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Jetting/plug chop opinion.


13B-RX3

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Might just be the oko's iirc they have a bad rep. ?
I guess anything is possible, but I don't see how, at wot it's basically a jet holder. Maybe I'm missing something? The midrange and idle are flawless, it's just full throttle.

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I'd think it'd be worse in a rd than a quad, running bowls dry !  i'd be careful, and / or  some were drilling out inlet ( dont think that could be more restrictive than @ needle) but...
I ran across a thread that have all the dimensions of the keihin and they are the same on these carbs. Needle passage, holes under needles, etc. I guess they are slowly making "improvements". I honestly don't think it's running out of fuel. I get the same results weather it's a 1-3 chop, or on the shift light in 6th. It never falls on its face like it's ruining out of fuel, it just keeps going till you let off or hit the rev limiter. Had y'all not known what the plugs came out of, what's your opinion of the last plugs I posted (168/172)?

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I use a digital caliper for measuring, harbor freight one will do. Until you main is correct make sure your needle is in the middle it is the last circuit you tune.

My Procedure is to set idol Circuit first making sure that it is not too fat or too lean in the bottom and second I just the top end because the mid range is a combination of the idle circuit in the top and circuit

Does your carburetor have a power jet on it on the top on the back? They usually have a hose going from the bowl to that jet.

028D864B-8EAF-4C49-9A76-BF9003A2191B.jpeg

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If so take off your filters and make sure the slides are going all the way up on both sides. The power jet kicks in at 98 to 100 percent throttle. Also make sure they are even at wide open throttle. Looking at your plugs ngk recommends color on top 3 threads. I only see color on 1  this would mean your plug is too cold of a heat range br7es would be better for your bike also the first 1/2 mm of the electrode should be shiny which means your engine is too retarded. If you plan on advancing the timing now is the time so you don't have to start over with jetting. There is no sign of transfer of aluminum at the base of the plug so I see no signs of ping or detonation. I would advance 3 to 4 deg. 

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I use a digital caliper for measuring, harbor freight one will do. Until you main is correct make sure your needle is in the middle it is the last circuit you tune.

My Procedure is to set idol Circuit first making sure that it is not too fat or too lean in the bottom and second I just the top end because the mid range is a combination of the idle circuit in the top and circuit

Does your carburetor have a power jet on it on the top on the back? They usually have a hose going from the bowl to that jet.

028D864B-8EAF-4C49-9A76-BF9003A2191B.jpeg.62edc56a707516d6f611d1d39fd22f84.jpeg

Thank you so much for the reply! I have a 10X inspection magnifier with a measuring scale. From 160-172, I'm measuring 1.5mm, the only change being the color. I'm fairly certain the needle is correct and I know the pilot circuit is. I set them in the order you mentioned, the only thing I can think of that caused it to lean from where I had set it originally is that I replaced the reeds with a thinner (less stiff) reed. Maybe that's what caused it. It is a the slides are definitely opening all the way. It is a PV carb but I've done chops with it plugged and operational and don't really notice any difference in the plugs. With plugs that have been in the bike for more than 12 seconds I do see the cad plating burned off about 2-3 threads down and the timing definitely is conservative, I didn't want to push my luck until I was positive I had enough fuel. The ring on the electrode is maybe .007-.010. I was under the impression that timing doesn't drastically effect AFR, I was planning on getting the fuel sorted then setting the timing on a load bearing Dyno. The timing now is basically a banshee curve +3 degrees. The engine is fairly low compression so I'm sure I can get away with much more, but that'll have to wait till I strap it on the Dyno. My thinking on the width of the band is that being an air cooled motor, the plugs are going to run hotter than in a water cooled. That being said the area of the plug that will be at self cleaning temp will be wider, leaving a narrower band.I think 160 main is about the limit of what the engine can burn, anything beyond that and I start getting black bands in the smoke ring. I may be way off though, is just a theory. I thought turbo rotaries were finicky, they don't have shit on 2 strokes! Thanks again, I look forward to your reply!

 

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If the soot ring isn’t growing I would guess it is lean in the mid range color wise I like the 162 plugs any chance you can lift the needle 1 notch (lower the clip) with the 162  then do a 20 min ride no more than 1/2 throttle. Please post pick of 20 min plug whole then chopped only need to chop 1 plug for this test. Do you have a laser thermometer after your run take a temp of the cylinders and one of the pipe on each side about 3 inches off the jug. Thanks

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