J-Madd

200* exhaust, around 135* on the transfers I think. Don't know who ported them. Crank not for sale.Of coures the powervalves should keep the exhaust timing down until upper rpms.

Jeff @ F.A.S.T. has them in stock. A little play is common as the rubber/polyurethane cushions wear. A new basket will come with new cushions as well. There is a sticky at the top of the forum about changing the basket.

I can't help you with the mx vs dune port dyno charts, but I see that your planning on buying a Hinson basket and straight cut gears?? That money can best be spent elsewhere. Buy a magnum billet basket, and just run the stock helical gears.

Any make of crankshaft would work. Carbs would depend on your preference. 39 pwks, 41.5 Lectrons, 38(?) Mikunis. All would be fine.

So if you run your motor without the head, crank, pistons, or transmission, the cases won't flex?

Oh, and that's not including the cost of the powervalves or the block offs either. The block-offs are over $100; I don't know what the powervalves cost.

TTT These are $800 new, plus nikasil, plus polishing plus porting. $625 obo. Or trade for drag a-arms.

I don't see how the bike in your sig would be ridable with anything over 120 hp?? That's got to be a handful, even with a bar. I know that 20 mil laid down some good numbers at the track. If I remember correctly, I think he was running it with the triples at the last race at Outlaw last year.

I had a PVL on my 421 for a while and it sounded real fast. It wrapped 12,000 rpm probably with just a blip of the throttle. Track times were the same as stock lightened flywheel, though. ..and this was even on a 50 lb lighter chassis with the pvl. PVL is a different discussion altogether, I know; but I thought I'd add that, given it's extremely light weight flywheel.

If that's Denny's old bike, that s.o.b. will run! What is the bore on those cylinders? Those clyinders look huge in person.They dwarf my little twister cylinders.

Asking $625 shipped for these. They are dirty in these pics, but clean up to perfection. Nikasil and cylinder bore in good condtion. They appear to have been ported. You will get polished Trinity Stage IV powervalves also, not included in the pic. Block off plates are not polished. EDIT: 74.5 mm bore, 70 mm stroke (+16 mil). 610 cc. [

I had one and the slave cylinder took a crap in a couple of months.

Do you have a stator, flwheel, cdi, and ignition coil?

I don't think you'll get the 8-plate and lockup under that stock cover. You may get by without a lockup for a while. You will want an override either way, though.

The 8 lb BFH that I have today was originally purchased 7 years ago for that same job. I also had to cut the bearing races out with a dremel that was bought solely for that purpose.

I run them on my smaller motors. BUT I have had 2 slightly come apart enough that the magneto was bad/out of time, and one the started the shred on the outer radius. Looks like razor blades sticking out of it. We probably just had too much cut off of them....most of them lasted 3 years or so. I wouldn't hesitate to run a lightened flywheel for 300 ft drag racing with any rider weight. Just inspect them often, or don't get too greedy on the lathe. On bigger motors (14 mil+), I don't think it's such a good idea (nor is it needed, imo.)

Also..you want to run B9ES, BR9ES, B9EGV, etc plugs gapped at 0.018". I run my alky at 20:1 (1 pint to 5 gal). Learn how to read the plugs. No color on an alky plug means that it is rich (and safe). Black on an alky plug is very bad.

I have wondered why the Keihn dumps are not replaceable? You can take them out. I even took some out of one set of carbs and put them on another. Granted, it did not run right when I did that. They were drilled out way too big for the engine I was testing on. DOn't know if that was the reason, or something about the dumps not installing correctly in another set of carbs?

What he said.

Good luck and definitely keep us informed!

My (clean up ported by F.A.S.T.) 421 made 100 hp and 60+ ft*lbs tq on alky. A fully drag ported 421 made 104 hp on that same dyno on a different day.

70 hp Banshee = rideable and reliable 70 hp YFZ = ticking time bomb (Hell, Both '04 and '05 stock YFZ=ticking time bomb in my experience!) Also, 70 hp YFZ = $$$$$$$$$$

That's probably because your still reaching the same max RPM with either set of carbs. Surely your e.t.would be better with the bigger ones, assuming they are jetted correctly.

Pressure test it before you put the clutch and stator assembly on, just in case you have to split it back open for a leak. Use all new seals.

RDZ OOFs are freakin' loud. I love mine, but if decibels were an issue, I'd take the above suggestions, or go with some silenced OOFs.