karoo

28PS sind aber nun auch kein allzu üppiger Wert für 125ccm... Zumindest wenn's um nen modernen auf Leistung ausgelegten Motor geht. Mit Vergaser geht da sogar in Großserie für den Straßeneinsatz schon mehr... und das seit Jahren Ich hätte auch Bedenken mit der Ausdehnung des Zylinders. Wenn sich nun der Kolben kaum ausdehnt, der (immer noch luftgekühlte) Zylinder aber ziemlich passt das auch nicht wirklich zusammen. Schreiben die über Erfahrungswerte in luftgekühlten Zweitaktern? Oder nur wassergekühlt? Oder nur 4T?

Ist überhaupt schon Öl an den Membranzungen? Das dichtet zusätzlich. Durch manche nicht ganz optimale Plättchen kann man auch schon Lichtpunkte durchsehen wenn sie (noch) i.O. sind. Kritisch wirds nur, wenn an diesen Punkten aus irgendwelchen Gründen kein Harz ist, das dichten würde.

Die allerdings derzeit nicht mehr eingebunden sind und die daher meistens nicht beachtet wird

Du meinst doch den RZ Evo 2000 lefthand? Der sitzt mit nem 3.50-10er Reifen oft schon so nah, dass er beim Wackeln ab und an schleift. Umschweißen ist kein wesentliches Problem, verursacht aber gut Aufwand. Vor allem, wenn der Dämpfer hinterher wieder parallel zum Reifen laufen soll. Ich glaube du brauchst eher nen JL Performance in Schwarzblechausführung. Bei SIP heißt der z.B. SIP Evo. Der is von vornherein breitreifentauglich, hat sein Leistungsband aber ca. 200rpm höher liegend.

Also Tuning eingetragen -> Klasse 18, uneingetragen -> Klasse 23?

Wie ist bei euch der Unterschied zwischen den Klassen "Motorrad" und "offenes Motorrad" definiert? Bzw. gibt's irgendwelche Kriterien, nach denen ein (Renn-)Roller zwischen 126 und 250ccm nicht in Klasse 18 mitfahren dürfte sondern in Klasse 23 (offenes Motorrad < 650ccm) müsste?

7300rpm sound faster than it is - that's around 120-125km/h on a 3.50-10 rear tire, depending on the exact type of tire. But not bad either, especially when the engine still has a good pull in fourth gear. I completely misunderstood the meaning of the green line as you first posted it. After I reread it it was quite clear... That's a good way for gaining some extra cross sectional area if you need it. But I don't think it's enough to still have the same flow in combination with a (unmodified) full circle crank. Even if you add really much material (be it welded aluminium, epoxy or a bolted on fitting aluminium piece plus epoxy or whatever), you'd end up with a channel to the crankcase that barely has the necessary cross sectional area, but has a sharp turn at its entry. If you want to reduce crankcase volume, a modified full circle crank or HPC crank should be better in my opinion. To form the channel from the reed to the cylinder base you'd have to add at least as much volume like the volume you'd reduce crankcase volume by fitting a fully round clutch side crank web. The channel in itself could be somehow better in terms of flow when compared with the same cross sectional area (you should have more with a modified crank!), but its entry would be inferior. As for your pipe: it's difficult to predict exactly how it could help. At 8000rpm and 60°C of gas temperature the pressure pulse should travel ~7-8mm per degree of crankshaft rotation. 3° of gain should only make a minor difference... But that's not the point here as I think. I'm rather concerned about the entry to the pipe. The gasses would have to take a sharp turn to flow into that pipe which would result in increased flow resistance. Hmm... but I think it shouldn't hurt things, anyway. Provided you don't add 100ccm of volume to your crank case, of course Devcon F: I have never worked with Devcon products, but they seem to have a good name. A quick google search showed, that quite some tuners have used it with success in their two-stroke engines, so I think it should be okay. I personally like to use Loctite AL1, which has now been replaced by Loctite A1. But afaik it's only available in big packages (500g minimum).

Was ist im Malossi-Cup an Bearbeitung erlaubt? Speziell an Einlass und Zylinder?

Stimm den Vergaser ab. Nur die Hauptdüse zu wechseln bringt in dem von dir angesprochenen Bereich gar nix -> Einstellanleitung von Lucifer.

Piaggio misst den Kolbendurchmesser aber anders als der Rest der Welt!

Die Cross-Hersteller geben aber für ihre Zylinder durchweg niedrigere Überströmsteuerzeiten an als Zirri verwendet... Die liegen eher um 128°-130° herum. Hat das schonmal jemand auf dem originalen Cross-Motor nachgemessen?

Aber ruckartig Gas zu geben ist halt doch Beschiss... da kann man das auch gleich mit der Kupplung erledigen. Richtig freuen tu ich mich erst über nen Motor, wenn er ohne ruckartiges Gasgeben bei völlig normaler Sitzposition und ohne sonstwie nachzuhelfen das Vorderrad hebt. Und das bitte bei vernünftig langer Übersetzung. Also keine 2,86er auf 130ccm oder sowas...

Viele zählen es auch als hochgehen ohne Kupplung, wenn sie in Resodrehzahl das Gas voll aufreißen und dabei am Lenker ziehen. Wichtig ist dabei auch nicht die Leitung, sondern das Drehmoment, das am Hinterrad ankommt. Also gemessenes Drehmoment + Übersetzung. Da sollten deine 20Nm aber eigentlich gut ausreichen wenn du ne 2,56 drin hast... Was auch sehr hilft: Roller vorne erleichtern! Kotflügel weg, Zierblenden und Aufkleber weg, abgefahrene Bremsbeläge ( ), Kunststoffhebel, Scheinwerfer weg, Tacho weg, kein Handschuhfach oder Reserverad montieren etc. Dann aufrecht in die Mitte der Sitzbank setzen und sogar ein eher schwächlicher Motor kann das Vorderrad heben. So geschehen bei meinem Rennroller beim letzten RnR: 133er, VSP, 2,54, 24er auf Membran beschissen eingestellt. Hat den Vierten eigentlich gar nicht gezogen, kam selten über 100, aber hat bei aufrechter Sitzhaltung in der Mitte der Sitzbank das Vorderrad zumindest spürbar angehoben. Ohne am Lenker zu ziehen oder am Gas zu reißen. In ner PV mit Handschuhfach, Kotflügel etc. ist das Vorderrad dagegen immer satt auf dem Boden geblieben, ich hab nichtmal spüren können, dass das Ding vorne wesentlich leichter geworden wäre. (Okay, da hatte der Motor auch 1° weniger Vorzündung... aber das is nun auch nicht die Welt)

Until now I haven't been on the dyno with my engine. So I can only tell you, that the power delivery is as smooth as I want it to be on a engine intended for touring. Maximum horsepower has never been my goal. It doesn't rev past 7300rpm, but it reaches this speed regardless of if I'm driving up or down a hill in fourth gear. This is a pic I took of my intake when it was nearly finished (you also see that some material has been taken off the crankshaft, but I don't have a picture of the crank alone): The reed casing is designed to take a Malossi reed. The reed will even slip a little bit into the engine casing and sit just several millimeters above the crankshaft! The Malossi reed isn't bad, but for a 30mm carb I'd go for RD or TZR, they look much more promising. I have to admit that the reed casing looks somehow twisted and crude, but it gets the job done and flows well. This thing was at first only intended to check if it was possible to fit a Malossi reed under a SI24 carb (which by the way seems to work out) and has been machined in minimum time without having taken the exact dimensions of the engine and the reed cage. I've first run the engine with a Mikuni TMX32, although I really hate this carb. But it was registered in the papers of the chassis I first run the engine in. Later on I now plan to use a carb of 28mm diameter. I think it's gonna be a PHBH28, they're the cheapest As to your drawing: It's a little difficult to interpret. If I understand you right, you're talkink about two ways of fitting the reed valve: The first way is to mount it in front of the crankshaft, so that the new intake will sit entirely in front of the crankshaft. That way the intake would correspond to the horizontal part of the green line you've drawn. This is a very good way which should, in theory, yield the best results! But until now there hasn't been any real comparison of similar engines with only differing intakes, so it's difficult to tell if the theoretical advantage really works out. In addition to that you'd have to weld the casing and remachine the sealing surfaces. This is not only costly, but also bears the risk that the casings might warp after welding. The second way is to mount the reed in a more traditional way (somehow like mine or the intake manifolds designed by MRB, Malossi, MMW, Planet Scooter et al). But apart from enlargening the original intake you plan to fit a pipe from the reed casing directly to the boost port? I don't see any real advantage through this tube. A properly enlarged intake will always connect the reed to the crankcase. If you the add a machined crankshaft you have a pretty good cross sectional area whenever your engine is able to intake. The pipe would shorten the way of the suction pulses rather marginally and had to be of reasonable diameter to be able to flow some extra mixture. Also you'd have to find a place to fit it so that the gasses escaping out of the reed can be drawn in through this tube... plus you'd have two new joints to seal, but this shouldn't be a real problem there. You can even take the second concept a step further and fit the reed in a way, so that its flow is aimed directly between the crank webs. This can be done without welding, here you can find some pictures of the very good work from an austrian tuner (Stroh). But there's plenty other ways to do it. If you remove one engine bolt you could move the intake a bit towards the cylinder which helps the flow bypassing the crank. This can be done with epoxy if you trust it in a street engine (I do). Welding will only be necessary (or desirable) if you want to place the reed completely in front of the crankshaft.

Es gibt keinen Kupplungsabzieher für PX. An welchem Gewinde oder welcher Vorrichtung an der Kupplung sollte der denn auch festgemacht werden?

Ah, okay! Also die RD-Leute bohren bohren einfach neue Löcher in die TZR-Membran und gut is. Scheint wohl recht einfach dicht zu kriegen zu sein...

Zumindest der Ansaugstutzen ist aber ein deutlich anderer als oben abgebildet... und würde bedeuten den Gaser quer zur Fahrtrichtung zu montieren!? Was is das fürn Teil? edit: Wo is dir da was zu kurz? Da is doch überall genügend Dichtfläche da? Löcher in der Membran aufzufeilen ist zwar nicht wirklich die feine Art, aber funktionieren sollte das...

Irgendwann '86 wurde m.W. umgestellt. Die ersten Lussos hatten also noch das alte Getriebe. Bei entsprechend hoher Motorleistung kann z.B., wenn's blöd läuft, schon ein einziges mal Gangspringen reichen um den Motor platzen zu lassen... mal davon abgesehen, dass sich das Lusso-Getriebe durch geringeren Schaltkreuzverschleiß bald bezahlt macht und es sich ohne springende Gänge einfach besser fährt

This pic shows my Polini as it's being shortened on a mill. I only took material off on the inside of the sealing surface to have the head self-center it afterwards. If you look at the head from the bottom, you see that its sealing surface sticks out quite a bit and is round (with exception of the ears where the cylinder studs go). I then removed these ears, milled the cylinder to have 0,6mm more diameter than the outer diameter of the head and had a perfect fit (that's because of thermal expansion. The head will expand more than the cylinder, so you have to have some clearance there) Which RS-reed valve do you have in mind? The one from the RS125 is not same as the one fitted in the RS250. The RS250 engine is bought from Suzuki, it's exactly the same like the RGV250 engine, except the signs on the cylinder (and probably on the casings, too) read "Aprilia" instead of "Suzuki". I don't know Exhaust Calculator 2, but I'll try to have a look at it. I build expansion chambers myself, but until now I have only done some for a tuned 200 engine. I already had the PM, so there was no need to build it on my own... But someday I'll have a try for my small Polini, that's for sure! The difference in gearboxes isn't the cruciform alone, the main drive shaft of the Lusso has some little slots in it, into which the cruciform is pressed when driving, so it can't jump out that easily. The gear wheels are also slightly different (thicker section where the cruciform engages, different contour on the fourth gear on the tire side). So swapping the cruciform alone wouldn't be helpful in any way.

In der Flow-Bindung von meinem Bruder brech ich mir immer halber die Haxen und hab nach spätestens zwei Stunden richtig Druckstellen und Schmerzen. Probefahrt schadet bei solchen Bindungen halt nie... Könnte aber auch daran liegen, dass ich eigentlich nur Hardboots fahre und anders belaste.

Okay, hatte mich schon gewundert wie 0,3mm am Auslass so eine Änderung in der Leistungskurve hervorrufen sollen Hut ab vor der Leistung!

Dass die Dichtfläche auf der Welle auf keinen Fall angekratzt werden darf müsste ich eigentlich gar nicht extra erwähnen oder? :wasntme:

I think that the reedvalve you're planning to fit is way too big to be used with a carb of 28-30mm diameter. I'd consider the reed valve of the rgv 250 if you're planning to use a 34mm carb. For 28-30mm, the reed valve of the RD350YPVS or TZR125 should be just right. It's also easier to construct a carb flange with no sudden changes in area which helps throttle response for the smaller reed valve. The smaller reed valve won't be any restriction for a carb of 28-30mm. Is the hand made exhaust you mention custom made or off the shelf like PM Evo etc.? Regarding the gear box, you should check to have the new type of gearbox fitted since '86 (the one with the flat cruciform) installed. It withstands the stress in tuned enginges much better than the old type when it comes to jumping gears. Resulting from that, you also have longer intervals between changes of the cruciform. The 36 4th gear is also fine, though a good Polini engine would also pull the longer 35 4th gear with the 23/65. The original crankshaft should be fine! When fitting reed valves it is often desirable to mill down the crankshaft even further to let the gasses flow easier. A full-circle crank only has benefits where the reed-valve is positioned directly under the cylinder base (and the original inlet is closed completely), so that the incoming gasses don't interfere with the crankshaft! A clutch ring is only necessery in high revving engines, so it depends on your port timings and the exhaust pipe. If your powerband ends at 7500 you probably won't need it. Some people also say that fitting a very light flywheel can cause clutch damage if it isn't reinforced. What port timings are you planning to use? Do you rather want a racing or a touring engine? For touring I'm quite happy with port timings of 120° at the transfers and 178° at the (mildly broadened) exhaust port. With these timings you won't get the most power out of the engine, but it has good torque at the bottom and a strong midrange (with an old PM 24). But to achieve these timings you'd have to add a spacer under the cylinder base to raise the cylinder and you'd also have to shorten it at the head sealing surface (by the same amount that you raised it). Greetings to Italy!

Aber dein Diagramm kannst doch sicher trotzdem einstellen? Das könnte evtl. einige kritische Stimmen zum Verstummen bringen

Der Nichtbesitz eines solchen Gerätes bedeutet aber nicht automatisch das Nichterreichen von (deutlich) >30 Hinterrad-PS aus nem 200er-Motor... dazu reicht schon ein Standard-Billig-Dremelverschnitt völlig aus. Is aber schon was anderes, mit so nem dicken Gerät zu arbeiten :love: