Carb Setup

[Turtleface]

Alright, just about ready to get things back together. Carbs are dipped, orifices are clean. Engine's stock, internally. V&H exhaust, stock airbox with a K&N OEM style filter. I was planning on installing my Dynojet kit per the Stage One instructions. I also buggered up a few pilot jets, so I'll be ordering some new ones. Any advantage to ordering a different size? Plug chops will be done once I get the bike up and running again, and the carbs are synced properly.

 

[TheCafeKid]

If youre going with a Dynojet kit, there is NO advantage to increase in pilot jet size. In fact, they call for retention of the STOCK pilot set up, as that is what they designed their jetting around.

Some guys will swear up and down that a pilot increase will help. I think its simply cock and bull on a stock motor, with pods or without, and a high flow pipe. You dont spend enough time in straight pilot to make a difference, and the back popping you might get is coming back through the needle pilot transition as the slides come down and the circuits switch..

 

[Guest]

117.5 main jet
47.5 pilot jet
2.5-3 turns out in mixture screw.
With the 45 pilot you will have popping through the exhaust coasting down hills or on decell

 

[Turtleface]

117.5 main jet
47.5 pilot jet
2.5-3 turns out in mixture screw.
With the 45 pilot you will have popping through the exhaust coasting down hills or on decell

Closest I can get with the DJ kit is 114 on the main. Should I pony up and try to find 117.5s, or can I get away with the 114s?


I get the feeling I'm going to spend a lot of time doing plug chops. Good thing I like this sort of work.

 

[BassCliff]

Closest I can get with the DJ kit is 114 on the main. Should I pony up and try to find 117.5s, or can I get away with the 114s?


I get the feeling I'm going to spend a lot of time doing plug chops. Good thing I like this sort of work.

Hi,

Dynojet and Mikuni don't use the same criteria for labeling the "sizing" for their jets. The DJ size 115 is smaller than the Mikuni size 115. DJ labels their jets according to diameter (#150 = 1.5mm). Mikuni labels their jets according to flow rate (#150 = 150cc of fuel per minute). Mr. salty_monk has a conversion chart HERE. Or just google it, that's what I did.

Did Mr. chef1366 give us Mikuni sizes or Dynojet sizes? :-k


Thank you for your indulgence,

BassCliff

 

[Guest]

Those DJ mains are too small. I'd use the 132 DJ mains before using the 114.

 

[Turtleface]

Hi,

Dynojet and Mikuni don't use the same criteria for labeling the "sizing" for their jets. The DJ size 115 is smaller than the Mikuni size 115. DJ labels their jets according to diameter (#150 = 1.5mm). Mikuni labels their jets according to flow rate (#150 = 150cc of fuel per minute). Mr. salty_monk has a conversion chart HERE. Or just google it, that's what I did.

Did Mr. chef1366 give us Mikuni sizes or Dynojet sizes? :-k


Thank you for your indulgence,

BassCliff

I see. I'll give the old Google a shot, it appears your link has shuffled off this mortal coil. I'll get her sorted out one way or another. Hey mister Chef! Which numbering system were ya using?

Another query:

The DJ instructions say to enlarge the slide lift holes with the provided drill bit. I'm sorta at a loss as to where these holes are. The directions provided aren't clear, it just has a picture with approximately four different holes in it, none of which are specifically indicated. Is this the hole I'm after? Or does the slide assembly come apart further? I haven't tried to pry anything apart for fear of damaging anything.

Thanks for any help you guys can give, this place is a priceless wealth of knowledge.

 

[Guest]

That's the hole.
Angle the drill bit just slightly towards the center to follow the old bore. If the bit locks up you're not following the bore.

 

[Turtleface]

Those DJ mains are too small. I'd use the 132 DJ mains before using the 114.

Ah, good to know. Looking to keep away from any sort of lean condition. Bike runs pretty hot in the summer, and I'm pretty sure the previous carb tuning may have been a factor. I'll give what I've got a shot before I go off ordering new mains. Though Mike's XS has the 117.5 Mikuni type for about six bucks a pair, which seems pretty reasonable.

 

[Turtleface]

That's the hole.
Angle the drill bit just slightly towards the center to follow the old bore. If the bit locks up you're not following the bore.

Alright! Deep breaths, I always get nervous when I start doing irreversible modifications. Not that I have bad luck with them, I'm just a nervous sort when it comes to this. Which is why I'm grateful for the info I get from the many people who have gone before me, into the vast realm of carb modifications.

Hmm...feeling wordy today.

 

[Guest]

Alright! Deep breaths, I always get nervous when I start doing irreversible modifications. Not that I have bad luck with them, I'm just a nervous sort when it comes to this. Which is why I'm grateful for the info I get from the many people who have gone before me, into the vast realm of carb modifications.

Hmm...feeling wordy today.

I've reversed it with JB Weld and redrilled them stock.

 

[TheCafeKid]

117.5 main jet
47.5 pilot jet
2.5-3 turns out in mixture screw.
With the 45 pilot you will have popping through the exhaust coasting down hills or on decell

With the 47.5s you'll have black plugs and crappy fuel mileage. The 45s work just fine. Even in the 1150 carbs. The backpopping isn't the pilot circuit but the transition between. Move your needle till it stops.

 

[Guest]

With the 47.5s you'll have black plugs and crappy fuel mileage. The 45s work just fine. Even in the 1150 carbs. The backpopping isn't the pilot circuit but the transition between. Move your needle till it stops.

BS Josh
It's not the needle if the throttle is closed.

 

[Turtleface]

Sounds like a challenge. I'll see if I can scientifically document both ways, and see what happens. I should probably buy stock in a spark plug company...if this amazing piece of 1982 machinery could feel, it should feel lucky that I'm obsessed with the idea of getting it running in absolutely perfect fashion.

 

[Turtleface]

With the 47.5s you'll have black plugs and crappy fuel mileage. The 45s work just fine. Even in the 1150 carbs. The backpopping isn't the pilot circuit but the transition between. Move your needle till it stops.

When you say move your needle until it stops, you're referring to moving the e-clip up or down, correct? Or moving it via extra/less spacers/washers?

 

[BassCliff]

I see. I'll give the old Google a shot, it appears your link has shuffled off this mortal coil....

Sorry, here's the link.

Mikuni/Dynojet Conversion Spreadsheet


Thank you for your indulgence,

BassCliff