Wildcardracing

They can only be bored to 27.5mm. Call Lynn at LC performance in Salem, UT (801)423-1382. He'll do a real nice taper-bore and cut your intake boots to match for @ $90.00. That is the best deal I've seen on them. DO NOT let anyone tell you they can go to 28mm, I !@#$ed up a seet of mine having them bored to 28 ::

Get some K&N's then Get it ported!!!!! That will give you the best bang for your buck, Find a reputable builder ie: HerrJuggsRacing, F.A.S.T., PassionRacing, K&T ect. Have them do a port that matches the type of riding you do. K&N's $70.00 Port Job $300-$400 Cool Head $150-$250 Timing Plate $40.00 Reeds $60-$230

28, From Idaho near St. Antony now live in Utah 30 mins from Little Sahara. Always lived near the dunes and worked on everybody eles bikes, finally bought my own in 06.....I think it may have been a down-payment on a divorce she's jealous of the shee. lol

I run ported stock cages with boyesen pro-series reeds :thumbsup: I just trimmed down and knife edged the bridges in them and cleaned up the lip on the sides so they are smooth (careful not to take any mor material than needed to smooth them out) I also transitioned the floors and roof of the cages to smoothly flow to the pedals. Got about 20 hrs on them now with no problems. Sorry, can't post any pics I only have the basic account on here.

Also keep in mind that my sled is almost 600cc and the porting on a sled is more like drag porting and is designed to make a lot of power in a very small window up to 9,000 rpm. The turbo it has starts to spool at about 4,500 to 5,000 rpm. You may want to consider a somewhat smaller turbo for your displacement and you'll probably want it to spool at about 2,500 rpm. you're also gonna need a LOOOOOONGER swing arm, lol. When that thing starts to spool up HOOOOLY SHIIIIIIT!!!!!! :yelrotflmao:

It's an Aerocharger model # 114N250A, it measures @ 40mm at the intake impellor and 50mm at the mouth of the intake. A small turbo would spool up a hell of a lot faster (build more bottom and mid power) A larger one would have a lot of lag, but hold on when it finally spools. 2-strokes consume a lot of air, I've seen guys using turbos off diesel pickups on larger sleds (700+cc) for hillclimb competitions where they are wide open the whole time. guess turbo size would depend a lot on what kind of ridin u do. you might try one of those smart turbos and see if it spools enough in the top end, you might be surprised. I'll let ya know more if I can. SLO

Another idea is to do like the automotive guys with turbo/carb setups. Enclose the carbs in a box that is pressurized by the turbo. This would save space and aleviate the headache of drilling and tapping the carbs. you could make the box so it bolts right to the cylinders with your manifold bolts. Have a lid that bolts on top to get to the carbs, would look kinda trick I think.

I'm looking for a stock (nonported) Left cylinder at 64-64.5mm bore. I'm willing to buy a set. Please let me know. Thanks

This would make a great sleeper project, it's the equivelant of 19cc domes. make me an offer!

OK, sorry it took so long but I took a good look at the sled. Here's what I got: It has dual carbs, just regular VM 40 round slides with a fabbed aluminum intake box (dual out single in) fed directly by the turbo. As for your question on the vent lines, they have been clamped and plumbed into the intake box so the bowls are under the same pressure as the venturi. The carb caps have also been drilled/tapped and have lines to the intake box, to also provide equal pressure on top of slides so they will close. The carb flanges (manifold side) have been tapped into as well, Right one is plumbed into the wastegate (one of three lines on wastegate, other two go to hi/low switch and intake box) Left line goes to over-boost warning light and aux fuel pump switch (turns on electric pump when turbo spools). There is a small 12v battery to supply power for the pump and warning light. There have been two gages added one measures crankcase pressure and the other is fed off the intake box to measure boost pressure. I need to research it some more for how significantly the jetting was changed (low speed is stock, needle has been changed, and the mains are huge) I'll have to dig further and let you know. The waste gate opens at 6psi (any more and crank seals/base gasket start failing). I have to run 100+ octane at 7,000-10,000 ft. elev. The engine is a 583cc rotax otherwise completely stock, it dynoed at 155hp to the crank at 6psi. I'll try to research how much the jetting was changed from stock (might help give you an idea where to start). Hope this helps a little. :thumbsup:

Correct me if I'm wrong guys, but a 421 cub (unported) should be in the 70-80 HP range at sea level depending on setup.

Glad to see that the porting had the results you were looking for :thumbsup: Hope my advice was helpful. Once you get them bored and get the compression up they should be a lot more impressive, you'll have to let me know.

I've got a turboed snowmobile (2 stroke), I'll have to look at the carbs and get back to ya. They are just VM40 mikunis, but they have been modded a bunch for the turbo setup. My sled has rotary valve instead of reeds, my question is what effect would placing poitive preasure on the back sides of the reeds at all times have?? Would they close like they are supposed to? Has anyone successfully turboed a banshee?

That's a damn good deal if you're getting new pistons gaskets and o-rings included. I totaled my last rebuild up and was at about $275 for what you listed, once you include shipping you'll probably be around that. What pistons and gaskets is in his top end kit? I went with Wiseco's and Cometic from rockymountainatv

I have an oem head for sale, it has been milled .040" and comes with a new head gasket. It made 145psi static compression at 5000' elevation on a fresh topend w/stock port timing. Asking $50 obo, you pay shipping

Got a timing plate and some 21x12x8 10pdl haulers for christmas, and sent the crank to be welded and flywheel to be lightened. So, while it was apart I went into my porting a little more aggressively and polished the cylinders up. Shee's gonna look good and have a hard time keeping the front tires down with my +2 swinger. I can't wait to get out and pick a few races at the sand hill!!! :biggrin:

20's for a sraight line??? NO NO NO Go with some 21's or 22's on a 8" blue lable in 8-10 paddle Hauler not Extreams. The Extreams are for built 500+ cc drag bikes, IMO.

I would do what your builder recommended and run some 21 +2 domes. 205 is a lot of compression.

I disagree, depends on the race. If he's racing MX ect. go for the suspension. If he's drag racing go for the engine. I drag my bike mostly $1500 suspension won't do shit for me. JMO

Most of your power gain is in the exhaust ports (mid to top power) You can widen and raise them some (a couple of mm unless u want a drag bike) .The fine details in the intake, transfers and case bring back up the bottom end power and add a little more everywhere. The exhaust is the biggest deciding factor in how much power and where the power band is. Blend your transfers where the jug and sleeve meet on the bottom side and knife edge the bridges in them. You can also clean up the casting flaws where the transfers enter the cyl, but be carefull not to take too much out as this will hurt ur bottom end. The earlier pics are pretty good for the intake windows. Make sure both cylinders are identical (Measurement and shape) and be sure to chamfer the ports so you don't hang a ring.

The CPI's come on a little soonerso they are more rideable in the dunes, but are still a great drag pipe. My concern is your paddles, 18 pdl is way overkill on a stock stroke, dune ported bike. That is probably a lot of why you're not pulling more in sixth, I would recommend the 9pdl brats or 10pdl haulers for your bike 22x11x8 on blue lables.

Give Lynn at LC Performance a call. (801)423-1382 www.lcperformance.com He does 27.5mm taper bore on stockers for $90 a pair. Was just at his shop today, he does real nice work and is great to deal with. Don't let anyone tell you to go 28mm on them 27.5 is as far as they can go. Trust me !@#$ed up a set of my own having a machinist buddy bore mine to 28. Lynn will also cut your stock intakes to match the taper, I'll bet he would include that in the cost.

overbore won't change the duration, but it will change the crank degrees when the port opens because the ports angle downward.

They do make a "Smoked Honda" scent... It's called Banshee exhaust, I hear "Smoked 4 Stroke" scent is exactly the same lol :yelrotflmao:

It's a great thing if ur the parts guy or if u like burning holes in the top of ur pistons