Topic: CB400F drilled carburetor?

[PLS]

Hello I have an immaculate 1976 CB400F and after it had been sitting a while, the fuel wouldn't flow so I took it to a mechanic to clean out the carbs and make any adjustments to get it going again. However, although he got it going, it was running incredibly rich. He admitted to using drills (by hand or in a chuck) to clean out the main and slow jets until it 'cut brass' and thought this might have been the reason it was running rich. He also noted that the emulsion jets were badly pitted but didn't ask me to change these. I purchased new main and slow jets but after these were fitted, it stll ran rich and was laying thick black deposits on my plugs. This mechanic shocked me by charging for 24 hrs of labour. I then went to another mechanic, who insisted that I purchase emulsion jets before doing the job. This mechanic stripped the carbs down completely and reassembled them in 3hrs and it's been running fine since. Is it standard practice to drill out jets and how important are emulsion jets to running?

[dave400]

Blimey that sounds like it could have been expensive, I think the emulsion tubes on my 400 are a critical part of the combustion process so it was money well spent by you.

Dave

[05c50]

It's standard practice for idiots to drill out jets. The size of tiny holes in the jets are critical to the calibration of the fuel/air mixture in the carb! Many hours and dollars have been spent to find the right size to make the engine run correctly. The jets should only be cleaned in a manner that will not change the size.(chemically or possibly with a soft wire). I had a 550 that gave me fits....it always ran rich. I finally found that the emulsion tubes had corroded away on the inside and caused the over rich condition.
I'm glad the second mechanic found the problem for you.Three hours doesn't sound like a bad time to repair someone else's screw up.
Now about that 24 hour labor charge........If you need anything else screwed on your bike, I'd be happy to do it for substantially less.

[PLS]

 
Blimey that sounds like it could have been expensive, I think the emulsion tubes on my 400 are a critical part of the combustion process so it was money well spent by you.

Dave

Hello Dave. Thanks for your reply. The only money I've spent was on the 3 jets and the 3 hours labour, but it could obviously have been cheaper if the main and slow jets hadn't been drilled.

Cheers
Paul   

[PLS]

 
It's standard practice for idiots to drill out jets. The size of tiny holes in the jets are critical to the calibration of the fuel/air mixture in the carb! Many hours and dollars have been spent to find the right size to make the engine run correctly. The jets should only be cleaned in a manner that will not change the size.(chemically or possibly with a soft wire). I had a 550 that gave me fits....it always ran rich. I finally found that the emulsion tubes had corroded away on the inside and caused the over rich condition.
I'm glad the second mechanic found the problem for you.Three hours doesn't sound like a bad time to repair someone else's screw up.
Now about that 24 hour labor charge........If you need anything else screwed on your bike, I'd be happy to do it for substantially less.
 
Thanks for your response. Fortunately, I haven't paid for the 24hrs as I only enjoy being screwed by invitation rather than by surprise. The story gets worse. The first mechanic initially wanted me to get another set of second hand carbs from a local wrecker on appro so that he could spend more time pulling them apart and testing his drills on the borrowed main and slow jets to get the correct size. He would then solder up my jets and drill them out to the same size - making them 'just like new again'. I would then return the now equally screwed reassembled 2nd hand carburetor to the dealer paying him perhaps $20 for his trouble and saying they weren't really what I wanted. Perhaps you can see why I got a new mechanic?

[rbirkhan]

Yeah you gotta drill em jets out I use a 3/8ths wood bit and a rotary hammer drill or a 2 pound ball peen hammer and some 10w30 anti freeze and some medium weight ball bearings.   On all my carb work. Really gets the fuel flowing for extra horsepower. !! Let me see buy the carbs measure the jet size return said carbs to angry sales guy then solder jets and then redrill too big ......Brilliant!!! Why didnt I think of that one good for another 24 hr pay period. Good to hear you have a new mechanic.

[PLS]

Yeah you gotta drill em jets out I use a 3/8ths wood bit and a rotary hammer drill or a 2 pound ball peen hammer and some 10w30 anti freeze and some medium weight ball bearings.   On all my carb work. Really gets the fuel flowing for extra horsepower. !! Let me see buy the carbs measure the jet size return said carbs to angry sales guy then solder jets and then redrill too big ......Brilliant!!! Why didnt I think of that one good for another 24 hr pay period. Good to hear you have a new mechanic.

Nothing like the subtle touch. Matter has just been resolved with 1st mechanic's bill drastically reduced for work on other matters - brakes etc and a few hours for cleaning up green gone off fuel. He kept threatening court action, but when I said let's go, he became a much more flexible negotiator. Thanks for the feedback.

[oldfordguy]

You should never pay someone to destroy your property, and once they have, you should never let them touch anything you own ever again!  Not only that, but you need to let everyone you know know that he is totally incompetent, and to make sure they never let him touch anything that belongs to them either.  This kind of thing is inexcuseable.

[Scrubs]

agreed. he sounds like a waste of space. I personally wouldent go any where near a jet with a drill! or anything harder than
nylon brush bristle for that matter, I usually just soak them in some meth or bathroom cleaner for a very short time if they are very grimy.
and give them a blast with compressed air or carb cleaner.