J-Madd

What ignition timing are you running?

Jason Menz's n/a 397 Cub is faster than any 10 Mil Cub or similar size motor that I'm aware of, p/a or n/a. So if a 10 Mil Cub does have a record, it's not as fast as his 3.58. If anyone knows of any Cub running faster than that let us know. As far as pipes, that depends on the porting. I have a 10 mil that loves BB CPIs and one that loves SB Shearers.

If your running a 20" tire your gonna need 19/38 or so if the tires grow at the other end. If they don't, you may need a 20 on the front.. I've never ran the 8th, but you'll need to be geared to run 100+ mph, and that motor should pull it. 16/41 and you'll be out of gear at 1/2 track. http://home.earthlink.net/~gellett/banshee.htm

My guess is electrical. CHeck the pickup gap on the stator. If that's not it, start swapping out electrical stuff. Cub jetting is very forgiving, it would have to be waaaaayyyyyy off to not launch in grass without bogging.

I usually run EGN. 0.118" - 0.120" dumps work pretty good on a 10 mil Cub with those. I run Lectrons on one, and PWKs on the other (10 mil Cub).

Too many things to troubleshoot with the PVL. 2 stators and 2 coils. It's hard to tell what's wrong with a pvl when (not if) it starts screwing up. They also offer no advantage (imo) over stock. Like was said, the curve is real flat on them and they don't retard enough at higher rpms. That being said, some run them and love them. I basically gave a way about 5 complete pvl setups a couple of years ago.

You can run a standard direct drive style lockup and bigger cover, or a slingshot style lockup and run the stock cover. You may also get by running some heavy springs, but the clutch pull is gonna be harder.

I'll be there with 3 or 4 bikes.

Has it ever ran right since rebuild?

Make sure the TORS is unplugged. If so, try a different CDI and/or Stator. RM stator is junk, sometimes even brand new. What pipes, air filter, etc? What jets are in it now? I don't trust most "shops" to do the jetting. It takes less than 10 minutes to do your self.

There is no non resistor B9eix, only BR9eix, I think. I run BR10EIX in a motor.

They performed like BB Shearer's on my 10 Mil Cub. Made about the same hp as SB Shearers, but at a lower peak rpm. That's what the BB Shearers did as well.

Put the CPIs on there. The Toomeys are killing it. It could probably use bigger carbs as well. I ran 39mm on mine on gas or alky.

Thanks for the correction. Maximum makes more sense. Feet per second/meters per second is probably user preference of standard vs metric. But if meters per second is more commonly used, thanks for that correction as well.

I can't really tell whats going on in these pics. Is that new screw opening/closing an orifice in the carb body (acting like an air screw on other brands of carbs)? Or is it just an idle screw? Mine already have idle screws (that I don't use.) I'm not doubting the idea, just do know what it's doing to allow fine tuning between the notches in where the needle has to rest. I understand that raising/lowering the needle for tuning will also affect the idle. I need some more clarification, I guess.

Maybe try some OKO 30 mm carbs?? They're cheap enough, and you can get some of your money back out of them if you don't like them.

I won't pretend to know much about how to set up a dome. I am just regurgitating what I have read over the years. MSV is mean squish velocity and there is a certain speed your looking for (I don't recall what it is), measured usually in fps (feet per second). When you change the squish band width or clearance it changes the velocity. YOu get too much velocity and you can get deto (or maybe preignition), too little and you don't maximize the power output of the motor. The MSV can also dictate how far the motor revs out, or when it starts pulling. This would have to be matched to the rpm range of the pipes I would think, to optimize power out put. The squish band is the part of the dome that is near parallel with the piston crown. Builders tend to run a narrower (or is it wider?) band for for the quarter mile vs 300 ft. The band can also be varied to accommodate for rider weight I believe. Same can be said for the angle, I think . Builders may run a different angle for 1/4 mile vs 300 ft. It would be best to talk to a builder to get the best dome for your motor. If you don't know the deckheight, here's what I do (I find it hard to measure it using feeler gauges, and I don't have a stationary dial indicator). Check the squish with any dome and make a note of it. Measure the step in the dome (the height of the sealing surface that the o-ring goes around, measured on the inside), and subtract the difference. If you have for example a 0.050" squish clearance with a dome with a 0.045" step, your deckheight should be -0.005" ( 0.005" in the hole). You'll need this info when you go to order the dome. Your builder can tell you what angle, width, and clearance to run, but he'll need the deckheight to get the clearance right. If you know what specs you want to run, you can call or email Noss and you'll have your custom domes in a couple of days.

What does the head look like? It's ALWAYS a good idea to pressure test before tearing down after a failure. That way you know if and where it was leaking. Now you won't know for sure, though it does appear to be an air leak. We've all made the mistake of hastily tearing them apart without pressure testing, though.

Most just use a cordless drill battery for such things.

Yeah, some will run a different angle and squish band for longer runs. Keeps the MSV in check.

I like 25 pilots with those pipes.

These motors aren't finicky at all, in the way they run. LOTS of room for error (at least in 300 ft dirt racing; less forgiving in the quarter.) You can change all sorts of things on my Cubs and they still run about the same (not saying that's a good thing.) Now a bigger motor - you can just have the air/fuel, timing, or domes a little off and sometimes they won't even run down the track.

On my stock carbs I've ALWAYS set the idle with the cable. I even ran a set with the TORS delete and didn't have the idle screws installed. I never ran into any issues. None of the drag bikes idle, so I don't worry about those anyway.

Are you launching in 1st or 2nd? I don't think your main jetting is that far off, and if it was it wouldn't drastically affect the way the bike launches. And most do run the pro wedges/4 snows backwards. FYI.

And to address the question about backloading in 5th gear. It's ok, but no one does it. I'd say the main reason not to just let the engine slow it down at the end of the track is that it keeps the pistons and crank moving at a high rpm, yet your off the throttle and not feeding the motor with oil/gas(alky). I have seen 5th backloaded on the dyno lots of times to help slow down the drum (no brake on the drum.) You must have a pancake bearing if you have an override. FYI.