What do these figures mean in real terms?

[bristolmod]

Been playing around with an old TV175 barrel, and I've used the calc section to produce the following figures:-

Exhaust duration 167
Transfer duration 113
Inlet duration 157

Can someone tell me in Janet and John terms what this means on a road going scooter?

Will have a 22mm Carb and a 42mm Clubman

ta

Chris

[bristolmod]

anyone?

[sean brady scooters]

just guessing really but maybe 11/12 bhp/65 mph tops...
let us know

[bristolmod]

Thanks Sean- I'm more concerned that it actually starts OK and runs!!

Chris

[sean brady scooters]

the tansfer timing is very low ,but apart from that i,m sure it will start and run

[bristolmod]

refitted the new top end this morning. New piston. Cylinder bored to suit with 3 thou clearance. 22mm Jetex and the 42mm Clubman.

2nd kick. Idles perfectly and runs really smoothly- good take up of power.

Just need to run it in now

Chris

[jonny snatchsniffer]

3 thou might be a tad tight

[bristolmod]

that was my thoughts- however, the guy that does all my rebores, and of whom I've got the greatest respect, recommended we went down that route (I normally go for 3 thou on steel lined alloy barrels) to eliminate any rattles (there are none)

He's also put two 1.5mm holes either side of the piston to aid cooling/ provide additional lubrication- these holes "service" the areas either side of the widened exhaust port.

Bike is running very well and I'm hopeful a good running in over the next 750 miles will be OK

Chris

[oldbiker]

The aditional 1.5mm holes are a damned good idea. Yamaha did this from the mid 80`s on their track bikes such as TZ`s and some of the mass market bikes like the DTR and YZ types.

[Supereibar]

Pics?