Bandit carb clean

It's been delayed a bit this year with one thing or another but the Bandit has been dug out from the side of the shed and in it's summer position. The Z500 is covered up for a while but will still get the odd bit of work done. The motor is the next job.

At the end of every season the Bandit's fuel system gets drained and a bit of either DW50 (Smith and Allen's WD40) or GT85 sprayed into tank and carbs. Each spring just a flush with fuel and is ready to go. This year been a good while since they were fully cleaned out. I can do my jets and small stuff in the 1.3ltr Ultrasonic cleaner but obviously would have to split the carbs to do the bodies. So.... as well as going round my mates and using his compressor I though about a good way to flush out the body drillings etc.

After removing the jets etc (placed in an egg box labelled 1-4) I got out my large syringe from the brake bleeding box and rigged up a high pressure jet wash with the aid of tubing and suitable plugs.

The pilot / slow running circuit was the main target. At idle with the CV carbs the mixture screw does most of the metering with a small amount of mixture delivered through the bypass ports just on and behind the throttle butterfly.

As the throttle is opened, due to changes in vacuum as the butterfly opens more mixture is drawn through the bypass holes than the metered pilot hole. You can get a situation that I have noticed on my No1 cylinder of a fluff just off idle and at low speed running. This is not to be confused with the usual cough the Bandit has when cold.

closeup up of bypass and pilot hole (note pilot screw in the fully seated position)

First cleaned the pilot adjusting screw and o ring, then reassemble the screw and lightly seated it down to stop the flow from the adjusting screw forcing everything to go through the bypass holes. Dripped some Acetone (could use carb cleaner or brake cleaner) into the pilot air hole at the rear of carb with the pilot jet plugged and left it for a few minutes. Plugged the air jet hole and blew air from the syringe down the pilot jet hole. I could see a spray from the bypass holes but could not see if all 3 were clear. Next put some Isopropyl Alcohol in the syringe and saw liquid freely coming out of 2 of the 3 holes sort of proving my fault diagnosis. Did the same process on carbs 2,3 and 4 and got a full stream from the 3 port holes. Please note that the wearing of eye protection, chemical resistant gloves, doing this in well ventilated area and away from any source of ignition is a must. A respirator is a good idea too.

After about 30 mins with acetone and then air squirted with the syringe as hard as I could the 3rd hole was free. While I was on gave the start circuit and mixing chamber a good flush. Finally remembering to back off the pilot screw to 3 1/4 turns out, manual says 3 but get better pick up a bit richer.

They will be refitted this weekend as got side tracked and did the valve clearances. Will post next the tale of woe regarding the tappet screw.

Love to hear if anyone has methods of carb cleaning

Rob B

Sounds fun, tbh with mine I just get on a ride, and its ridden that often that nothing builds up to stop it running properly, it's my year round transport

I admire your thorougness but to be honest all I ever did after a winter lay up with the GSXR was to stick some fresh petrol in it and give it a thrash up the Warwick Bypass ( A46 ) That always got rid of any hesitation issues .

Cheers Bob, I always promise myself to just brim it and then it's ready anytime but old habits die hard. Carbs back on and leak tested, will post this evening about my tappet adjuster but you may guess. Anyhoo time for tea.

Rob B

Cheers Bob, I always promise myself to just brim it and then it's ready anytime but old habits die hard. Carbs back on and leak tested, will post this evening about my tappet adjuster but you may guess. Anyhoo time for tea.

Rob B

Maybe this will cheer you up . Apparently it's the same part for inlet and exhaust and left and right . Did I guess right ? https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F123727661488

Good guess Bob, with my paranoia of not tightening the tappet lock nuts up enough over the years, using the 6" 8 mm ring spanner has made it easy to damage the very fine pitch threads on these small screws. This is the 8th time I have done the valve clearances on the bandit in it's 56000 miles.

No2 inlet and No3 exhaust had to be removed. repaired No2 inlet but No3 exhaust was too bad.

My local dealer had 2 sets in stock so popped over on the 125 and bought both. £20.00 for both sets eeek!!! Lesson well leaned so now use my short 8 mm ring spanner. Clearances set to as near half way as a could, so all set for the next 7000 miles or so.

Rob B

It all looks a bit too technical for me. I generally ride 10 months of the year and for the two months Dec and Jan that I don't, I add this https://www.ebay.co.uk/i/163492131721 to my tank and run the engine for a couple of minutes so it gets into the injectors. Always starts on the button and hopefully keeps things squeaky clean. I've been using it for carb bikes as well with always the same good results.

Glad it's all sorted . At least you have tappets instead of the trauma of having to remove your camshafts and then buy or swap shims . I just hate torquing down cam caps because something always goes wrong . On my first GSXR nearly all the bolts snapped on the way OUT but there was enough protruding to get them out with fingers , weird . Of course all that bollocks is behind me now because Harleys have self adjusting hydraulic lifters and push rods .