Help! Quick! Cleaning carbs, problem with idle mix screw

Hey all,

Cleaning my carbs for the first time...

The problem was - on startup, left cylinder was firing, right wasn't (sometimes for up to 10 minutes) - cold exhaust on right. After a while, would start to fire - puh.......puh.......puh..puh..puh..puhpuhpuhpuh. Leaked gas like a bugger. A co-worker, who rides the same bike as myself (83 maxim 400) said pull the carbs - sounds like a stuck float.

The problem now: left carb (where gas line feeds in) - idle mixture screw has spring, washer, and o-ring. Right carb - spring, no washer, no o-ring! Can I re-assemble without these components? Or may that have been the problem (the carbs looked pretty damn clean, although I didn't do a clunk test before I cleaned to see if that was the problem)? The issue - I have very limited time to work on this, and the bike needs to get back together today. Help?

Mark.

 

You are going to want those parts. Not sure if they caused your problem.

 

There's no way that screw is effective without the oring!

 

The washer and o-ring may still be in the carb body. It's often hard to tell without a good light. I've had to fish them out with a piece of wire on several occasions.... and like the guys said, you _will_ need them.

if one of the carbs leaks fuel even when the bike is not running, it's almost guaranteed to be a stuck float or a piece of crud in the float valve assembly. did you take the float needle out and make sure there's nothing stuck in there?

 

So....

I ended up going to a local motorcycle shop - Action Motorcycles in Esquimalt. Highly recommend them. Anyhoo - fellow there confirmed my co-worker's and stereomind's thoughts - either a stuck float valve or a worn pin in the valve. Although mine showed signs of wear, it seemed to not leak when I filled the valve with fuel.

So - the carbs got a thorough cleaning, thanks to a combination of resources here (Chacal's "church of clean" article was helpful, although I did not rebuild as he recommends) and at http://faq.ninja250.org/index.php/Cleaning_the_carbs_1.

To be honest, I didn't really know what I was doing, so I took pics at every step of dissasembly, followed them in reverse for assembly, and basically made sure that I removed every rubber/plastic part before cleaning. I used a combination of canadian tire brand dunk to submerse the carbs, and canadian tire brand carb cleaner spray to get in the nooks and crannies. I tested a brass brush I had on a small area of brass, and was surprised to see a small scratch, so stuck to a nylon brush and used copper wire for the jets. The most difficult part was removal/isntallation, especially as I was working outside in near-zero (celsius) weather, meaning the air box boots and intake boots were not very flexible at all. The hammer handle for leverage was the best piece of advice I've ever had! Would have been screwed without it! Also, the removal/installation article at the ninja faq sight (partially administered by a member here) was extremely useful. Anyways, they are back in, the bike starts, runs more smoothly, idles better, chokes better - be interested to see if it still begins to bog down in high RPM's in 1st/2nd as it has since I bought it. So it would appear the float valve pin was indeed sticking - hopefully it does not wear out as the fellow said, as they are 90 CAD a pop!

As for the mixture screw: the fellow at Action (and they are knowledgeable) said it is not unusual to find a mixture screw missing the o-ring/washer, as it has happened to a number of bikes they have serviced and that he has bought. The issue - can't buy the parts off the shelf, as technically they are not supposed to be removed (tamper-proof and all). So - they found an o-ring, but no washer. The fellow said he once ran a bike for years without the washer/o-ring on one mixture screw, to no ill effect. Anyhoo - I installed it with the o-ring, but no washer. The spring seems to be seated ok for now, and I'll try and salvage a washer from Victoria Motorcycle Salvage sooner or later (I need to find some replacement starter button parts anyways, as the piece of plastic with the contacts is currently jb welded, and my starter button is a piece of sheet metal cut/bent to function as a starter).

Thanks all for your feedback, especially bill getting a reply in within an hour - too bad I had already left for Action at that point...

Cheers