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  • Jokke75
    replied
    Thanks, davej, yes it’s off season for us here now...garage months ahead and back out riding hopefully in April again. (Yes, we know, the weather here in Nordics suck!

    Leave a comment:


  • davej
    replied
    yes that will be the jetting for your bike with those mods. You may have to play with the PMS just a little with the weather being colder this time of year. you may need to turn it out 1/4 turn or so

    Leave a comment:


  • Jokke75
    replied
    I put a follow up question here: for my 2003 XV1600 I have K&N airbox and plan to go for Cobra HP 2-1, carb is stock now. I have Barons jet kit coming + plus mikuni 37,5 pilot jet on top. Shall I go with 167,5 main, the 37,5 pilot and clip on the 4th groove in Barons needle, PMS 2,5 turns out? This is what I’m picking up here but would that fit with the K&N - Cobra -combo?

    Any other tips / things I should consider? Many thanks!!

    Leave a comment:


  • Doc_V
    commented on 's reply
    The older I get, the more I forget... I'm like Homer Simpson, if I learn something new, it pushes out something old. ...So I went back and did some more digging; the Hypercharger comes with a 1.3 air bleed. As you probably know, if you do a full on re-jet, sticking with the 1.3 air bleed can make proper tuning difficult. Switching back to the stock 2.0 essentially treats the HC as typical BAK and makes things easier. And yes, at one time, based on a recommendation, I did have a 1.0; I was looking at those old records late last night when I posted. But after checking further, I did switch to the 2.0 back in 2016, when I got my 1700. So that much is good. Thanks again for pointing that out.

  • RRS_07RdStar
    replied
    Originally posted by davej View Post
    Install the dj pilot and see if it helps. If not install a Mikuni 37.5 pilot. I'd be curious to know. As Said I would never put out that type of info based on my assumption, It was from research and talking to DJ tech support to obtain that info. I guess the only assumption on my part was assuming that the tech support guy knew what he was talking about. lol
    Also there should only be 1 washer Under the clip. Putting 2 under the clip only richens the fuel mixture at cruising speed by about a 1/2 groove on an adjustable needle. In the stock configuration the cruising speed AFR does not need to be richened at all. The 2nd washer should be placed on top of the clip for the little spring to set on.
    I finally got around to installing DJ 37 pilot jet. I also removed 1 of the washers from under the needle clip and placed it on top. I had the PMS screw out 3.5 turns with the Mikuni 35, I took a guess and moved it back to 2-3/4 turns for initial setting. I tried starting the bike with the enrichener in (running position) to check if pilot circuit might be to rich, but wouldn't start. I pulled out the enrichener, and it started right up. I was going to take it for a long test run, but I got a mile or 2 away and it started pouring, so I turned around and came back. I had let it warm up enough before I left, and I think it's really close to where it needs to be, no hesitation, blipping throttle seemed crisp, and bike seemed to accelerate nicely. Throttle returned to idle quickly when letting off. I have to check the idle rpm, may try turning PMS back another 1/4-1/2 a turn to see how it compares, than take it for a longer run to verify it running well.

    I did take measurements of all the holes in both Mikuni and DJ jets for comparison. I have full set number drills to #80. I used the shank end of bits to test until I found one that fit snugly and the next size wouldn't fit. One thing I noticed, and I ran into this recently on aftermarket jets for a 72 Honda CB500 I recently restored, the DJ jet didn't do a good job of cleaning burrs off the back of holes. When I was trying to measure the id of the emulsion end of the DJ pilot, there were burrs on the back of some of the 8 perpendicular through holes. I had to use the drill end to clean the burrs off. The Mikuni jet was well machined with all sharp edges de-burred and the 8 holes on emulsion are chamfered (see attachment) Click image for larger version

Name:	20201017_PilotJets resized.jpg
Views:	135
Size:	74.2 KB
ID:	111093 . Keeping all holes clean from burrs will give the max flow it can. Burrs obviously can impede the flow. Anyway if you want dimensions, I can give them to you, I just didn't want to give you my scribble, I'd make a little nicer sketch.

    Leave a comment:


  • davej
    replied
    Doc,If I remember correctly the 1.0 was the jet that comes with a HC kit.

    Edit: I just looked at your profile and it says you have a hypercharger. If you do then the 1.0 is the correct one for your bike. If you get rid of the HC then you will need to swap back to the 2.0

    Leave a comment:


  • Doc_V
    commented on 's reply
    Well cut off my pinky and call me Betty... I've been running a 1.0 for years, in both my 1600 and 1700, based on the recommendation of another RSC member; who shall remain nameless. But it's right there in the on line factory parts catalogs: 2.0 https://www.yamahasportsplaza.com/oe...2a4/carburetor

    Thanks for the heads up Dave. Looks like I need to order a new one.

  • davej
    replied
    Doc, that is wrong. the one under the diaphragm cover is a 2.0

    Pilot Jet, Air (2.0)

    #239-14172-20-00

    Retail Price: $5.49

    The one in the mouth of the carb is a 100

    Jet,Pilot Air (#100)

    1HX-14231-20-00

    Retail Price: $6.49

    Leave a comment:


  • Jmcdonner
    replied
    Anyone know the size of the pilot air jet on a 1700?

    Leave a comment:


  • Jmcdonner
    replied
    Thanks!

    Leave a comment:


  • davej
    replied
    If you have a 1700 start with a 172.5 mikuni main jet and a 40 mikuni pilot jet. Clip in the 4the groove on a barons needle. PMS 2 1/2 turns out. with the Hypercharger you may have to go to a 175 main jet but I would start with a 172.5.

    Leave a comment:


  • Jmcdonner
    replied
    Newbie question...though reading many of the articles I think I have a good idea where to start. Putchased 2005 Midnight Silverado 1700 tgat had been sitting a while....a number of years. Set up has tge Kuryakin Pro Hypercharger with Hard Krome Bug Staights. Pullrd tge carb to clean it up and Looks like carb was never jetted by original owner. Ordera rebuild kit, Baron adjustable needle, and jets. Seems like I should start with 167.5 , 40, and needle on 2nd clip. Agree. Live in Northern Virginia.

    Leave a comment:


  • brianmac
    replied
    If nobody already said it, while you're in there pull out all the air Jets and make sure they are correct also. If there were dynojet jets in there, the PO could have put in a hypercharger at some point, and at one point they've required a different air jet up to the top of the carb, if I remember correctly. Don't leave any Stones unturned

    Leave a comment:


  • davej
    replied
    Also there should only be 1 washer Under the clip. Putting 2 under the clip only richens the fuel mixture at cruising speed by about a 1/2 groove on an adjustable needle. In the stock configuration the cruising speed AFR does not need to be richened at all. The 2nd washer should be placed on top of the clip for the little spring to set on.

    Leave a comment:


  • davej
    replied
    Install the dj pilot and see if it helps. If not install a Mikuni 37.5 pilot. I'd be curious to know. As Said I would never put out that type of info based on my assumption, It was from research and talking to DJ tech support to obtain that info. I guess the only assumption on my part was assuming that the tech support guy knew what he was talking about. lol

    Leave a comment:


  • RRS_07RdStar
    replied
    Originally posted by davej View Post
    The info that I quote that the dj 37.5 pilot flows the same amount of fuel as the mikuni 35 pilot jet come right from Dyno jet tech support on a phone call that I made to them inquiring about it
    It's hard to argue actual flows at same given head pressure from my test. Only difference in the bike is the fuel is pulled through in inches of mercury of vacuum instead of head pressure. I wasn't trying to be negative or prove you wrong, I just thought you may have assumed that from the way the main jets sizing compares. My real point was to question if using the DJ (assuming my DJ37 flows more)) seems like a way to possibly eliminate the stock idle leaness? The needle already has both washers and the plastic spacer under the E-clip. Sorry if I came off the wrong way.

    Leave a comment:


  • davej
    replied
    The info that I quote that the dj 37.5 pilot flows the same amount of fuel as the mikuni 35 pilot jet come right from Dyno jet tech support on a phone call that I made to them inquiring about it.

    Leave a comment:


  • RRS_07RdStar
    replied
    Mikuni and Dynojet pilot jet size comparison

    Originally posted by davej View Post
    So what parts are different? None of the jets that come with that kit are the correct size for your bike. But that is what Dynojet corp thinks is right for the bike and they are wrong. That is one of the problems with the dyno jet kit. Their jetting recommendations are wrong for your bike. You can use the needle from that kit but order some mikuni jets. You should order a 167.5 Mikuni main jet and a mikuni 37.5 pilot jet. The dynojet 37.5 that comes in that kit is not the same as a Mikuni 37.5 the Dynojet 37.5 is the same fuel flow as the OEM 35 Mikuni pilot jet.
    I know this is an old topic, but I wanted to point out something that I just discovered and thought it is useful knowledge about Mikuni and DJ pilot jets.
    Background behind this is I'm selling my Roadstar and I removed my V&H Bigshots (replaced with stock stage1 exhaust) and went back to a stock airbox with a OEM filter. All I had was DJ jets but I didn't want to mess around with trying to re-tune it again. So Davej was nice enough to provide me with the stock main and pilot jets, and stock single slot needle. I put the stock parts back in, but I couldn't remember what the PMS turns out for stock motor was, so I started by searching the forum and came up with this thread. Reading through I found the stock PMS is 3.5 turns out. So I tried that and found the bike hesitates off idle, which seems to be typical for stock according to what I read here. It seems from the info here, that you really don't want to turn the PMS out much more than 3.5 turns, so my thinking is to use the DJ #37, assuming it would deliver more fuel that the Mikuni #35. I saw Davej comment above, that the DJ# 37 was about the same fuel flow as Mikuni #35 pilot.

    So I decided to actually measure the flow to compare the 2 jets. The attached pictures clearly show the emulsion end is much larger diameter on the DJ compared to the Mikuni. I was going to measure the orifice, but that won't tell the whole story. I have a couple of pictures of the setup I used, a 60cc syringe, open on the top. I used some clear plastic tubing that fits the end of the syringe and over the large end of the jet. I did 2 separate test to verify the validity using gasoline. The first test I filled the syringe to about 44cc and waited until level got to 40cc and started stop watch, and end test when level got to 20cc. The second test I didn't want to wait so long, so I filled the syringe to about 44 and started stop watch at 42cc and ended test at 38cc. Below is the results:

    DynoJet37, 20cc in 130.53 seconds. Mikuni35, 20cc in 315.41 seconds
    DynoJet37, 4cc in 132.94 seconds. Mikuni35, 4cc in 169.69 seconds

    So clearly the DJ37 flows more than the Mikuni 35. I'm sure the 37 Mikuni probably flows a lot more than the DJ37. But for my particular situation, I just want to add a little more fuel to the pilot circuit instead of trying to back out the PMS more and worry about loosing screw with not having enough spring tension. I'm hoping I can set the PMS out between 2-3 turns out with the DJ37 and eliminate the lean off idle hesitation.

    Davej, what's your opinion on this, or anyone else's for that mater?
    Attached Files

    Leave a comment:


  • brianmac
    commented on 's reply
    hotrod460 what kind of fuel do you get in the UK, may need slightly different jetting?

  • Spydr
    commented on 's reply
    Did you vent your gas cap?

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