Wildcardracing

How many HQr's made it to Little Sahara for the Easter weekend madness?? I was out there from Friday to Sunday. Couldn't have asked for better weather. The sand was great and it was a blast to get the shee out for the first ride of the year and the first ride on my new engine. I really can't complain at all, it ran awesome all weekend long flogging the hell out of it. Maybe some of you saw me around... all black frame and plastics, polished and chromed engine with blue case covers, CPI inframes and the seat says sand on the back. Anyone on here race me??? I was damn happy, was able to stay within a couple of lengths with 2 cubs and a 7 mill K&T drag ported shee with oofs only pulled 5 lengths on me, other than that I was able to handle the stock stroke/cyl/frame banshees all weekend and not once lost to a 4stroke not even 2 that were set up for drags. :biggrin: Not too bad for a garage built stocker.

220 seems awfully LEAN to me, just put FMF fatties on the wifes shee...hers is jetted at 250 and the pipes are absolutetly the only modification. You need to clean your air filters and do a plug chop! A rich condition in the pilot or needle can mask a lean condition on top when just pulling a plug and looking at it. Also, are you certain you got your oil mixture right?? Also, when reading a spark plug you look at the flat on the end of the threads not at the side.

Sure, advanced timing will cause the engine to run hotter. Too much and you can overheat if you're not running enough octane. As with compression, the more timing you run... the more octane you need.

Yes, those are the ports I was referring to, many people call them boost ports or boyesen ports or worm holes. As I understand the "boost port" or dust port as it is otherwise known is the one in the center above your intake windows. BTW, is that pic of the blaster cylinder one from Kevin's website??

The term blueprinting is very broad when applied to engine building. It can be but is not limited to weighing and balancing pistons, connecting rods, using a torque-plate when boring the cylinders, decking the cylinders, balancing the flywheel, correcting casting flaws or differences between two like parts ect. ect. ect. As bansh-eman said it's not a paper blueprint like when you build a house.

Some of the big builders I have talked to and seen portwork done by don't use auxillary ports. I had cut them in my first set of cylinders and Lynn at LC Performance told me to fill them in because he has expirimented with them extensively and found that they slow you down. Rudy Kurtz (Port Magic) doesn't use them and I also don't think K&T uses them either. Also, you're running more exhaust duration than me along with about the same trans duration, I was told I should increase my transfer duration even more to work with my exhaust duration. Keep in mind my porting is a dune port for stock stroke and I am at 26.5mm (196 deg) on my exhaust and 42mm (125.5 deg) on my transfers.... I was told I would see more gain if I increased my trans duration into the high 120's or about 41.2mm from the deck. You may want to research your timing a little more before you go throwing it together.

Advancing your timing ignites your air/fuel mixture sooner in the stroke, thus changing the time at which the strongest part of the explosion hapens in the crankshaft rotation. This will show an improvement in the bottom end power but a very slight decrease on top. Too much timing will cause pre-ignition, thus increasing your octane requirements. Both the pros and cons of timing adavance are very similar to increased compression.

I ended up going up 4 sizes, but that was also going from an aggressive trail port with FMF's to a dune port with CPI's. I am now running 330 mains, needle in the middle clip, stock pilots and air screws 2 turns out on stock carbsat 5000' elevation. (Larger carbs are my next mod) I would say up 2 sizes and do a plug chop.

Kevin Herr, hooked me up converting my measurements , my transfer duration is 125.5 deg. If I'm not mistaken that should put me at 70.5 degrees of blowdown. Like said above I plan on raising them a little more next time shee's apart. Also checked my compression and I'm at 141 in both cylinders. Thanks for all of your replies fellas.

Domes are sold. Thanks XxsinnerxX

Don't know if I'll be out there that weekend, I'm going this Saturday and/or Sunday weather permitting. Will anyone on here be there (Easter!!!)??

How tight are the trails you "sometimes ride"??? I don't know that a cub motor will be very enjoyable for many trails. They are awesome!!! for drag and hillshooting though. I would go with the stroker or stock stroke small bore, You can still use your existing head with these. As I understand the super cubs require a different head and I would think they would limit your transfer area significantly due to the larger bore. I think yoiu would see more usable tq and hp with the stroker vs the big bore.

Sounds kinda half assed to me, what about the transfer ports and boost port??? I would first recommend that he send them to a reputable builder. Second, the tranfer ports need to be raised some to correct the transfer blowdown (something I'm still playing with). I have had the best luck reshaping the intake, not enlarging or raising the intake windows. The goal is to flow more air without decreasing intake velocity. The exhaust can also be widened. Raising the exhaust 2.5 mm sound like an aggressive trail type port to me. What type of riding does he generally do and what pipes is he planning on running as this will make a difference in what exhaust duration to run. Best bet is to talk to some of the experts on here: KEVSWS6, F.A.S.T, FLOTEK, Passion ect. These guys will steer you in the right direction and who knows, you might find a better price on a better port job. Just my $.02

If your compression is 115 in both cylinders I wouldn't touch the topend. Rebuilds should only be done when absolutely neccissary, your cylinders only have so many rebuilds in them so use them sparingly.

I would personally stay away from the T-6 pipes if you intend to do many mods, from what I've heard they don't respond well to porting ect. Look for T-5's if you want a good all around pipe that still does well with other engine mod. I guess it all comes down to what you plan on doing to and with the bike.

Yes you need to rejet for your pipes. I would start with 260 mains and your needle in the middle clip position. That should give you a start, then do plug chops to get it dialed in exactly. That is if it has stock air filter, no porting or any mods besides the pipes.

Thanks for the replies fellas This is the fourth port job I've done, I've got over 20 hrs cutting alone in these cylinders and countless more hours changing and tinkering with them to make them run better. I'd like to dyno them eventually just to see how much power they make. I don't actually know the exact degree of duration on my transfers, these are on a stock stroke bike and the tranfers are at 42mm from the deck. These pull pretty damn hard and still sign on real early, I am very pleased with the results on these. I am probably going to raise the transfers an other .5mm next time it is apart. :thumbsup:

Running CPI's, I use several 1/4 and 1/8 inch air and electric tools/bits to do them. Yes, they are ramped...the step above the intake windows is completely gone. Haven't got it all back together yet, my comp. should be around low 140's with my 19's (5000')

Here ya go guys, just thought I would post a few quick pics of my portwork. It's a dune port the intakes have been reshaped, the exhaust widened...raised (196 deg.)and polished, the transfers raised a little to match the exhaust work and the boost port raised to come on at the same time as the transfers. Let me know what you think??? I'm not affraid of a little constructive critisism, so let me have it!

I smooth out the lip on the outer edges, knife edge the bridges and cut them to match the windows on my boyesens. I also blend in the transition in front of the screws and knife edge the bridge along the lip of the reed. The only thing you might be able to do to open them up more is to cut the bridges down more for single stage reeds. The outer edges are as far as you can cut once the lip is smoothed. Don't cut the ruber right where the reed touches the cage. Hope that all helps.

Here are a few pics for ya, not real good ones but I hope they help.

Jeff should be able to answer all of your questions and give you any advice you'll need for your 4mill build. :thumbsup:

I've used chem-dip to remove the paint on mine, got a can of it around for cleaning carbs...works great for both. Then I use 400 grit to smooth them up and 500 to shine them before the final polish, they turn out real nice. :thumbsup:

20 mill DM lol :yelrotflmao:

You're probably thinking of a boost bottle (don't bother wasing ur money on one) I've never heard of a cool head cracking. I would recomend 21cc domes for your elevation if you want to run pump gas.