profiling head, why, how..?
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rosscla
- registered user
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- Joined: Tue Oct 25, 2011 9:50 pm
- Main scooter: Lambretta
- Location: Lanarkshire
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looking at bolting an old bit of chopping board inside the cowl...
"Our dilemma is that we hate change and love it at the same time; what we really want is for things to remain the same but get better."
big hammers sorted mine not all on there own i also had a block o'wood and a big cardboard tube twas same size as fan: i put tube on cowl: put block of wood on top: and hit wood while bolted to engine: 1mm gap sorted, :fb:GP Kevo wrote:Btw, what's a good way to reduce the fan cowl to fan clearance? Mine is more than 2 mm. Quite a bit more.
muppet,
C’est la vie
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rosscla
- registered user
- Posts: 4823
- Joined: Tue Oct 25, 2011 9:50 pm
- Main scooter: Lambretta
- Location: Lanarkshire
- Contact:
Barooom chaawarts wrote:Might help if you are cutting up other road users.rosscla wrote:looking at bolting an old bit of chopping board inside the cowl...
"Our dilemma is that we hate change and love it at the same time; what we really want is for things to remain the same but get better."
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Terrible Taff
- Dealer
- Posts: 71
- Joined: Tue Apr 28, 2009 8:26 pm
- Main scooter: Lambretta's & Vespa's
- Location: 21 Meyricks, Coed Eva, Cwmbran, Torfaen, NP44 6TU
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You need to use a Yamaha YFS200 Blaster 89-02 66mm Std Piston kit.
Various prices on Ebay - just need to know the piston size normally standard comes as 65.95mm giving 0.05mm clearance (0.002") on a 66.0mm Bore.
However I replate the RB20 Cylinder to 66.02mm so there is about 0.003" clearance which allows for the cylinder/Piston assembly to run hotter without seizing, thats if the jetting is set on the rich side so as to use the fuel as a coolant!
This also allows for night time running when there is much more cold air about & moisture which leans off the jetting compared to daytime warm weather use.
Most of the RB scooters I have built end up running between 220'C-240'C at high rpm, checked using a CHT unit with a Mychron 4 Kart Data logger.
Various prices on Ebay - just need to know the piston size normally standard comes as 65.95mm giving 0.05mm clearance (0.002") on a 66.0mm Bore.
However I replate the RB20 Cylinder to 66.02mm so there is about 0.003" clearance which allows for the cylinder/Piston assembly to run hotter without seizing, thats if the jetting is set on the rich side so as to use the fuel as a coolant!
This also allows for night time running when there is much more cold air about & moisture which leans off the jetting compared to daytime warm weather use.
Most of the RB scooters I have built end up running between 220'C-240'C at high rpm, checked using a CHT unit with a Mychron 4 Kart Data logger.