Author Topic: Keihin PB41B carburetor problem (Read 6010 times)

Roscoe · « **on:** March 10, 2008, 05:40:20 PM »

Help!!! While cleaning the carburetors from my 78 CB750 F2 the bit that should look like this below:

Now looks like this:

It broke off.

I think it was corroded. Thats my story anyway. Is there any way this tube can be removed and replaced? Or can I just leave the bottom in and don't bleed the float bowl ever again?
Cheers
Roscoe

TwoTired · « **Reply #1 on:** March 10, 2008, 05:46:12 PM »

In theory, you could drill out the remains, find a hobby shop that sells brass tubing of an appropriate size, solder up one end, drill a hole the same size as the old one in the end, and then press it into place to repair the old bowl.

But, it may be easier to get a replacement bowl.

Anyway, you need to have that stand pipe in place or fuel will stream out the bottom. The drain screw does NOT block that tube on these carbs!

Cheers,

Cvillechopper · « **Reply #2 on:** March 10, 2008, 05:48:59 PM »

That's not for bleeding, that's the overflow tube. You might be able to get away with some JB weld but I don't know if it's suitable for gas submersion. What ever you do, don't just plug it. There are stories around here of overflow tubes being clogged and a bad float valve letting fuel fill up the bowl. With no where to go it just fills up the intake and works its way into the case.

You should be able to find another bowl relatively easily. As to the corroded state, stick to your story

*Edit* TT was too quick for me

Roscoe · « **Reply #3 on:** March 10, 2008, 05:51:28 PM »

Thanks guys. I thought that may be the case. As you say it's probably easier to get another bowl. I just hope all the others don't go the same way. Bloody clumsy.Cheers

Roscoe · « **Reply #4 on:** March 10, 2008, 06:12:46 PM »

That tube must be in 2 parts because the drain screw goes right through where the tube should be. So if I drilled out the top bit thats left in and do what TT suggests then it should work?? If so what would you suggest to use as a "glue"or should it just be press fitted with a sealer?

sbc1320 · « **Reply #5 on:** March 10, 2008, 06:45:14 PM »

Might try screwing the appropriate size sheet metal screw in there and pulling it out with pliers.

Roscoe · « **Reply #6 on:** March 11, 2008, 12:44:56 AM »

Thanks sbc1320. I'll give it a try and let you know if it worked. Cheers

jtb · « **Reply #7 on:** March 11, 2008, 04:57:23 AM »

Roscoe, Which carb was it from. I probably have one.
John

Roscoe · « **Reply #8 on:** March 11, 2008, 02:09:29 PM »

Quote from: jtb on March 11, 2008, 04:57:23 AM

Roscoe, Which carb was it from. I probably have one.
John

Hi John, its the Keihin PD41B. If you have one it would be great. Cheers, Roscoe
Its the No 1 carb.

scondon · « **Reply #9 on:** March 11, 2008, 02:17:13 PM »

I was going to ask if you needed any carb bits as I have a set of parts carbs for my '78 f2. I can throw a float bowl in with your brake bits if you like. Keep attacking those carbs and see if anything else breaks, I won't be shipping until the weekend

Roscoe · « **Reply #10 on:** March 11, 2008, 02:22:45 PM »

Quote from: scondon on March 11, 2008, 02:17:13 PM

I was going to ask if you needed any carb bits as I have a set of parts carbs for my '78 f2. I can throw a float bowl in with your brake bits if you like. Keep attacking those carbs and see if anything else breaks, I won't be shipping until the weekend

Yes please

I've done the other three without incident but I haven't split the rack yet. At least knowing that a float bowl is coming while mean that I can try to take out the tube and see if it can be replaced cause if I stuff it up, no worries. Thanks again for the bits and let me know the all up cost. Do you have paypal?

scondon · « **Reply #11 on:** March 11, 2008, 02:34:40 PM »

Yes, I've got Paypal. I'm going to go by the post office this week and see what size "flat rate" boxes they have for international shipping. Hopefully I can stuff all these small bits into one of those to keep costs down. I'll PM ya when I get it all sorted.

Also have to pick up your front MC from joeb's house. Do you want me to include the brake lines with the brake parts, or will you be replacing with new?

jtb · « **Reply #12 on:** March 11, 2008, 03:45:54 PM »

Roscoe, I've got a number on carb bowl, if Scondon's doesn't work out. Let me know if you need it.

John

Roscoe · « **Reply #13 on:** March 11, 2008, 04:39:04 PM »

Quote from: scondon on March 11, 2008, 02:34:40 PM

Yes, I've got Paypal. I'm going to go by the post office this week and see what size "flat rate" boxes they have for international shipping. Hopefully I can stuff all these small bits into one of those to keep costs down. I'll PM ya when I get it all sorted.

Also have to pick up your front MC from joeb's house. Do you want me to include the brake lines with the brake parts, or will you be replacing with new?

If they are in good condition you can include them otherwise I'll be getting new ones. What do you think about the stainless braided lines?

Roscoe · « **Reply #14 on:** March 11, 2008, 04:40:41 PM »

Quote from: jtb on March 11, 2008, 03:45:54 PM

Roscoe, I've got a number on carb bowl, if Scondon's doesn't work out. Let me know if you need it.

John

Thanks for that John. I appreciate all the help I can get. Man this is one awsome forum. I'll let you know how I get on.

scondon · « **Reply #15 on:** March 11, 2008, 05:11:34 PM »

Quote from: Roscoe on March 11, 2008, 04:39:04 PM

Quote from: scondon on March 11, 2008, 02:34:40 PM
Yes, I've got Paypal. I'm going to go by the post office this week and see what size "flat rate" boxes they have for international shipping. Hopefully I can stuff all these small bits into one of those to keep costs down. I'll PM ya when I get it all sorted.

Also have to pick up your front MC from joeb's house. Do you want me to include the brake lines with the brake parts, or will you be replacing with new?
If they are in good condition you can include them otherwise I'll be getting new ones. What do you think about the stainless braided lines?

I add braided lines up front after the bike is roadworthy. I'm in the habit of running two long lines straight from the MC to the brake calipers rather than one short one to the splitter and two medium ones from splitter to calipers.

If you've got brake lines on hand that are good enough to start with then I'd suggest using them until you're ready to upgrade. If they're too snotty to even use then I can send the old ones I have so you can at least get the system set up and road worthy.

Roscoe · « **Reply #16 on:** March 11, 2008, 05:20:36 PM »

Thanks Sean. I've just checked the lines and the ones are knackered as is the rear. I might be able to resurect the rear but not sure. I'll probably need to get new oil bolts anyway. If you could send yours that would be great. This is really appreciated.

Roscoe · « **Reply #17 on:** March 11, 2008, 05:22:28 PM »

Quote from: scondon on March 11, 2008, 05:11:34 PM

Quote from: Roscoe on March 11, 2008, 04:39:04 PM
Quote from: scondon on March 11, 2008, 02:34:40 PM
Yes, I've got Paypal. I'm going to go by the post office this week and see what size "flat rate" boxes they have for international shipping. Hopefully I can stuff all these small bits into one of those to keep costs down. I'll PM ya when I get it all sorted.

Also have to pick up your front MC from joeb's house. Do you want me to include the brake lines with the brake parts, or will you be replacing with new?
If they are in good condition you can include them otherwise I'll be getting new ones. What do you think about the stainless braided lines?

I add braided lines up front after the bike is roadworthy. I'm in the habit of running two long lines straight from the MC to the brake calipers rather than one short one to the splitter and two medium ones from splitter to calipers.

If you've got brake lines on hand that are good enough to start with then I'd suggest using them until you're ready to upgrade. If they're too snotty to even use then I can send the old ones I have so you can at least get the system set up and road worthy.

Is there any advantage in doing what you do? (ie having 2 braided lines from the MC instead of using the splitter).

scondon · « **Reply #18 on:** March 11, 2008, 05:27:26 PM »

No worries, Roscoe. I'll stuff'em in the box

You have to get a longer banjo bolt in order to fit both lines to the MC. Other than that the benifits are buying just two braided lines instead of three and having less places for air to get trapped in the lines(splitter). Getting three lines and using the splitter is neater in the bar area. Either way is good really.

Roscoe · « **Reply #19 on:** March 11, 2008, 05:39:55 PM »

Thanks for the advise Sean. I'll continue cleaning up the carbies although I'm a bit worried about unlinking them. I might not remember how they went back together

scondon · « **Reply #20 on:** March 11, 2008, 06:12:30 PM »

Not too much to worry about as there are plenty of members here with the same carbs that can help if you forget something. Some of the rubber bits might not like getting seperated after all these years(hard fuel lines between carbs have o-rings at either end, small rubber air vent connectors, etc...) and may give when pulled apart.

Being the cheap/lazy bastard that I am I just dump the whole carb rack(after pulling jets and everything else that can be removed from each carb) into some rubber safe carb cleaner like Yamaha carb dip. Stuff is around $12 a quart here so I get a plastic container just big enough to fit the carbs in and fill half way with cleaner. Immerse bottom half for a day then flip carbs and soak top half. Spray liberally with auto carb cleaner when done to remove residue and gunk from exterior and passages.

Everything gets clean and I don't have to worry about getting everything back on the rack. Sometimes the real fun is taking everything down to the last bit and inspecting and cleaning/refurbishing it though, so don't let me talk ya out of anything

Roscoe · « **Reply #21 on:** March 11, 2008, 08:46:53 PM »

Quote from: scondon on March 11, 2008, 06:12:30 PM

Not too much to worry about as there are plenty of members here with the same carbs that can help if you forget something. Some of the rubber bits might not like getting seperated after all these years(hard fuel lines between carbs have o-rings at either end, small rubber air vent connectors, etc...) and may give when pulled apart.

Being the cheap/lazy bastard that I am I just dump the whole carb rack(after pulling jets and everything else that can be removed from each carb) into some rubber safe carb cleaner like Yamaha carb dip. Stuff is around $12 a quart here so I get a plastic container just big enough to fit the carbs in and fill half way with cleaner. Immerse bottom half for a day then flip carbs and soak top half. Spray liberally with auto carb cleaner when done to remove residue and gunk from exterior and passages.

Everything gets clean and I don't have to worry about getting everything back on the rack. Sometimes the real fun is taking everything down to the last bit and inspecting and cleaning/refurbishing it though, so don't let me talk ya out of anything

I agree with you. Part of the fun is trying things to see if I have the intelligence to put everything back together correctly so they work. So I will strip them down as much as I can. I have taken about a zillion photos from all angles to make sure it looks the same when done. I'll let you know how I get on. Cheers.

Roscoe · « **Reply #22 on:** March 15, 2008, 02:30:35 AM »

Further to my cleaning the carbs does anyone know what is the best to use to get the carb bodies looking brand new again? I don't have a parts cleaner so at the moment I'm using a spray carb cleaner and elbow grease. Any ideas??? $:-\$ $:-\$

mystic_1 · « **Reply #23 on:** March 15, 2008, 06:33:48 AM »

Elbow grease seems to be the active ingredient in nice looking carbs. I've seen people paint or polish them, but never saw any kind of miracle cure. With all the nooks and crannies, any method of reconditioning will be some work.

How bad off are they?

mystic_1

scondon · « **Reply #24 on:** March 15, 2008, 12:17:20 PM »

Roscoe, I pulled your #1 float bowl to put in a box with your brake bits, and the darn thing is missing the overflow stem. I've sent a PM to John(jtb) inquiring about his, so hopefully this is just a hiccup.

I really should have pulled the bowl and checked first, but I had no reason to think that the stem would be absent. The other three are there, must be a production line problem with the worker in charge of producing the #1 carbs. I'll send an email to Sochiro right away

Roscoe · « **Reply #25 on:** March 15, 2008, 04:06:11 PM »

Quote from: scondon on March 15, 2008, 12:17:20 PM

Roscoe, I pulled your #1 float bowl to put in a box with your brake bits, and the darn thing is missing the overflow stem. I've sent a PM to John(jtb) inquiring about his, so hopefully this is just a hiccup.

I really should have pulled the bowl and checked first, but I had no reason to think that the stem would be absent. The other three are there, must be a production line problem with the worker in charge of producing the #1 carbs. I'll send an email to Sochiro right away

No problem mate. I drilled out the broken stem and got some brass tubing from the hobby shop. It was a slightly smaller dia so I "Tinned" the tube with solder and pressed it in. I also soldered up the hole then redrilled a smaller one. I filled it with petrol and left it for a day sitting on white paper. No leaks so hopefully that will work. Fingers crossed.
Let me know if you get a reply from Sochiro. It'll be worth millions.
Cheers
Roscoe

Roscoe · « **Reply #26 on:** March 15, 2008, 04:08:33 PM »

Quote from: mystic_1 on March 15, 2008, 06:33:48 AM

Elbow grease seems to be the active ingredient in nice looking carbs. I've seen people paint or polish them, but never saw any kind of miracle cure. With all the nooks and crannies, any method of reconditioning will be some work.

How bad off are they?

mystic_1

They're not too bad. They've been sitting on the bike outside under a cover for over 12 years. I've done one and it took a while. Especially trying to get into the nooks and crannies. I had hoped that there would be something that would disolve the crap easily but I suppose I'll just keep using elbow grease. Cheers, Roscoe

News:

Author Topic: Keihin PB41B carburetor problem (Read 6010 times)

Roscoe

Roscoe

Roscoe

sbc1320

Roscoe

Roscoe

Roscoe

Roscoe

Roscoe

Roscoe

Roscoe

Roscoe

Roscoe

Roscoe

Roscoe

Roscoe