another AV7 porting thread

I have a 25 mph cylinder Motobecane, a dellorto 15.15 on the way and eventually will be getting a ninja g3, but will be running stock exhaust till I can save the money. I checked out the Motobecane wiki page and it has the awesome port maps for the fast Will these be pretty much the same on the 25 mph cylinder or am I looking at something totally different?

All stock right now I GPS'ed at 22 mph (i weigh 235). Will I be able to get high 30's without buying a kit?

Re: another AV7 porting thread

Mike Scouty McScoutington /

Yes, for sure. If you do some piston work you should be able to get a little bit more out of your bike. I would also get a new belt and grease your wheel bearings and such. You would be amazed at how much well lubricated or new bearings will help. I weigh about 190 and have a 25 mph cylinder with a 15:15, stock pipe, and a little piston work and I have been GPSed at 37.7 on a good long straight. If you are feeling real crazy you can crack the bottom end and do some port matching and help your cause more. Quarterkick has a stock replacement fast cylinder that you could check out. It is ported will and comes with new chrome plated rings. My buddywho is your size was running that with the 15 and stock pipe with no porting and hitting mid 30s.

Re: another AV7 porting thread

There are some more accurate port mapping specs floating around online right now then what is in the wiki. If you follow those specifications exactly, you should be able to be hitting the mid to high 40's.

They are buried somewhere in this forum:

and other moby-heads know them as well.

Shhh... it's a secret to everyone

Ahh, the thread you speak of is here break>

Translators play hell with the words but you get the main meaning. The magic numbers are 140 degrees intake, 150-155 exhaust, 110 transfers. In practice those are hard to make on the intake and transfers. You have to cut the intake down pretty far and cut the piston up pretty far. The exhaust, make it an oval, about 23-24mm wide and 150 degrees up. These forums are not the same as ours, the expect you to know a lot more and tune a lot further than most of the threads here.

Another great thread is this break> It's for the AV10 but the information applies mostly. Notice the level of detail in the breakdowns. He gives you fuel consumption rates for christ sakes.

Re: Shhh... it's a secret to everyone

I'll have to take a read through the av10 porting page when I'm a bit more sober and see what can apply to the Malossi 70cc kit that I have. I'm excited to break that sucker in ASAP (once a nasty air leak is fixed)!

Thanks a lot Jesse for the av7 porting page, I think I stumbled over that before but figured it was nothing important since there as not much in terms of details.

Re: Shhh... it's a secret to everyone

🇮🇹💦 Of the Loin /

that av10 porting page is kinda funny.

funny in that the porting and piston shaping they tell you to do is remarkably close to the bidalot 50 kit porting. and piston shape

« Go to Topics — end of thread

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account