300/440/550 440 Aftermarket Exhaust Manifold and pipe on 550?

F

Freakshow

Location
Florida
fastgtfairlane said:
Those carbs are not easy to tune. I ran them for a season or two when I built my conversion ski several years ago. I can recall going up on the pilot and middle jets 1 or 2 sizes. I did lower popoff a little as well and removed 2 of the 3 screens as well as the rubber grommets on the air box. I want to say popoff was in rhe5mid 20s but I can't completely remember. I had a Westcoast 650 pipe that I cut the ribs off and extended 3 inches. It had a skat 20/22 impeller with a 68 or 69mm bored nozzle.
Click to expand...
I've come across quite a few people saying the same thing. It has AM flame arrestors on it so I'm guessing I'll have to lower the popoff from where it is now. It was a crude gauge I measured with but theyre popping somewhere around 30psi and damn near perfectly evenly. Its jetted at 45, 72 and 135 --- 45, 72 and 125 seems to be stock for this setup.

Its the damnedest thing though, no matter where I set the screws, it always acts like its running on 1.5 cylinders, (except for 3 seconds per session apparently) almost sounds as if its four stroking except the sound doesn't have the dull/flat quality like a rich mixture does, it feels and somewhat sounds like ignition cut. But it also does respond to jetting changes. It likes the low screws at 1 1/4 best, leaner and it will bog or even die with a quick throttle stab right off idle and then rich feels just feels like its rich without ever clearing out.

I first rode it after the carb rebuild yesterday and was too pooped to tear into it tonight but my plan is to cut the plug wires back and redo the boots (I believe theyre supposed to be resistor boots but I'll check on that and test/replace them accordingly). I'll test the stator resistance, which isnt all that indicative unless its out of spec but better than nothing. I also came across one post where someone had their stator polarity backwards and was giving them a misfire throughout the rev range so I'll test that theory. And then I'll go in the ebox and test the coil and inspect wiring etc. Check the grounds everywhere.

Anyways, it'll be fun to have 85+ horsepower in this thing.


Myself said:
Woo-hoo!!........Sounds like a nice grab......where's our pics?
Click to expand...
I haven't taken any good ones yet. I will soon though! I will say it has a fairly well done amateur paint job that's a hulk-ish green with lotsssssss of fine gold flakes. I don't think its ever been cut or buffed so it should clean up pretty well, minus all the runs.

It had the widest 0 degree bars on it that I've ever seen, and no quick steer. Felt like I was trying to ride a bus first time out. I cut 3 inches off both sides and now its about right lmao.
 
F

Freakshow

Location
Florida
Ok dope, thanks for checking on that. Do you happen to know a good source for jets?

And couldve been mx bars but the bends didnt seem quite right. Goofy af no matter what they are.
 
You must log in or register to reply here.
Top Bottom