Topic: 400/4 head bolts/ studs.

[Tomshep]

My bike has been sitting in a barn in France for a while and needs to be repatriated. Time I got on with the work.
I have a '76 with the short head bolts or studs. It weeps so I am intending to change the head gasket over the Christmas break. Is it feasable to change them out for the long ones to keep the engine oil tight? I haven't really understood why the bolts are an improvement; are they bedded deeper into the upper crankcase to allow for a bit more torque up top? If so, are the earlier engines threaded deeply enough to allow the longer ones to be used or have I got the wrong end of the stick?
Thanks for reading this and thanks again if you can advise me.

[robvangulik]

If I remember correctly the difference in length is about 1 millimeter?
And it was oiltight for some 40 years? I'd renew the gaskets and wait for the next 40 years

[Kevin]

This is the first I have heard of longer cylinder studs, I know the exhaust studs on the F2 were longer.
I'd just replace the head and base gasket, be sure to also replace the copper washers too.
I have installed A.P.E. heavy duty cylinder studs on a few of my high performance engines but I do not think they are necessary on a stock engine. 

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[robvangulik]

This is what I think he was referring to, the complete  guide was too big to upload so this is the part that matters

[Tomshep]

Thank you very much. That was exactly the information I needed. I think my bike is mid '76 but the frame number is a huge help as I shall know one way or the other.

[Kevin]

This is what I think he was referring to, the complete  guide was too big to upload so this is the part that matters

Thanks Rob, I learn something new every day.
Great information and I think some he is refering to UK bikes.
My USA spec F2 has pillion pegs on the swing arm. I'm sure it is stock...it only has 701 original miles.

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[robvangulik]

If I remember well that guide came from the UK sohc site....

[Tomshep]

Yes, the bike is in France but was exported from Britain. It is now due to come back.

[robvangulik]

This should give you the rest of the article http://www.sohc.co.uk/index.php/topic,19303.0.html

[Nurse Julie]

Tom. As yours is a UK bike and it's coming back to UK, maybe consider joining us on SOHC.co.uk if you haven't already?

[Tim2005]

Great information and I think some he is refering to UK bikes.
My USA spec F2 has pillion pegs on the swing arm. I'm sure it is stock...it only has 701 original miles.

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Presumably that's a 77 bike? The US 77 models had the pillion pegs like that. It's odd that they moved back to that earlier configuration, I've no idea why.

And as for the rest of the topic, I wouldn't bother changing the studs, I've never seen any evidence that this modification made any difference. Also removing the studs can be extremely difficult.

[Redline it]

be sure to also replace the copper washers too.

where do you get those copper washers?

[bryanj]

Genuine Honda parts