Wednesday, December 10, 2008

Tuesday, July 29, 2008

Sunday, July 13, 2008

vespa carnage. 

vespa carnage. 

Wednesday, June 4, 2008

Started hacking into the cylinder last night. Took about an hour to get one transfer port semi-done.
And about a half hour to widen out the exhaust port. I plan on doing more work to the exhaust as I want to widen the port. I've been told I can go as wide as 25mm in the cylinder, but I need to measure where the edge of the ring travels in the cylinder.

I also need more Dremel bits...

TIP: Make sure you stuff the cylinder with a rag while doing port work. There were a couple of times where my Dremel slipped and if I hadn't had the rag in place I would have gouged the inner wall of the cylinder.

Tuesday, June 3, 2008

Here are marks for some of the porting to be done to the cylinder.
I can't widen the transfers quite as much as marked, but I can take out quite a bit. The TCCD kit bulges out on the sides to have enough room for the huge transfer ports.

I can really take out a lot of the material on the exhaust port, but need to be careful to maintain the ramp as that helps draw the charge back in to scavenge the cylinder of fuel.

And here's the mark for cutting the sleeve.

Sunday, June 1, 2008

Port job. Matched to a TCCD 50cc kit. Started with a Dremel high speed cutting bit to take out most of the meat. Moved to a slim stone grinding bit to even out the ramp. Next some hand sanding with 180 grit sand paper, and finished off with some 400 grit sand paper to smooth out the finish. 

Results look good. 

Tuesday, May 27, 2008

The Boss pipe came. I have to do some major grinding on the header to get it to seat properly within the recesses on the cylinder. 

I also did some Dremel grinding to flatten out a couple of manufacturing flaws on the header's mating surface, followed by some wet sanding with 180 grit on a small piece of bathroom tile to further flush the header surface. I rounded it out with some 400 grit, and now it looks to be an even surface. 

I cracked the case yesterday and installed new bearings and seals. Next is to case match to the ports on the TCCD 50 kit. 

Wednesday, May 21, 2008

Going to try out a digital bicycle speedo on the Puch. This should help figure out the fine tuning aspects better while I'm trying to dial in the bike.

CatEye Enduro 8

With an 8lb rare earth magnet.

Should do the trick.

Wednesday, May 14, 2008

Need to build a cafe fairing. I'm thinking if I can find a rigid plastic bucket sort of thing that's rounded on one end, I can cut the shape out similar to the picture. A few mounting brackets on the handlebars and a quick paint job, and I'll be ready to go.

Monday, May 12, 2008

Tecno Boss pipe is what I need. The Estoril is nice, but is really limiting in the high RPMs and it seems to have a ceiling around 45mph, I'm having a hard time pushing the Puch beyond that. Shaw uses these almost exclusively on 60mph bikes. And at $60 a pipe, it's a bargain. Hopefully Benji has one left in stock...

Thursday, May 8, 2008

First blueprint.
New parts for the rebuild:

Stock #3 cylinder
Matching piston
New rings
38 tooth rear sprocket
Three-shoe clutch w/ Paz springs
Replacement points
16mm Dellorto PHBG carb
Custom 16.5mm "Naz" intake
Malossi velocity stack air filter (no foam packing)
Replacement main gear
Drop bars
Sava M11 2.25" semi-slick tires
All new bearings, seals and gaskets
I've got a used #3 stock cylinder and matching piston on the way from Jon, one of the general forum users. I'll pick up a new set of rings from Dean, at Seattle Mopeds. And Benji from Treats is shipping out a 38 tooth rear sprocket.

One of the race rules is that you must use a stock cylinder, but can modify it anyway you'd like. The #3 is what I had on the bike, originally. I broke the exhaust studs, and a couple of fins from my original cylinder, so I've decided to replace it with the same thing. The #3s are nice since they have larger ports. The new rings should ensure solid high compression.

I'm concerned about using the 38 tooth sprocket. Currently the 41 tooth helps get me up to higher speeds, but takes at least a block or two to reach full speed. My concern is that, while the 38 will increase top speed, it'll take me even longer to get up to my potential. And in a racing situation, with only a 1.7 mile drag, it could cause me to fall behind and my top speed not giving me enough to catch up.

The BMX freewheel allows me to pedal up to about 18mph very quickly. I need to tune my clutch springs to engage, conservatively, at about 15mph. I may set the grab even lower for the race and go for an instant grab, even though it puts a lot of stress on the clutch and bell. I'm hoping a stock cylinder will give me more of a low end advantage than the TCCD kit (which is notorious for lack of low-end power). Although I may have better luck tuning the clutch to the Estoril's power band, and having them both kick at the same time, allowing for a noticeable power boost at around 25mph.
This blog is, more than anything, simply a way for me to document the performance work I do to my Puch Maxi moped. It's been a labor of love since 2005, and I've continued to modify the bike over the past several years. This current incarnation will be to change the bike from a 50cc kitted moped into a stock-modified racer. I'll be testing my tuning mettle in an upcoming race between Puddle Cutters and Mosquito Fleet.

Current set up:

TCCD 50cc kit
Slightly milled hi-comp head
1 head gasket
1 base gasket
15mm Bing w/ 82 jet
Carb needle position set at bottom notch (rich)
K&N-style foam filter
15mm intake
Rito stuffed race crank
Two shoe clutch with orange Paz springs
17 x 41 gearing
Tecno Estoril pipe
BMX 17 tooth freewheel on pedal sid