This Seems Counter-Intuitive

[1948man]

I acquired an airbox for my 1100GL and am replacing the PODS. I have a Dynojet kit currently set up Stage 3 with the PODS and a V and H 4 into 1. I am going Stage 1 and keeping the aftermarket exhaust. The 2 sets of main jets for the stage 3 setup were pretty big, 165's and 170's. I realize you use a conversion factor of .9375 to relate those jets to Mikuni's. The Main jets provided for the Stage 1 setup seem smaller than the OEM. They are 114's and 118's (you use the one which works best). If you take the larger 118 main jets and apply the conversion factor, it seems they are the equivalent to a 110.6 Mikuni whereas the stock setup had 115 Mikuni mains. Even though I will have the original airbox. I will have a more free-flowing exhaust and it seems odd that I would be provided a main jet small than stock.

I know Dynojet needles supposedly function more efficiently than OEM needles but I can't understand how the Dynojet main jets would be any different other than size. An orifice is and orifice, right? My original mains were labeled 115 but the PO had bored them out to about 160 so I don't have any stock mains. I will get what I need from Z-1 if the Dyno's are insufficient but I wanted to see if maybe I'm misunderstanding something. Thanks, Jim M

[1948man]

Well, I finally got through to Dynojet support. The engineer said 2 things. The conversiion factor is not truly accurate although Dynojet jets do run a little smaller than Mikunis of the same number designation.
Also, the size is not totally relevant because the way the Dynojet needles behave affects the main jet performance. Hope this might be useful to someone.

[koolaid_kid]

My own personal experience with the kit (I have a Stage 3 in my GPz) was that the mains were incorrect. I did not mind too much as they are only $2 each plus shipping. I just did the normal tuning of the mains, dialed them in, and went on with my business. Every single engine is just a bit different and DynaJet has no way to tell what you really need. Put in what they send you, determine which way you need to go, buy 2-3 ranges that way, and dial it in. The jets are cheap. The needles, which are the important part, will work just dandy, although I did adjust mine from their recommended position, but the above caveat applies here as well. Overall I am very pleased with the performance once I dialed the kit in.

[1948man]

Thanks, that sounds like a good approach to take.

[Steve]

Did you also put the main air jet correctors in there when the Dyno Jets were installed?

I think they might richen up the mixture a bit, too.

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[koolaid_kid]

Absolutely. This is a highly modified engine, so my thought pattern was that I should do it all. I received 180 & 185 mains. I ended up with 170s installed. I got lots of mains now. YMMV.

[1948man]

On mine, the instructions said to use the air correctors on Stage 3 but not use them for Stage 1. I used a dry wall screw to thread slightly into each corrector and yanked them out to go back to Stage 1 configuration. Sage advice on extraction I got from a GSR expert. The bike is back together now and running very well. Will watch it over the next few days.

[koolaid_kid]

Super. I never looked at the Stage 1 instructions, to be honest. Never was in the cards.

[Steve]

Sage advice on extraction I got from a GSR expert.

I have known that guy all my life, he's no "expert".

Someone nominated him for "Superstar" status a few years ago, he is still fighting that accolade.

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