WTB XJ550 Carb

Long story short, I need the left outer carb, had a problem with the pilot jet, now I have a problem with an easy out...

I will buy the whole set if need be, but I need this to be as cheap as possible. I'm on a "unemployed single father of three" kind of budget.

Please email me, as I've had some weird issues with the PM system... or I'm old and un-forum-edumucated.

rustydatsun510 at hot(mail) dot com

Thanks guys.

 

still need...

 

hmm I will keep my eyes open. is this for a seca or maxim?? I spoke with someone via telephone near my area last Sunday evening who had a very similar situation, and failed to mention about this site. what's your location? it'd be crazy if you were the same guy! sorry that's not much help though I know...I don't have an extra set lying around

I started taking my 550 carbs apart last evening *gulp* and needless to say it is in sorry shape as well. hope I don't stumble into what you guys have gotten yourselves into *knocks on wood*

 

550 maxim and 550 seca's have the same engine, so carbs should be the same, too.

Dave F

 

Well... I found a great set today at a local shop. They'd been on the shelf for quite some time.

The old guy who runs the place made me feel a little silly... "dont even think about trying to remove the jets without first applying heat and penetrating fluid"... working on bikes for 50 years teaches you a few things, and I'll take his word as gospel.

 

Kroil !!!!

invest in the stuff. it works & I even convinced my dad to use it too. he's hard-headed machinist who uses it and was surprised as well.

 

Not exactly.

The 550 Seca and 550 Maxim motors have different cams; and as a result the carbs have some internal differences although they do use the same bodies.

The PILOT AIR jet and main JET NEEDLE are different and would need to be retained from the original carb if swapping between a Seca and Maxim.

BTW, there are some transmission drive-ratio differences between the two as well; the motors only LOOK the same.

 

Thanks for the info bigfitz. I'll have to check those now... I was planning on rejetting them anyway, since the bike came with a kerker 4-1 exhaust and stock jetting.

 

Is it just the cams, and nothing else, that is different? I thought that the compression ratio and/or heads were also different. I have a line on a maxim 550 motor to rebuild my seca 550 motor, but not sure what I can actually use.

 

Just stick the engine in and go.

 

ALL info is pulled straight from the INFORMATION OVERLOAD HOUR

XJ550 Maxim and Seca cams can be swapped between these engines (but not with any of the 650-up engines). The 550 Seca cams are "hotter", they have more lift, and probably also have increased duration and possibly overlap.

tech:

XJ550 Maxim:

Intake Lift: 6.80mm
Exhaust Lift: 6.80mm

Duration: not given

Overlap: not given


XJ550 Seca:

Intake Lift: 7.80mm
Exhaust Lift: 7.10mm

Duration: not given

Overlap: not given

carbs are the same... small differences in jetting:
XJ550 Models:

Years & Models: 1981-83 XJ550 Maxim North American models
Carb Manufacturer: Mikuni
Carb Series: BS28
Carb Model ID: 5K500
Main FUEL Jet Size: #112.5
Pilot FUEL Jet Size: #35
Main AIR Jet Size: #70 (non-removable, in carb throat)
Pilot AIR Jet Size: #165
AIR COMPENSATOR Jet Size: not used.
Starter FUEL Jet Size: #35 (non-replaceable, in float bowl)
Main jet NEEDLE ID: #4GN
Main needle JET Size: #O-8 (the main needle JET is also known as the "power valve" or "emulsion tube").
Fuel Level in float bowls: 2mm +/- 1mm (.08" +/- .039")
Idle RPM's: 1,200 rpms
Vacuum reading at idle: not specified
Vacuum, allowable difference between cylinders, at idle: not given

Although not part of your carbs, your valve clearances should be considered as part of your "intake system", so here are those specs, too. Note that valve clearances should be measured with the engine "cold", meaning 70-degrees Fahrenheit or less:

Valve Clearance Intake: 0.11 - 0.15mm ( = 0.004 - 0.006")
Valve Clearance Exhaust: 0.16 - 0.20mm (= 0.006 - 0.008")


Years & Models: 1981-83 XJ550 Seca North American models
Carb Manufacturer: Mikuni
Carb Series: BS28
Carb Model ID: 4U800
Main FUEL Jet Size: #112.5
Pilot FUEL Jet Size: #35
Main AIR Jet Size: #70 (non-removable, in carb throat)
Pilot AIR Jet Size: #170
AIR COMPENSATOR Jet Size: not used.
Starter FUEL Jet Size: #35 (non-replaceable, in float bowl)
Main jet NEEDLE ID: #4GZ11
Main needle JET Size: #O-8 (the main needle JET is also known as the "power valve" or "emulsion tube").
Fuel Level in float bowls: 2mm +/- 1mm (.08" +/- .039")
Idle RPM's: 1,200 rpms
Vacuum reading at idle: not specified
Vacuum, allowable difference between cylinders, at idle: not given