Been reading this great forum for a few weeks now but have never posted yet, very informative. I put the dynojet needles in last week but had trouble getting the screws off on the backside of the carbs, plus ran out of time. Put everything back together and tried it out. The bike seemed more responsive with just the new needles in. Anyhow, today I got the screws off and put the jets in, 124 in the front and 128 in the back. I took it down the block and back a few times, it pulled really nice. I want to get it out in the open for a significant amount of time asap to see if it truly runs the way I need it to. I still need to do something about the popping and backfiring when letting off the throttle. I am glad I did it myself, it was my first time getting into a carb. This is also the first wheeler I have owned, sold my Honda CBR to get this wheeler. I had great success with jetting, exhaust, ignition adv. etc. on my bike so I hope this goes well. Oh yeah, Nyrocs info is awesome!!

 

I'm not familiar with dynojet size conversion from the kehin but 124 and 128 sounds rather lean unless you are 8000 -10,000 feet.
That may be causing the backfiring. If this is the main jet you should be 138-142 with the kehin and I would think a similar size with the dynojet.

I would not run the Prairie hard if at all until someone with more knowledge answers the post. You sound way under jetted and may burn your piston.

 

Just looked it up on dj web page main jets front 132 and rear 136 if below 3000'.
So you are way under jetted.

It is in a pdf file under the p-700 jetting info.

 

You can't make that assumption that he is lean.

I have 124/128 dynojets in mine with the needles on the 4th position. I had 132/136 dynojets and the needles on the 2nd position. But, after I did my V cam swap I was way lean in the mid range.

At the dyno yesterday we found I was too rich on the mains, but the needles were spot on. I was shocked that I was too rich. I expected lean before rich. But, now it runs like a raped ape and I gained HP as we leaned it up. So, live and learn.

For what it is worth, I am running modified intake, Twin air filter, QS1 exhaust, V cams, and Dyna ignition. I'm under 1,000ft elevation.


Nutsy,

What are you pilots set at? How many turns out? You need to get to WOT to test the mains. How does a plug chop look? Jetting tips

 

Well, according to the directions I was to use the 5th notch and the mains were actually a smaller number than the ones I put in, I mean I thought I would use the 124 and 128 which was recommended for someone with exhaust mods. I do not have an exhaust mod or aftermarket one for that matter. I just thought I would try it and see how it ran. I had my pilots turned out 2.5 turns. Today I rode the bike again up and down the street and in a little strip next to the field by my townhouse, same as yesterday, but I turned them out 3 turns. Seemed like the popping diminished quite a bit. By looking at the holes in my stock mains you could definitely see the difference in size to the DJ's. Looking at the DJ's mains only you could barely see any hole changes amongst them with the naked eye, good thing they have those #'s on em'. My girly friend got on and drove it (she has not ridden it since before the mods) I asked her how it felt to her. She said it felt different, I say what do you mean, she says it feels like it wants to go fast. I just laughed. Blondes I tell ya....

 

What model dynojet kit do you have? For what it is worth, the stage 1 kit recommends 132/136 and 3rd notch for under 5,000ft (not 2nd as I recalled). Do you recall how much shorter the new needles were compared to stock?

I'd try moving the needles in and see how that goes. We had a V in Tennessee with the same problem. He was way rich on the needles and his pilots were turned out too far.

Why did you rejet? Did you have popping and backfiring beforehand? If so, then check the fuel pump pressure to eliminate it as source of trouble.

 

I have the Moose Dynojet Kit. It says to install needles on groove #5 below 5000 ft. For the mains it says to use 120's in the front and 124's in rear below 3000 ft. The needles are tapered differently, I wanna say the DJ's needles were a tad shorter but I am not for sure. The bike had popped ever since the temp got warmer, I bought it in march. The internet says my elevation is 988 ft. above sealevel. I just remembered that the last few tanks of gas came from my girlfriends parents farm, I am sure it is 87 octane. Would this have anything to do with the popping and such? I normally would get premium at the gas stations

 

Sounds like you have the kit for the V and not the Prairie. Move the needles in a notch at a time until it improves. The V dynojet needles might be shorter than the Prairie dynojet needles. They are a different number, but I don't know the exact difference. It may be the same length and just a different taper though. You may have to go in several notches to get it right. If it lean pops out the carbs then go back up a notch. If it still backfires on decel then try turning the pilots in to 2 turns and see what happens.

Make sure you have good plugs in there beforehand.

You shouldn't have to worry about the gas unless it is bad. I run 87 as do many others.

 

I put 138 and 142 dynojets in mine at 1800', holes looked almost the same as stock 138 and 142 keins, followed instructions except used 4th slot instead of third, mine guite popping when letting off after the timing key

 

Your right, I almost forgot it is for the V, my dealer I bought my bike from said I could use that kit.