400/4 Exhaust

[Norniron]

I have but id need to post from NI.

[Saisei]

Thanks for the offer Norniron, I may take you up on it (I can arrange collection) if nobody has some closer.

[AshimotoK0]

You've done a lot for us on here David. Not using my bike at the moment so prepared to take it off and loan you for,  say a month? It was new Genuine Honda and never hardly  been run other than about 4 minutes when I first ran up the rebuilt engine.

I am in East Yorkshire but could arrange delivery via work. I need to go to Northallerton in about a months time to go to the North Yorks. County  Records Office for data on my 750K0 as it's 'AJ' reg which is North Yorkshire, so I could collect it back then.

Cheers ... Ash

[Saisei]

Hi Ash, thank you for your kind offer I really don't want to put you to the trouble an risk of removing pipes from your bike. It may be easier for me to send you the stock downpipes/collector for you to make compare?

What do think?

Dave

[AshimotoK0]

Hi Ash, thank you for your kind offer I really don't want to put you to the trouble an risk of removing pipes from your bike. It may be easier for me to send you the stock downpipes/collector for you to make compare?

What do think?

Dave

I am easy, whatever you want to do David. Realistically,I will have to take the pipes off anyway to compare. I suppose having the bike here  to look at the fit may be an advantage though. If it helps you and others, I will do whatever is necessary.

Ash

[Saisei]

Hi Ash, I am thinking of going to Cadwell on Sunday, might be able to kill two birds with one stone?

[AshimotoK0]

Sorry Dave .. away most of weekend probably best to send.

Ash

[Saisei]

It looks like I will have to miss Cadwell this weekend anyway. I can come down when it is convenient to you.

Cheers

Dave

[AshimotoK0]

Had fun and games checking the Saisei pipes with a NOS Honda silencer. I can get it all to fit but only after slackening the header clamps then inserting the two silencer to frame bolts ('75 bike no bracket), Then gradually tightening everything up . There is a gap about 8mm  between the collector and the sump. Not sure on the fit of the slencer to header junction though. Does this look correct? Not sure if the collar welded to the collector pipe should be in engagement with the clamp on the silencer or not. Bloody freezing in the garage and the 400/4 is rammed into my garage with an MG Midget stopping me from getting really good access. off for a beer

[ Guests cannot view attachments ]

[ Guests cannot view attachments ] .

[AshimotoK0]

Anyone?

I need to get these off my bike and back to Saisei ASAP... I am only doing this for the benefit of other members / David @ Saisei, owning  400's, as I have the NOS original Honda pipes on my bike, so not really of any use to me other than anorak fodder.

Perhaps if I remove the headers and make measurements from the two fixed header pipes to a specific point on the output pipe that may reveal any differences. Or does anybody have any other suggestions please?

Cheers  ... Ash

[Nurse Julie]

Hi Ash
Not quite sure what measurement your looking for but I have just looked at mine and I have 8-10mm between the side of the collector and the sump. Mine are standard original down pipes / collector. The silencer to collector box join on mine has no gap at all.

[AshimotoK0]

Thinking of removing the Saisei = CMS NL = Yamiya downpipes and comparing with my NOS Honda set. Like in photo attached. Also push the collector towards the wall and make comparison measurements from wall to relevant points. Open to suggestions?

Any thoughts.

My initial opinion of these pipes is:-
Chroming/welding as good if not better than OEM (OEM Honda had silver paint on some of the welded joints HONEST !!!)
Appearance ... almost like OEM..... would need anorak like me to fault it and much better than the initial repro's that DS sold (he sells much nicer ones now ..not sure if the same as Ymiya/CMS)
Will fit but needs tweaking with bracketry possibly (F2 late F1).. May need to open the slotted holes on  frame mount lugs on F/F1 (pillion mounted footrests like mine).
Worst point is NOT double skinned like OEM which is a bl**dy shame , that in this day and age nobody can successfully manufacture within a budget.

Cheers ...Ash [ Guests cannot view attachments ]

[stevush]

I have standard pipes already off the bike, tatty and rusty but may serve your  purpose, in Seaham ?

Steve

[AshimotoK0]

I have standard pipes already off the bike, tatty and rusty but may serve your  purpose, in Seaham ?

Steve

Cheers I already have the NOS Honda set taken off my 400/4 and then the plan is to remove the Saisei ones I have for evaluation and compare. Cheers for the offer though.

[AshimotoK0]

Measured 'em and looking at the assemblies side by side there is a slight difference.

This results in the angle of the exit of the outlet pipe being slightly different. Therefore, with the Saisei assembly, you have to lift the rear end slightly more to get the silencer to fit the bracket and in doing so there is a tendency to  move the collector slightly closer to the sump. Having said that I could get the Saisei pipes to fit OK  after carefully readjustment and tightening gradually, achieving  a sump to collector clearance of around 8mm . This was greater on the stock pipes by about 5mm (12-13mm). This was with a standard HM377 Honda silencer, not the Brituro/Yamiya/Dave Silver replica and on an Aug '75 F model with pillion mounted footrests (exhaust mounts welded on frame, not separate bracket as on late F1/F2's)

Hope this helps!

P.S. You can tell Honda double skinned headers on 400/4, 500/4 by the four spot welds at the flanged end of the pipes. Presumably they take two concentric tubes, spot weld them at the flanged end  and then bend. I don't know why this has to be so difficult to do nowadays as opposed to 1975. Not dissected pipe but I think the double skinning extends to about 1/3 of the pipe length, enough to take the heat out of the exhaust gases. [ Guests cannot view attachments ]