle for 1 min and check the plugs for color.

Check your compression. If salt water testing, make sure you don't have electrical issues.

You're just guessing on your jetting. If it runs enough to ride then get a few sizes of jets larger and smaller than whan you have and try them. Always start by going richer. Too much fuel is much less likely to hurt the motor than too little.

 

[Vumad]

some oil was dripping from my oil injection hose, got in the water and lightly coated the bottom...when water gets in there i bet it hits the muffler and creates a air thats not what it should be...great catch..ill have to clean this

i switched and got blockoff plate

any suggestions on if i should order jets to better it or leave it and thats not my main issue?

If your pipe can turn the oil in the water in the bottom of the hull into smoke that chokes the motor, you have a major cooling issue. An exhaust leak would be from the pipe, gaskets or hoses. Oil/gas in the hull could create a fire hazard but is unlikely to cause a carburation issue.

In anycase, get and oil injection block off kit and go to premixed fuel.