07-31-2014, 05:02 PM | #16 |
Join Date: Jul 2014
Posts: 64
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Ok my 127.5 main jet arrived today and I finally tore apart my carb. The two jets in the float bowl are the main and pilot jets I assume? The bigger being the main and the smaller being the pilot? The main pilot jet (127.5) that arrived from jets are us has a smaller screw head than the stock main that was already in the carb. I ordered the genuine mikuni jet so I'm confused if maybe I ordered the wrong jet somehow (which I double checked) or if they just changed the jet head size and it doesn't matter? The other thing that I found is there is a third jet on the top side of the carb near the needle, not sure what it is for, maybe air? but the jet I received from jets are us has the same size head as this top jet does.. defiantly could use some help and advice on this one.. Thanks
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07-31-2014, 06:27 PM | #17 |
Join Date: Jul 2014
Posts: 64
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Top jet by the needle.
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07-31-2014, 06:35 PM | #18 |
Join Date: Jul 2014
Posts: 64
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Jet on the left is stock out of top of carb near the needle.
Jet on the right is the 127.5 main jet that I ordered through jets are us. I checked my order from my email and the 127.5 is and has the same stock # as the jet on their site under main jets.. But as the next pic shows it has a smaller head than the stock 122.5 jet. Though with the washer from the stock jet it fits in the main jet socket fine.. |
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07-31-2014, 06:37 PM | #19 |
Join Date: Jul 2014
Posts: 64
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Size comparison on the new and stock jet.
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07-31-2014, 08:54 PM | #20 |
Join Date: Feb 2009
Location: Green Bay, WI
Posts: 82
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looks fine to me. did you do a plug chop before changing the main jet?
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07-31-2014, 09:40 PM | #21 |
Join Date: Jul 2014
Posts: 64
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Not sure what a plug chop is? I'm a semi novice mechanic... I did take a pic of what the plug looked like right before I changed the main jet.
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07-31-2014, 09:45 PM | #22 |
Join Date: Jul 2014
Posts: 64
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This plug is fairly new maybe 20-30 miles on it. Pic took before jet change.
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07-31-2014, 11:32 PM | #23 |
Join Date: Feb 2011
Posts: 141
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As long as the jet fits and is secure give it a try, if it's an OCD thing and you're gonna lose sleep over it pm me your details and i'll mail you a jet. The third jet top side is the air jet, just make sure it's clean and be very careful putting the diaphram back in the correct way. Now is the time to inspect what the needle clip position is and adjust it at the 3rd or 4th position from the top: moving the clip up the needle leans the mixture and down is to richen. Turn the air screw all the way in until lighly snug and count how many turns did it take, was it 1? 1 1/2? and then turn the air screw back to where it was before and write down on a pad everything that you have done to the carburetor i.e.: main jet 127.5, pilot 35, air jet #?, needle clip n-3, air screw 1 and then neatly write this on your float bowl with a paint pen. This is you base line for adjustments from stock: did moving the needle clip to the 4th position improve response or not? idle is a little rough with the air screw at 1 1/2 try 1 1/4 or 1 turn from tight and so on. Also you plug can still be used for a reading meaniing in a week is the plug color a nice light tan or is it brown another tool is determining if your new jetting is performing for the better or worse for your engine.
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Bikes: Yamaha 1974 Yz125a, Yamaha 1974 Sc500, Yamaha 1977 Rd400, Yamaha 1978 Yz125, 1988 Harley Davidson Xlh 883, 2006 Ktm 450 smr, Ekeleton 2006 Beast 200cc the worst bike I have ever owned |
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07-31-2014, 11:53 PM | #24 |
Join Date: Mar 2009
Location: Sardis, BC, Canada
Posts: 25,977
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Excellent guidance from Trevort.
As a point of trivia, I refer to the large jet as main and the small jet as the slow jet. The screw is the pilot mixture screw.
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Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer |
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07-31-2014, 11:58 PM | #25 |
Join Date: Mar 2009
Location: Sardis, BC, Canada
Posts: 25,977
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Pulling the plug and checking it only references the moment in time when it last ran. If your bike was idling, mid-throttle, full throttle, etc.
A plug chop means to hold the throttle at a specific position and hit the kill switch. After the engine is off, release the throttle, some to a stop, allow the plug to cool and remove it. If you really want to quantify things, tag that specific plug according to conditions (ie full throttle in top gear) and install a new plug. Repeat throughout the throttle range as desired, although only idle, slow speed, mid throttle and full throttle are really helpful. Show us pics, and we'll try to determine what's happening and what needs to be done.
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Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer |
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08-01-2014, 12:00 AM | #26 |
Join Date: Feb 2011
Posts: 141
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Bikes: Yamaha 1974 Yz125a, Yamaha 1974 Sc500, Yamaha 1977 Rd400, Yamaha 1978 Yz125, 1988 Harley Davidson Xlh 883, 2006 Ktm 450 smr, Ekeleton 2006 Beast 200cc the worst bike I have ever owned |
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08-01-2014, 12:04 AM | #27 |
Join Date: Mar 2009
Location: Sardis, BC, Canada
Posts: 25,977
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^ Coolest XF ever. ^
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Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer |
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08-01-2014, 12:18 AM | #28 |
Join Date: Jul 2014
Posts: 64
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I went ahead and installed the 127.5 main moved the needle clip to the 3rd position down and readjusted the air screw from 1 & 1/2 out (how it was when I got the bike) to 1 1/4 out. (Great idea to write everything on the float bowl) haven't yet but I will. Took the bike on a 5-6 mile ride. It seems to have a little more top end but not much. I ordered a 35 smooth side pilot jet. Bought 3 new plugs and my pro circuit exhaust and moose air filter should be here by Monday. Im sure I'm going to have to adjust the air screw, check plugs, and tweak things a lot after installing everything. Hopefully I won't have to change the jetting again once the muffler and air filter are on...but I took my best edjamacated guess based on what I'd researched others had done.
My main concern was that I wasn't going to somehow mess up my carb or engine by putting in the smaller head sized main. It seems fine and it defiantly puts me at ease to hear that it should be ok. Thanks again! |
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08-01-2014, 12:25 AM | #29 | |
Join Date: Jul 2014
Posts: 64
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Quote:
Man Trevort that bike is SUPERSICK!!! Love it, those pro taper bars are sweet! |
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08-01-2014, 01:36 AM | #30 |
Join Date: Mar 2009
Location: Sardis, BC, Canada
Posts: 25,977
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There are several awesome details in that bike, because he raced-prepped it. Search for it.
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Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer |
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