CB400T Carb repair, etc

Maraakate said:
Did not know that, thanks for the info. I don't think we had those in our market or if we did it must have been very uncommon?
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I scanned all the US entries for the SOHC 400s and 450s from the Honda ID Guide, it should say which version had 5 or 6 speed.
 
OK..........
I just got back from a ride.
and...........
before I parked it last time I took LDR's advice and filled it with 87. I put some Lucas gas treatment in also.
I was using 93.
I cruised at 70mph for 10 miles, if I twisted the throttle it was smooth, now it didn't take off like a CBX, but it was smooth.
It actually felt better through the gears as well.
it could be as was said above that the 87 is fresher..................
So.........
The ol guy can both listen and learn!
and now that I'm spending less on gas, well.......
as my dad used to say, save yur money, retire early!
Thanks again guys!
bob
 
Just from personal experience, I've tried the Lucas Ethanol Treatment in the past and it did not work. I've had the best luck with Sta-Bil. Star Tron is recommended, but I've never tried so I can't vouch for it.

I don't want to get into a whole thing, however I worked at a distribution warehouse that carried a lot of Lucas products and as such we'd get damaged bottles, etc. for free. Their only stuff IMO that was worth it is the Red N' Tacky grease and their gear oil/hub oil. I had bottles of that gear oil for YEARS that I used on my drive chains. Their Red N' Tacky I still use. They tend to be the cheapest or close to it. Chevron's version of it is also excellent. Their additives I was never too impressed with. If you're really into that stuff and have way too much time on your hands you can see a lot of comparisons of those additives over at Bob Is The Oil Guy forums.

Good to hear regular 87 is working for you. Just keep fuel stabilizer in it year-round and you should be fine. It's a good idea to drain the bowls in the carbs at the end of the season out of general principle. Running carbs "dry" i.e. until it stalls out will not remove all the gas in the float bowls. They must be drained.
 
Maraakate said:
Just from personal experience, I've tried the Lucas Ethanol Treatment in the past and it did not work. I've had the best luck with Sta-Bil. Star Tron is recommended, but I've never tried so I can't vouch for it.

I don't want to get into a whole thing, however I worked at a distribution warehouse that carried a lot of Lucas products and as such we'd get damaged bottles, etc. for free. Their only stuff IMO that was worth it is the Red N' Tacky grease and their gear oil/hub oil. I had bottles of that gear oil for YEARS that I used on my drive chains. Their Red N' Tacky I still use. They tend to be the cheapest or close to it. Chevron's version of it is also excellent. Their additives I was never too impressed with. If you're really into that stuff and have way too much time on your hands you can see a lot of comparisons of those additives over at Bob Is The Oil Guy forums.

Good to hear regular 87 is working for you. Just keep fuel stabilizer in it year-round and you should be fine. It's a good idea to drain the bowls in the carbs at the end of the season out of general principle. Running carbs "dry" i.e. until it stalls out will not remove all the gas in the float bowls. They must be drained.
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Yes, I do run stabilizer in my fuel, I just had a bottle of this lucas given to me so I thought I'd use it.
I do drain the bowls at season's end, and fill the tank, and add Sta-Bil, which I get at Canadian Tire.
I have also been running some STP fuel injector and carburetor cleaner in a tank from time to time.
It's nice to have it running smoothly now, thanks guys!
bob
 
I remembered something, it's been bothering me. You said 60+ MPG. This does not sound right. Best you can do on these is 50-55MPG. Maybe. The bike has to be tuned very well to achieve that. Realistic numbers are about 38-45MPG depending on many factors.

Are you sure you didn't mean KM? How are you calculating MPG? If you're resetting the trip meter on fill ups that is the best way, but are you sure the trip meter is accurate? Have you GPS verified it?

If you're truly getting 65MPG I'd love to know the secret.
 
Maraakate said:
I remembered something, it's been bothering me. You said 60+ MPG. This does not sound right. Best you can do on these is 50-55MPG. Maybe. The bike has to be tuned very well to achieve that. Realistic numbers are about 38-45MPG depending on many factors.

Are you sure you didn't mean KM? How are you calculating MPG? If you're resetting the trip meter on fill ups that is the best way, but are you sure the trip meter is accurate? Have you GPS verified it?

If you're truly getting 65MPG I'd love to know the secret.
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The highest MPG I've had was 71.79. I regularly am pulling high 50's to mid 60's. Here's a sample of MPG from my last trip 2014, showing miles/fuel added/MPG. Properly tuned and well setup maintained engine/bike including tire pressures. The 6 speed 400cc bikes are different than your A models.
152.62.5260.56
129.42.6149.58
165.52.859.11
1362.554.40
125.92.2555.96
146.62.3462.65
160.12.2371.79
162.12.6960.26
43.60.8352.53
137.32.4556.04
1663.2950.46
117.91.7866.24
1241.9762.94
158.72.3866.68
53.50.8662.21
145.62.2863.86
178.32.9959.63
90.61.8249.78
164.62.7659.64
142.82.5256.67
194.83.162.84
171.62.5667.03
125.42.0960.00
170.72.6464.66
170.33.0655.65
 
Maraakate said:
I remembered something, it's been bothering me. You said 60+ MPG. This does not sound right. Best you can do on these is 50-55MPG. Maybe. The bike has to be tuned very well to achieve that. Realistic numbers are about 38-45MPG depending on many factors.

Are you sure you didn't mean KM? How are you calculating MPG? If you're resetting the trip meter on fill ups that is the best way, but are you sure the trip meter is accurate? Have you GPS verified it?

If you're truly getting 65MPG I'd love to know the secret.
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I typically get 65 to 70 mpg on mine and I do reset the trip meter and get a printed receipt that a do the calculations from for those numbers. Never done the GPS check as that isn’t an option on my old stuff. I run 32 psi front and 34 psi rear on my tires.
Remember in Canada our gallon is Imperial and 4.5 litres vs a US gallon of 3.8 litres, so about a 16% difference.
 
I keep forgetting there's 6 speeds here. I have ran a fair amount of 5 speed manuals around and 50MPG seems to be some sort of average for those.

You can do a GPS check as an option. Just download a GPS speedometer app and keep it in your pocket.
 
I do my own mileage conversion........
I use these figures......
also, I am in Canada so our gallon is larger.
4.5461 Litres equals one Imperial gallon
0.6214 Miles to one Killometer.
I am getting bettween 60 and 63mpg on the roads that I ride.
Also, the roads I ride are mostly 50MPH roads, so the speed is not as high as it would be on a highway.
The bike runs very well that to all of you!
bob
 
Too high an octane actually will create lower MPG. Octane is a measurement of flame propagation, the higher the number the slower the flame front, slower burn. Also can contribute to unburnt fuel accumulation in the combustion chamber, carbon deposits.
 
Sounds like you have sorted your issue now. What RPM are you spinning at 75 MPH? I wonder if your geared different, as I think you have an earlier model than my 1984 450SC?
I find the high frequency vibes increase once I am above 5K RPM which is about 100-110 KPH on my bike? I am just so used to very smooth bigger bore machines and it takes awhile to get accustomed to the small cc bikes.
 
Flyin900 said:
Sounds like you have sorted your issue now. What RPM are you spinning at 75 MPH? I wonder if your geared different, as I think you have an earlier model than my 1984 450SC?
I find the high frequency vibes increase once I am above 5K RPM which is about 100-110 KPH on my bike? I am just so used to very smooth bigger bore machines and it takes awhile to get accustomed to the small cc bikes.
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I forget what I was turning at 75, but at 60 I am at 54, I will check when I am out again.
I was probably around 7, but I'll let you know the next time I'm out.
bob
 
Bobs twin said:
I forget what I was turning at 75, but at 60 I am at 54, I will check when I am out again.
I was probably around 7, but I'll let you know the next time I'm out.
bob
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Just wondering if we are close to the same RPM. I ride backroads mostly and typically ride at 80-100 KPH so in the lower sub 5K RPM range.
 
Thanks for that Jim,

That number in 6th gear at around 60 MPH and 4500 RPM is where I am mostly riding up to just under 5K RPM. So it confirms the gearing on my bike and likely why I am getting good gas mileage numbers from the bike.
 
Flyin900 said:
Just wondering if we are close to the same RPM. I ride backroads mostly and typically ride at 80-100 KPH so in the lower sub 5K RPM range.
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most of my rides are between 5 and 6, and I try to ride forwards.
my bike is around 54 at 100kph.
your bike must have more power, and can run at a lower rpm.
bob
 
Bobs twin said:
OK.........
I just went for a short stint on the 406.
that way I wouldn't get a ticket.
110kph = 6200
120kph = 6700
130kph = 7400
bob
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Thanks Bob,

The gearing seems to possibly be different on your bike. Which isn't unusual, as I am sure Honda changed sprockets on various models over the years. I am definately below 5K RPM at 100 KPH. I think around 4700 RPM from what I recall.
 
Flyin900 said:
Thanks Bob,

The gearing seems to possibly be different on your bike. Which isn't unusual, as I am sure Honda changed sprockets on various models over the years. I am definately below 5K RPM at 100 KPH. I think around 4700 RPM from what I recall.
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I think that because mine is a 400 it uses the revs to get up to speed.
the red line is 10,000.
it is very smooth at 110 to 130 for sure.
not much vibration at all.
bob
 
Just got back from a ride. Some trees are starting to change colour.
I still find it difficult to accept just how much better this bike runs on regular, as apposed to high test.
between 90 and 110 kph the bike almost purrs.
Thanks again guys!
bob
 
well guys.........
it happened again.
my tach started to bounce between 5 and 55.
so.........
I took the cluster apart, removed the tach, and the speedo..........
because it was proibably not far behind.
set them upside down on an angle so the stem was verticle.
put two drops of #10 in each, waited 10 minues.
reinstalled them.
and all is well again.
bob
 
I got out for a ride today, it was perfect!
I noticed something though.
As I was riding, I checked the clearance on the clutch, both at the grip and on the engine.
When this CB400T warms up the clearance seems to reduce?
So, I gave it some more clearance.
Interesting.............
Bob
 
Just got back from a ride, the fall colours are almost their peak.
there is a storm coming in so I had to time things right.
I've noticed that there is a fair difference between a bigger bike and the CB400T.
in the wind, and especially the gusts, the bike gets pushed around more than I am used to.
just something I need to adjust to.
bob
 
I just watched a video of interesting bike engines over the years.
it had a CBX accelerating through the gears, and it sounds other worldly!
bob
 
ballbearian said:
He called the CB350 a 360 crank, not a 180.
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Yeah, just another guy who has over a million subscribers (who clearly know less than he thinks he does if they believe that about the 350 and 450) reading from his poorly-researched script. Sure, SOME 350s and 450s were 360° crankshafts, but none sold in the land of American English where he's from.
 
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went for another ride this morning.
it was 36 degrees when I left, with a light drizzly rain, which cleared in about 10 minutes.
I cheated today, I wore my chaps.
I think it was 39 when I came back, covered 80K.
the colours and smeels of fall were great!
some might call this crazy............
but..............
they aren't on this site!
bob
 
I have a question............
Once in a while when I am shifting at higher RPM, the clutch will slip.
I am shifting at 7 or above.
Is it time to change the clutch?
or stop shifting that high?
bob
 
the side cover gasket is ordered, from the Honda dealer.
the spring set, clutch friction plates and new oil filter are on their way.
this will give me a nice opportunity to polish that case again!
winter projects..............
bob
p.s. - I orderd the friction plates because, if it's apart, I might as well change them.
 
OK, it's been a while, but...........
I think I need to wet these clutch friction plates before reassembly?
If correct, is it ok to just wet them with oil as I reassemble, or should they soak in oil for a while?
Just checking before I do something stupid.
bob
 
Bobs twin said:
OK, it's been a while, but...........
I think I need to wet these clutch friction plates before reassembly?
If correct, is it ok to just wet them with oil as I reassemble, or should they soak in oil for a while?
Just checking before I do something stupid.
bob
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I've done it both ways, wet with oil or just dry out of the package. As soon as the engine is running more than a minute or so the clutch will be covered in oil and all that would remain would be to get oil between them. A few pulls of the clutch lever with it running in neutral would be enough to get them wet before using the clutch to get moving.
 
ancientdad said:
I've done it both ways, wet with oil or just dry out of the package. As soon as the engine is running more than a minute or so the clutch will be covered in oil and all that would remain would be to get oil between them. A few pulls of the clutch lever with it running in neutral would be enough to get them wet before using the clutch to get moving.
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sounds like an excellent way to do it, thanks!
bob
 
I did an oops........
I checked the service manual and found that I need 7 friction plates, not six.
One of the plates is a bit thicker than the others.........
time to order more parts.
bob
 
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