GB250 twin carb removal - help!

[reggie]

This is my first post - i'm new to motorcycling and can't wait to get out on my recently purchased 'project'.
it's a 1987 GB250 (twin carb) that was sitting idle for almost 3 years.
I've cleaned and resealed the tank with POR15 as it was pretty rusty. However the jets are blocked in one of the carbs and as such it'll only rev above 5000rpm which makes it a bit of a monster to ride - particularly for a learner!

Heres my issue - before i start tearing down the bike, is there someone out there who has removed, cleaned and replaced the carbs on this bike? Just need to know what needs to come off in what order so that i don't remove things unnessesarily.
Do I need to remove the airbox? The cleaning part I can do myself.
No manual for this bike in English so any advice and or help would be appreciated!

Cheers!

[Serialunderachiever]

This is my first post - i'm new to motorcycling and can't wait to get out on my recently purchased 'project'.
it's a 1987 GB250 (twin carb) that was sitting idle for almost 3 years.
I've cleaned and resealed the tank with POR15 as it was pretty rusty. However the jets are blocked in one of the carbs and as such it'll only rev above 5000rpm which makes it a bit of a monster to ride - particularly for a learner!

Heres my issue - before i start tearing down the bike, is there someone out there who has removed, cleaned and replaced the carbs on this bike? Just need to know what needs to come off in what order so that i don't remove things unnessesarily.
Do I need to remove the airbox? The cleaning part I can do myself.
No manual for this bike in English so any advice and or help would be appreciated!

Cheers!

OK - done it a few times. It's a twat of a job and no mistake. First time I did it, it took half a day, but I now have it down to an hour and a quarter or so.

Take both side covers off, disconnect the fuel pipe from the carb. Take the seat off (back half first, obviously), take the tank off. Disconnect the battery and take it out.

Remove the two bolts holding in the starter motor, the terminal bolts for the wiring, and take the starter out.

Take the breather tube out - it locates at the back of the head and onto the airbox. Disconnect the airbox connection first and then the head end, and slide it out forwards and upwards.

Take the breather box off the front of the airbox - you need to do this to give you room to drop the carbs off the stubs on the airbox. Disconnect the breather hose and leave it where it is on the bike - makes it easier to relocate it when you put it back together.

Disconnect the choke cable (easy) and the throttle cable (not).

Take out the airbox bolts; lots of them, everywhere - just keep undoing bolts until it moves.

The CBX250 RS manual and I diverge here; the manual says undo the screws on the carb clips and then slide the inlet manifolds off the carbs. I say undo the manifold bolts, slide the whole thing back as far as you can and drop the carbs+manifold+airbox down a bit to give you room to lever the stubs off the carbs at the airbox end. I pull off the 2 float bowl drain tubes and leave them in place on the bike because they are a bugger to locate once you get the carbs back on.

That's basically it. Have fun Give us a PM if you get stuck.

I have a parts book for the GB250E (in Japanese, obviously), and the CBX250RS English manual

[Serialunderachiever]

The other thing worth bearing in mind about the GB with the two carbs is that they aren't TWIN carbs (i.e. identical) - they are DUAL carbs. The primary has a different sized main jet from the secondary, and they have different cutaways on the throttle slides and different profile needles. The secondary carb has no pilot jet.

If you're thinking of taking the carbs to bits, it's well worth not getting the two main jets or the needles transposed. Some idiot did it to mine before I got hold of it, and it took a wee while to work out why it wouldn't rev beyond 6 thousand in 5th and top.