Are two stroke and Four stroke carbs diffirent?

Jamie S · World Chat Champion Joined: 28 Dec 2006 Karma :

Any one know ?

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

Believe there are differences in the style of atomiser nozzle used. Not sure of what other things are changed (beyond a carb for a 2 stroke possibly having a connection point for a 2 stroke oil feed pipe).

All the best

Keith
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chaz e z · Derestricted Danger Joined: 17 Apr 2009 Karma :

They are different, iv owned a 4 stroke in the past and there are a few differences. Four stroke carbs have the throttle cable on the side, bigger main jet and a plastic diaphram which uses compression to move the needle. Were as a 2 stroke has the throttle cable on top, smaller main jets and throttle cable moves the needle. I am on basing this on the carbs i have worked with.
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sickpup · Old Timer Joined: 21 Apr 2004 Karma :

Sort of.

Very few 2 strokes use CV carbs as the intake pressure isn't as low so less vacuum to open them. Other than that most 2 stroke carbs are pretty much like flat slides, the throttle cable is connected directly to the slide not to a butterfly as on a CV carb.

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Barry_M2 · World Chat Champion Joined: 09 Sep 2004 Karma :

The Artist · Super Spammer Joined: 06 Jan 2008 Karma :

Premix 2 atroke carbs will have a bigger main jet to cope with the extra viscosity of the fuel/oil mix.

dougon2wheels · Nitrous Nuisance Joined: 28 Feb 2006 Karma :

KevTM · World Chat Champion Joined: 15 Apr 2004 Karma :

Am I right in saying 2-stroke carbs have an Air pilot screw and 4-stroke carbs use a Fuel pilot screw.. something to do with vacuum or the likes?

binge · Emo Kiddy Joined: 02 Jul 2004 Karma :

My Pit bike is a 150cc 4 stroke single. It uses a VM24 Mikuni Slide carb. It has an Air Pilot/bypass screw. Screw it in to Richen the mixture, Out to Lean it out.

My old scooter was a speedfight, 70cc. It was running a 19mm Delorto slide carb. And I believe that had an air pilot/bypass screw too. In for Rich, And out for lean.

Ben

chaz e z · Derestricted Danger Joined: 17 Apr 2009 Karma :

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

80sbiker · L Plate Warrior Joined: 22 Apr 2009 Karma :

In general 2t carbs have the mixture screw on the air box side of the carb and 4t carbs have it on the engine inlet side, can be either cv, flatslide or normal round slide type.

Very Happy