posted by unfamilia on 5/21 6:19 GMT

Sick of the stuffing around from so called auto stores, called pirtek for the fittings.
In stock tomorrow arvo.

posted by D on 5/21 23:46 GMT




Mik you saying these downdraft carbs are the ones you used???

posted by unfamilia on 5/22 1:18 GMT

Well thats same model bike (not exact bike) they are from.
I didnt know they were mounted like that when I bought them so...... I guess thats why im having issues. But some bike carb folk say they should be ok but need less pressure and tight floats from my understsnding.
Wonder if its completely dodgey to use the fuel overflows as a return line to the tank lol

posted by D on 5/22 9:01 GMT

Being downdraft in design its quite a challenge to not splash fuel into the drain hole when vertical from back and forth acceleration. A gravity feed setup would be your best bet.

dodgey return line back to the tank sounds good but can be done to a gravity fed unit with only one line

posted by ddgonzal on 5/22 9:20 GMT

How do it gravity feed when the 1200 fuel tank is lower than the carburetors?

posted by unfamilia on 5/22 9:24 GMT

Cause its in a stanza not a 1200. Need a swirl pot in engine bay to gravity feed it into carbs.

Stock pump pumps into pot. Just need an overflow with return line to tank.

Sourced another metal fuel line. Just need to pick up. I had to do similar on the 1200 when it had petrol and su's for some reason

posted by unfamilia on 5/23 15:14 GMT




fuel pressure reg system all mounted. Test in the morning. Hope all is better.

damn 3/8 npt fitting. What a pain to find. Has taken me most of week to find 2 in melb. Even enzed and pirtek didnt have. All sorted now I hope.

posted by unfamilia on 5/24 2:51 GMT

Had to take out adjustment screw to get to 1psi. Stock pump putting out 4.5psi. 10 mins no flooding out couple more mins and started dripping. Whats that spring do in the reg? Can it be removed. Will need to reset floats lower.

Anyway im seriously contemplating just running a return line from overflows if resetting fliats doesnt work.
apparently old school racers used to do this but also carb return lines come stock on some carbs

posted by unfamilia on 5/24 8:01 GMT

So floats set to 1mm travel let idle 20mins no leaks at 1psi fuel pressure. Took for drive. Leans out at just over 5k...got detonation . but getting to 5k much better even with retarded timing.
15min drive idles at 1700rpm still and no leaks. Yay. But now worried floats too low lol.

posted by unfamilia on 5/25 13:37 GMT

Measured the fuel levels in float bowls just now. Missed start of f1, that's how much im into these carbs lol.
fitted clear hose from fuel bowl drain and measured wherevthe level sits externely on bowls.
Cyl 1 was half way up bowl
cyl 2 to the top of fuel bowl closest the engine
cyl 3 to the top of fuel bowl half way along length of bowl
cyl 4 top of fuel bowl almost at furthest edge away from motor.

ok good guessing floats. Set them all the same but as carbs also angle down away from cyl 1 no suprise levels increase as I move from 1 to 4

fuel levels measured with 10ml syringe.

Cyl 1 36ml
cyl 2 50ml
Cyl 3 58ml
cyl 4 64ml

well carb one concerned me but rest arent too bad. Could trim cyl 4 a little.

From my reckoning (flawed logic most likely) my webber held only approx 130-150ml for all 4 cyl.
so 50-60ml per carb seems ok.

Hope bowls arent drained fully under accel. So tomorrow or tuesday might reset cyl 1 for bit more movement. Will leave rest for now seeing their levels are at top of bowls at least. Could get little more into cyl 2.

Knowing its leaning out 5k under full throttle debating on drilling mains to 1.8 before tuning at simons.