First time cb400 Project

I am starting off with some small easy clean ups. This past Sunday I cleaned out the crabs again (rust poured out of the jets like sand so I can confirm that this was a problem) and got those all nice and pretty again. I started to prep the second tank I bought in anticipation that the original one would not end up being clean enough, obviously that was a proff positive realization as well. this tank is much cleaner on the inside and it has its first coat of etching primer on it from last night. I also bought some fuel system cleaner and Im hoping that all of this will free p the stuck piston so I dont have to open up the engine to get it free.

If not then its back to the posts. Thanks for all of the suggestions, people. You guys rock!

Keep your fingers crossed for me!
 
sxecafe said:
I am starting off with some small easy clean ups. This past Sunday I cleaned out the crabs again (rust poured out of the jets like sand so I can confirm that this was a problem) and got those all nice and pretty again. I started to prep the second tank I bought in anticipation that the original one would not end up being clean enough, obviously that was a proff positive realization as well. this tank is much cleaner on the inside and it has its first coat of etching primer on it from last night. I also bought some fuel system cleaner and Im hoping that all of this will free p the stuck piston so I dont have to open up the engine to get it free.

If not then its back to the posts. Thanks for all of the suggestions, people. You guys rock!

Keep your fingers crossed for me!
Click to expand...

You keep saying "stuck piston",if your bike is running,even if it's only firing on one cylinder the piston not firing is NOT stuck.
It just means that particular cylinder is not firing. This can be due to a number factors such as compression too low,no or weak spark,spark at wrong timing,valves timed wrong,not enough fuel or too much fuel in the combustion chamber,air restriction etc.

If a piston was actually stuck you would not be able to turn the engine over,start or run it at all. Both pistons in your bike are connected to their own connecting rods which in turn is connected to ONE common crankshaft. If one piston is stuck(won't move in the cylinder bore)then the other piston would not be able to move up or down as well.

Take out the spark plug of the cylinder not firing,turn over the engine,shine a light down into the spark plug whole and you will see the "stuck" piston moving up and down. If you could see it with the engine running you would notice that the cylinder/piston that IS firing has enough power/energy to transfer to the common crank and actually move the dead piston up and down even though that cylinder isn't running.
 
Wow that was awesome, humbling and yet humiliating all at the same time haha. That makes total sense and I cant believe I hadnt thought like that since the begining. Thanks man!

- I have spark,
- Timing wouldnt have been screwed up cause it was running really well before this happened but maybe thats an issue to try if Im really stuck
- The fuel mixture doesnt seem like its too bad cause I have dry brown plugs
I do think it could be that its not getting fuel which is why I cleaned the carbs out. I guess what Im trying to say it that we will see after tomorrow.

RT
 
sxecafe said:
Wow that was awesome, humbling and yet humiliating all at the same time haha. That makes total sense and I cant believe I hadnt thought like that since the begining. Thanks man!

- I have spark,
- Timing wouldnt have been screwed up cause it was running really well before this happened but maybe thats an issue to try if Im really stuck
- The fuel mixture doesnt seem like its too bad cause I have dry brown plugs
I do think it could be that its not getting fuel which is why I cleaned the carbs out. I guess what Im trying to say it that we will see after tomorrow.

RT
Click to expand...

Make sure you set up the float levels correctly for your bike/set-up.
A lot of people blame bad carboration on wrong jetting which may be the case,but a lot of times the float level(s) are way off causing the bike to run like crap. Setting the right float level for your particular bike is critical. Too lean it surges(could damage valves,plugs,pistons),too rich it bogs or worse,could wash down the cylinders causing fouled plugs,engine damage(even hydro lock if a float needle is stuck open when bike is shut off).

The correct float level/proper working float needle are just as important as the jets maybe even more so because a bad float needle letting raw fuel by-pass right down into the cylinder is very,very bad. I almost lost a engine once because of it,a very expensive FZR1000 engine,but was lucky enough(dumb luck) to catch it before I could get the engine to fire over and run.

The jets,needles and float levels have to all work together in order to meter out the correct(safe) amount of fuel all the way through the rev range of the engine.
 
So I don’t have much of an update... I have been trying to get this piston to Fire. I cleaned out carbs again, saw that I have spark on both sides, fuel system cleaner, still nothing. I have notice that I have fuel coming out of another tube which I think it the valve breather tube, which obviously can’t be good maybe I cracked a valve or have a valve stuck or who knows. The bottom line is that I don’t know what to do at this point so I have to take it to a sick Honda guy in the valley to have a look at it.

This does however, mean that I can really get in to tearing the bike down and getting in to some stuff that originally I didn’t intend to do on this build. So when the motor comes out Imp going to change the color scheme. I bought some pods the other day to through on it. Imp about to get some header wrap, Paint the frame and get busy with the can on some other parts.

I was going to fill the emblem holes with bondo but a friend told me it might flex and crack. I don’t believe him... I mean there is truth to the fact that it will flex but I don’t think it will be enough to crack that area... Any thoughts or responses to this?

I have an old seat on the way so I can start my seat build and now that I have another tank I am going to chop the back of the old one and mod out a sweet seat.

So much for "Not much of an Update"...
 
Shouldnt have too much trouble filling the emblem holes. I did it and it worked fine on the 400 tank.

IMG_0168.jpg


Primed.. (old tank)

IMG_0097.jpg
 
brewtown16 said:
your speedo- can i get some info on that?! i want one really bad. was it pretty easy to hook up?
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Hey Man,
I got it from Mikes XS (http://www.mikesxs.net/mikesxs-accessories.php?category_id=8.5) There are a few different ones. I really like the white ones but the tach wouldn’t match if I did that (I got from a different place. If you want that let me know). Its a pretty sweet looking deal. Most of the lights were pretty easy to hook up. I still haven’t gotten to the neutral or the oil pressure light but that’s cause my wiring is a little messed up. Let me know if you need anything else!
 
Just found this off google.

I just picked the exact same bike up Sunday, with the exception of quite a bit of rust and an ugly fairing. My project starts Saturday but I'm interested in your project. If you happen to find the name of that paint stripper could you post it?
 
Canuck Plumber said:
Hey another 400T? I think we're on to something here.
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Yup, no pictures because today was getting the engine running, taking the old fairing off, and getting the lights and other electrical fixed up.

Can I just ask anyone who has run these bikes before, is there a terrible dead zone before 4K rpms? I was taking it around the block and it had no power, I gave it a good bit of throttle and it struggled to about 4K, then out of no where just took off, almost pulled the front tire. If you have ever driven a car with a large turbo, it had that same feeling.
 
I was too lazy to measure the carbs air intake when I had them off, do you know if they are actually 52mm? I'm looking for pod filters. I'm having the same problem with my bike, so I'm looking for a good rebuild kit, let me know what you find?
 
I'll have the carbs off this week at some point, I'll measure them. Might try scrubbin them with some carb cleaner first. Only rebuild kits I found were on Ebay.

Anyone happen to know if they got rid of kick start in 81? There is a spot for the kicker however one is not there. Is it possible to install one? I just find kick start engines cooler than pushing a button.
 
you guys try sync-ing the carbs? that might be a reason, or theres an intake leak somewhere
 
aaandht said:
Just found this off google.

I just picked the exact same bike up Sunday, with the exception of quite a bit of rust and an ugly fairing. My project starts Saturday but I'm interested in your project. If you happen to find the name of that paint stripper could you post it?
Click to expand...

YEA!!! Welcome to the 400t club. Its like the slow adults, you know... We get there just a little bit after the others... just kidding guys. Let me know when you have pics. The paint stripper I found at WalMart (although I hate the place) its in the automotive paint section and it is just called "AirCraft Stripper" Tall light blue and white can thats locked inside the glass so little kids dont take a spray fit to their ex-boyfriends fresh ride.

Whats your plan for the ride?

RT
 
ericngsta said:
I was too lazy to measure the carbs air intake when I had them off, do you know if they are actually 52mm? I'm looking for pod filters. I'm having the same problem with my bike, so I'm looking for a good rebuild kit, let me know what you find?
Click to expand...

I just got my pods in andI bought 52mm. However, I have to be honest I didnt measure and with my lick on this bike I have bought the wrong size. Ill let you know when I slam those things on.

Anyone know how you have to adjust the carbs after these pods are on? is it alot more fuel in the mixture or just like a half a turn.
 
Just planning on flat black body, chrome fender, some chrome on the handles. Maybe get new pipes and powder coat them black. Right now the bike smells like ass when it runs, my friends refuse to ride behind me ;D

As for the engine, just add a kick start, clean the carbs, maybe a K&N filter.

I think thats it :)
 
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