Honda-SOHC
SOHC.co.uk Forums => CB350/400 => Topic started by: mike the bike on November 06, 2016, 04:00:01 PM
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I started on the strip down I've been promising for years, primarily to cure the oil leak from the head and to fit the newer/better camshaft and get some parts powdercoated.
As it's progressing, a few queries have emerged, which I hope the more knowledgeable forum members could shed some light on.
As I was removing the rocker cover, those 2 head nuts with the M6 female thread (that the rocker cover bolts attach to) were fairly loose. The one on the LH side was so loose that that special nut loosened off the head when I undid the rocker cover bolt.
As the leak is from the LH side, would that have caused the leak, rather than a warped head?
The other head securing nuts weren't over tight either. I did torque everything up when I built the engine, although I may have missed the aforementioned special nuts with the M6 threads
The other query is the spark plugs are very sooty. Could it be because, with the vibration, the choke has a tendency to turn itself on during a ride or do I need to faff about with the air mixture screws and, if so, what direction?
The float heights, clip positions, jet sizes are all standard, as Soichiro intended.
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Undertorqued or loose bolts will cause both an oil leak and a warped head. never had a choke vibrate to on if the locking pin was OK.
I would have the head and block checked for level, rebuild with accurate torque wrench and leave to sit for 24 hours with rocker cover off and check torque before finishing.
I have known both studs and nuts strip threads
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There's no stripped threads, I think you misunderstood. I was thinking of just torquing everything up again but as it's off the road for the winter, I may as well check for flat anyway.
What locking pin is that then?
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Not misunderstood, just commenting i have seen stripped ones, from memory isn't there a steel small diameter pin that sticks out of the carb body and locates in an indentation on the mechanism to stop it vibrating shut---It is a long time since i worked on a 400 so that may be a different model
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I think it's just friction that keeps the choke open, I think I'll tighten it up a bit to stop it moving, although I suspect the air screws may need adjusting. I'll do a search, there's probably something about it on here somewhere.
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When I torqued the head down on my 400/4 I used a calibrated torque wrench. A couple of days later when I came to fit the rocker cover I thought I would check the head bolts one last time and found I could get another 1/4 turn on the torque wrench! I put this down to the copper washers under the bolts having a bit of 'give' in them as I had annealed them before reusing.
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The choke lever on no.1 carb has a very, very small ball held by a spring. The spring pushes the ball into an indent when the choke is off. The ball and spring get gummed up and stick in the carb but can be easily lost if the carb is deep cleaned.
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I don't recall that but I'll take a closer look at it. I'll let y ou know what I find.
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The choke lever on no.1 carb has a very, very small ball held by a spring. The spring pushes the ball into an indent when the choke is off.
Are you sure? I have been looking at the Parts List diagram and the assembly on my bike and I can't see anything like this, and in operation there doesn't feel to be any sort of location of this sort.
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The choke lever on no.1 carb has a very, very small ball held by a spring. The spring pushes the ball into an indent when the choke is off.
Are you sure? I have been looking at the Parts List diagram and the assembly on my bike and I can't see anything like this, and in operation there doesn't feel to be any sort of location of this sort.
Nope, my choke doesn't have any of those parts either
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I stand corrected, well sort of. Yes, definitely a click but cannot see spring or ball bearing. He that knows all has just shown me on another set of carbs that are off of a bike where the spring and ball bearing is located. No wonder I couldn't see them !!!
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I stand corrected, well sort of. Yes, definitely a click but cannot see spring or ball bearing. He that knows all has just shown me on another set of carbs that are off of a bike where the spring and ball bearing is located. No wonder I couldn't see them !!!
Which bit should I be looking at Julie?
I still can't see a spring or a ball bearing, and I had looked at exploded diagrams and the CMSNL part before the earlier post.
Can't see anything that looks the part in the picture of the Link Set (CMSNL part 91).
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I stand corrected, well sort of. Yes, definitely a click but cannot see spring or ball bearing. He that knows all has just shown me on another set of carbs that are off of a bike where the spring and ball bearing is located. No wonder I couldn't see them !!!
Which bit should I be looking at Julie?
I still can't see a spring or a ball bearing, and I had looked at exploded diagrams and the CMSNL part before the earlier post.
Can't see anything that looks the part in the picture of the Link Set (CMSNL part 91).
It's the bit you can't see Chris ;D ;D ;D Under part 91 on CMSNL it shows the spring and ball bearing. It's on the inner side of carb No 1, on the carb body
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It's the bit you can't see Chris ....
Well that explains it then!
Actually I can see it now; it is clearer on the diagram on P35 in the 350/400F Shop Manual.
I also hadn't realised that part 91 on the CMSNL diagram is shown in two parts - I need to look more closely! Thanks Julie.
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We both learnt something there then Chris. So if we ever loose out 'click' at least we know where to start looking now
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I've got a set of carb bodies in the shed, I'll have a look tomorrow.
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We both learnt something there then Chris. So if we ever loose out 'click' at least we know where to start looking now
Very true Julie. I'll just have to hope my ball never drops ....
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Well x3.
Just removed the carbs, partially split the carbs and... no ball or spring. I've had those carbs apart a few times over the decades and I've never noticed. I'll have to see what biro has the most suitable spring.
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We both learnt something there then Chris. So if we ever loose out 'click' at least we know where to start looking now
Very true Julie. I'll just have to hope my ball never drops ....
;D ;D ;D ;D ;D
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Well x3.
Just removed the carbs, partially split the carbs and... no ball or spring. I've had those carbs apart a few times over the decades and I've never noticed. I'll have to see what biro has the most suitable spring.
That's weird. Does your choke lever still make a clicking noise? Are you looking in the right place?
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No, it doesn't click. Now it's apart, I can see where it's supposed to fit.
It's always been like it so Soichiro's little workers may have forgotten it. It may still be on the floor in the factory for all I know.
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No, it doesn't click. Now it's apart, I can see where it's supposed to fit.
It's always been like it so Soichiro's little workers may have forgotten it. It may still be on the floor in the factory for all I know.
it seems you have a tiny ball missing
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And the spring. I hope my spare carbs have got them.
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Came across this thread on the US forum. Someone has already had this problem ....
http://forums.sohc4.net/index.php?topic=85415.0
Beats me why it's not in the Parts List though, surely other bikes might use something the same or similar.
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It seems there's more than one under Soichiro's workbench.
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I have just dismantled a scrap LH switchgear and there are two springs as part of the indicator switch.
Free length is a shade over 9mm, O/D is 3.8mm so one of those might do the job even if it needed shortening slightly.
Can send you one if it helps.
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Thanks for the offer Chris but not required. I dismantled the ratty spare set and found the parts. I hope this solves the over-rich running.
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No problem Mike, at least I know what is in the switch now!
If your other set is basically complete and you want to have a play and see if the spring would do the job then just let me know.
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Ok I'll do just that
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I've shown the sizes of the ball and spring, the spring requires a lot of force to compress it, so a biro spring wouldn't do. A spring from inside a switch (kill switch ?) may fit OK.
I've now got my click back that I didn't realise was missing. Thanks for the advice O wise ones.
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After gunking off the head and further cleaning in the dishwasher, I noticed the cam journals don't look too healthy. There's quite a bit of swarf had scored the ally, probably the left overs from the vapour blasting years ago.
Q1. is the head and rocker cover scrap?
Q2. Can I just carry on using is as it is?
Q3. Why didn't the oil filter clean all the crap out?