Author Topic: CB350F full engine rebuild (Read 10232 times)

camshaft1991 · « **Reply #25 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..

Sent from my iPhone using Tapatalk

camshaft1991 · « **Reply #26 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

Sent from my iPhone using Tapatalk

carnivorous chicken · « **Reply #27 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 #28 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

Sent from my iPhone using Tapatalk

innovativems · « **Reply #29 on:** June 06, 2018, 05:36:08 AM »

You need to disassemble this carbs completely for dip

Sent from my iPhone using Tapatalk

camshaft1991 · « **Reply #30 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.

Sent from my iPhone using Tapatalk

carnivorous chicken · « **Reply #31 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 #32 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;)

Sent from my iPhone using Tapatalk

carnivorous chicken · « **Reply #33 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 #34 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

Sent from my iPhone using Tapatalk

MRieck · « **Reply #35 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 #36 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

Sent from my iPhone using Tapatalk

camshaft1991 · « **Reply #37 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.

Sent from my iPhone using Tapatalk

camshaft1991 · « **Reply #38 on:** June 06, 2018, 11:16:32 PM »

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

Sent from my iPhone using Tapatalk

Little_Phil · « **Reply #39 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 #40 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

Sent from my iPhone using Tapatalk

camshaft1991 · « **Reply #41 on:** June 07, 2018, 06:03:59 PM »

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

Sent from my iPhone using Tapatalk

MRieck · « **Reply #42 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?

Sent from my iPhone using Tapatalk

The Yamaha cleaner does not hurt rubber or plastic

camshaft1991 · « **Reply #43 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.

Sent from my iPhone using Tapatalk

PeWe · « **Reply #44 on:** June 07, 2018, 09:52:15 PM »

Quote from: MRieck 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?

Sent from my iPhone using Tapatalk
The Yamaha cleaner does not hurt rubber or plastic

Motorex chain cleaner work fine too. It cleaned better than the CRC carb cleaner I also used. I used it for the oil pump clean too.

camshaft1991 · « **Reply #45 on:** June 08, 2018, 11:45:14 AM »

I think I'm going to go with the yammi dip and then use tooth picks, chopsticks, and cue tips for cleaning build up on carbs. I'm going to have to just buy a bunch of o-rings from 4into1 because the quotes I got from manufactures said they would be special orders for each which is a lot of money.
What do y'all use to replace carburetor linkage tubes? The CB350F tubing between the carbs is 2.5x16mm. I've traditionally used windshield wiper tubing and zip ties, but I feel like it doesn't make the vacuum seal I need. Any suggestions? Also how important are the felt washers for the butterfly valves? I know it has nothing to do with vacuum sealing. Can they be omitted on reassembly?

camshaft1991 · « **Reply #46 on:** June 08, 2018, 01:00:56 PM »

I came across this old post on CB350F carb o-rings. His dimensions differ from what 4into1 has for o-rings

Quote from: danfr on May 12, 2013, 11:31:39 PM

thanks for the reply Bryan.

I did some more digging around and I think I found the sizes although I'm not too sure how credible the sources are. I figure I'd post my findings in case someone with a 350F or 400F is looking....

Main jet O-ring:
1.2mm cross section x 3mm I.D. Quantity 4

Float Valve Seat Seal
1.5mm cross section x 5mm I.D Quantity 4

Fuel Connect
1.9mm cross section x 5.8mm I.D Quantity 12

I think I remember Hondaman stating that most metric O-rings range by 0.5mm so I may need to do some rounding. Also I think he mentioned Buna fits a bit bigger than Viton or Visa Versa...??

I still need one top gasket. Maybe I'll search the salvage yard this weekend.

http://4into1.com/replica-keihin-press-fit-secondary-main-jet-o-ring/
4into1 has 4.2mm x 1.1mm for the primary jet o-ring
danf has 3mmx1.2mm for the primary jet o-ring.
I bought fuel connector o-rings based on his post. They hold up good but they are a tight fit. However I chose to go with Viton o-rings and the seller on ebay didn't have the Durometer listed. Buna-N is usually 70 and Viton is usually 75 by default, but those values can be changed upon order from a manufacturer.
Anyways, whose dimensions should I go with? I can find danf's o-ring dimensions on manufacture sites but not 4into1's dimensions, unless I place a special order.
I was able to find the o-ring dimensions according to danf on ebay and the drain plug o-rings according to 4int1 on ebay as well.

camshaft1991 · « **Reply #47 on:** June 11, 2018, 10:48:52 PM »

What is the the default jetting for the CB350F with the 4into4 exhaust configuration? And can any 350F owners in the south or Gulf coast states shed light on what jetings they chose? Where I live it's hot, humid, and at or below sea level.

camshaft1991 · « **Reply #48 on:** June 21, 2018, 11:48:50 PM »

I got all the the stuff I needed for my carb rebuild including the new o-rings that i'm going to see if they can fit with my jets. my carbs are soaking in Yamalube (Yamaha chem dip) for the night.

It looks like Chem-Dip initially, but it turns into milk after you add warm water. Letting them sit overnight. instructions say for 8 hours but I'm going to check after 6.

On sad note I found my boy Clint Eastwood dead in his case. I had it in the the bottom of a cabinet in my dad's shop. We don't know when this happened exactly, but it happened when no one was around. There was a 10" water line indicated on a few things like on a mini fridge we have but there were other containers and stuff that had no water line. Next to it is my compression kit. It doesn't have a computer built into it but there does not look like there is water in the compression gauge.

Anyways I don't plan on doing any torquing or compression test this weekend coming up. I will post more later

camshaft1991 · « **Reply #49 on:** June 23, 2018, 02:59:02 PM »

Almost done cleaning my carbs. The milk spa treatment with the yamidip worked great but rinsing with water and scrubbing with a toothbrush didn’t quite get it all off. They began to oxidize so I took some cue tips and xylene to it. The xylene not only stops the oxidation but it really brings out that chem-dip rainbow

Going to get more cue tips. Still haven’t heard word on the felt washers. Are they related to the vacuum? Let me know

Sent from my iPhone using Tapatalk

News:

Author Topic: CB350F full engine rebuild (Read 10232 times)