Anyone done an engine rebuild on a CB400T

[longhorn717]

My baby needs new gaskets and seals and was thinking of rebuilding the insides while I've got her torn apart. Was wondering what y'all would suggest to clean, replace, rebuild. Never taken apart an engine and don't have a lot of tools. Is this over my head? Any advice or suggestions would be greatly appreciated. Wouldn't mind throwing a BBQ with the fixin's if any of y'all are near the Texas Hill Country. The Carbs need doing also but I'd like to make them suited to the pods and straight 2-n-1 pipes I'm going to make for it.

Y'all keep the rubber down and the shiny side up,
G

 

[Big R]

I've never been inside a 400T, but check the manual to see if you need an oil filter wrench. It looks like a normal socket with 4 teeth instead of a hex head. And a new cam chain and tensioner is a good bet on older Hondas.

But wait for somebody else to chime in before spending cash on my advice.

 

[longhorn717]

If you're referring to the filter on the bottom on the engine its just a metric hexhead bolt. Was wondering about porting and polishing the head or doing something with the cam. I have an extra cylinder jug and was wondering about over-sizing the bore. Wasn't sure if the little bit I could bore out would make a significant difference. I'm thinking new rings for sure.

 

[Big R]

Not the oil drain bolt, the oil filter nut. On a centerfuge type oil filter, there is a nut that looks something like a castle nut (like on the axles) except there's no hex shape to it. Just 4 sections cut away for the oil filter socket/wrench/whatever it's called. But like I said, you may not even need it.

If you do go for an over bore, try to find larger pistons. Stock pistons with the sleeves bored out +1 don't give you a lot of wiggle room if you need to get back in the motor......

 

[HerrDeacon]

I've performed surgery on a 400T before, dead simple engines. Not much too them and real easy to work on. Worse part of them was getting them back in the frame by yourself real pain.

No worries on the oil filter on these bikes, just a normal socket holding it all on, no special tools.

If you're opening up the bottom end, just give it a good cleaning to clear out any sludge that was accumulating in the bottom of the pan. Also, remove the oil pickup and clean it up and ensure the screen is not blocked. Also a good idea to 'reset' the balancer chain so that you don't run out of adjustment once you have it buttoned up. The procedure for this is in the manual. If you do remove the bottom half, note that the alternator is bolted to both the top and bottom case halves, so it has to be removed before splitting.

Top end is real simple as well, just SOHC and dead simple to retime after having it apart. Valves are adjustable with just a turn of a screw, no shims like the Kawi's.

Only special tools required that I remember are a special socket to remove the clutch nut and 'bolt' to pop the alternator off. Other than that, just a manual, metric socket set, torque wrench, etc.

 

[longhorn717]

Only thing I don't currently have is a torque wrench and haven't ever used one. My understanding is that they are hard to use. May borrow one. The reason for all of this is, that this is my first bike and I "learned" to use the clutch on this bike. PO's advice was to say "just feel it" haha. Couple of days of going around the block and numerous laughs from my neighbors and I was doing pretty well. But all that killing the engine I think wore out some the seals and gaskets. Its leaking oil out of almost every space it can. Anyone powdercoat engine parts? if so what was the outcome? I'm going to do a two-tone scheme depending on the reviews. I really don't want the headache of keeping all that aluminum/chrome clean. Worked at a bike shop and got to clean and detail bikes as part of my employ. Wasn't difficult but learned that the sports and standards were much easier to keep clean than the cruisers.

Anybody else have some .02 to add?

 

[devon]

longhorn, torque wrenches are dead simple to use. I've personally seen two types but I'm sure there are more out there.


Beam type:

Shows your current torque on the slider.


Click type:

You set the torque with the screw thingy at the base of the wrench once you get to that torque the wrench clicks to tell you you're there.


Devon 8)


BTW, I'll be doing a CB400T rebuild this fall (my first one as well) There's a genuine Honda service manual available to download in the service manuals section of this forum. It should be near the top as I posted there recently. It's an AWESOME resource. There's also a haynes one somewhere in that section of the forum.

 

[Maritime]

only issue I ran into was rusty head bolts. broke one and stripped another. I believer there are 8 and 4 are oil channels and come right out while 4 are dry and can get rusted in. If you feel they are hard to remove, spray pb blaster in there and let it sit for a day or more to help free them up. Get the manual and it shows how to rebuild the top end. It can be done without removing the engine from the frame. Only motor easier would eb a lawn mower so you should be fine. But make sure you use a torque wrench. If you over torque steel bolts in aluminum you will wreck it easily.