scootergangbang

Ah yes, I am showing my lack of Vespa terminology here! Also, what I have failed to show you is that the cylinder in the video I posted is totally different to the one I have developed! The still photos in the clip are very old, and I no longer use that cylander, as it was designed a little poorly for us to work with! I am very sorry for the confusion guys! On sunday I will post some pictures of the new cylander! But check out this! Also, see attached graph!

(Cyl. Vol. + Trapped Vol.) / (Trapped Vol.) = UCCR:1 Hello! Please tell me why this piston can not make use of these. Do you think that if I put a piston in that did not have these holes, I would have more PS? You cant Pantent Phisical Science factors! Seriously, please tell me why the holes dont work! I want to know! 21.5 ps IS GOOD FOR ME! GNF forever!

Thank you for your well educated obsevations. I am sure you are well aware that there are many "redeveloped" prototypes is circultion at the moment. For example, the FALK cylander is obviously a complete "redeveloped" Honda RS125R cylander, coupled with a "redevelped", and "Adapted" Honda RS125R Exhaust, this is easliy identified by several facors, the least of which is the shape of the exhaust. If any body does not agree with me, then I will prove it!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! I Know this Bike Very Well!!!!!!!!!!!!!! Who ever made that cylander/exhaust is very clever, and more intelligent than me, and I have respect for them, but the fact remains, they simply COPIED, AND ADAPTED SOMEONE ELSES WORK. What is wrong with that? That is how we develop technolgy. You draw reference to the fact that our cylander is a copy of somebody elses? do you have proof of that? Because I disagree! This cylander has a exhaust shape that has NEVER been in production, as well as a piston that has never been in production., I know this, because we developed them! yet, it still makes over 21 PS, and has no welding on the crankcase, and currently uses and old ignition that was in the box of parts that I built the engine from, and a carburettor that is of unknown origin (maybe Bagdad?) You also query the spec I gave you of 1.7mm squish. Initialy, when I started this project, I was suspicious of using squish of less that 1.8mm, using "Pump" fuel, so I decided to go the safe rout, and use a low compression ratio, as well as a low squish. (Because, of course you know, the two components are releated, but also different) Now I am happy to run 1.3mm In my ealier posts, I mentioned that we now run 1.3mm squish, and this is what we now will develop the cylander on, as the fuel available at the pump is now less than 91 octane Remember that modern two stroke road machines run an average of 2.2 mm squish! Please remember that "a raised exhaust port height also raises the Dynamic compression ratio of your engine, reguardless of your squish!" The formula I have based this cylander porting and squish on is thus: (Cyl. Vol. + Trapped Vol.) / (Trapped Vol.) = UCCR:1 (I prefer to work in UCCR, rather than CCR whan I work out my port timing.) It is very important to rember this. "WHEN THE FLAG DROPS, THE BULL SHIT STOPS!" And the proof will be a 20 PS cylander, "plug and play", I believe will be available next summer from GPS. Thank you for responding in English, I really appreciate it!

Thank you for advice reguarding the sensor, I will contact them! In reguards to the carb size, I intially was using a 26mm round slide Dellorto, and recieved very poor results. So decided to move to a carb type that I was familure with (sometimes called a "D slide") THe Koso was not my first choice, but was easily available. THe attached graphs show the lower figure (RED) using the same exhaust,(A redeveloped PM) ignition timing,and cylander, and only changing the Carburettor. The Green line is with the correct needle, main jet, and ignition timing. The cylander has porting as per the origonal, and squish of 1.7mm It is important to remeber that this cylander is being developed with a "Plug and Play" road rider in mind, and we need to find a compromise on almost every factor, so the customer can chose a carburettor, exhaust and ignition that they want, and still be rideable. I would like an opportunity to go "Full noise" on the tuning, but at this tage, that is not really viable. In reguards to the casting, Yes, they are cast in Vietnam, it is simply a decision based on cost, given the low volume demands (currently). I agree that there are some very poor quality items coming from there, but this cylander is not poor quality. Being only a prototype, it would be on par with most any other. I would like too see more Zinc used in the melt (just to get sharper lines) I understand your desire to call the chamber the "HammerZombi", and respect your hard work and effort, just as much as I respect Norri Kerr's efforts. I just don't want to start a war that no one wins. In respect for your work, I will call it A "Modified Hammer Zombi"

I am still working on the details from the starting point so I can post it, but yesterday we fitted a MODIFIED Norri Kerr designed exhaust, than was redesigned to improve overall horse power, and torque. The cylander remains the same as the previous run, and the only other change is that we now are able to run a 32 mm Koso non power jet model (previously we could not run anything bigger than 28, with a power jet) I am currently happy with the porting on the cylander, and will leave that for the next few stages, as today the machine shop returned our next prototype part for the reed block, which earlier tests have shown increased torque and power at earlier RPM, although the testing was done with a different exhaust system, I feel very confident that by next Tuesday, we will have 20NM The next days will involve testing of the opening and duration times of the Reed Petals (although we will not be using carbon reeds), and Wolfi fabricated a new part for me today that makes this stage more simple. I have a new idea involving the exhaust that I want to try as well, so it's a very busy time for us all at the moment! Can any one tell me where I can get an exhaust gas temperature sensor from in Germany?

New Zealand (#4 in the photo) Full throttle from here to Bagdad you say? That's good for you! Maybe we can ride there together?

Hey, That's good for you! It's always goos to have something to aim for! I always like to see an engine that revs! My computer is not very good, I can't see clearly if there is a readout for torque on your runs. Is that possable for me too see? Very cool results!

OK, will do then! This is a preview of a cylander we are still playing with, and will include the developments we have learned with this on the current cylander (the parts should be here next week), and as the graph shows, increases torque significantly!

O.k, After all that, with a little help from a computer/scooter Nerd, I have all the screen shots I need. If anyone has the interest, I can write a small story on the development so far, and include some graphs as well. Neil

Hey, That is a topic I have discussed with several people, since the day we started! And it's a really good question! The fault you mention (in racing circles, often called "cold siezure"), was a common problem in the late 80's, and mainly occurred on "high port" exhausts (much like any performance cylander of today) Initially, I was was concerned with this being a factor, but after more than 300 hundred dyno runs (and several ride outs,) I still have not had any problems with this. I put this down to the correct quality of Cast Iron used, the correct piston to bore clearance, as well as a "high silicon" piston, that also uses a low friction coating (much like KTM) I have now increased the exhaust temperature quite alot (with revised exhaust port shape and timing,) and still have seen no problem with this yet. In the next year, I hope to get an exhaust gas temperature sensor (was well as a detonation counter) to help eliminate this problem occuring in the future I hope this picture comes through clearly! Reguards Neil

Hey Everyone! Unfortunatly, my German is a little poor (too say the least), and it is much easier for me to type in English. I read a few disparaging comments reguarding the GPS cylander, in particular it's design and development. Firstly, I should indroduce myself! Those of you who havn't met me, My Name is Neil Freeman, and I work for Tom and Wolfi at Die Roller Fabrik, and am responsable for the development of the new GPS cylander. I have been in the motorcyle industry for 13 years. I spent 5 years racing 125 and 250cc GP motorcyles at a national level, and learned alot of development skills in the process. In addition to this, I have been operating different Dyno's, in several different countries for the past few years, so I like to think I know how to interpret the data I get! Oh, and I am also the person who put the Video on Youtube last week! A few members of this forum seem to think it is clever to find fault with my/our results so far, and I think I deserve a right of reply! Currently, the cylander is producing 21.3 PS, with 17.5 NM, which, from what I can see from other peoples results, is not too bad, considering the crankcases are not welded, and only matched to the (now larger) transfers of the Cylander, while the squish is currently 1.3mm, and currently we run a 28mm Koso carburettor, but by next week, I intend to have developed the system to run a 30mm Koso, and hope to gain another 2NM. I am having some trouble converting the screen shots I have into Jpeg format, and hope to be able to remedy that shortly, but I hope that the image I attach with this message will be visible, though it is very poor quality, when I get the correct software, I will convert all relevent runs to Jpeg If anyone has any comments/questions reguarding the cylander, please feel free to post them on this site (using as much English as possable please!), and I will answer them myself, so there is no confusion! Reguards Neil