rb0804

Looking for a modquad, Noss, or Chariot style head shell. Let me know what you have. I am not looking for the pro design style as they have too many pieces. Thanks

I have a RZ350 Pro Design cool head for sale. It is fairly new I have about two rides on it. I am switching back to banshee cylinders and can no-longer use this head so it is up for sale. It needs a cleaning, I just pulled it off and snapped some pictures of it. Comes with the 20cc prodesign domes, studs and acorn nuts. These are hard to find used and I am asking $150 for it. I am also open to a trade as I need a head for the banshee cylinders. Thanks

Glad to see someone is giving it a shot. I am going to assume your spraying 60 total (30 per hole). I have found that if you run the fuel side of the nozzle a little on the rich side (stagger the fuel jet a size or two larger then the NOS jet), it will be a bit 'softer' on the hit You can change the timing and the plugs back to what you would normally run if you weren't using the nitrous. The Dyna box makes that easy because you can switch between curves. The down side of the Dyna box is that I have heard that running +10 on the plate is not the same as running +10 in the box. That really sucks, sorry to hear about your situation. Have any pictures of the clutch failure? Hope things work out for you. That is the problem with those type of blowers, they take a decent bit of power to turn. To answer your question, No I have not seen a Roots style supercharged two stroke (other then the one that trick racing did). I thought that there were some centrifugal supercharged 250R's out in Cali, maybe the guy that did a lot of testing for the Puma? At any rate, I forgot the word 'should' in my last statement, in that they should run better with a roots. Sorry of the confusion. I have also seen the turbos go both ways with some running good sometimes and not so good other times. It is something that interests me and hopefully I will be able to play with it here sometime in the future.

Does anyone know if they make a boot for a larger carb?

because if the crankshaft is turning it is producing boost. Positive displacement means that if the blower is turning it is making boost. With the turbo you have to worry about the exhaust velocity and temperature. If you loose some fresh charge out of the exhaust it is going to cool the exhaust gases and slow the turbo down. The problem with the roots is that they make excessive heat when you try to spin them hard and it takes a good bit of power to make them turn. A centrifugal blower (like a vortec) would probably work well also as it is more efficient then the roots and takes less power to turn. I am not sure how hard you have to turn them to make boost though. Nitrous is the best option for a two stroke as it is fairly simple, cheap, and requires no power to get power. I haven't seen anyone build a nitrous only engine yet, they are all high HP NA engines and then they spray a little bit of NOS to increase the ET/MPH a bit. If someone was to build a nitrous specific engine it would run really well, but would be a bit on the slow side without it. Every setup has its pros and cons.

Maybe he gave up? No updates for awhile. The two strokes have problems with the losing the charge out of the exhaust which is going to make it hard to tune. The turbo also has to be matched to the application or it will never work, no matter how hard you try. The two strokes work better with a positive displacement blower like the 'roots'style, but they don't like to pull a lot of RPM. I have seen plenty of people try to turbo a banshee and when it gets down to the end like this, you hear very little about it. I will be building a turbo shee here shortly and will be trying some things that have not been tried before. If it works out I am sure you will hear about it, and if it doesn't then you probably won't. lol

Are you guys talking about that little 'window' that is cut out of the sleeve in the area of the rear transfer port?

Counter offer in.

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What is the purpose of the cutout circled in red on the shift shaft itself? What does this mod do?

I could never figure out why they took the time to cast their own cylinders with tripple exhaust ports but they never bothered to 'beef up' the intake side where you would be cutting the Boyseen ports. Seems like the exhaust duration is a little much also. The mismatch of pipes and that high of duration could be the root of some of the problems that I have seen listed such as being jetting sensitive, bogging, etc.

If you look at the run data the alky run was done in warmer weather with more humidity which tells me if the runs were done back to back that there would have been more of a gain switching over to alky. I do however agree that there should be some independent testing, especially when there is another dyno right up the road. The pipes do look promising and I guess validation will come in due time.

Purchased a set of cylinders after posting a wanted add in the wanted section. Super smooth transaction, great guy to deal with.

Have you ever tried to measure the sections of a stamped pipe? Its not cut and dry like measuring sections of a coned pipe. It is slightly more difficult. Pipes are often more desirable then domes and are traded more second and third hand. Maybe asking for a serial number is too much, but I was just making a suggestion since they asked if anyone else had any concerns. I still think that they should issue them with a spec card, that way you know FOR SURE what you have (as a first time buyer of course).

How many times have you seen someone buy a complete engine package (including pipes) and then they end up parting it out. Sometimes the engine goes as a complete item, other times it does not. Same with the pipes. Dave, you belong to several forums. How often do you see an engine advertised with a set of pipes? I agree that they should go together, but this is seldom the case. There are also people out there that will just buy a pipe because it is supposed to be the best. They may not know that there are four different version and probably couldn't even guess as to which one it is. My concern is say if someone is running a shearer or CPI pipe and then they purchase a used Sniper pipe and it doesn't run up to par, then they are going say that it doesn't run as well as the other pipes. When in reality they could have had the wrong pipe for the combination, and it might have worked really well. It is a nice addition that they are going to use builder tabs to help keep some of this straight. There has to be some small changes to the design to fit each builder and each engine combination. That is a necessity. Just curious if the builder is going to have the task of changing the design a bit or are they going to come from you guys (the manufacture) ready to go for each builder style?

Just a concern that I have, and I have had for sometime now, even with other manufactures. If you offer a 'custom' tweak to fit someones certain setup (or even a design change) and they decided to go in a different direction or sell their stuff off (for whatever reason). Then someone who has a totally different setup may purchase and run those pipes. They might not work so good with the new combination. How do I know if I have the new one or the old one? Which one would work better? If a guy is selling a Sniper pipe that was tweaked for the 421 and I go bolting it on my 370, we might have an issue. Basically what I am getting at is that you should do one of two things. Either serial number each pipe and keep a note of it so when someone calls, they know exactly what they are getting or send them out with a spec 'card.' In the 4 poke world when you purchase a camshaft you get a cam card with the cam specs on it. Really, the same should apply to two stroke pipes. This should include the bore x stroke as well as the port timing that these particular pipes were setup for. This card should be kept by the purchaser and passed along to any potentail buyers down the road. This will help keep your name on top and will help keep things straight if you start to offer 'custom tweaks'. I am curious to hear some thoughts on this.

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any idea how deep that scratch/bevel is? Thanks

any one else?

can you send me a few more pictures of the exhaust port to [email protected]? thanks

how much you looking to get for the cylinders and pistons?

looking for a set of reasonably priced stock unported cylinders under 66mm bore. Let me know what you have.

looking for an ouboard bearing support. PM me if you have one. thanks.

you have a problem building boost, and the pipes are contributing to the situation, along with the other things mentioned above. Could be the turbo is wrong for the application. It might be as simple as changing the exhaust housing ot the exhaust wheel, or you might have to buy a new turbo. Even without the fuel injection there is alot of things that you have to get right.

your boost problems are exhaust related. You either do not have enough volume trying to spin the exhaust wheel (wrong turbo for the application), your tune up may be way too fat. The engine needs to be in a fine state of tune to have the exhaust gases expanded to their full potential. There is a common misconception that turbos need backpressure. Backpressure is a necessary evil with the turbo setup. When setup correctly there will be some. Too much and you will hit a wall where you cannot shove any more air into the engine because the exhaust is all backed up. Turbos also do not like feeling the 'pulses' from the engine. The pipes need to be merged before the turbo collector and is why you always see turbo setups with the dyno port two into one pipe. The fuel injection is going to solve a lot of the tuning issues associated with the blow through setup commonly used. as for the nitrous that is a trick that has been used since the 80's for a turbo that is too big for the application where they were unable to make boost sitting still at the starting line. It was usually used for the first 60' to get things moving. Some people running gas would run the nitrous all the way down the track and use it as sort of an intercooler.