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Carb repair CB400T

Youre complicating the filter just get one of those red disc filters for a lawn mower and put it inline. It fits and works fine.
 
Maraakate said:
Youre complicating the filter just get one of those red disc filters for a lawn mower and put it inline. It fits and works fine.
Click to expand...
I did manage to fit a right angle filter on the bike but found that I still got very fine particulate managed to clog the carb, again.
The filter I used had a fine stainless scfreen in it, which I believe is what is used in the small lawn mower types, so I would like to adapt a paper filter unit instead.
After I clean the tank and clean the carbs again.
Yes, I am not looking forward to taking them off again, this will be my sixth time.
I will attach a pic of the filter that I used, that didn't work.
bob
filter.jpg
Bob
 
 
Also I see 1/4" fuel line with worm gear clamps. Don't use these, get 5.5mm fuel line with the clips from the dealer. The mower line degrades and causes leaks. If you don't get the worm gears very tight sometimes it leaks at the fitting and you think the carbs are overflowing.
 
Keihin jets are marked in mm's so yes, a #75 jet is .75mm
Do not drill the jets unless there's no recourse like needing a 122 jet when only 120 &125 are offered.
 
Winter decided to return so I have a week.
I ordered the new jets, 75/117.5 from FortNine; they should be here this week.
I am ready with the vinegar, and I purchased some stainless 1/4-20 nuts to put in the tank to shake the stubborn rust off.
I picked up 2 small filters from our local lawn mower place that give a 70 micron filtration.
Hopefully this time I end up with a dependable machine, summer is getting close!
Thanks for all of your help and guidance guys!
bob
 
Is the tank spewing out rust chunks? Hows it look in there? Some surface rust is normal and won't harm anything. I will say, stay away from liners. Too many horror stories.
 
Maraakate said:
Is the tank spewing out rust chunks? Hows it look in there? Some surface rust is normal and won't harm anything. I will say, stay away from liners. Too many horror stories.
Click to expand...
I've gone through the carbs five times now, and only on the last attempt did they start to work fine. When I took it for a safety the mechanic tried to adjust the idle on the left carb and didn't get a good result. He has a few old bikes and he checked the tank and recommended the vinegar treatment. I heard of quite a few fellows using this approach, so.... I did purchase a new fuel petcock with a fine tube screen on it and when I removed it, it had a fair bit of fine residue on it, and this is what I think is getting in to the carbs, even though I have an extra inline filter from the petcock to the carb. So..... It's not so much chunks of rust but a fine residue which I believe the vinegar will help with. The bike sat for 37 years and this must be the result. When it warms up out there, and the snow goes away I'll pull the carbs again, pull the press in metering jet and spray and blow out the passages, I have a feeling that this will help. I will also install a 70 micron inline filter, which after the cleaning of the tank I may not need, but.....
I will also install the 75/118 jets that Jim recommended.
Bob
 
If you do vinegar it will work but takes a long time. I did it on a rusty moped over the winter took me like 2 months with a severely rusted puny 1 gallon tank. I had to dump the vinegar out every week and put new vinegar. Afterwards. Immediately neutralize it. I sprayed some penetrating oil in there too and immediately top off the tank. If you don't do this it will flash rust quickly and you'll be back where you started. With vinegar it will also cause corrosion in places the vinegar doesn't touch, like near the gas cap.
 
Maraakate said:
If you do vinegar it will work but takes a long time. I did it on a rusty moped over the winter took me like 2 months with a severely rusted puny 1 gallon tank. I had to dump the vinegar out every week and put new vinegar. Afterwards. Immediately neutralize it. I sprayed some penetrating oil in there too and immediately top off the tank. If you don't do this it will flash rust quickly and you'll be back where you started. With vinegar it will also cause corrosion in places the vinegar doesn't touch, like near the gas cap.
Click to expand...
I've checked in to this quite a bit, and when the mechanic that did the safety told me that I needed to this, then gave me step by step instructions on how to do I decided to give it a try. I have to get this tank clean, removing the carbs and cleaning the passages this often has to stop. I am unable to find a replacement tank also, there are none available, and even if I could find one I think I would be in the same place that I am. Also, this mechanic is local and willing to talk to me about how to do it, and he has done this successfully a few times himself.
 
I would not go bigger on the primary main jet.
Get a box of metric micro drills from e-Bay, less than $10.00 and less than $20.00 with a pin chuck.
The carbide PCB drills are pretty worthless as they are way too brittle and break if you look at them sideways
www.ebay.com

59Pcs Precision Pin Vise Mini Micro Hand Twist Drill Bits Set Rotary Tools Kit | eBay

Quantity 59Pcs(1Pcs pin vise hand drill, 48Pcs micro twist drill bits (0.5-3.0mm), 10Pcs PCB mini drill bits (0.3-1.2mm)). This hand drill bits set includes 1 piece pin vise hand drill, 48 pieces of micro twist drill bits (0.5-3.0mm), 10 pieces of PCB mini drill bits (0.3-1.2mm), a total of 59...
www.ebay.com
 
Maraakate said:
If you do vinegar it will work but takes a long time. I did it on a rusty moped over the winter took me like 2 months with a severely rusted puny 1 gallon tank. I had to dump the vinegar out every week and put new vinegar. Afterwards. Immediately neutralize it. I sprayed some penetrating oil in there too and immediately top off the tank. If you don't do this it will flash rust quickly and you'll be back where you started. With vinegar it will also cause corrosion in places the vinegar doesn't touch, like near the gas cap.
Click to expand...
Weeks?? Man, it must've been horrible. I've never gone more than a few days using vinegar on some pretty ugly ones.

This sounds very promising.

Rust911 Ultra-Concentrate Rust Removal

Hello everyone, figured I would give my experience with Rust911 Rust Removal. I know that the king of rust removal is Evaporust, but spending close to $31/gallon to clean a 2.8 gallon gas tank can get very expensive. I know there is another option, Bilt Hamber Deox-C, but I haven't seen it in...
www.vintagehondatwins.com www.vintagehondatwins.com
 
ballbearian said:
Weeks?? Man, it must've been horrible. I've never gone more than a few days using vinegar on some pretty ugly ones.

This sounds very promising.

Rust911 Ultra-Concentrate Rust Removal

Hello everyone, figured I would give my experience with Rust911 Rust Removal. I know that the king of rust removal is Evaporust, but spending close to $31/gallon to clean a 2.8 gallon gas tank can get very expensive. I know there is another option, Bilt Hamber Deox-C, but I haven't seen it in...
www.vintagehondatwins.com www.vintagehondatwins.com
Click to expand...
Theres that bilt chamber (sp?) stuff that Jim used with good results.

Yes it was bad. Fouled a fuel filter every months.
 
Maraakate said:
Theres that bilt chamber (sp?) stuff that Jim used with good results.

Yes it was bad. Fouled a fuel filter every months.
Click to expand...
My Hawk was the worst due to not only rust but something like tree sap from a half tankful sitting for 20+ years. Vinegar and even toilet bowl cleaner barely did much. Eventually added gravel and shaking a bunch and gas rinsing got it tolerable.
I'm still using my 5 gallon mix (1Kg powder) of the Bilt Hamber Deox-C after 3 tanks, fender set, couple battery boxes, toolbox, and a bunch of other stuff. It's about toast (takes days, not hours) and leaves a black film that washes off with detergent and hot water (probably from all the dissolved zinc coatings). I have one more very bad tank (already a pinhole or two), then I'll pitch it.
Unfortunately, Jim will get notified when it's available, but not yet.
Member Danager4792 with his 450 reported good results, with pics of his tank, with this Rust 911 stuff so it sounds worth a try.
 
ballbearian said:
My Hawk was the worst due to not only rust but something like tree sap from a half tankful sitting for 20+ years. Vinegar and even toilet bowl cleaner barely did much. Eventually added gravel and shaking a bunch and gas rinsing got it tolerable.
I'm still using my 5 gallon mix (1Kg powder) of the Bilt Hamber Deox-C after 3 tanks, fender set, couple battery boxes, toolbox, and a bunch of other stuff. It's about toast (takes days, not hours) and leaves a black film that washes off with detergent and hot water (probably from all the dissolved zinc coatings). I have one more very bad tank (already a pinhole or two), then I'll pitch it.
Unfortunately, Jim will get notified when it's available, but not yet.
Member Danager4792 with his 450 reported good results, with pics of his tank, with this Rust 911 stuff so it sounds worth a try.
Click to expand...
OT: I'd invest in derusting stuff but more concerned with trying to get the 550 mechanically sound which will be $$. Basically same level as obsession as the 400.
 
ballbearian said:
My Hawk was the worst due to not only rust but something like tree sap from a half tankful sitting for 20+ years. Vinegar and even toilet bowl cleaner barely did much. Eventually added gravel and shaking a bunch and gas rinsing got it tolerable.
I'm still using my 5 gallon mix (1Kg powder) of the Bilt Hamber Deox-C after 3 tanks, fender set, couple battery boxes, toolbox, and a bunch of other stuff. It's about toast (takes days, not hours) and leaves a black film that washes off with detergent and hot water (probably from all the dissolved zinc coatings). I have one more very bad tank (already a pinhole or two), then I'll pitch it.
Unfortunately, Jim will get notified when it's available, but not yet.
Member Danager4792 with his 450 reported good results, with pics of his tank, with this Rust 911 stuff so it sounds worth a try.
Click to expand...
I found that tree sap glop broke down when soaked with E85 gas-o-hol. And that stuff is cheap compared to all the derust chemicals.
 
Did you remove the fine-mesh filter screen tube from inside the tank first ?
I don't know if vinegar will harm or soften the mesh screen or plastic, but it's something I'm considering when I soak-clean my tank.
 
Boosted said:
Did you remove the fine-mesh filter screen tube from inside the tank first ?
I don't know if vinegar will harm or soften the mesh screen or plastic, but it's something I'm considering when I soak-clean my tank.
Click to expand...
What I did was this, I purchased a new fuel petcock, cut the nut off of the old one, silver soldered a cap on it, made a rubber gasket for it and plugged the tank with the made up nut. I didn't want the petcock, or the plastic/stainless screen left in the vinegar either. Also, I used cleaning vinegar, it's twice as strong as just white vinegar.
Tomorrow morning should tell me if it is working.
Bob
 
This is after two days.
I have now filtered the vinegar and put it back in for one more day.
On3 pic shows the sediment that came out while draining.
The other pic shows the mud that came out after I gave it a fuel/oil wash.
It seems to be working.sediment.jpgmud.jpgfirst.jpgsecond.jpgthird.jpg
Bob
 
Nice filter, I like the idea of the transparent one you might have a chance to see if you have any crud accumulating.
 
Is that a sintered bronze filter? I ask because I seem to remember someone having trouble with the speed fuel passes through them.
 
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ancientdad said:
Is that a sintered bronze filter? I ask because I seem to remember someone having trouble with the speed fuel passes through them.
Click to expand...
Yes, it is a sintered bronze filter.
I will give it a try, I also have more than 5 other filters that I can substitute in if it doesn't work.
Bob
 
These are the filters that I've tried so far.
Except for the right angle sintered bronze one, I'll try that next.
The right angle one with the stainless screen seemed to allow fine silt through.
Bobfilters-5.jpg
 
I think you'll find that the filters are unneeded now that you have a clean tank. It seems to be more about the rate of stuff passing through. All filters will pass something but it's usually not a problem, unless it's too much too fast. Once in a while just open the bowl drains and turn on the petcock to flush the bowls out some.
If the problem persists, you'll just have to clean the tank some more.
 
ballbearian said:
I think you'll find that the filters are unneeded now that you have a clean tank. It seems to be more about the rate of stuff passing through. All filters will pass something but it's usually not a problem, unless it's too much too fast. Once in a while just open the bowl drains and turn on the petcock to flush the bowls out some.
If the problem persists, you'll just have to clean the tank some more.
Click to expand...
For now I want to have the filter in the system, then I can watch it to see just how clean I have the tank.
After a while, if things look good I remove it, and just have the fine screen on the stem of the petcock in the tank.
Removing and replacing these carbs is a challenge, not one that I look forward to.
Using a filter for a while to me is cheap insurance.
Bob
 
ancientdad said:
Agree, as long as it doesn't restrict fuel flow.
Click to expand...
So far I know that the right angle one with the stainless screen does not restrict.
I'll try a sintered one and if it restricts I'll go back to the screen one.
I just want to monitor the fuel delivery for a while.
the sun is out now, so it will soon be tank shakin time!
then magnet fishing time, which isn't quite as much fun........
Bob
 
Well guys, it might surprise you, but I was the only guy out on his bike today.
I guess 35 to 38 degrees is a tad cool for some.
Anyway, it is alive again!
It's running the best that it has ever run.
I am even able to cruise around town at 2800 to 3200 with no trouble whatsoever.
Throttle response is very smooth also, the best it has been.
I will attach a pic of the third thru fifth tank flush with fuel to show what they looked like.
I will also add a pic of the sintered bronze filter setup that is working very well, excellent flow.
The filter tucks right up and out of the way also.
On the pic showing the filter there is a step down tube with clamps, the petcock is a different diameter than the carn inlet, so...
This way all connections seal.
And, yes, at 60 to 70 mph it was a tad cool, but hey, it's my first "legal" ride!
Have a great weekend guys!
Bobfilter steps.jpgtank.jpgfilter-2.jpg
 
You can check fuel flow restriction thru the filter by using a measuring cup of some sort and timing how long it takes to hit a fill mark with and without the filter.
 
LongDistanceRider said:
You can check fuel flow restriction thru the filter by using a measuring cup of some sort and timing how long it takes to hit a fill mark with and without the filter.
Click to expand...
For now I just want to have the filter in place so I can monitor for dirt.
The flow was good on the ride that I took, so I have a feeling it will be ok for the immediate future.
Bob
 
Bob, good job on the bike! You must have inspired me, cause I got on both bikes and took them both out for short rides. They are both fussy starters in the cold. Around 42F here in MN, yes a bit chilly, but sunny, dry roads, and you can dress for success!
 
LongDistanceRider said:
You can check fuel flow restriction thru the filter by using a measuring cup of some sort and timing how long it takes to hit a fill mark with and without the filter.
Click to expand...
What I did was this.

When I got the filter installed the way that I wanted it, and the tank on, I watched the fuel flow through the filter as the float bowls filled for the first time.
the flow was good.
As I was riding along at 50 to 60 mph I could give it a good shot with now fuel deprivation present.
So, for now, until I get a chance to go for a longer ride this seems to be fine.
Thanks for the tip though!
Bob
 
ancientdad said:
While it's in the high 70s and low 80s here today and I'm sweating in my garage after an overnight low of 45° cooled it down nicely for me. :ROFLMAO:
Click to expand...
Man, that was a low blow.............
here, after the ride my knees didn't want to work, and this morning it looks like there might even be some snow!
But, hey, good for you!
I am glad that someone is getting some great riding weather!
Enjoy that sun, enough for both of us!
Bob
 
kbongos said:
Bob, good job on the bike! You must have inspired me, cause I got on both bikes and took them both out for short rides. They are both fussy starters in the cold. Around 42F here in MN, yes a bit chilly, but sunny, dry roads, and you can dress for success!
Click to expand...
Hey, good for you!
and yes, you can dress for a cool ride for sure.
This bike seems to start fine in the cold, the choke on these carbs is great!
All in all I am very pleased with this bike, and very happy that it turned out so well.
It gave an ol guy something to do, and kept me out of trouble for sure!
I am also very happy that I was directed to this site, (Thanks again Tom!), all of you guys helped me get this bike up and running, and I am very thankful for all of your help, guidance and encouragement!
Have a great weekend!
Bob
 
Bobs twin said:
Man, that was a low blow.............
here, after the ride my knees didn't want to work, and this morning it looks like there might even be some snow!
But, hey, good for you!
I am glad that someone is getting some great riding weather!
Enjoy that sun, enough for both of us!
Bob
Click to expand...
It's nice now, but remember I'll be sweating during every minute outdoors here in only a couple months. We have to enjoy our early spring and short, milder winters because the mid-90s are coming soon and will last until November :rolleyes:
 
ancientdad said:
It's nice now, but remember I'll be sweating during every minute outdoors here in only a couple months. We have to enjoy our early spring and short, milder winters because the mid-90s are coming soon and will last until November :rolleyes:
Click to expand...
You know..............
This may surprise you, but...........
I am finding it difficult to feel any level of sympathy right now for your plight!
Anyway, enjoy this weather and all of that sunshine!
And thanks again!
Bob
 
Just in case you were wondering Tom, it is raining here which will likely turn to snow later on.
I thought you should know.
Also, I am going to try to take the left muffler off today to measure for the size stepped sleeve I will need to adapt the Sportster slip-ons to the bike.
Bob
 
Bobs twin said:
Just in case you were wondering Tom, it is raining here which will likely turn to snow later on.
I thought you should know.
Click to expand...
We're about to get some serious rain here today as a front moves across the state in a few hours. But, it won't get to the point of snow, it will just bring one more blast of cold air before our short spring arrives... and after that, the air conditioners will be on until November. There are times I think it would be nice to be further north, and then I'm reminded of what it's like when it snows for days and you're stuck at home freezing. I'm spoiled after 63 years here and I'm too old to move again, even if I truly wanted to.
 
ancientdad said:
We're about to get some serious rain here today as a front moves across the state in a few hours. But, it won't get to the point of snow, it will just bring one more blast of cold air before our short spring arrives... and after that, the air conditioners will be on until November. There are times I think it would be nice to be further north, and then I'm reminded of what it's like when it snows for days and you're stuck at home freezing. I'm spoiled after 63 years here and I'm too old to move again, even if I truly wanted to.
Click to expand...
I hear you very clearing on the too old to move, but you shouldn't need to, you are in a very nice state for sure!
Also, I managed to get the left muffler off, in two pieces unfortunately. I checked our local muffler shop and they do not have any 43mm stainless tubing, their smallest is 1.75" dim. They cannot swage either, so I am on the hunt for a reducer to go from 1 3/4" OD to 43mm OD.
Hopefully I can find some material to make this from. Living in the States makes it so much easier to source things. Ho to be Canadian!
 
as you can see..........reducer.jpg
I was unsuccessful in getting the left muffler off in one piece.
it was rotten on the inside.
no choice now..........
I need to get these Harley mufflers on.
bob
 
ancientdad said:
Looks like some welding repair is in your future.
Click to expand...
Yes, I agree.
I have a piece of 1.75" OD stainless pipe which does not fit in to the slip-ons, yet..........
I have been filing and sanding for 2 hours, stainless does not cooperate!
I've spoken with a local fellow that does stainless exhaust systems, he says to bring by the pieces and he can fix me up.
I've cut the pipe that goes in to the power chamber off of the stub that was left, and hope to be able to weld it to the stainless pipe, even though one if stainless and the other carbon. maybe brazing?
He also may be able to make a reducer for me from stainless, I will find out when I go.
Then I will need to make a decent hanger for each side that will allow me to use the rear foot pegs, and protect the centre stand and kick stand from hitting the underside of the new slip-ons.
just a couple of things to tackle!
bob
 
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