Topic: 400F rebuild

[rz350ypvs]

I'm new to the forum and I thought I'd start a rebuild thread for my '76 CB400F. I got it a few years ago, but I'm just starting to work on it now.

[taymoor]

how do the short cut headers w/o mufflers work in combination with the pods?  better, worse, excessively loud?  Also, did you have to rejet the carbs?

[rz350ypvs]

   It's a lot rougher than it looks in the picture. I am going to strip it down to the frame and restore it. I am going to paint it red... I don't really like the yellow.

I'm working on the engine right now, I took the head off and there is cross hatching in the cylinders, so I'm thinking it was rebuilt and not run very much. I did start it before I took it apart and it ran decently, but I could hear some cam chain rattle.. at least i thought it was. I can't get the cylinder(s) off... anyone have any tips?  I'll have some pics to post up later

[rz350ypvs]

how do the short cut headers w/o mufflers work in combination with the pods?  better, worse, excessively loud?  Also, did you have to rejet the carbs?

That is how i got it. It is very loud and runs like crap with that setup. I'm not sure if it could be tuned to run better though.. I would think it would need at least some back pressure though.

[DollarBill]

Oh man I really want a 400f.  It's the bike I was really looking for when I found my 750.  One day I will have one.....  Good luck with the rebuild!

Soundgarden rocks!

[gregk]

Looks like a good start.  Lots of parts available on e-bay lately.  Might want to find a rear brake stay and link rod. 
You'll enjoy it!

greg

[rz350ypvs]

Good luck with the rebuild!
Soundgarden rocks!

Thanks. Yes they do.

Looks like a good start.  Lots of parts available on e-bay lately.  Might want to find a rear brake stay and link rod. 
You'll enjoy it!

My dad has a '77, maybe I will just steal parts off it when hes not looking   We were on a ride and it was parked in front of a farm for sale. My dad also has a '73 CB750 that he bought new in '73.

good luck getting the stock cam chain rattle out of there.   

Is it near impossible to totally silence it? The sliders/tensioners that I removed actually looked pretty good.. but it still made noise. Thanks for the tips on removing the cylinder too.

[kghost]

Hey good luck and have fun.

I did one last year and love the little bike.

[Industrial Rat400f Killer]

Keep us posted and good luck.

[rz350ypvs]

I have been slowly working on the bike. I pulled the engine and took it all apart to paint it and replace the cam chain. I got my oil seal and gasket kit from Reproduction Decals. I ended up painting the engine with duplicolor engine enamel. I still need to finish assembly.

[Joel]

That's a great lookin' engine.    I've got a 400 as well but mine has yellowed, peeling clear coat and a layer of black paint on the cylinder fins from the previous owner.

I tightened my cam chain tensioner by pushing down on the plunger with a screwdriver.  I think the springs on mine aren't doing the job anymore.  Mine still has a rattle to it when running.  I believe I was told that out of sync carburetors can give the engine a rattle sound as well.  Also, be sure the tappet clearances are correct and that should help.

[kghost]

Engines looking clean.

YOu think about polishing those sidecovers?



DollarBill......your in Kville?


You can come down and sample mine 

[bigtuna]

dude that effin engine is lookin awesome, carry on more pics please. thanks

[rz350ypvs]

I tightened my cam chain tensioner by pushing down on the plunger with a screwdriver.  I think the springs on mine aren't doing the job anymore.  Mine still has a rattle to it when running.  I believe I was told that out of sync carburetors can give the engine a rattle sound as well.  Also, be sure the tappet clearances are correct and that should help.

Thanks for the tips. My dad has a '77 that has the rattle to it also.

YOu think about polishing those sidecovers?

I did  think about it. I have a 350F sprocket cover that I will probably polish and see how it looks on the motor ( I think it fits the 400). The little triangular piece that bolts on the clutch cover is polished. That alone may give it a little more contrast.

dude that effin engine is lookin awesome, carry on more pics please. thanks

Thanks! I will definitely be posting more pics as I progress.

[rz350ypvs]

Very slow Progress...

[Stormer]

Nice bike and keep going my friend!
Very nice to see another 400F rescued and going back on the road.

[rz350ypvs]

^ Thanks.

Tank still needs clear.

[gerryw]

Looks great, keep the info (and pic's)coming

gerry (oshawa)

[rz350ypvs]

[EkiF]

You're close! Very nice job...
What exhaust you are going to use?

[rz350ypvs]

Thanks.  My dad has a really nice stock exhaust from his '77 that he is donating to me. I will probably buy an aftermarket header/pipe for him.

[supersports400]

Hi,

In despite of the fast looks of the CB400F, the RZ350 ypvs is a lot faster.
I have both, lucky me, a CB400f '75 and a RD350YPVS '89.

For the sound I like the CB400f @ 10000 rpm, the handling of both bikes differ a lot.

btw, the RZ (RD in Europe) is safer to ride because of it's front brake.

It's good that you're restoring the CB400f and put some money in it.
maybe you will never get the money back, put it will pay you back in pure pleasure,

Jensen

[rz350ypvs]

^ The RZ350 will destroy the 400F in every way.. My dad has a '77. My RZ can outrun my dad's CB750 pretty easily too. But, they are totally different bikes and I like them all.

Got a little more work done.

[rz350ypvs]

[HalfFastMoto]

Looking real nice.  You're doing a great job!