KTy

Very very very very strange indeed... Over 4000-5000rpm, the engine *should* happily knock and not give maximum power. Do you have any explanation ?

Just on original PX/Smallframe 10" rims ? Was it Zippy 1 or S1 ? By any chance, do you have a picture of it ? :)

Yeah ok :) But, what about the rim (Cosa, PX, SS,...???) ? And do I have to cut part of the engine arm ?

I need advice and feedback from experience to mount this kind of tyre (probably Zippy1 or S1) on a smallframe... Actually, is it possible ? Thanks !

Yep, I was refering to these indicative prices !

No problem with that, the connecting width is the same as a dell'orto VHSA32 :) @Amazombi: Did you keep the carb after trying it ? Or did you switch back to another one ? I saw in setup.de that you were running a PHBH28, is this obsolete ? EDIT: I just had a reply they are selling the 32mm for 119euros... Coudl find it on their website though... A Keihin PWK 32 is about $150... And euro is strong Cheers,

Tooo bad they don't seem to sell bigger carb than 28mm (

As usual ;), thank you Olli :) Errrrr, no 30mm or 32mm Koso carbs ? Should I mail scooter-attack?

Yes, I get that ;) But I coudn't find anything on their website about Koso carbs. (

Couldn't find my way in german

Hi there ! I have some troubles setting up my scooter with a used and probably tired PHBH 28... I was thinking getting this carburetor from scootRS as lots of pple seems to say it's pretty good (and it's also quite cheap !!)... http://scootrs.com/moreinfo.cfm?Product_ID=443 Do you have any experience with this carb ? And what about KOSO carbs (very good Taiwanese copy of the Keihin PWK according to Gerhard :) ) ? European dealer ? Thank you for your help and advices ;) KTy

Congrats BDB ;) Impressive... I wish I have the same power curves... I dunno yet :) I have about the same inlet design and I have a question for you; What crankshaft did you use ?

The easiest thing would be to change the language file in a .ini or .cfg file that your program will load when starting up. Yes, please, send me the english to ktylife AT free DOT fr , I'll do my best to translate it to french... Even if I will probably use the english language for myself, I find it more convinient for technical terms !

Actually, I'm asking for the english translation, but if you want to make a french one, it's fine for me too :)

Any chance to see this nice peace of software translated to english ? Congrats !

Okay ! As for the crappy sound files, I'll make a video soon !

That's my engine ! I'm not sure i understand what you've said... Anyway, just to let you know, the engine kicks a$$ :)

Hey !! Yes, I'm in the process of running in... I already drove a few kilometers, it feels great and powerful. As expected the powerband is quite high, but the engine revs amazingly well ! I have to calm down to finish a proper running in ! Right now, I'm also working on a simlple variable ignition timing, but for running in purpose I set the ignition timing to a modest 16-17°... Actually at first I've made a mistake ! I set the timing to about 20-22°... Crazy how the engine was happy-revying ! But it was running hot; about 110°C at the cylinder head. I also need to jet properly the carb, right now i'm running 110 main jet, I suppose it won't be enough, but because I'm driving not at full throtlle / full speed, i'm not in a hurry. Finally, here is my new air-box, for street use, because else, it's way too loud !! I'll keep you informed when the engine brakes ;) Actually, I believe my modified crank won't last too much, but whatever, I did what I wanted to do :) And maybe before this tragedy I will try to find a honnest shop to do a dyno, but I'm thinking of buying PowerDyn (google it if needed). And the rest of the picture of KyT 1.0beta can be found here. Cheers,

More Updates for the pple who cares about my project :) Admission With TZR reed valve Engine in the frame I'm waiting for the HP4 fans before I first kick the engine... Polini133 based, 5mm alu spacer, exhaust: 185°, admission: 133°, zirri silent, 2.54 primary, 28mm carb (to start with :) )

** Sorry english only for me... ** @mistelfix: No real answer for you... Not yet ;) I will be firing up my engine soon (Polini 134, TZR reed valve, 2.56, Zirri Silent) The admission look like this: The whole assembly will be something like: And my first attempt for the crank is based on a modified (and balanced) piaggio crank. This is one cheek, you can imagine the other part slightly "slimmed": Some ppl say it won't work well because of the lack pf pre-compression, other ppl says it should work anyway, in any case, every ppl laugh :) I will first run in the engine (if it works !!), then, if it's not broken, I will probably try a full circle crank, and then, maybe, a modified full circle crank where the cheek are slimmed on the inside. More to come soon ;)

Hi guys, little update just to have some feedback ;) link to pictures; http://ktylife.free.fr/vespa/KTy133/CrazyIntake1.jpg http://ktylife.free.fr/vespa/KTy133/CrazyIntake2.jpg http://ktylife.free.fr/vespa/KTy133/CrazyIntake3.jpg http://ktylife.free.fr/vespa/KTy133/CrazyIntake4.jpg http://ktylife.free.fr/vespa/KTy133/CrazyIntake5.jpg http://ktylife.free.fr/vespa/KTy133/CrazyIntake6.jpg and http://ktylife.free.fr/vespa/KTy133/CrazyIntakeProject.jpg I will remove the few epoxy that are on my casing, then I will make the reed cage (in 2 parts I think) from aluminum and ask a colleague of mine to weld it to the case. Then I will probably finish the intake with some smooooooth epoxy ! The reedvalve will be exactly centered on the crankshaft, so maybe a full-circle one or worb5 style one will do it better than a regular cutted one like mazuchelli. The reed valve is from yamaha TZR 125, 6 reeds. Cheers, KTy

The point is, when you DON'T have full circle crank (like me, because I'm working on a Polini cylinder with case admission !), then to me, it seems it's not a good choice to aimed the airflow "against" (as shown in the picture) the rotation crankshaft... Is this assertion also wrong ?? I agree that with perfect surface full circle crankshaft, the airflow is not going to be (too) much disturbed. @Polinizei: I know your(?) scooter, it's impressive, but your admission is directly in the cylinder and in the "good" direction according to the crankshaft rotation.

I was thinking about the airflow direction... On a smallframe with non-reversed barrel and case admission, You have maybe to take into account the crankshaft direction, i.e, the engine turns clockwise, so I think if you aimed upward toward the bottom of the piston, the airflow is going to be "disturbed" by the crank movement... What do you think ? I guess that's why the most powerfull engine have "reversed-barrel" and admission the from the other side so that everything "match"... That's also why you can get more power from a largeframe engine as the carb seat over the crank... Here is the picture that shows what I meant... To me, actually, I think it would better to aimed the airflow downard the crankcase considering the crank rotation direction... Discuss !!

@Gerhard: Sorry, you can't access the forum as you need to register and besides that, it's all in french ! (Anyway, here is the link http://forum.vespalambretta.org/index.php?showtopic=10247). But now, the discussion is way more interesting here on GSF ! @kan_Kuma: Very good point about "To keep the volumetric flow as high as possible, the area of the inlet after passing the reed petals should match the exit area of the valve in open position". I didn't really thought about that, but since I don't use (of course) full circle crank, it's indeed a good idea not to enlarge too much the inlet. Thank you to all of you for your advice, I will try to make a little schematic of the best "theorical" inlet admission to see if we understood each other ;) ... @Gerhard: What did you weld this time ? ;) Thanks for the pics...

Actually, I discussed this on another forum and it appears that the venturi is useless as what really matters is the *quantity* of fluid that I want to maximize, not its speed (that's what a venturi does). So in the end, to minimize "lost of load" we thought that the best solution is to have b = c ! Feel free to comment ;)