Stingray

Nice bike

Im reading 10 marks on the ruler so one cm or 10 mm and when I blow up the pic I see over 2 mm from start of soot ring to the end. If I’m reading it correctly that plug would be slightly rich

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

Is the place your doing the plug chop flat. The best info comes from a hard pull a hill climb is a good thing coasting is not.

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.

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.

If it changed that much you need to do a leak down test those plugs are extremely lean they should have a 2 mm soot ring and yours are not even close. At least start it and spray starter fluid around all gaskets and intakes and listen for rpm change better safe than sorry

Buy a leak down kit off eBay and do a leak down test before the tear down. Might have lost oil seal to trans

Nuff said

Why dose everyone guess at jetting. Do a plug chop and you will know what you need to do. Warm bike up on old plugs till hot change plugs ride bike wide open like you are racing through all the gears clear to top safe rpm pull clutch and kill bike, keep clutch in till stopped do not idle cut threads off plug or slide a 3/4 hole saw over top of plug cut down till ceramic comes out easily measure soot ring with caliper 2 mm perfect smaller lean larger rich

Yes it will have + and - 10 deg with 0 in the middle and the pointer is the split in the case

Best power gains are 1 port job 2 compression 3 pipe 4 timing 5 carbs

I run race fuel 40 to 1 with 927 castor 10 deg advance cool head with 15 cc domes and 68.5 mm big bore Pistons. I do plug chop after every mod and show no pinging (aluminum transfer at base of plug). If everything is sealed no leaks and jetted correctly you should be able to run 4 deg all day long. A plug chop will tell you everything you want to know about your timing and jetting.

Check compression

Don't forget the o ring on the pipe going to water pump

I agree with others. Sounds like an air leak another quick test is to spray starting fluid at all the gasket surfaces while it idles if the rpm changes you have a leak. This is not a replacement for a preasure test but a quick test if something feels off.

Yes they can make a lot of power beware of cast ones I had one come apart and destroy the stator. Now I run a billet one. Unless you run race fuel I would run 3 or 4 deg max 91 to 93 octane. If it back it down or run better fuel it will KILL an engine quickley. If you run race fuel I start at 6 deg and alky 10 or more depending on compression

That is a 8 percent gain in air flow so it shouldn't be that crazy I would check my float and make sure it is full of fuel. If it is slow filling it can lean out and it will rev like that pull the bowel and check flow by hooking ip fuel and move the float check the flow if that is good pull the main jet out re assemble and start. If it falls on its face when you give it gas then the jet is way off if it revs the tube that holds the jet is blocked

What size are the jets in the new carbs and what size in the old carbs. If you run the chokes does it help?

Check the toe in on the front end bad alignment becomes apparent at high speed

Are they jetted correctly?

Sounds like the neadle and seat is not sealing so your float level is to high on that side flooding that cylinder. pull the carb take off the bowl, hook a fuel line to it and close the float manually to make sure the fuel stops.

Your displacement is 384.92\2= 192.46\dome cc stock is 27 = 7.12 compression 20 cc domes would give you 9.623 knowing the CCs of your head would help calculate your compression ratio and the safe advance with the fuel you want to run. If you calculate off the exhaust port closing your stroke becomes 29mm from port close to head due to your longer stroke. This gives you a displacement of 192.46\2= 96.23\27= 3.56 to 1 by the Japanese calculation. Ktm runs 13 .2 to 1 with a recommended fuel of 93 octane (250 xc) standard compression not Japanese .

How far is your cut. The problem is it might ping with too much advance. I would try 4 deg if it pings back it off. If you can't tell if it is pinging do a wide open pull and a plug chop if you see aluminum spots on the very base of the plug then you have detonation and need the back off the timing.

12 tooth front sprocket port job smaller domes 4deg advance woodruff key