Attempt #2
 

Ok some back ground. Parked the girl when i busted my elbow, and she sat for about 6 months. Had surgery and rebuilt the elbow. Got back on and she ran fine, but doctor got upset so she got parked again. Another 4 months, in the garage and finally got cleared by the doc. Backed her out to go for a ride the day he cleared me and she would not run without choke and stumbbled badly under initial acceleration, hard acceleration and she ran like the old days.

Fought with it for several days thinking it would clear out, new gas, seafoam but never got better. Finally pulled out the sync tool and carb cleaner and started checking lines, vac hoses, and tried to sync. Not a chance she would sync at all.

Pulled the carbs, and removed the lower bowls and cleaned had some rust colored stains in all bowls, and the idle jets were all plugged, cleaned / blew them out and cleaned the bowls. hooked everything back up and tried to sync again. 3 hours and they never really got close, it would idle for a couple minutes and then die. It would start right back up, but die each time if left to idle. Finally gave up and put her back in the garage depressed. That was October, now weather is starting to warm up and I am looking to try again.


My thoughts, thinking there was still some "junk" in the tank and when i hooked everything back up and started her up she just sucked in some more nasty gas (Crosses fingers) looking to get inline filter installed as i discovered there is no filter stock from the factory. Looking to pull the carbs again, and clean out the bowls and jets once more.

Should i just break down and put rebuild kits in since I am having so many problems?

Keep in mind I am a novice at carb work.

Or should i try and tear down the top and bottom and clean? how delicate are the top end spring needle assembly? what about the top diaphragm? Are these easy to remove and clean without damaging them? Is there anything i should be aware of if I go that route? what do i gain from the disassembly of the top end versus the bottom of the carbs?

Sorry for all the questions but i really want to get my Girl back on the road.


Also as a last question, should i pass at this point and call in a pro? i have asked about and been told it is about 120 per carb for a rebuild and sync, so a little shy of 500us for the job at the local dealer.

Hi, I tend to leave carb work alone apart from blowing out the jets. But my last cbr prior to this one had been stood 2yrs outside. Rather than strip the carbs I drained the tank put a gallon of petrol in + 2 egg cups of acitone. I got it from my local chemist, or pharmacy as you call it. Or it is available on the internet. it disolves all the gum that forms when petrol is left to stand. After some coughing and a few back fires it fired up. That`s my 2 penneth. You will no doubt get more ideas on here the guys are very helpful.

Hi, me again. there are some sets of carbs on ebay both in the USA and UK if you wanted to go down that route.

Will give it a look when i get home. Might be an idea. Got a call back from a motorcycle mechanic i did some computer work for, he has offered to clean, rebuild and resync them for cost, no labor. Think i will take him up on the offer. 80$ total for the rebuild kits :)

Sounds like a good deal about £50 I put my off side mid section fairing in for respray today. Its going to cost me £150. Ouch!

It seems this tory has found its own happy ending.
Good luck with the carbs Hots. Let us know if that sorts your problem out.

Steve, are you sure acetone is safe on the rubber hoses? I know you're using it quite well diluted in the petrol but I would suggest you check if it's had any effect on the fuel pipes. It's quite an aggressive solvent.

£150 for a fairing respray sounds about right. Never easy to stomach though. Well done for keeping her in shape. Sometimes you just got to bite the bullet.

Dam good plan man !! http://www.cbr-riders.com/forum/imag...s/smiley20.gif the carbs and associated bits can be a bitch .

..fixed once and for all is the go if you can swing that deal ... :icon_wink:

Finally got her back Tuesday. Man is she running great again! very happy, the Mechanic said the carbs were really bad, he had to go through the m a couple times he said. then there were some vac hose issues, he swapped them out and synced them up perfect. she purrs like a kitten again, of course the next day it rained me out :( So much for the nice sunny Florida weather.

But all is well in the world again.

Good deal, man. Nothin' like nice clean and tuned carbs! :)
I suggest a little seafoam now and again to try and keep 'em clean.

Hate to revive an old thread but the saga continues:(

Having ridden her now for a few days i discovered the gas mileage is horrible.

before problems 1 tank 4.5 gal us was about 145-150 miles before the stutter to go to reserve... i don't like riding below that much.

now 4.5 gallons approx and 96miles before stutter?

holly smoke batman that is like a 45+mile per tank loss.

She does run rich smelling, but runs smooth as can be. idles easily and doesn't need the choke to start anymore.... something i can adjust or is this back into the carbs?

Choke travelling , as in opening and closing fully ????

Sounds closed.......... they always need choke to fire up

Might not be reconnected properly

would the choke cause the drop in mileage?

If it was holding the choke closed just a little ..... it sure would eat the fuel ...

sounds like my first check.

Thanks

Remember automobile carburetors that had a butterfly valve at the top that would close and choke off the air supply to make the mixture rich? If it stuck closed or partly closed, the car ran rich and wasted fuel.

The CBR's Keihin choke doesn't work that way. Opening the choke lever allows (lower?) air pressure inside the upper chamber of the carbs to raise the piston/needle out of the main jet. That richens the mixture making quick starting. Closing the choke lever allows less air into the upper chamber, lowering the needle, and lowering the idle speed.

The problem is that one or more of the piston/needles can hang up in a dirty bore. They usually hang up in the fully open position, or close very slowly so the engine runs very rich. I think this is the most common carb problem. The tops of the carbs have to come off and the pistons and walls have to be cleaned. See the "How To" section.

The first time cleaning them is kind of strange. But you will see the ingenious way the needle comes out of the main jet, and the ingenious way the choke works. With the carbs completely clean, you will be amazed at the way the bike responds to the throttle.

Excellent info Slowp. Thanks.

Ok looks like slowpoke is the winner. i checked the choke and it is opening fully no problem. Since the carbs were just pulled and cleaned i don't think i should be having this problem. i guess i will be calling the mechanic back, hate to have to go back :(

spoke with the mechanic and he thinks it is just finally getting the gas it wanted.. the carbs were very varnished he said. he did not change the jets or timing so he said he is at a loss for what might be the problem. His gauges said it was running fine when he gave it back, but he will look at it again. getting a funny feeling about this, but not much choice at this point. will drop it off later this week and see what he comes up with.