This thread discusses the Content article: Mikuni

What type of Mikuni jets are used in comparison to the Dynojet jets?
I went to 3 dealers looking for a Mikuni(185/187.5) jet to replace the 195 Dynojet.
All they had was a hex type and the id was a hell of a lot smaller than the 195 Dynojet jet.

Firstly, make sure you use the same jets as you have the needle; don't mix brands.

A 185 Mikuni would be too rich for most applications. Normally you would use a 185 DJ or less which would be about a 175.2 Mikuni or less.

Doc

DocShadow wrote:
Firstly, make sure you use the same jets as you have the needle; don't mix brands.

Doc,I dont understand your above statement.When you buy a dynojet kit,it does not come with Mikuni jets.

Anyway I should have included my mods.
V&H Pro pipe,K&N filter,Dyna 3000,Dyno jet stage 2 kit?(dont remember)

I have been running a 195 Dynojet main for a couple years.Out here in hollister,Ca we are about 100-200'(?) above sea level.
No way this jet is too rich,bike runs great.Plugs are white to light tan.
Seemed like it was a little lean on WOT,thats why I wanted to increase main jet size.
If you saw the 185 Mikuni jet I looked at,I think you would agree that it would be to small.The ID was almost half the size of the 195 DJ jet.
Now it is possible the parts people were showing me the wrong jets.
The ID of the 195 DJ jet measured .077".
Since I could not find a Mikuni replacement,I reamed out the DJ jet to .082".

So ,are all Mikuni main jets the same?

No ... Dynojet and Mikuni make different parts (different companies) and the parts should not be interchanged.

If you have the DJ jet kit then stick with DJ mains.

I guess I don't understand your 'problem'. If the plugs look OK and the bike runs great then ????

If you think it's lean on WOT and want to replace the 195 DJ main then you need a 200 DJ main.

I haven't had a look at a lot of jets so I can't comment on the hole.

Doc

Might I also suggest that you consider that you may not be lean on the WOT test, but the carb MAY be starving for gas. lot's of guys that are running large jets find that they have the symptoms of a lean WOT but are actully sucking the gas out of the carb faster than it can flow in. (see the "changing the float valve article&quot
.
I also agree with Doc on the using the same name on your initial jet set up. I think every company uses either DJ or mikuni jets but they all use different needles (barons - small needle) (speedstar - huge needle) - (dj - I don't know) the stock yamaha needle = HUGE. In jetting my '05 I went from a 182 (stock I think) mikuni to a 167.5 mikuni (baron's needle)
.
Which is better? better to ask how you like your coffee... everyone has an opinion. IT SEEMS (opinion alert) that a lot of people like the baron's needle / jet kit... that's why I chose it...
~Guido (dave)

davehrn wrote:
Might I also suggest that you consider that you may not be lean on the WOT test, but the carb MAY be starving for gas. lot's of guys that are running large jets find that they have the symptoms of a lean WOT but are actully sucking the gas out of the carb faster than it can flow in.

OK,maybe this is whats going on.

I do understand that the jets are different from Mikuni and DJ.

The comparison chart lead me to believe that Mikuni and DJ jets could be interchanged.

I know i contridicted myself when I said the bike runs great,Just thought it could be fattened up a little.

Thanks for the help you guy's.

anything can be tried... and I always say, "if you're gonna end up spending the money anyways, try the cheap way" the worse thing you could do is learn that it doesn't work. of course come back and tell us how it went, so that we will know for the future. I don't know to many people out there who've tried mixing the different needles and jets, it may very well work, but you're navigating through uncharted teritory... most of us can tell you generally how to adjust the mix.

For what it's worth, if you're running good in the low and mid range of the RPMs, I'd be inclined to tell you to raise your needle one slot, or even a half a slot, so at full throttle, less of the needle will be in hole, by changing just the jet, you will get more fuel all the way across the board, where raising the needle will have less of that effect and more effect toward the top end.

Secondly, our roadstars can run VERY rich, but won't RUN lean (without acting like you're running out of gas.) and, running your roadstar rich can lead to problems. especially if you're riding an '04 or newer. they frequenly develop a sticky exhaust valve from the carbon build up. so if you think you're running a little bit on the lean side, you are set up perfect. You might also try adjusting the PMS for a slight adjustment, I KNOW I'm a little on the lean side with my set up. but I'm not doing any adjustments untill the weather here gets a little warmer (bikes get lean in the winter). I'm hoping spring time will show that I'm now adjusted perfect, but if I'm still slightly lean, I'll turn the PMS out 1/8 to 1/4 of a turn, and this I know will richen up the mix in all ranges.

well this is probably more info than you wanted, but I don't mind talking about my bike (hahaha). If you're interested, or want more info, tell us SPECIFICALLY what symptoms you are having and when and prehaps we can help you more ~Guido