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What do these figures mean in real terms?
Posted: Wed Jul 14, 2010 12:47 pm
by 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
Re: What do these figures mean in real terms?
Posted: Thu Jul 15, 2010 8:21 pm
by bristolmod
anyone?
Re: What do these figures mean in real terms?
Posted: Thu Jul 15, 2010 9:35 pm
by sean brady scooters
just guessing really but maybe 11/12 bhp/65 mph tops...
let us know
Re: What do these figures mean in real terms?
Posted: Thu Jul 15, 2010 9:40 pm
by bristolmod
Thanks Sean- I'm more concerned that it actually starts OK and runs!!
Chris
Re: What do these figures mean in real terms?
Posted: Thu Jul 15, 2010 9:49 pm
by sean brady scooters
the tansfer timing is very low ,but apart from that i,m sure it will start and run
Re: What do these figures mean in real terms?
Posted: Sun Jul 18, 2010 11:52 am
by 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
Re: What do these figures mean in real terms?
Posted: Sun Jul 18, 2010 4:47 pm
by jonny snatchsniffer
3 thou might be a tad tight
Re: What do these figures mean in real terms?
Posted: Sun Jul 18, 2010 5:07 pm
by 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
Re: What do these figures mean in real terms?
Posted: Sun Jul 18, 2010 9:25 pm
by 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.
Re: What do these figures mean in real terms?
Posted: Mon Jul 19, 2010 9:43 am
by Supereibar
Pics?