Raising puch cylinder

Richard Vestersund /

Hello i got a many years Tomos tuning project. The motor is a Tomos APN engine with 5 gears (same stroke as puch) And i got transfers welded and recut for puch cylinder. Right now i got a PSR 70cc and its a exact copy of TCCD 70cc. I have driven it many miles but it has always lacked the top end. Then yesterday i checked port timings with a degree wheel and found out my port timings were

intake 136°

Transfer 110°

Exhaust 175°

Boost 100°

So yea Horrible! And it has been ported at exhaust 1.5mm and intake (skirt)

So i put 1 2mm washer to each cylinder stud and my port timings got much more suitable for a shifter like i have!

188° exhaust

127° transfer

125° Intake (will be ported more trugh skirt shortening)

BUT. Now when piston is at BDC the pistons boost port cutout is visable (not ported) about 2.5mm. Would this be a problem for performance?

I already have made a 1.5mm spacer and gaskets to use

Thanks!

Re: Raising puch cylinder

Popcorn in microwave....

Re: Raising puch cylinder

Richard Vestersund /

Dang. Thanks! I will just put it back together how it was until i find someone who can rise transfer ports.

Re: Raising puch cylinder

Close up the boost hole in the piston and reposition it after.

Re: Raising puch cylinder

there was actually a guy on here last summer from europe that was doing one on a shifty, cant remember what exactly. might have actually been an APN.

there are so many good puch kits out there, i cant see why you'd put the time into trying to polish that turd.

and yes, you cannot raise the cylinder or the boost ports will go into the intake, ideally you want at least 2 mm of separation between the boosts and the intake.

Re: Raising puch cylinder

> Rebel Moby Wrote:

> -------------------------------------------------------

> Close up the boost hole in the piston and reposition it after.

its already right up next to the ring, there is nowhere to go

Re: Raising puch cylinder

Richard Vestersund /

Can someone recommend a good cylinder thats already or easily ported to suit shifter engines and high rpm. I know gila is a fantastic kit but i like to play around porting and souch. My wallet isnt that thick so hopefully under 140$ for a kit. I was thinking the "MK" 70cc Athena Big reed copy. I know the cylinder has to be tinkered to get right port height vs piston crown.

Re: Raising puch cylinder

Thats shyte... time to break out the rifler files and raise the transfers by hand.

> Graham Motzing Wrote:

> -------------------------------------------------------

>

> its already right up next to the ring, there is nowhere to go

>

> https://cdn3.volusion.com/vod3d.s9orw/v/vspfiles/photos/puch-tccd-piston-2.jpg

Re: Raising puch cylinder

ehh yeah that athena/ajh/mk cylinder needs a lot of work, custom made head or the top deck cut off.

how about a tomos reed cylinder like the treats reed or alukit? not much out of the box but if you port the exhaust they fly

Re: Raising puch cylinder

yeah thats the puch version, but it is a tomos a35 kit that had the exhaust port machined flat to fit the puch exhaust.

you can either buy the tomos one or the puch one, but seeing as its going on an APN, probably easier to buy the tomos one, i dunno what you are dealing with for exhaust.

44 mm has more conservative porting, but really really stupidly ridiculously cheap

https://www.treatland.tv/tomos-A35-alukit-p/tomos-alukit-70cc-kit-44mm.htm

45 mm with better porting

https://www.treatland.tv/tomos-a35-alukit-p/tomos-45mm-alukit-70cc-kit.htm

Re: Raising puch cylinder

Richard Vestersund /

My setup is a follows

Apn type engine 5 gears

Top Racing Crankshaft

Upgraded Clutch +2 springs and 1 more clutch plate

Stock transfers welded and grinded for puch cylinders

L17 to standard C3 crank bearings

PHBG 21 Black edition + Custom intake

Custom diy 10000 rpm exhaust welded

Ducati AM6 Cdi ignition and flywheel at 18° full rpm

I rather go with puch exhaust flamge sence i got a exhaust made i did for it

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