KTy

Thank you for these explainations ;) I am going to see how much it will cost me for such project... Btw, combining 2 or 3 smaller and lighter inertia wheels, wouldn't be possible to build a more compact solution ? Bye,

Nobody knows ?? (

Is it a (very) good help for fine tuning, safely running and monitoring an engine ? Fast and accurate enough ? KOSO or Stage6 experience ? Finally, would you say that there is something more useful than en EGT sensor ? KTy -

Here is a "50" :plemplem: compared to a "45/140" ... Besides the size difference, are they compatible ? Can you mount the "50" on a SI 20/20D ?? What would be the equivalent in air ?

But I suppose that the weigth of the cylinder is important alos, no ? What do you use as RPM counter ? Last one (for now ), I saw pictures of your cylinder, it is made of only one piece ?? Simpler ? Cheaper ?... Thanks ! Edit: I must be stupid, I can't find the excel sheet you're talking about !

Sorry for not reading the whole post, can anyone tells me the following : 1. Minimum dimension/weigth for the inertia wheel for up to 40hp ? 2. Don't you need *perfect* alignement for the bearing holder or do you leave some free clearance to prevent damaging the bearings ? 3. Do you need a brake or a rpm counter on the wheel ? 4. Are you using sportdevices or Atom007 software ? 5. What is the prefered material for the wheel ? Thank you KTy -

@Atom007 and others : Can one say that measuring with an inertia wheel is as good as recording while driving ? Does one need anything else that a simple cylinder wheel ?? Wheel brake ? Sensors ? I may want to build one to put just under my rear wheel, I just a bought this : http://www.2roo.com/images/234943_1740FO8xgMvPCNN5.jpg I cannot find the topic taking about inertia wheel.... :wasntme:

Congrats to all for those great results ! KTy -

Alloha, I have this error whenever I try to reply quoting a message... i.e if I click the "AddReply" button it works fine, but if I click on the "Reply" button just below a specific post I got the error... ( Could this be related to the fact that I'm using the english language ? KTy EDIT: it seems it happens only on some post... On this one for example: http://www.germanscooterforum.de/index.php...mp;qpid=1255951 (I try to reply to the last message of http://www.germanscooterforum.de/index.php?showtopic=92034 : "Sprint mit Pinasco 177 Gaser Frage" in the Vespa Oldies subforum)

Interesting... It's GT VNL2T from 1967, what do you mean by "engine is too small" ??? The intake ? I forgot to mentioned that I have enlarged a little bit (3mm+3mm) and smoothed the intake, and that it has also a home-made racing crankshaft (~15mm) . It's a carb from a PX, so it has the long air filter, with the extra-hole made ("heart"). I'll get a BE3, as for the main jet, I can put a 110, even if it's not so different. What about the idle jet ? what about the air corrector (160) ? Thnks

Alloha I have a Sprint 125 engine casing, the 3rd transfer has been grind, Pinasco 177 (the old one, not in alu), SI20/20D, original PX exhaust and points ignition. I have tuned the carb with the jets that I had, but I find the result quite surprising; Main jet is 160 BE5 112 Idle jet is 45/140, bigger will make the engine rattles a lot ! And the mixture screw is unscrewed for only 1 turn !! What surprise me is the size of the idle jet,... If I unscrew the mixture screw for 1.5 turns, the engine rattles more at 1/3 throttle... :uargh: mid and high RPM is fine, low-mid to high rpm is smooth and powerfull... Any advices for my carb setup ?

Alloha, For a project, I was looking for a PX125-150 crankshaft, longstroke (60mm) AND full-circle, I couldn't find any... it doesn't exist ? Best KTy

Alloha, My birthday is coming soon and I might want to make myself a nice present in buying a device for monitoring (and maybe logging) some important parameters of an engine. CHT, EGT and RPM monitoring with max-value are absolute necessary, a TPS input and other various inputs along with a logger ability could be nice... I guess one can find interesting things in the go-kart and light-aviation market, but maybe you have some good experience with some specific products... Thank you for your ideas KTy

New pictures here : http://lnx.et3.it/phpBB-2.0.17/phpBB2/view...r=asc&start=149

Okay, I was given other stuff to investigate: My clutch bearing could be moving in the case AND my primary bearing and/or primary axis could be in bad shape. Actually, last week-end I saw that my primary transmission could move for about 0.5-1mm, I did not realize how bad it could be... Damn'it :grr:

So, the bearing on the clutch side is a 613912, same as SKF, but with one more ball ! But I won't blame to rapidly the bearing as I had the same problem with a "regular" bearing from SKF. I will investigate on my flywheel balance, on the possibility of a twisted crankshaft and on the 22/68 primary combo that I find more and more suspicious !!! Again, if someone can gives me the exact references of an original Piaggio 22/68 primary ratio, I would appreciate. Also, could anyone explain to me (mechanically speaking) how a clutch with 22 tooth from a 22/67 engine (early P125X and early P150X) can be fitted in place of a 20 or 21 tooth on a PX125E, PX125 EFL, early PX150 EFL ...

:plemplem: ( I will try to find the exact references... :uargh:

With my friend we have just double-checked that the bearing were *way* overrated for a vespa engine... The first set of bearing that I screwed was from a "vespa" dealer... Are you sure ??? I cannot find any information on a scooter with original 22/68... I start thinking it could be the crankshaft...

I'm not sure if the crank is perfectly aligned, that's a good point. Visually, even at mid-high RPM I cannot see the crankshaft misaligned (from the flywheel point of view). However, just after a quick ride from my work place to where I live (5km, 15minutes city driving with some short acceleration), I realized that the flywheel is *really* hot... I cannot put my hand on it ! Could be a clearance trouble.... Anyone riding a 22/68 with no problem at all ? Help !!!!

Alloha, Let me explain what's going on, I need your opinion on this one... I have a VNB5T in 8" fitted with a PX125E Arcobaleno engine (EFL for germany ?). The original primary ratio is 20/68. From Piaggio, the 21/68 exists, the 22/67 also, but not the 22/68, even if it referenced here: http://scooterhelp.com/tuning/vespa.gear.calc.html I properly rebuilt the engine (bearings and so forth), I drove a 22/68 primary with the standard 125cc cylinder, for 3000km. After ~2000km, I had a strange noise, I could "remove" it when I disengage the clutch... So far, the crank bearings were on my target. I put a Polini 177 plug'n play on it, I drove 300km and the crankshaft bearing really start to make me pity... I opened the engine, I changed everything (gasket, the whole clutch, bearings, gear spacer, cruciform,...etc), matched the transfers, anticipated the crank and put a Polini manifold along with a PHB28, Leo pipe is "okay" with the 177. So far so good. Engine is powerful, really good fun... Except that crankshaft bearings start again to cry ( So, basically, I ruined 2 sets of crankshaft bearings in ~4000km, I started investigate... :plemplem: Bearings were given by a friend of mine who works in this buisness, he says they are *really* good quality ("better than SKF"). So far I have two options in my mind (assuming that I carrefully put the bearings in the cases): :uargh: * My flywheel is unbalanced (it is an original PX without the teeth for the elestart) * The 22/68 primary can be fitted, BUT it is the responsable for my troubles.... :grr: Any help, feedbacks or ideas would help, thank you !!! It's not me , but this guy is saying "Whouuuu, nice engine !!" KTy -

Up ?!

Alloha I'm looking for a PK 20mm conus for an HP4 conversion !! Cheap please :wasntme: Danke ! KTy

You can buy *only* the conus of the flywheel ?? :plemplem: If so, I'm glad !! I couldn't find it on SIP or SCK !

Sorry for the off-topic, but does anywone know where and if I can buy a PK (20mm) conus for an HP4 ??

Alright.... :plemplem: As far as I have understood you're talking about the "first part" of the pipe that has a constant diameter... Am I right ? (The part that has an outside diameter of 32mm here, http://ktylife.free.fr/vespa/KTy133/zirriDimension.jpg) Is there some known modifications to do to my zirri exhaust or downpipe ? If I make a 32mm (inner diameter) downpipe for my zirri, how one recommend making the junction with the rest of the exhaust ?? Okay, first I have to do a dyno... okay... :grr: Thanks KTy