sly-sy
28-04-2009, 12:16
New poster! (less than 10 posts)
Basically have just rebuilt my engine with various mods but the only one that really could affect anything is the 9 slotted fly wheel i have fitted,
pistons, liner, head & cam are all standard -
plus as far as i'm aware the carb is standard ( venturi is but unsure of jetting )
there's a receipt from a previous owner for jets and rebuild kit etc but was many years ago & doenst list what sizes they were.. Anyway
Tickover is my grey area:
reading 14.8 >16.2 - manily 15 > to 16 but fluctuates
Tickover is set to 1000 rpm
engine was hunting between 1000 & 1500 rpm, had issues with air leakage at base of carb found crack in plastic spacer so all sorted and engine is just now slightly lumpy +/- 100 rpm
( have put this down to slotted flywheel) plus i blanked off breather to inlet manifold pipe, blanked off the branch of the restrictor tee but kept tee in situ with the big restrictor and run pipe to catch tank with pipercross cam cover type breather fitted to top of catch tank
light throttle usage: AFR goes down and hit 9.8 VERY breifly if i snap open the throttle but not flat out position: sits roughly 10.5 > 11.3 if i ease the revs up to light cruising/load situation
put foot down more & boost now quickly building up to 8psi (manifold)
AFR: leans out to 14.6 as boost reaches 3 psi but then does the following coming up to 8 psi
On boost / full throttle:
goes from 14.6 and now on full boost and quickly changes to a near perfect 12.2 > 12.6, sometimes sitting at 11.6 to 11.8 if i'm on boost with quick gear changes
So my issues seem to be with tickover and light running....
have found thread showing how the set up pump jet cam/lever spring setup with the 5mm drill bit which i have never done so tiz my next task.
Any idea and thoughts much appreciated - am gonna buy a set of standard jets so i know setup is defo back standard and try again from there.
Mainly - what is a good selection of sizes to order up?
Basically have just rebuilt my engine with various mods but the only one that really could affect anything is the 9 slotted fly wheel i have fitted,
pistons, liner, head & cam are all standard -
plus as far as i'm aware the carb is standard ( venturi is but unsure of jetting )
there's a receipt from a previous owner for jets and rebuild kit etc but was many years ago & doenst list what sizes they were.. Anyway
Tickover is my grey area:
reading 14.8 >16.2 - manily 15 > to 16 but fluctuates
Tickover is set to 1000 rpm
engine was hunting between 1000 & 1500 rpm, had issues with air leakage at base of carb found crack in plastic spacer so all sorted and engine is just now slightly lumpy +/- 100 rpm
( have put this down to slotted flywheel) plus i blanked off breather to inlet manifold pipe, blanked off the branch of the restrictor tee but kept tee in situ with the big restrictor and run pipe to catch tank with pipercross cam cover type breather fitted to top of catch tank
light throttle usage: AFR goes down and hit 9.8 VERY breifly if i snap open the throttle but not flat out position: sits roughly 10.5 > 11.3 if i ease the revs up to light cruising/load situation
put foot down more & boost now quickly building up to 8psi (manifold)
AFR: leans out to 14.6 as boost reaches 3 psi but then does the following coming up to 8 psi
On boost / full throttle:
goes from 14.6 and now on full boost and quickly changes to a near perfect 12.2 > 12.6, sometimes sitting at 11.6 to 11.8 if i'm on boost with quick gear changes
So my issues seem to be with tickover and light running....
have found thread showing how the set up pump jet cam/lever spring setup with the 5mm drill bit which i have never done so tiz my next task.
Any idea and thoughts much appreciated - am gonna buy a set of standard jets so i know setup is defo back standard and try again from there.
Mainly - what is a good selection of sizes to order up?