Carb specs/mods

[The other Alex]

Heres the deal, I have this 6m6 motor in my new ski with some clean-up porting, a coffman pipe, and an after market flame arrestor on the motor.
When I did some searching to find what size jets I need to go up to, I was told that the internal fuel circuits need to be drilled as well to allow for more fuel, this was later confirmed by another. I found a local guy who can do it here fast and cheap if I bring the carb in disassembled and the specs to drill. Cool, I asked Group K if they could let me in on their specs, unfortunately that is against policy which is totally understandble, as that could bring in liability issues and so forth.

I'm hoping someone else has had a similar set up on the 6m6 motor that could share their specs on the carb or reccomend something. I would no doubt send the carb out to Group K since they are very reputable, but it would just be easier for me to take it to this guy close to home, so I can have it back the same day and not pay for shipping.
Anyone have any suggestions?

Thanks!

 

[2lick]

I have a 650 sleeper motor form group k.... they did carb work too. I bought this form some one else so I dont know...

What exactly are you looking for.

 

[unclehulka13]

wait. Isnt a 44sbn carb on there? if so, just change the jetting. You shouldnt have to drill a sbn. i probably wrong, but if i remember, its only a sbn.

 

[The other Alex]

Not sure, Group K said that the earlier model carb, 89-94 or something like that, the fuel circuits need to be drilled larger, in addition to re-jetting. Once they switched to the 701 carb and carbs, re-jetting was good enough.

 

[romack991]

i'd call magoo and ask his advice, i've never heard the 90-93 44 mikuni was any different than the 94-95 (701 SJ). Could go to a yami parts finder and see if the number is any different.

 

[WAB]

hulka is right, you can just rejet the carb as long as it is the SuperBN. No drilling needed. 1989 Yamaha's had the old BN carb I think, but 650 SJ's have the SuperBN.
I'd call or email Paul @ Jr.Magoo, he can prolly get you really close to perfect jetting on that 650. I used to have almost that same setup and paul helped me out with jetting back then, but I don't remember what it was now though.
The stock 650 flame arrester works best for keeping water out of the carb. Might want to remove a few screens from it and put it back on if you still have it.
Good luck.

 

[The other Alex]

hulka is right, you can just rejet the carb as long as it is the SuperBN. No drilling needed. 1989 Yamaha's had the old BN carb I think, but 650 SJ's have the SuperBN.
I'd call or email Paul @ Jr.Magoo, he can prolly get you really close to perfect jetting on that 650. I used to have almost that same setup and paul helped me out with jetting back then, but I don't remember what it was now though.
The stock 650 flame arrester works best for keeping water out of the carb. Might want to remove a few screens from it and put it back on if you still have it.
Good luck.

Cool, this ski is a 1990. I'll call around.
About the stock air filter, I know, the motor already had the after market though, I was going to take it off and get a stocker, but it came with a prefilter, so hopefully that will help keep some water out.

That was the biggest pain with my 550, was the K and N filter, that thing sucked water up constantly. Whenever I took a bad spill, water would get in it and I'd lose all bottom end power until I took it off and let it dry out.