Author Topic: CB350F full engine rebuild (Read 9680 times)

carnivorous chicken · « **Reply #25 on:** June 04, 2018, 01:06:33 PM »

Although I also have to admit I kind of like the overhead #2 pipe. Could catch on.

camshaft1991 · « **Reply #26 on:** June 04, 2018, 01:41:28 PM »

Fits but was more of a pain than pipes 3&4 but I still have trust issues with that kickstand, may be warped, so I’ll leave it off for now

I’m going to take them off after tuning because I need to do some engine cleaning and polishing. My head seems a little out of place next to the rest of my engine

Before I take them off I think I’ll try to make my pipes look like an X-Wing from star wars lol

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carnivorous chicken · « **Reply #27 on:** June 04, 2018, 01:43:55 PM »

The kickstand mount on these (but more so on 400Fs in my experience) can be a weak spot -- people sitting on the bike on its side stand can definitely bend it or even tear the mount off.

camshaft1991 · « **Reply #28 on:** June 04, 2018, 08:02:45 PM »

If it is the kickstand I can always try find another.
So the bike runs but the carb floats are locked up so I have to nurse it gas. Also my clutch only works when it is set as tight as can be. Any looser, it doesn’t work. But the bike runs clean and doesn’t burn anymore oil . I tried to tune it for 30 min before a rain came in and I put the tank on to cover everything and I noticed I didn’t have my filter or air box lid after opening my seat up. Maybe tuning will go better the second tome around

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carnivorous chicken · « **Reply #29 on:** June 05, 2018, 06:29:30 AM »

Quote from: camshaft1991 on June 04, 2018, 08:02:45 PM

So the bike runs but the carb floats are locked up so I have to nurse it gas.

Help me out with this one. All of your floats are stuck -- up? or down? how are you feeding it gas? Regardless -- pull them, clean them, make sure everything is work ing as it should, check float height, verify with clear tube, and make sure the floats are opeating as they should. Sometimes the tang will bind on the float valve.

Do you have a carb sync tool? That's got to be part of the equation as well.

Sounds like you're making progress regardless.

camshaft1991 · « **Reply #30 on:** June 05, 2018, 04:01:37 PM »

Yeah I have a carb synch with vacuum gauges but I just want to have engine run in full range. Currently it’s limited to 6500 rpm. I’m Running ethanol free gas through it but I don’t think the floats will unstick anytime soon. The floats are stuck in the open/down position so no control on the amount of fuel. So I give it a little gas bit by bit until it drips from the overflow. Then shut off the fuel after a few drips. It’s not safe but I got a full extinguisher at hand. I also only smoke when I drink so I try not to drink when I work on my bike

It could be the floats locked up or the float needles themselves.

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camshaft1991 · « **Reply #31 on:** June 05, 2018, 04:46:51 PM »

I keep making idiot mistakes. Not grave ones but I was trying tune my bike with the choke on. Found out when I was taking the carb boot clamps off. Well at least I have extra plugs..

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camshaft1991 · « **Reply #32 on:** June 05, 2018, 04:58:58 PM »

Ok so it is the carbs. I mean the floats are locked but it chokes at wide open throttle even with fuel flowing

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carnivorous chicken · « **Reply #33 on:** June 05, 2018, 07:20:07 PM »

If your floats are closing the valves (all of them at the same time?) then you'd better get that sorted first. Check float height. Check to make sure your floats aren't upside down -- someone railed at me to say that was impossible, then posted a photo of an upside down float syaing that was just to show you it couldn't be done, but there it was). then float valves. Make sure the floats aren't impeded. Make sure your float bowl overflow tubes aren't cracked (would be crazy for all four to be...).

It's kind of a pain, but you can pull a float bowl (1,4 easier, 3 harder, 2 hardest) with the carbs on the bike and check to see if the valve closes.

So you were running it with the choke closed? Bike shouldn't run or should bog and stall once warmed up if the choke is on.

camshaft1991 · « **Reply #34 on:** June 05, 2018, 11:05:55 PM »

I just took them off. I don’t want to spill gas on the engine. I know what a little gas sitting on the crank can do. I can handle gas underneath the engine but gas sitting underneath carbs that could be a problem. Also it’s not good for light clear coats like Protectaclear, but most of it has probably already dissipated from the dark look of the engine. It doesn’t turn your engine yellow but it will evaporate in a year or sooner if not reapplied and exposer to chemicals can shorten that.

Anyways carb float #1 was the culprit. All it took was the push of a finger to set it free. A carb bowl full of gas wasn’t enough.

Carnivorous chicken: the bike can run on a full choke so long as the air screws are screwed out enough, which is what I did unknowingly. For the 350F, there is also a little flap on the butterfly valve face that opens if there is too much vacuum or if an idiot leaves the choke on. The floats aren’t upside down. Been there done that and with gas pouring out from carb intakes. When gas starts to leak from the big boot on the carb intakes, that’s when they’re all dumping endless gas. The only way I can measure the float height is by measuring how high it sits with the carbs turned upside down. The little tang piece on the floats would rest on top of the fuel valve pins. From there my book says to measure from where bowls seal on the carb bodies to the highest point of the float (21mm). Aside from drilling a hole through carb drain screw and feeding tubing through it, I don’t have any other means to actually measure the level of gas in the bowl.

Here are some lovely photos of some gas fungus

(Or oxidation of brass with gas)

1-4 left to right in all three pictures.
I tried to dislodge the float pins with a toothpick and bunt end of small 3/8” to 6” adjustable wrench but no give.

From previous carb disassemblies I know that this is the best way to do so without breaking the float towers but I’m going to need to do some soaking.

I don’t have enough chem dip to pour in a tub-o-ware container but all I have in bulk is a gallon of xylene and Acetone but I feel like both will dissolve the tub-o-ware. And is flat out dangerous

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innovativems · « **Reply #35 on:** June 06, 2018, 05:36:08 AM »

You need to disassemble this carbs completely for dip

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camshaft1991 · « **Reply #36 on:** June 06, 2018, 11:36:36 AM »

Everything brass is stuck in place and it won’t budge with light hammer taps and wood blocks. Yeah.. it’s gonna cause swelling to anything that is an o-ring. It’s very easy exert too much force on these pieces. I’m going to put the bottom ends of the carbs in an open container so I can get the brass out for cleaning.

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carnivorous chicken · « **Reply #37 on:** June 06, 2018, 11:41:23 AM »

Use heat and PB blaster. Even as little as a hair dryer can loosen them up.

camshaft1991 · « **Reply #38 on:** June 06, 2018, 12:05:54 PM »

Just bought some PB along with Berryman Chem dip and carb cleaner. Berryman carb cleaner claims it can peal paint unlike CRC’s carb cleaner. When one has more warning labels than the other you know it’s better;)

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carnivorous chicken · « **Reply #39 on:** June 06, 2018, 12:38:57 PM »

Your bike, your decisions. People are offering some good advice here, up to you whether you want to take it. I'd recommend getting proper tools as well -- banging on carb towers with a wrench and a toothpick might work, but they're not the best things for the job. Dipping the bottom half of your carbs in chemical cleaner might help to free up the floats, but it might also destroy the floats.

innovativems · « **Reply #40 on:** June 06, 2018, 01:23:53 PM »

Agreed. Follow the quality advise and it will save you hours of time from having to redo it or try another method. Don’t put those floats I. Carb dip. The carbs need disassembled to go in it. Work the float pin free with penetrating oil and a little heat. Support the outside tower and gently tap the pin out

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MRieck · « **Reply #41 on:** June 06, 2018, 02:50:25 PM »

A good soak in Yamaha carb cleaner than some heat. You mix the Yamaha cleaner with H20. https://www.ebay.com/p/OEM-Yamaha-Carburetor-Cleaner-DIP-Quart-Acc-carbc-le-nr/704607630?iid=142800236413&chn=ps

camshaft1991 · « **Reply #42 on:** June 06, 2018, 05:05:05 PM »

Hey mike! The cylinder head is holding up! I already bought a can of chem dip but will definitely keep that in mind for another carb rebuild.

Well guys I spent the last couple of hours trying figure out how to safely put my carbs in a wood vice without breaking anything and got lunch.. Before doing so I spent 30 min trying to get an exchange for my broken can of PB, but I’m finally ready to start.

It looks worse than it works but it gives the choke pieces some room and keeps pressure off them. I’m going to start with a hairdryer then use the PB

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camshaft1991 · « **Reply #43 on:** June 06, 2018, 07:04:34 PM »

Got the float pins out. Couple dozen toothpicks later along with everything else. Haven’t taken anything else off. It’s hard to tell what helped the most between PB, Freeze Off, carb spray, or hair dryer, but it’s best to start tapping out with a nail then use tooth picks to shove through the towers. That is if toothpicks don’t work initially. They go in pretty easy with gentle hammer taps but they can leave little splinters behind too. I need to file edges of the pins before I put them back in.

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camshaft1991 · « **Reply #44 on:** June 06, 2018, 11:16:32 PM »

Dissolves nitrile gloves and probably o-rings too. Is all carb cleaner this aggressive?

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Little_Phil · « **Reply #45 on:** June 07, 2018, 02:32:36 AM »

Always a relief getting those pins out. If using a hammer I use small 2-3oz head and lots of tiny taps. (also support the tower with your hand which can also hold a flattened off nail or whatever on the shaft) +the heat and whatever solution you find works.

camshaft1991 · « **Reply #46 on:** June 07, 2018, 02:29:39 PM »

Year, I’ve never had anything bracing the tower before, but I probably should have. Chopsticks are great for knocking out emulsifier tubes

Can you put carbs in chem dip with butterfly valve in tact? These little screws never come out easy

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camshaft1991 · « **Reply #47 on:** June 07, 2018, 06:03:59 PM »

Nvm I thought they would be frozen in place, but they did leave some metal shavings.

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MRieck · « **Reply #48 on:** June 07, 2018, 06:21:13 PM »

Quote from: camshaft1991 on June 06, 2018, 11:16:32 PM

Dissolves nitrile gloves and probably o-rings too. Is all carb cleaner this aggressive?

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The Yamaha cleaner does not hurt rubber or plastic

camshaft1991 · « **Reply #49 on:** June 07, 2018, 06:36:02 PM »

Even felt? Yeah im going to have to order that because I broke one of my felt washers for my butterfly switches

And all of my o-rings for my jets as well but I’m going to try to find a bulk supplier for my jet o-rings. Does anyone know if anyone sells those felt o rings for the 656c carbs on the 350f? I’ve managed to save the felt
O-rings that go to carb slide assembly. I think I’ll just buy that yammi chem dip and replace the chem dip in my old chem dip can with it.

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Author Topic: CB350F full engine rebuild (Read 9680 times)