New CB 400/4 owner with questions

[Biggles]

Hi all.

Hopefully will be spending a bit of time looming on these here forums!

This is the 1977 CB 400/4 I picked up yesterday.. I've had allsorts of bikes from the 80's to 00's (currently own two mzs and a gs 500.. had several cx's and a few modern things too)
Always wanted a real 70's no compromise Japanese classic this is definitely that!

I've got a couple of questions though and hopefully somebody will be able to help.



I'm told this is a us import (imported in 89) and I'm also told that for some reason some came sans kickstart.. now I love a kickstart, its worth many cool points as far as I'm concerned, if its not got one its really missing something as far as I'm concerned.

In its place is this guy! I daren't detach the weird nobble but can only assume the kickstart shaft and all its associated bits and bobs are contained within?

So if i took this cap off (presumeably fitted onto the splines)

    is the shaft there in its entirety with springs and everything else it needs to work?
    will it spring a leak if the cap is removed?
    will there be an o-ring that needs changing before it can be used (since its never been used its safe to assume it will be perished)
    anything else to be aware of?

Has anyone else seen this before?


Also, theres some pretty major camchain rattle, the previous owner seemed a little confused on how to use the choke and VERY rarely rode the bike, I can only guess it hasn't been adjusted for some time. Apparently the carbs were balanced 400 miles previous but knowing garage monkeys it might not have been sealed with anything and therefore could well have gone off..

My question is, anything to watch out for while adjusting the cam chain via the small bolt at the front (supposedly it needs to be done while the engine is running) the bolt looks a little rusty, are they still available from honda/anywhere?
If the bolt does come out would there be any catastrophic problems? can it be unscrewed to give it a clean up (thinking electrolysis perhaps)
Between automatic cam chain tensioners and 2 strokes I've never adjusted a cam chain on anything before!

Anyway, appart from the minor service things that could do with sorting I'm extremely chuffed!

Reading the 70's reviews made me think it'd be quite uncomfortable to ride but its very comfy, beautifully balanced and brakes work very well without the front end diving.. a joy to ride, exactly what I have been looking for!

The engine could be a little more responsive but 20 odd years of hardly ever being ridden might have a part to play there!

I might be able to get several bits from a cb550 (the kicksart and exhaust for example) are many parts compatible between the two?

Anyways, any info would be much appreciated!

Thanks for reading!

[SteveD CB500K0]

It looks like that's just a cover for the exposed kickstart splines. Never seen anything like it!

You won't find many bits swappable between the 400 and the 550 I'm afraid.

If you are going to do the camshaft, do the tappets and timing at the same time. Then balance the carbs.

Do you have a manual?

Steve

[kent400]

Looks like just a blanking cap over the kick start shaft and with a grub screw securing it on the shaft. You should just be able to remove it and fit a kick start lever. The lever isn't the same as any other SOHC models other than perhaps the CB350f. They do turn up on ebay but tend to sell for quite a high price.

As for the cam chain, great care is needed with the adjuster bolt. They easily broken, only attempt it when the engine is hot and after a good dose of releasing fluid. That's very important if you suspect it's not been adjusted for years. I have some very usefull info on cam chain adjustment that will help you understand how it works. PM me with your email if you think that would help.

[Biggles]

Well I've adjusted the cam chain as per the manual (there was a definite feel of something springy on rescrewing in so sure its done right) there was a worrying moment when it lurched and spluttered in response to tweaking, this was the fuel running out because I'd turned the tap was set to off.
Turns out the bolt wasn't so bad, just surface.. I'll be plastering it in grease and putting a bit of fuel hose over it to keep it clean.

shame about the non swapable parts thanks though saves me allot of messing about!

as for the kickstart, I'm quite happy to fit something that just works for now and invest in a proper one later.. I'll get the measurements and head off to the breakers next week and see if there is anything suitable. my concern is that it could cause a leak if its used (I can't see an o-ring under there, is it bathed in oil or does it not get that high?.. any idea if the kickstart needs to be removed when changing the clutch? that was done recently.

Also the fuel tap.. if its not turned off is it likely to overflow? or so anything it shouldn't? AND the tap is very stiff, would some normal light oil or some wd40 be ok to get it moving?

I've got a workshop manual (in fact clymer and haynes book of lies) is there a downloadable owners manual as supplied by honda anywhere?

The cam chain adjustment didn't make any difference (I'd appreciate that info regarding adjustment though kent, I have a good idea of how its working from the manual but any tips would be much appreciated) my next plan is to check the clearances an balance the carbs (have a set of gauges)

I do have a spare camchain but I'd prefer not to be doing anything quite so drastic so soon! it is a fairly straightforward job? guessing its not a split link job? do the guides need to be taken out at the same time? can this all be done by simply taking off the top inspection cover?


Thanks for the advice upto now!

[exvalvesetdabbler]

There are two likely causes of noisey cam chains.

1. 30 year old adjuster spring getting tired or the pushrod tube full of cr*p
2. Previous loose chain rubbing on adjuster pivot.

1). A workaround for this is to help the spring on its way a little while carrying out the adjustment. Next to the adjuster bolt and locking nut there is another nut with a flat washer, this blanks of the end of the adjuster push rod tube. You can insert a short metal rod about 3-4 mm dia and push on the push rod while slackening off the adjuster locking bolt. Only use hand/thumb  pressure and be careful of the hot exhausts. If the adjuster mechanism is free, you should hear the cam chain quieten down. If it doesn't quieten down or you can't feel any movement of the pushrod then its either stuck in its tube or the piviot has seized. With the engine running and the locking bolt loose, you should be able to feel slight movement/vibration on the push rod as the chain pushes against the tensioner.

2.) Sometimes if the chain has been left too loose for too long it rubs on the adjuster pivot and peens over some of the metal making the pivot very tight. This is the u shaped bit at the bottom that the push rod pushes on and the tensioner blade sits on the other side. If you have the sump off have a look at the pivot with a dentists mirror.

If the tension is about right you should be able to hear a slight whine as you rev it when the chain is thrown against the tensioner blade.

The cam chain on these are well engineered ( I read somewhere that the Z900 used the same type/size of chain) so it should be more than up to the job. shame about the adjuster.


Regards
Dave

[Biggles]

Thanks for the info!


I did notice after getting the bike upto full temperature the bike won't idle lower than 1.5k, this seems extremely high and is making me think tuning is badly needed..
There does seem to be a buzz at the front while riding as well, not sure if thats related
Next week I'm going to adjust the valves and balance the carbs so will see what this does. As said the clutch was only done 400 miles ago and thinking about it no self respecting garage would ignore major camchain noise considering the extra opportunitys for fleecing the previous owner for yet more money.

Also... I've never owned a bike of this age or configuration so my expectations of noise are probably quite different to all of you with more experience!


I'll give it a tune up monday and see how that goes!

[exvalvesetdabbler]

If it won't idle when warm I would suspect the pilot mixture is wrong,

Do you have the standard air box and filter?

The pilot jets are quite small and it doesn't take much to block them. However if the exhaust smells of petrol then there may be other reasons such as float heights or worn needles.