J-Madd

Hey FIREHEAD, not really questioning you at all,but we've read (on Planet Sand) that the mini twisters need a lot of port work/machining to make them right. Why have we heard wrong? I know you know your shit.

OK. BTW, 175 seems a little low for 19 cc domes; I've got 180 with 20 cc domes on my 421 Cub...but every motor is different, and even different testers will yield different results (so I've heard).

I didn't change domes when I went to alky. I've also heard about alky domes, just don't know the difference...and you'll need to actually test the compression, and not go by the chart.

You may be able to bump up you timing a little, especially if you go to alky. I went from what you have now to what's on your list (besides changing the domes and drag porting), and it is night and day. Dropped 4 tenths or so in 300ft. Don't forget to gear up a little if/when you go to alky.

Yes, you have to split the cases. Go ahead and replace both seals while you're in there. I think my right side seal is bad, too; my tranny oil level keeps slowly dropping....and I just split my cases and put in new seals when I installed my override.

I know of guy that runs 400 mains in one of Jeffs Dune ported motors, and it screams. Not sure of the pilots or needle clip position.

Stock air filter? Lid? Temperature? Approximate elevaton? Any other mods? A little more info, and we can help ya out. :beer:

Nght and day.....at least on the Cub. I have a motor like yours and a 4mil Cub. Probably only about 3 tenths or so difference in 300 ft, but the 4 mil pulls 10 times harder it seems. I've ran +9 timing on my Cub, but I think its back at +7 right now. It was getting hot quicker than I'd like.

I'm in the same boat you're in. (4 mil Cub, 39 mm keihns, egn needles) I got my mains and dumps drilled out to 1/8'' drill bit (supposed to measure 0.125 '', but I mic'd it at 0.122'') and power jets all the way out most of the time. I'll lean them out a little if I'm competing and not just playing around. Let me know how the 2nd power jet works out for you, Im thinking about doing the same for the colder weather, just to be safe.. BTW, you runnin' a fuel pump? Will a second pj drain the bowls quicker if not? As far as gearing, Im running 15/42, 1-5 override and I'm through all of the gears as quick as I can shift them.

That's just how I tune them. I'm on alky now, and richer than everyone else, and still running great.

Man...on my stock stroke Cub (392) w/ 35 PWKs the smallest main I've ran is 165, and 52 or 55 pilot...on my 4 mil 421 w/39s, 170 main and 60 pilot.(300 ft elev) What needle you runnin'? I'd put a fat main in there and see how it likes it, and lean it out from there...maybe 170 or 175. You don't want that thing leaning out in the 8th mile...and why the gearing so high; to shift less? And if you're on gas, I'd put the br8es back in..9's are for alky. jmo

b, Was that you saying that you ran a few tenths slower against the fastest pass of the weekend, but barely got beat? You prolly treed the guy out of the gate, that's why he ran the faster e.t, but at the finish line, the race really didn't reflect that great of difference. Just something to think about. :thumbsup: I ran slower e.t.s in my class, but won due to reaction time.

Thanks...you didn't do so bad either..what was it?? Only 4 first place trophies and 2 second places? :thumbsup:

Well the dome of the two pistons look identical....Blaster style, but one piston is shorter than the other.

If you already have the Boyesens, it's probably not worth the $300 bucks or so. But if you can sell the Boyesens to recoup some of that, I'd say yes.

Thanks for correcting me!! Yeah, you would have clutch pull in the absence of fibers, because it is dependent upon the pressure plate moving against the springs, not the movement of the plates/fibers.

If for some reason the basket was "Stuck" to the inner hub, the crank would turn the drive train, but you would have no clutch pull, and the clutch would be useless...when you put it in gear it would just go.

Is this a joke? :shrug:

Yeah, its about time we got a peice of that DS What scares me is what you're gonna have for US next time, lol. We will definitely be at the The Clash next week. Gonna leave early Thursday AM. We were gonna leave Friday morning, then realized we would have zero practice if we did that. We're staying at Winnsboro..I think Jeff is gonna ride my slower Banshee in the 400 and under limited class; and I'll be stuck running in the 400 and up limited class ..but regardless, we'll have a good time..

I have 34 mm keihns already converted for methanol, along with pro design intake (made for a big boost bottle, although it has been removed and capped off) I'd like to get rid of. I know they're 34 mm flat slide ..i think they're PJs...I can look for sure if you're interested.

I'll have to check the various "ash trays" in my shop to see what pistons they are. I just ordered big bore domes and put it together (the first time), sent it to Jeff the second time to have the crank trued and welded. I was pretty sure they were 68 mm Banshee pistons...I'll let ya know.

With those mods and + timing I ran 25 pilots, stock needle in middle, and 350 mains. A little rich, but it ran great. 300 ft elevation, 60-95 degrees F*.

I have a stock stroke, stock rod length 68 mm Cub. It's a 392 cc. Regardless, it sounds like it's not the best setup for dinner, though.

Dave, I thought the stock stroke 68 mm Cubs ran Banshee pistons, and the long rod 68 mm ran Blaster pistons!!?? I've got a few pistons my buddies use for ash trays from my 4 mil 68 mm and my stock crank 68 lying around..I can double check for sure.

Swap plug wires left to right and see if the problem follows. If not check for a leaking head gasket,air leaks around the intake, broken reeds, etc. ..And unplug the TORS and parking brake and check the compression in each cylinder.