Cast iron 225 factory tune 30phbh

[Markymark]

Hi all,

Have the above fitted and porting cleaned up with a 30mm phbh with the following jetting
Pilot 53
40 slide
Av266
X7 needle
Main jet 126
My panel filter

After not running in properly (should know better) had a seizure at 70 but have managed to salvage the piston and fit new rings with a view to running properly!

Interested in any other jetting combos you might have?

[coaster]

What does it run like with the current settings, have you done any plug chops?

[eden]

main jet looks way too small to me

[Markymark]

Hi eden/coaster,
Apologies for the late reply,
Just got her back together and have changed to 55 pilot and 128 main but have yet to take her for a run.

Eden,
You mentioned the main being to small?

What do you think I should be running safety wise for the main? Have a af 9.5.1 head if that helps

Many thanks for your advice

Mark

[eden]

it is dependant on each motor but I would have thought 135 or bigger

it maybe that your atomiser /needle setting is too rich so your having to compensate with a smaller main jet!

jetting is a minefield if you don't have a good ear and feel for it

you can get the atomiser/needle closer by running with no main jet in, you also get a better idea of at what throttle position the main jets takes over from the needle/atomiser. Then start to dial in the main jet, starting BIG and coming down.

[tavspeed]

i have a similar set up to yours,but with a saigon/taffspeed copy,have just got a new 30mm phbh as couldnt get it to run without 4 stroking with a pwk

started with 55 pilot

av266

x13 needle 2nd clip from top

125 main

no air filter and 60mm crank
was very boggy from 1/4 to 3/4 throttle,so changed needle to a x7,runs nice and crisp,tried diffrent clip settings,but spark plug is grey/white

so went back to x13 with 120 main 2nd clip from top,runs nice but plug still looks grey,am i going in the right direction,should i try a 135 main with the x7 needle again at various clip positions

[eden]

try X13 on top clip with bigger main

[eden]

and remember it will be boggy when your fist set off until its warm, It can take over 5 miles to get up to temps, don't make the mistake of getting it just right as you leave home only to find it goes pop once you get on the open road at speed.

[eden]

also whats the timing set at and are the revs dropping off as they should? have you done a leak down test on the motor?

[tavspeed]

timing strobed at 16 deg btdc
had x13 on top clip with 125 main and 4 stroking after 1/4 throttle till main jet comes in
running a 60m crank , seems to have a lot of compression, squish is around 1.5mm