I’ve got a 3 cylinder 2 stroke that I can’t get to behave.
New rings, new reeds, new plugs, new wires,
MSD ignition box and getting good spark to all cylinder.
I can’t seem to get the carbs where they need to be.
What might this engine be? I got an idea that it’s not an outboard.
'06 Mckee Craft
184 Marathon
DF140 Suzuki
Close, It’s an Arctic Cat 800 cc triple. Same motor used in jet skis and snowmobiles.
Carbs are a triple rack of Mikuni 38 mm flat slides.
Boat drinks, Waitress I need 2 more boat drinks!
I thought I had carb issues but had bad gas. Start with the cheapest smallest fixes first. Try to use a portable tank to cut out any possible fuel line issues not in the motor. If you haven’t clean the carbs. Some aftermarket parts will have different affects like stacked reeds. So if you put on new none oem parts do a quick Google of them to trouble shoot the common problems with them. What are the symptoms rough idle, won’t idle, wont run, popping only idle at really high settings. It may also just need to be ran sometimes running the dawg out of them will clear them out. But it sounds like you did a rebuild so you probably should do a break in period. Most people break in 2 strokes by running rich gas like 40 to 1. I know I’ve had stuff run better after breaking them in. More info would make it easier to decipher a list of possible issues to start with.
It’s in my little A Mod scream machine
Boat drinks, Waitress I need 2 more boat drinks!
I’m running 40:1 for break in.
I keep getting at least one cylinder fouled out. This week I’m going to pull carbs again, clean, reassemble and set base line.
They have 035 pilots, 135 starter jets, I have a wide assortment of mains form 310 to 370.
Air cleaners are K&N and custom pipes. I don’t think these pipes are tuned for this motor.
Boat drinks, Waitress I need 2 more boat drinks!
I started typing before it was posted. That’s a racing high flow carb. Mikunis are Notorious for needing fine adjustments and being hard to tune. I’ve always heard to things about those motors bad ace and hard to keep them running good. Large 2 strokes that aren’t boat motors are a pain but thrilling.
That little thing is something glorious. Man I would have a smile so big driving that thing i look redicoulous. Where do you run it at.
quote:
Originally posted by Too BusyIt’s in my little A Mod scream machine
Boat drinks, Waitress I need 2 more boat drinks!
That’s friggin awesome!
I’m not a jet-ski or snowmobile mechanic, but I did clean/rebuild about a million outboard carbs. Never much tuned them, though. Are they synchronized properly?
'06 Mckee Craft
184 Marathon
DF140 Suzuki
The car is an autocross car. We have events every month in this region. Most fun / high speed is down at Roebling Road.
Carbs are a rack of triples Tigerfin. Linkages are aligned properly and the slides appear to be lifting at the same rate. There’s a single throttle cable.
I think my mismatch starts with the fuel and fine air adjustment screws.
The only thing that I haven’t checked ifs if there’s a leaking shaft seal throwing things off.
Boat drinks, Waitress I need 2 more boat drinks!
That is pretty awesome! Is there any kind of restrictions on the type of engines allowed in those events? Seems like one of those would be scary fast with something like a newer crotch rocket motor.
'06 Mckee Craft
184 Marathon
DF140 Suzuki
Flat slides are always fun to deal with and are like no other carb out there. Although they are very tempermental, they offer wide adjustability and sound freaking awesome when idling and cracking the throttle - clacking away!
Accelerator pumps in good shape? Are there any shims on the needles? The K&N’s could be culprit as well - have you tried foam filters?. I had several over the year with bad emulsion tubes (tube that the needle slides up and down in) that would allow fuel pass the needle and constantly flood the respective cylinder.
Worked on many race bikes years ago with these carbs and fouled plugs, back firing, spitting and sputtering were all extremely common unfortunately. When fuel injection came around I never looked back.
PM me and I can get you in contact with a tech I used to work with up in Charlotte. He’s been in the motorcycle business for nearly 40 years and has worked with many flat slide setups.
Best of luck
“A Rising Tide Lifts All Boats”</font id=“blue”></font id=“size3”>
quote:
Originally posted by tigerfinThat is pretty awesome! Is there any kind of restrictions on the type of engines allowed in those events? Seems like one of those would be scary fast with something like a newer crotch rocket motor.
'06 Mckee Craft
184 Marathon
DF140 Suzuki
A Mod class is pretty open. There’s a very specific rule book for safety and to make the playing field level. Different displacements carry different minimum weight requirements.
A buddy in TN has his Yamaha R1 powered A Mod up for sale right now and it is SCARY FAST. Geared right it has a top speed of about 150. Changed the gear setup and the acceleration is just a tad slower than a Formula 1 car.
I traded my Locost 7 for this project and have been struggling with carbs and CVT setup ever since.
Boat drinks, Waitress I need 2 more boat drinks!
quote:
Originally posted by Too Busyquote:
Originally posted by tigerfinThat is pretty awesome! Is there any kind of restrictions on the type of engines allowed in those events? Seems like one of those would be scary fast with something like a newer crotch rocket motor.
'06 Mckee Craft
184 Marathon
DF140 Suzuki
A Mod class is pretty open. There’s a very specific rule book for safety and to make the playing field level. Different displacements carry different minimum weight requirements.
A buddy in TN has his Yamaha R1 powered A Mod up for sale right now and it is SCARY FAST. Geared right it has a top speed of about 150. Changed the gear setup and the acceleration is just a tad slower than a Formula 1 car.
I traded my Locost 7 for this project and have been struggling with carbs and CVT setup ever since.
Boat drinks, Waitress I need 2 more boat drinks!
Funny you said that, as I saw a R1 motor on craigslist and that was my first thought when I saw your setup. Good luck, those big 2 strokes are powerful, but can he a real PITA.
'06 Mckee Craft
184 Marathon
DF140 Suzuki
I saw a Suzuki GSX 750 and an 1100 Kawasaki ski motor on Craigslist. Might be doing some shopping and swapping if I can’t get this setup to behave quickly.
I need it drivable. I can always upgrade and fine tune through the season.
Boat drinks, Waitress I need 2 more boat drinks!
Sorry, not craigslist, check Ebay, there’s a bunch of them on there. Pretty cheap, too.
'06 Mckee Craft
184 Marathon
DF140 Suzuki