RadarRacing

If it doesnt work then its not the timing being a couple degrees low. Loose squish usually doesnt improve anything by adding timing.

Most all the guys I know that got egt gauges ended up burning motors up within a year. Honestly the best advice you can be given is to tune correctly either with plug chops or on a dyno with and AFR gauge and you are good. The gauges are a terrific idea and would be terrific if they worked perfectly but they do not due to numerous factors. My 10 mil would probably read just fine and low egts even with piston burning temps.

No x2.

Thomas, if your deal on the stators falls thru I will take em and give your dad the cash. Todd

Plug chop?

170s too lean you say but ran better with 152s? This makes no sense. Do a good plug chop and post a pic.

Very nice clean bike. Glad something finally sold without parting for once.

Looking at my notes , I had a .020 base gasket on my 421. Hopefully it is just carb jetting , otherwise I would swap some ignition components. Definately check needle and low to mid jetting.

I hope guys that read this know that a not jetted right 421 cub, with not much timing, with the wrong thickness base gasket will bog. Thats the moral of the story there. Cubs and anything with high porting will not be happy with one or two things slightly off. If it has .040 squish with a .020 base gasket then that is honestly the biggest issue in my mind.

Ground strap burned off and porcelain missing is almost always from being lean and then detonation (hammering) causing the porcelain to break. You can be fine on jetting and run a bowl dry if you make a very long run and you run a bowl dry. Dont run any 2 stroke with stock bowls on any carbs for a long long pass. I have seen 90sn blasters , polaris 400s, and banshees all run bowls dry. The single cyls rarely do motor damage but a banshee will for sure.

1/2 lb for a few minutes is a PASS if you ask me. I never worry about em if they will hold for that long. It would proba ly be leaking slightly from the crank key, and washer if you want to seal it. Otherwise it passed IMO.

Cut and splice/solder if you want or compulsive concepts sells plugs, adapters and makes new harnesses.

38mm or bigger if its a dragbike. Lectrons, Keihins and Mikunis all have fans. 34-35mm carbs will only be down a couple hp on your stock cyl so if you have those you can keep em and convert them to alky to save a few bucks.

That intake wont do anything different for you. Tuning like jetting or timing can fix bottomend bogging issues. You dont say whether your bike is on gas or alky but both can bog off the bottom when rich.

It has higher c9mpression than that with 18cc domes. Since Kevin Herr did the porting how bout you call him and spend $60 or $100 or whatever he charges for his domes nd have him hook you up right. Spitting plugs out doesnt ALWAYS do damage quickly but it can. I dont even check cranking compression because it isnt necessarily correct depending on the motor and gauge. I check squish and CC the volume and check the math.

Detonation backs plugs out. Ditch those 18cc domes asap.

Made me laugh, Im not gonna lie. Bama, he means where do you have it set. Sluggish out of the hole is usually rich. Thats where most people have them tuned to and why they get beat by 4 strokes.

Gotcha , sorry bout my douche response sheerider11, I have drank about a half gallon of my home brew already tonight so wasnt thinkin right. You did exactly what you should to tune and have it running good.

If he thinks differentoy he shouldnt do the smart alek "hmmmm" there arent nearly as many helpful people on the forums as there were years ago. I have tuned more than a couple bikes and if that ring is 1.5mm tall like it looks then its plenty good and safe. Even 1mm tall has been good.

Yeah sprinkler is actually correct. 5k ohm (5000) not 5 ohm. Shoulda said 5k ......LB05F is what I get if they have that number. I also use a resistor plug but have used B8ES or B9ES tons of times as well.

Just use the resistor caps under 5ohm. This has been debated many times. I run ngk ones from the auto parts store, kawasaki ones for vtwin mowers, honda lawnmower ones, jetski ones. They all work just fine. I am picky about em and replace them every year or so. Im not saying NON resistor ones wont work just fine. The resistor ones help prevent cdi damage and interference.

Heck , dont blow it up. You can just get your stock cyls dune ported for $300 if you want. A serval with domes, pistons and cyl will be $1200 or more.

Clean up everything in there. The flywheel was painted but should be ok. I would clean it all and reassemble with the pickup gap set at 16 to 18 thousandths. You could even have all that blasted by someone who blasts with a softer media like crushed walnut shells. Most sandblasting places can do that.

I think on a dyno with air fuel ratio readings you will find you are still one or two jets safely rich. I think you are good and did a good job tuning.

You do not need to go for 10 seconds straight, it just needs to be wide open throttle and wound out hard for a few seconds. In that much time (10 secs or more) a really far run can run a bowl dry and do motor damage. Start over with new plugs, ride for a minute or two and get into 3rd and run it thru 5th hard and kill it. That will be close to probably a 4 second run. Honestly dont run your bike fully wound out for over 10 seconds unless you wanna blow it up. Lol.