Gio695

By any change someone running an MMW carb angle cover, the one in cnc alu, for pwk28? I would need to know the height of it. And if possible also other measurements and real life test I have very tight space above the carb… I have googled these but can not find the info i need.

This is what the manual suggests with an open mouth and franspeed exhaust: Dellorto PHBH30 (caution standard version of this carb has restricted access to air screw and idle stop adjustment when fitted to R/H manifold) Cable choke conversion Part number: 53003. Settings for open mouth with Franspeed race. Suggested jetting between 130 -135 main jet, AV268 atomiser, X13 (or X7) needle, 40 slide, 55 idle jet, Timing set at 17 degrees BTDC Mine, with a Gori sport and foam filter ran with 128 main, x7 needle, av266 or 264 and 54 pilot on a 28phbh. I later changed to a keihin 28pwk and now is on the shelf waiting for a new donor... i hope you have a good starting point with these numbers. It is a nice kit anyway... here is a link to the gt manual, if you did not have it yet: https://lambretta-images.com/wp-content/uploads/2020/03/GT-manual_3.pdf

Haha..ok.. then i can CONFIRM... I had the Gori with the original silencer, then i changed to an Bigger MR silencer (i think designed for BGM clubman), but still loud! But it runs great...

I can tell you that the Gori Sport (very first version, i think 36mm) i had on it before was definitely louder then the JL3! So the combination with the airbox and reso should be a lot nicer if all works out.

Yes, I know i have to redo the jetting. I don' have a sacchi, but i will try the LTH one if the bgm gives me trouble I understand it will be a bit of a problem to get it right and i will lose some power, but it's just too loud at the moment(for the ones behind me especially) If it still makes sense with a reso? I don't know yet...i will post my findings as soon as i can.

Perfect, that's exactly what i wanted to know! I have read this whole topic (more than once over the years) but most people used a bigger airbox, or more kart intakes than one. At first i wanted to build one complete from scratch (bigger then standard) or use a rs125 airbox, but if original style airbox would work it would be easier and look more "stock" because i have a left 30mm intake on the gt186 instead of a right intake. So i was wondering if a bgm (or same original modified) airbox would work without causing problems. Thank you very much for all the info! PS: you wrote in this topic that the BGM intake rubber needs reinforcing with a "Krinoline" because it sucks itself closed. Is this still the case with the latest version? If so i will build myself a reinforcement.

Yes, that and the BGM airbox. I want to know if someone uses both on a bigger carb, like the 28 Keihin without jetting problems or the so called "drosseln" At the moment i run a marchald filter, straight on the carb, through a hole in the panels, but it's to loud.

Does anybody know if the BGM airbox with new BGM Gummi will work with a 28PWK Keihin carb whitout modification? I'm trying to get met GT186 with JL3 a bit less loud Sorry for writing in englisch , i understand german, but i don't write or speak it very well!

OK thanx... So probably piston/crank problem?

I've changed the flywheel for a third time, also cleaned all grounds and checked sparkplug gap once again and now all is working. I think both flywheels i used had same problem (to little magnetisme?)But now i have some kind of knock/trembling sound coming out of top end. I hope its the flywheel thats slightly out of balance and notthing else broke .At least i now know how to fix the purple wire problem.Thanx to all for your help.this topic can be closedGrtz,Gio

I suppose it's something shorting out, but i've double checked grounds. All switches are new by the way. Today i've noticed that if i rev the engine when i put the switch in position 2 the bulbs light up for a second before the engine cuts off. At idle the engine cuts off immediately. In position 3 with all lights on and pushing horn or brakelights there are no problems at all at idle... Thank you for thinking with me, all tips are always welcome with this weird problem.

Thank you. junction box is new, even changed it twice and checked all connections. bulb holder where cleaner all connections and even changed place for purper wires. yesterday i even changed the coil with the purple wire for a third one, and another flywheel. Made an extra ground for the speedobulb and changed the two small lamps again...no luck.

Hi, My name is Gio, and i've been on the forum for a while, but i don't post much because of time (sorry for that) I've worked on a number of Lambretta's (or engines) but never had this problem and it's driving me mad! The Lambretta in question is an 1966 Italian 150 Silver Special. I've rebuild the engine but kept as much original parts as possible (also original paint etc). The ignition is the original 6 pole Ducati, 6V, no battery! I've been having a problem with the lights that work with the ignition switch in position 2, so the speedo bulb and bullet type lamp (position light?) and rear light. The Lambretta starts without a problem, first kick every time with the key in position 1 or 3 (headlights etc) but as soon as i put the key in position 2 it cuts out. I've checked everything and even changed the complete wiring loom, the ignition switch and the light switch, just in case... al ground cables and lamps are also new. The problem seems to be the purple wire coming from the ignition! If i put the brown cable in the place the purple needs to fit the speedo bulb and bullet lamp work! If i put the purple cable in the position the brown has to be, the bike cuts of with the ignition switch in position 3!! So, before you say change the stator....i already tried with a second one i had!!! This is the weirdest problem i ever had. Is there someone that had the same problem? Or does the Ducati 6pole stator have a known issue with the purple wire? I've checked everything else a million times and tried everything i know...always same problem! If i forgot something, please ask. I hope someone can help me. Sorry for writing in english... i understand german, but cannot speak or write it very good!

I've checked the cable. It looks ok. And it revs even when not on it. But i've already decided to change it anyway! If by misstaken the Grease i used is not the right high temp one, can this hurt? Anyway i want to think you all for the ideas!

Possibly it was too much, or maybe not high temp grease? I don't remember what i used. Could this give the high revs? Or should i continue looking?

Today i had a bit of time to check some things. Re-checked carbfitting, gaskets etc... nothing to see. So wanted to do air leak test, but because i didn't have the material i decided to start and strip some parts of the engine. One of the things was ignition. This is what i found behind the stator: Grease, and something that looks like oil/mixture or melted grease?? So i guess this is the problem... I'll replace both seals, and best to check all other while i'm at it. How can this much grease pass two pretty new oil seal and a new crank? Bad quality? Difference in size? (somebody maybe had this problem?) Or maybe just bad luck?

Thanx, Checked exhaust flange, looks ok and tight. Was changed only 300kms ago (MB one, these tend to blow once they get air) I will probably need to get engine off and seal the base gasket! Other ideas are always welcome.

Hi Guys, I've been having some problems with my Li the last two weeks. I've tried a few things, changed some things around and can't find the problem (for now). I would love the engine gurus, the riders, the experts...well...everybody if someone can give me an idea of what it can be. First the specs: Li 125 engine Used to have a Gori sport (modified by Gori himself) kit, but managed to destroy it, so now i have an unworked cilinder, basically a stockDL bored to 66mm, no tuning, stock portings 60mm GP Crank Li150 gearbox, 15/46, MB selector LTH chainpuller Surflex B clutchplates with stronger springs Gori Sport exhaust (36mm) slightly modified with bigger silencer (These are LOUD) Keihin 28PWK on MB intake, normally with LTH elbow and remote filter I run 3% Motul 800 (maybe a bit too much) Variotronic at 23° at 2000 to 4000rpm with NGK B9ES (maybe i should go down to 21° or less) If i've forgotten something, please ask Now the problem(s): Engine always ran well, pretty torquey for a low power engine. A few weeks ago i had to re-weld the exhaust because of poor fitting. I also checked piston, head, cilinder (light scoring around exhaust port after less then 1000km with this cilinder) The base gasket is 1mm aluminium, normally i put some sealant on it, but because it was al clean i put it on whitout (maybe one of the problems) Two weeks ago i went for a longer ride. Noticed it started not on first or second kick with choke, like usual. Thinking the mixture screw or pilot jet maybe wasn't perfect after i've put on the bigger silencer i didn't think much of it. When cold the bike ran as usual, except maybe a bit less smooth... Then after a couple of km's the engine began to rev high when letting loose of the throttle, changing gears and standing still at lights. Pulled aside and it looked like the rubber on carb maybe was a little bit loose, or it was the mixture screw. Turn off lammy, fettle a little, starts perfectly, first kick, runs great....form a km or so! Then it starts again. I carried on to where i was going, and checked everything. After sitting a while (cooling down) everything seemed normal...then it started again...worse and worse. In the week i changed the rubber carb mount, checked that everything was tight, changed sparkplug etc. Then checked jets, mixture screw and did some adjustments. Tried it a few times on the streets and everything looked good. Next day on a longer ride...again!! High revs and shaking when letting go of throttle, changing gears and standing still. If i let go of clutch a bit when standing still it lowers rpm a little (i now, not so good for clutch) I've checked everything i could think of: gaskets, rubbers, bolts, checked for oil/gasoline leaks etc I don't have a tool for an air leak test, so do the old school way with brake cleaner btw, no blue smoke! Anyone that has worked on same kind of problem? Sorry for the long text Gio