Forum

[Alan R]

Hi guys-----am in the process of fitting a 32mm AMAL Mk1 Concentric carb.this winter to my 2005 Classic 500. It has an 8.5:1 piston fitted but is otherwise standard...What jet settings, plug and ign. timing would be a good starting point ?? It will be breathing through a paper element "Pancake" type air filter, and has a semi-free-flow exhaust....Thanks for any help-----------

[Bullet Whisperer]

Hi Alan, I would go for somewhere around the 220 size to start with and you might need a slightly more advanced ignition timing than standard, or else your engine might seem a bit 'flat'. 38 deg BDC, as opposed to the usual 35 should do it. If you get pinking, try either a bigger main jet, 107 needle jet or raising the needle.
Regards, Paul.

[Alan R]

Hi BW, -------- thanks for the quick reply and tech. info.--------- Will be making a start fitting this week-end so should have some feedback for next week.... Haven't forgotten about the crank re-building etc. which will be sometime in FEB or MARCH 2013....Mr Xmas has promised a new con rod and forged piston from Mr.H (I hope).

[Bullet Whisperer]

No problem, Alan and, as you may have spotted my first reply should have read 38 deg BTDC and not BDC as typed above.

[Alan R]

Hi BW---- I'm used to double-acting pistons on steam reciprocating engines---- would be interesting to get an internal combustion engine to do the same !!