77 300

1977JD300 · Post by **1977JD300** » Sat Jan 27, 2007 10:41 am

hey, im in the process of switching my 300 over from the original WDB-31 walbro to a 34 mm Mikuni. i just wanted to get your views in this if you thought it was a good or a bad idea. the throttle lever needs to be moved out on the bar to work with a Mikuni right??

By the way, i am THINKING about parting my 600 out if there is enough interest and money in it to make it worth while. the sled is too much of a project and to expensive for me and the sled is not in good enough shape. there isnt really a lot of good parts on it. there is a CCW 440/5 engine, it doesnt run but it is free. Speedo and tach. a few other things. im not 100% positive im parting it out yet, i hate to do it but i dont want to let it just sit and rot away, might as well do something with it.

400brian · Post by **400brian** » Sat Jan 27, 2007 4:44 pm

Yes, you need a longer pull for the throttle cable. The enrichener lever will need a larger hole in the dash as well.

Before you make the mods, have you tried to make it run with the Mikuni?

afponiky · Post by **afponiky** » Sat Jan 27, 2007 8:23 pm

1977JD300,

I might be interested in a few things!

GRP

Rodimus Prime · Post by **Rodimus Prime** » Sat Jan 27, 2007 10:02 pm

if you look carefully at the throttle handle the original hole is inside but towards outside is a small plastic mark on one side for drilling out for mikuni carbs.

1977JD300 · Post by **1977JD300** » Mon Jan 29, 2007 1:49 pm

hey, thanks guys, 400brian, im assuming you ment have i tried running it with the original walbro not the mikuni, i have and it did run fine. but the diaphrams in that are junk now and i had the mikuni so i figured i'd try that, also the mikuni would be easier to maintain than the walbro.

afponiky, e-mail me at skidoo_manrd04@yahoo.com with what you might be interested in for parts and then we'll talk.

thanks

grasscutter97 · Post by **grasscutter97** » Mon Jan 29, 2007 4:42 pm

I know a lot of people have serious issues with the ol wally carb. But if it did run, then a new OEM walbro carb kit is pretty cheap to install, and you won't be tracking down non-running carb issues.

I've had good success (so far) with keeping the wallys on. You can upgrade to a WRA-31, which is a pretty decent carb, that will boost you up a bit in power too!!

400brian · Post by **400brian** » Mon Jan 29, 2007 7:37 pm

No, I meant have you tried the Mikuni yet.

You'll have to acquire the rubber carb boot, drill the dash for the enrichening assembly, drill the hand grip ( if it is the syle that can be ) Then figure out the correct jetting.

I've done this, then went back to the Walbro because I wanted the airbox back on to reduce the sound level.

Only you know if it is worth it, Walbro diaphram kits are less than $10.

1977JD300 · Post by **1977JD300** » Mon Jan 29, 2007 11:54 pm

hey, no i havnt tried the mikuni yet. as for the other things, i have machined a mounting flange out of aluminum and going to use a rubber hose to attatch the carb. im not going to drill any holes in the sled until i can make it run that way i can go back to the walbro and keep in original.

im just going by what people have told me about mikuni's being better, i just wanted to see what you guys had to say about it.

i figure i will try it out and if it works then great but if not then i'll switch back to the walbro and lesson learned right?

thanks for the replies

basketdators · Post by **basketdators** » Fri Feb 02, 2007 1:17 am

My son and I switched our 74? 300 to a 34 Mik these fall, used a 230 main. We had a carb off an old 5500 Blizzard ,fabbed a flange and used rubber sleeve from the skidoo. My son went to local jobber place and bought a cable that fit right on, but ours is an older sled. No intake silencer,there is less than 3 in.available, but plan on checking at wreckers for something, it is louder. Good mid and high ,plugs nice and tan. bottom end still needs some work, just haven't spent the time yet. Its -23 C here these days-----8 pumps on primer[4 with fuel],One pull ,----- it might stall once! Wallys in the corner in a box,and he's going to stay there.
Bill

basketdators · Post by **basketdators** » Fri Feb 02, 2007 10:20 pm

Throttle cable we used was same as 79' Spit,nice 90`elbow,perfect length. These carbs did not have choke,just primer.
Bill

basketdators · Post by **basketdators** » Thu Feb 08, 2007 11:15 pm

our 75 300 runs good with vm 34 mikuni with 230 main and 40 pilot jet. Trying a 45 pilot and possibly getting a different throttle slide for some better power out of the hole. with these settings it goes like stink from15-55mph. good luck and let us know.

HoosierDeereMan · Post by **HoosierDeereMan** » Fri Feb 09, 2007 9:19 am

I tried replacing a WDA-32 with a VM-32 on a 400. I had to buy the carb, carb boot, air horn, fuel pump, throttle and choke cables. Had some $$$$ tied up in this. Only real modification made was I had to drill the dash to accomodate the choke cable. I worked endlessly on this thing. It idled good, and ran good up to about 30 MPH and than fell flat on its face. I bought numerous jets and just about wore the threads out changing jets. I never got the thing right. It was very loud! I also didn't like the fact that it would sometimes spit gas back out the air horn. The original silencer for the Walbro would prevent this. I constantly read plugs but got nervous about burning a piston. Also, when we had snow I wanted to ride and have fun, didn't like the wife and kids giving me disgusted looks while dressed to ride wanting to know if it was fixed yet? I found a good WDA-34, replaced the dash and have been quietly enjoying some very good performance for an older machine. If you master this thing I would be very curious what your final jetting was? Good Luck!

400brian · Post by **400brian** » Fri Feb 09, 2007 5:13 pm

Hi Troy

I bought a 300 with a 340/5 in it with a Mikuni carb.
I was way too rich with a 250 main and a 35 pilot. It would spit back at speed once warmed up, and the top end was very flat.

I improved it by going to a 25 pilot, and dropped main sizes until I was down to a 210 I think. During the off season, I went back to a Walbro and airbox.

1977JD300 · Post by **1977JD300** » Sat Feb 10, 2007 3:05 pm

hey, i've got the carb almost all on, just need a throttle cable and some gas line when i get the time. the carb i have came off of a Safari 377 and it has a 230 main jet and i cant remember what the pilot jet was. and for the mounting flange i found one off of an Everest 440 and all i needed to do was drill the mounting holes out 1 drill size bigger and it bolted right up. im not drilling any holes in the dash until i know that it works. even then i might find another spot to put the primmer instead of ruining the dash. i'll let you guys know how it turns out when i get it done.