Most extreme Av7 port??

Christopher Manning /

Im looking to port my Av7 and I want to know the most extreme and effective ports?

I discovered this information http://www.mopedarmy.com/wiki/Motobecane_porting

http://www.mopedarmy.com/wiki/Motobecane_porting_the_right_way

Any advice would be great! I am trying to figure out the max/best port job I can do on an Av7 to make it go faster. I have heard that the ports above will increase the speed up to the mid 40s mph range.

Re: Most extreme Av7 port??

You wanted extreme here ya go - https://www.mopedarmy.com/forums/read.php?7,3550723,page=1

Not for your first port job or if you intend on keeping the same pipe or variator. I did it, fun stuff.

Re: Most extreme Av7 port??

If you're staying piston port, don't go too extreme. Best to do a good job but limit your porting.

Motomatic Nate has a Moby stock fast cyl with no porting that easily goes 45 I think.

The trick is rebuilding and porting the bottom end to match transfers.

Re: Most extreme Av7 port??

IMG_0133.JPG

HOwever,

My crazy reeded ported 25mph cyl av7 is nuts, but I had to mod the clutch a lot, and use a really strong pipe, and make a water cooled head, but it climbs mountains easily now.

Re: Most extreme Av7 port??

Speed costs $$$ also you need the speed to be used right because if it is stop n go you want more bottom end, if you have no stops, traffic or hills it is totally different... also depends on laden weight of bike and gearing... I share 3 known to be reliable and streetable event timing recipies so you can get some performance but also be able to tune some idle and be able to run all day long and into the night. There are more aggressive recipes but there are compromises so I just suggest this as good for a beginning, you can judge your own abilities to tune.

If you are running a CDI then set the timing for 1,2 btdc rather than 1,5 and let the pipe do the work for you and keep the heat out of the motor.

For general use (traffic n such) getting up in the 30s mph

Exhaust - 145 degrees Transfers - 100 degrees Intake - 130 degrees spark 1,5mm.

Nice derestricted circuit pipe and SHA15:15 with derestricted Malossi 15mm intake and match port the unions.

Based on the C & D series Mobys, this is a good timing event recipe

Exhaust 150 degrees Transfer 104 degrees Intake 124 degree Spark 1,5mm

Same exahuse, intake and carb will give you 2,5hp at the pto so goodly for all day long traffic and upper 30s or better.

Based on the 72020 cylinder used on the Speciales

Exhaust 160 degree Transfer 110 degree Intake 120 degree Spark 1,5mm

Same exahuse, intake and carb will give you 2,8hp with long power band can give you 40s.

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