Carburetor Help

[sfc]

So I started thinking about changing out the stock carburetor and I got the obvious stuff like the PAIR, though I don't know what to use to plug it at the engine, and the cooling system, I'm going to use a coupler to loop it. But I didn't think about the throttle! What the hell do I do about that?

Here is the carb:

www.sudco.com/catalog105/114-115.pdf

I'm going to need all your pistons firing to get this thing in and running.

Thanks

[sfc]

I've stumbled upon another problem. The carb is too long. The bottom hits the engine block before it even lines up with the manifold intake. It is 2.118 inches long from the bottom of the exit mouth.

[sfc]

I got the rubber boot on the carb, I've got to get another sized clamp, no biggie. I put it on the manifold intake and the carb does hit the engine. It will be resting on the engine.

So now what?

[sfc]

I got a piece of rubber and gasket sealant to put on the engine block to keep it from hitting metal to metal. I think the biggest hurdle I'm going to have now is the throttle cable. I need a normal throttle cable that is going to fit into the ruckus handlebar lever and long enough to reach back to the carb. The problem is that motorcycles have their engines mounted really close to the the front of the bike where as scooters are in the rear. It would probably be worth looking at the vespas et4 cable and see how that worked but I may end up just modifying the end of the cable I have, though that creates some other questions because of the large metal piece will be difficult to manage.

I just had another thought that maybe the bigger ruckus 250 goes into a normal carb...I'll check it out.

Where did Dandy Dan and Chanito go? Ruckster? or Abe?

[chanito]

;D Congrats on your mods, so far you are doing OK, about the cable, you can reroute the cable so instead of going thru the center of the handle bars it just hang into the batt cover, that will give you a couple of inches and probably be enough. Sorry i did not got in earlier, but i been extremely busy

[Ruckass]

Chanito, what about the throttle position control sensor when switching carbs? Is it affected and need to be adjusted?

Ruckass

[sfc]

I found a website called motionpro.com who specialize in cables and the such. I am going to contact them tomorrow and see what they have...even with the extra inches it is feet too short. I will report tomorrow what I find.

Chanito,

Can you look at the picture of the carb and tell what the 2 tubes coming off the carb are for?

I posted the link in my first post.

Thanks

[sfc]

Talked to Joe at Motion Pro and they talked me into shipping them the throttle assembly, OEM throttle cable, and the Keihin Carb. They will make me a custom cable for $30 plus shipping that will be calibrated for my specific assembly and carb. I figured the cable would cost me 20-30 anyways so getting it for 30 and it will be perfect sounds pretty good to me and will save me hours of calling and driving around to motorcycle shops trying to find something.

I'm getting sick of guys giving me a blank pause or look when I mention I am trying to modify my scooter. My mechanic has already asked, "Why don't you just get a motorcycle?"

They just don't get it...

Chanito,

Whenever you get a chance your input on the carb would be awesome.

Thanks

[chanito]

I am not sure on the protocol on this particular ECM but the throttle position switch should be so the ECM can retard the timing at idle (to smooth the idle and make the starting easier) and at full throttle so the engine runs cooler, now the carburetor that sfc is installing is a slide throttle carb (almost impossible to install throttle switches) but the great advantage is that at wide open throttle there is nothing restricting the flow thru the carb (plate carbs have the axle and the throttle plate), the disadvantage is that they are not smooth so acceleration is snappy, but releasing the throttle feels like applying the brakes, on another note since a CDI control the timing having a throttle switch is irrelevant.
Most carbs have two fittings, one is for feeding the gas to the carb and other to allow venting the carburetor bowl so it has to go to filtered air, some have two more that supply and take away coolant (like the stock one in the ruckus) normally the one for the gas is smaller than the one for venting Hope this helps.

[sfc]

Chanito.

There are two pink tubes, which you can see in the explosion and the picture, and there is a gold part that is right next to the air intake. I figured one pink tube was the vent and the other the gas until I saw that gold intake and how I'm thinking the gold intake is the gas, because of its proximity to the air intake and then there's the vent and you might be right about the coolant, but I don't see an exit for that so I'm not sure what to make of it.

I try calling Sudco and see what they have to say.

Thanks

[chanito]

;D Yeah! getting in touch with the people at Sudco is the best option, you are right the pipe at front should be the gas intake, judging by the pictures it vent thru the intake, you can see the holes facing forward, the other pipes should be either coolant or vacuum supply, so you can blow thru them and see where the air goes, but sudco should be able to let you know for sure

[sfc]

Chanito,

You might be jealous but I actually live about 20 miles from Sudco! Anyways, I called them up and the guy said that both tubes were vents, which I am skepitcal of, but I will confirm it later by calling a couple other places that specialize in racing modifications.

UPDATE** Just called a local shop and the service guy confirmed the same thing...they are both vents.

So I just have to wait for the carb to get back from Motion Pro with the custom cable and I should be able to get it in and running.

One thing that did come up was that I was talking with Jason at Battlescooter and he mentioned that I do not want it stepping from the carb to the intake.

I am concerned that the OEM boot has a rubber seperator that keeps the carb from hitting the intake and I suspect that it is stepping down to seal the intake. The intake itself is nearly 10mm smaller so that seems like a problem as well.

I was thinking about dremelling the rubber boot out but then the air is hitting the intake manifold anyway...so it might be a waste of time...

Your thoughts appreciated

[Dandy Dan]

When I intially ported my engine I grinded out the intake port piece so that it gradually drops to the diameter of the port. I made it as big as possible on the carb end. The rubber boot piece slides over both the the intake port and the carb exit so I don't think the rubber boot is blocking any flow. You can't change the outer diameter of the intake port where the rubber carb piece slides over (unless you got a different piece) so if you dremel out the rubber boot it'll just fit sloppily. Another option is to buy a different intake port thinger that gradual steps down or make one but both of these options would be difficult.

Basically the only mod I can see reason for making to the stock intake and carb. boot is to dremel out the intake port so it gradually drops in diameter.

[sfc]

One other question I have is the crankcase breather. Since I am removing the stock airbox and putting a pod directly on the air intake of the new carb, I am also going to pull the PAIR system from the engine.

So do I just have to do something with the crankcase breather cause the vacuum tube for the OEM carb is going away too?

Thanks

Should I put a filter on the end of the breather or will something else suffice?

[chanito]

;D The better option is the one that DandyDan said, dremel a smooth transition from the carb bore to the engine intake, and yes please install a filter in the fitting in the valve cover for the crankcase breather, you do not want dirt getting into the crankcase and getting jiggy with your bearings

[sfc]

What should I use to cap the PAIR port on the engine?

[chanito]

Get a heater hose cap (5/8 should do it), but check other sizes just in case,

[sfc]

There are two PAIR that are coming off the engine it seems:

1) This one:


2) And this one:



3) And then I want to confirm that this is the crankcase breather:



The first hose is small and goes just behind the manifold intake.

The second hose is pretty clear

Can you set me straight?

Thanks

[Dandy Dan]

Wow those are some fuzzy pics, I don't even know were the first one is on the engine. Actually I'm no even gonna guess an answer cuz I really don't know.

Just to set the record straight: The Pair system does absolutely nothing to slow me down or drop fuel economy. I simply adds air to the exhaust to burn up unburn stuff for lower emissions. Correct? And the only reason people get rid of this is because it's annoying if you're adding a POD filter or because you want a cleaner look (or both). Right?

P.S. Nice edit on fixed the picture links. Personally I recommend going to photobucket.com and registering. It takes 2 sec and then you upload pics to your page and it little boxes below the pics it gives a link you can copy/paste to link people there or the HTML code you can copy/paste into places like this post so the pic appears. It's really easy to use.

[chanito]

Ok here is my quick answer, the top one i do not know i will need a clearer pic, the middle one is the Pair valve, the lower one is your pcv or as you called it the crankcase breather, just to let you know the other pair valve vacuum hose is a small diameter hose that goes from the intake to that black valve behind the air box