I know this is a shit ton to read, but if you are looking for some help with your stock Pug, you'll read it!!!
I just got a 103 lvs-u2, and I ripped in to it. I'm super stoked to be learning another bike, especially something french! I had so much fun extracting every little bit of stock performance out of my Puch e50 (first bike). One mod at a time and feeling every little difference that it makes was stupid fun, and I'm ready to relive those days with my pug!
So far it's been bitter sweet but I'll get in to that. I know there has been threads on shit you can do to make your stock pug faster, but I'm going to try and put everything I have learned so far into one thread for future reference!
I hope to add pics to this asap. But here we go
Okay, with the lvs-u2 (read about model differences in the wiki) it has a dinky leaky Gurtner 10 or 12 mm carb on it. LOOSE DAT!! I'm going with the "I'm not buying shit for this bike" apraoch right now so I salvaged an old 14:12 Dellorto SHA carb that Jamie Buzzard previously drilled out for his stock Garelli SSXL. It worked great for him so it made since. You may not have one of these laying around so you will have to either heat up a 14:12, snatch out the atomizer, and drill out your own, or buy a 15:15 or a 16:16 SHA. I also scavenged an 16mm sha intake that Jon Buzzard isn't using any more... (you will have to replace the hardware for the intake. I used some that came with my Puch Polini) This is another place where you might have to hit up Treats or 77 where as I didn't. The reed block that came in my bike was LAUGHABLE... Stupid restrictive. If you are lucky you have some old tomos reeds or maybe even an extra set of polini two petals laying around as did I. If so chunk them in there and breeeev!
I also took the stock exhaust apart. I had heard of "restricting" them but didn't know what that meant, so i just took the nut off the back of it, and pried the lid off it. Pull that baffle out of there. It will let it breath alot better. Also if you are feeling froggie, you can remove your cylinder and look through the exhaust port. There is a little lip in there. Take your Dremel and shave that bad boi down. I used a carbide grout removal bit. It will get in there with ease.
On to the vario/clutch. I read the wiki first and got pretty familiar with the inner workings of the variator/clutch assembly. (Thanks to Cheetachrome) I suggest you do the same. That way you aren't confused with what goes up and what goes where. I removed three of the 6 balls from the clutch. These balls sling out centrifugally and force the clutch plate to make contact with the clutch bell. You remove three balls and when it trys to force that plate over, well... It has less "balls", there for allowing your clutch to engage later and thus allowing your motor to gain slightly more momentum than before. It's better. I have not modded my vario yet. But you can lighten the weights that are in there and it will stay in a lower "gear" longer. (I also salvaged a Polini launch lever from Jon Buzzard cause he has three! It will bolt up to the stock cases just fine, I'll get in to what that does later) When I do mod the vario I will take pics. BLKBLK Jon-o already did a write up on this, but the links to the pics are broken so I'll try to do another one.
I was super lucky when it came to ignition. I popped that flyhwheel off and saw a 5 coil and went through the roof! That's the good one. The three or two coils are garbage from what I hear. So try to find one of these. (I'll snap some pics, but there is some info in the wiki on these also. There is said to be a weak spot even with these with the internal condenser. (internal meaning it's housed within the flywheel) Fret not if you have one, or if you have managed to find one, because there is said to be a Volkswagon condenser that you can mount externally that will fix you up! I'll do a write up and pics on that when I cross that bridge. (Which will be soon. It's best to change it before the internal stock one shits the bed) When I'm sure that I'm Timing it right, I'll do a write up, maybe a video on that also. This has been done but I'm sure if it's done more Pug exclusively it will help people out a lot more, lol.
I also replaced my stock 56 tooth rear sprocket with a 52 tooth sprocket. This was super easy and didn't require I cut/shorten the stock chain. (my bike had 200 original miles on it. Yours may be stretched by now, and may need replacing any ways.) I did have to use some washers on the tensioners to get them to pull the wheel back far enough to tighten the chain though. So if that happens don't fret, just look around for some small washers. ( I happened to have a 52 tooth laying around also, What can I say, I'm lucky I guess) This made a 2 to 3 mph difference in my top end and didn't kill my take off surprisingly.
So that's where I am as of now. With no cash spent. Not even on the Pug, I got it for free too, lol.
Recap, my set up is:
Stock lvs-u2 Cylinder, removed the lip in the exhaust port
Removed 3 balls from the stock vario/clutch
Stock 5 coil stator, timed to where the points open right at 1.8mm before TDC
Derestricted stock exhaust
16mm Dellorto SHA intake
Polini 2 Petal reed block
Drilled out 14:12 Dellorto SHA carb (71 jet cause its all I had laying around, seems fine though)
I can't get my shit to idle for the world. I pedal it off the kickstand and hold it WOT, and it's off to the races. Stock it idled fine and did all of 23mph gps'ed. With said modifications I got it to 27mph gps'ed, but it was raining and I didn't get to stretch her out. I think it has 2 or 3 more miles per hour in there, but we'll see. That was with out any tuck and on flat road.
I have had a friend bring it to my attention that the 14:12 SHA may not be capable of idling low enough to allow the stock clutch to disengage. So to remedy this, I'm going to attempt to run the clutch with 2 balls. If this doesn't help, I'm going to find a spare 14:12 SHA slide, and notch the bottom of it slightly with a Dremel Cutting wheel. Hopefully this will allow a little more air in at closed throttle and allow it to idle. I'll take pics of this as well and let you know if it worked. I have read about a similar process done to drilled out 12mm Bing carbs! So fingers crossed!
Any Idea's? You have some stock pug tuning knowledge you wanna drop on us? Do it here! I created this thread cause when I was researching during my stock Puch tuning there was an abundance of puch knowledge on the threads. Even stock porting threads!! Not so much with the 103's. So maybe this thread will become the one stop shop for stock Pug Tuning. They are amazing bikes (so far) all though finicky, they are challenging and fast stock bikes. That makes for tons of fun!