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Plug Chop


kenyounot

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Hey K. Many factors will make one bike need different jetting. If I had to guess I would say your domes were pretty aggressive or exhaust port is somewhat higher than the guys running mainjets in the 150s. If you want that bike to run quite a bit better it looks to be able to handle quite a bit more timing by looking at the ground strap. Adding timing requires quite a bit more fuel as well however. One thing adding timing does is it takes heat away from the pipes. You stated that the pipes were getting very hot. If I were tuning that bike I would go up on timing from where it is at right now and start at least 3 or 4 jets richer. I really dont think that chop looks lean. If its between the thickness of a dime and nickle it shouldnt be lean regardless of that grayish color. It appears to be a darkish thick gray and wide enough band. Some fuels and oils give wierd colors. Sometimes gray, brown or even yellow ring. For a rider or duner bike I shoot for a smoke ring the thickness of a nickle/quarter. On a 300 foot dragbike I tune a hair thinner/leaner.

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If you see the color change on the groundstrap it is out towards the end a hair. I think it will like 2 degrees more and if you go up a few jet sizes I think your plug chops will look a bit more pronounced and give you a good reading. The bike will also become much snappier down low and off idle. Just watch the jetting on the needle. If you do a plug chop at 1/2 throttle you want richer than WOT and more color on the plug.

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Welp went to do the plug chop even had my helmet on and just had a irk to look into the heat problem more. I took the rad cap off and started her up. No air bubbles... gave it alittle chop on the throttle and it bubbled a little. Something just didnt look right. So I pop the exhaust off and the gas tank to retorque heads for a 3rd time. As I was under the bike I noticed green liquid building up around the exhaust spring bracket. Look up and noticed a green lining in between the head and jug. Retorqued again at this point it was too late to start it and check. So I decided I'm going to run another leak down tomorrow since the exhaust is off. Then start it and see what happens. If all is well I'll continue my plug chop adventure, if not then well I'm beat. Gasket was OEM torqued to specs and retorqued after break in.

 

As for the timing, I'm at +6 timing right now should I still advance or would a coolant leak cause the discoloration at the strap?

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i would have never said advance the timing anymore. strap already looked sand blasted which is a good indication there was detonation. either lack of fuel or too much timing or both. you can cover it up with fuel, back the timing off or both, but hey i'm sure someone will correct my advice. start safe and then start the leaning process. it's not a drag bike....

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K boys. Leak down test passed. I should have done the leak test before retorqueing the head bolts to see if it was leaking there. I kept the same 162 mains in to see if there was a difference and in my opinion there is. Head gasket must have been leaking. Still kinda grey looking though.

 

Sorry for second plug my cutter went dull and the replacements I bought were for a different quick connect on the dremel.

 

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