Honda CB400NA Superdream - new money puddle.

[Laverda Dave]

Just back from Stafford Show, it was dry but there were lots of empty stalls inside with a lower attendance it seemed. We did not find a Honda stand or see a 400N with just one 250 Superdream.

Ran the engine when I got back, the oil looks as though it's leaking mainly  from the very  top  cover, oil then runs along the top fins on the cylinder head down the valley between the two cylinders. It made me wonder if the vent pipe is trapped.

I can see that the invoices included fitting two Time Serts as they do not use long studs but very long head bolts that reach through the head & block screwing into the upper engine case.

From your diagnoses Ted I think someone has taken the 400 engine out and substituted it with a 350 Triumph engine, my Triton has exactly the same symptoms. The advantage is your boots will be totally waterproof 

[McCabe-Thiele (Ted)]

Just back from Stafford Show, it was dry but there were lots of empty stalls inside with a lower attendance it seemed. We did not find a Honda stand or see a 400N with just one 250 Superdream.

Ran the engine when I got back, the oil looks as though it's leaking mainly  from the very  top  cover, oil then runs along the top fins on the cylinder head down the valley between the two cylinders. It made me wonder if the vent pipe is trapped.

I can see that the invoices included fitting two Time Serts as they do not use long studs but very long head bolts that reach through the head & block screwing into the upper engine case.

From your diagnoses Ted I think someone has taken the 400 engine out and substituted it with a 350 Triumph engine, my Triton has exactly the same symptoms. The advantage is your boots will be totally waterproof 
[/quote

To be fair to my old Triumph 21 it only leaked oil when stood overnight - it did not pump out when the engine running.

[Laverda Dave]

I've just come in from the garage Ted. I took the rocker covers  off the Triton engine today attempting to cure the oil weep. I've fitted copper gaskets with wellseal! The trouble with old British bike engines is they were made using worn out tooling and the world and his brother have all had a go at them on the cheap😏.
Give me a Japanese engine (or an Italian one) anyday!

I'm going to get back on finishing Ratty in the next few days, I had to take a break from it after all the aggravation of the carbs. I'm refreshed enough to strip them......again!

[Laverda Dave]

The genuine seal at DS is £19.70, aftermarket part £9.00 is the cheaper option as good?

The top seal/washers are £7.70 each, so it's a total of £35.10 or £24.40 - just to cheer me up there might be a second leak lower down!

For the sake of an extra £10 I would always go for the genuine part (assuming the DSS part is genuine Honda and in a Honda bag). Imagine fitting a pattern part and it still leaks, you wouldn't know if it was the pattern part or another issue. If a genuine part is still available I would always use it just for peace of mind that you know it's correct and it will fit properly.

[K2-K6]

An interesting project Ted, looking forward to seeing it progress.

Isn't the rocker cover fitted and secured by two sleeve bolts on these with rubber seals  ?  Much like a A series BMC type but with that T fitment instead of traditional cork 

[McCabe-Thiele (Ted)]

The genuine seal at DS is £19.70, aftermarket part £9.00 is the cheaper option as good?

The top seal/washers are £7.70 each, so it's a total of £35.10 or £24.40 - just to cheer me up there might be a second leak lower down!

For the sake of an extra £10 I would always go for the genuine part (assuming the DSS part is genuine Honda and in a Honda bag). Imagine fitting a pattern part and it still leaks, you wouldn't know if it was the pattern part or another issue. If a genuine part is still available I would always use it just for peace of mind that you know it's correct and it will fit properly.

I've come to doubt a lot of parts that are in bags marked Honda much like genuine NGK plugs that look the real deal.
The advice on the Superdream forum was they use aftermarket ones without issue.
As I have a spare top cover I will check it sits on the cylinder head as it should without the seal in place.
It appears that a PO has tried to put sealant including silver paint on the joint area so I'm hoping it's just some bodgery.

[McCabe-Thiele (Ted)]

An interesting project Ted, looking forward to seeing it progress.

Isn't the rocker cover fitted and secured by two sleeve bolts on these with rubber seals  ?  Much like a A series BMC type but with that T fitment instead of traditional cork 

Yes Nigel very similar to a BL A series rocker cover, if you under or over tightened the cork gasket they would leak.

Looking at my spare top cover the top mounting holes look like a slightly tapered recess with a bolt that has a metal/rubber sealing washer .

When I take the tank off I will know more - the old parts books are pretty poor on detail. Ken told me that when fitting if you were not careful the sealing ring could be knocked out of place, it could then split or just become trapped. I think Bryan or Ken mentioned it was worth applying an adhesive to keep the profile correct in the cover groove.

[Bryanj]

They aint cheap but its worth changing the rubber cones on the bolts as the bolt tightens down to a built in stop so if cone deteriorates cover is looser

[McCabe-Thiele (Ted)]

I will be replacing the top seal arrangement - DS sells  them.

A PO has fitted new front brake lines with no guide brackets on the mudguard for the two calipers the skinny braided hose in white just look wrong.

Original replacement guid brackets are NLA so looks as if I'll have to find some aftermarket ones to fit my none genuine front mudguard.  The existing  front mudguard looks nice enough as a plastic replacement, I just need to find a pair of brackets  that will fit.

[Johnny4428]

No guides or brackets in your stash of spares that came with the bike Ted?

[McCabe-Thiele (Ted)]

The big box of spares that the last owner bought online as a job lot is mainly junk. The upper crankcase that was coded BBB had no bearing caps so is scrap. Some parts are not for the 400N out of the three starter motors two are working. There were a load of used cam chains & balancer chains all binned. The bike has a pair of Hagon shocks fitted, the rusty foot rests I've binned the bad ones that are not for my bike. I've kept what looks good. There is one small bracket that looks like a choke top fitting. Two pairs of long alloy side brackets that hold the rear foot pegs etc are pretty decent. I haven't the space for a load of rusty junk. Unidentified useable parts I've kept.

[AshimotoK0]

Out of interest Ted was there  a massive price difference between your project and what Charlie at Oxford Classics was asking?
Admittedly even his had a pattern front mudguard fitted. I guess the original chrome guard must be a bit of a hens teeth item then?

[Bryanj]

Ted parts you need are
90441413830
Cms say €9 each

[McCabe-Thiele (Ted)]

Ted parts you need are
90441413830
Cms say €9 each

Thanks for that information Bryan.

[McCabe-Thiele (Ted)]

Out of interest Ted was there  a massive price difference between your project and what Charlie at Oxford Classics was asking?
Admittedly even his had a pattern front mudguard fitted. I guess the original chrome guard must be a bit of a hens teeth item then?

He did not give me a firm price, he indicated something in the £3250 3450 area iirc  Mine cost me £1300.
As you know I was really looking for a sensible project, this should keep me busy for at least 18 months.
Aside from some daft bodgery it's pretty complete in most areas, I'm not a purist so it looks like I have a good starting base to keep me busy. I'm enjoying the fact that its quite different to my 4 cylinder bikes.