New Member from North Yorks

[Sesman]

The Vesrah sets work fine, but doesn’t include the cam cover ‘pontefract cakes’. Take Teds advice on the head gasket/o ring dimensions as the Vesrah head gasket has a slightly different thickness. I haven’t used it myself, but I believe the copper spray gasket can be used to good effect….others may have opinions on this.

[SandyRob]

Re Head gasket replacement:
OK, thanks everyone, has anyone put together a list of parts and their sizes needed to do this job? as any help would be greatly appreciated.

[Bryanj]

You wont get the seals/washers pattern, you have to go gasket set

[SandyRob]

That sounds like the O ring on the cylinder head - replacement gaskets are a different thickness since the banning of Asbestos so there are issues when you fit the original O rings that come with the gasket sets.

which "o" ring do you mean, the ones round the dowels or the ones round the oil restrictors? as they look like small seals, or are there some other ones?

[McCabe-Thiele (Ted)]

That sounds like the O ring on the cylinder head - replacement gaskets are a different thickness since the banning of Asbestos so there are issues when you fit the original O rings that come with the gasket sets.

which "o" ring do you mean, the ones round the dowels or the ones round the oil restrictors? as they look like small seals, or are there some other ones?

It's over 2 years since I worked on my 400 cylinder head, yes I was referring to the oil restrictor that fits between the block & cylinder head that has an O ring type seal (item32).
I have been slightly confused by Bryans description of a tubular sleeve - I think that is the lower block part. (item31 in my parts book).
The part I am thinking of  is item 32 in the parts book I remember that as a typical O ring (1290-333-000) that I thought was the seal that leaks oil as it is insufficiently compressed by the later head gaskets. Sorry I do not know the size of the part or what to use as an alternative. Nurse Julie might know as we discussed it briefly but I no longer have the message. I used the engine gasket set that came with my bike I am not sure of the brand. After measuring my gasket thickness I ended up fitting the rings that were in the kit.

If it helps I might be able to find the Brand as I think I kept some unused gaskets - it was not the Vesrah that is said to be the best.

[SandyRob]

Thanks for your reply Ted, I will check my parts list and see whats what. I think I might remove the cam cover for now and re tighten/Torque the head down to see if that needs doing as I was told the engine had been rebuilt before I bought it.

[McCabe-Thiele (Ted)]

Thanks for your reply Ted, I will check my parts list and see whats what. I think I might remove the cam cover for now and re tighten/Torque the head down to see if that needs doing as I was told the engine had been rebuilt before I bought it.

Certainly worth trying they always seem easy to reach the torque settings in the manual when fitting the cylinder head - my 400 has done just a tad over 400 miles with no oil leaks to date - touch wood etc.

[Bryanj]

If you look up the part number at cms its def a sleeve not an O ring, the 500 is an O ring though

[McCabe-Thiele (Ted)]

If you look up the part number at cms its def a sleeve not an O ring, the 500 is an O ring though

You are right Bryan I'm confusing the 400 with my more recent 500 build it is a sort of sleeve shape - I have had it in my brain that someone here suggested fitting an O ring underneath.

Looking again at the 400 manual the upper & lower seals are sleeve shaped not O rings - I should have gone to spec savers.
The lower one looks taller - thats my poor excuse.

This is my block when removed - it does not help my case at all.
At the end of the day you are far more experienced.

.IMG_20210307_135436 by Macabe Thiele, on Flickr

[SandyRob]

Hi, so on CMSNL Honda 400/4 engine page is it

332 (Pin,Dowel) / 32 (gasket cylinder stud)  or

28 (Valve oil control orifice) / 33 (Gasket orifice valve)

which one leaks / needs the extra O ring?

[Bryanj]

Ted, i had to go and check on cmsnl to be sure.
In all honesty the 400 was normally so reliable they were only in for service or mot.

[McCabe-Thiele (Ted)]

I'm surprised NJ has not added her experience from her 400 engine rebuild as I think that is where the idea originated.

My thinking is do you know where the leak is left or right side, front or rear half of block, above, at cylinder head or below. That should point to where the problem seal is.
I have a feeling someone recorded the original asbestos based thickness for reference.

Update
I found my old post about the oils seal rings, it just read I've sent you a PM from Nurse Julie but I culled a load of my old PM's as part of my housekeeping so the reply has gone.

[McCabe-Thiele (Ted)]

Looking back at some old posts a member attributed head gasket leaks to using synthetic base oils.

Also flagged up if re-torquing head to loosen all bolts in sequence then torque up rather than just tightening the odd loose one.

I found this parts list posted by Deano400 This is a list I started to put together a while back. Can't remember if it's complete or accurate but may help you putting your list together.

Diagram      Part No.   Description                            Quantity
Gasket Set           
D1   107   16173-253-004   Carb insulator O-ring 27 x 2.4             4
C1   277   91302-001-020   Tappet cover O-ring 30.8 x 3           8
D2   18   12209-333-005   Valve stem seal                                   4
C2   31   12909-333-000   Cylinder stud seal                           2
C2   32   12910-333-000   Oil orifice seal                                   2
C2   276   91301-377-000   Cylinder base O-ring 55.5 x 2           4
C2   14   12191-377-000   Base gasket                                   1
C1   19   12251-377-000   Head gasket                                   1
C1   24   12391-333-000   Rocker gasket                                   1
C1   22   12329-333-010   Breather gasket                                   1
C1   275   91301-333-000   R oil way O-ring 7 x 1.7                   1
D2   280   91305-333-000   L oil way O-ring 5 x 1.7                   1
E1   8   11394-377-000   Clutch gasket                                   1
F2   9   11398-333-020   Sump gasket                                   1
G2   12   11691-333-000   Alternator gasket                           1
Oil Seal Kit           
A2   265   91201-300-003   Crank oil seal 30x42x8                   1
B2   266   91201-323-005   Crank oil seal 30x45x8                   1
C1   267   91201-324-010   Tacho oil seal 6.5x14.5x7                   1
E1   268   91202-216-005   Clutch oil seal 14x24x5                   1
E1   269   91204-259-000   Kick start oil seal 16x28x7                   1
H1   270   91205-333-005   Drive shaft oil seal 34x52x13.5x15.5   1
H1   271   91206-286-005   Gear change oil seal 14x28x7           1
H2   272   91207-333-000   Mainshaft oil seal 34x9                   1
Oil Pump O-ring Kit           
H2   278   91302-044-010   Oil Pump O-ring 6.9 x 1.5                   2
H2   279   91302-377-000   Oil Pump O-ring 15 x 2.5                   2
H2   215   41123-516-00   Oil pump O-ring 63 x 2.5                   1
Separate Items           
B1   45   14401-333-003   Camchain                                           1
G2   140   23131-323-000   Primary chain                                   1
G2   139   23114-323-000   Primary drive damper                           8
E1   238   90431-292-000   Washer.Lock 16mm                           1
G2   239   90433-283-000   Washer.Lock 6mm                           1
H1   240   90435-333-000   Washer.Lock 8mm                           1
F2   287   91329-590-003   Sump filter O-ring 16.5 x 2.8           1
C1   242   90442-377-000   Seal Washer 18od x 2.2 x 8mm thread   2
F2   283   91315-044-000   R main oil way O-ring 19.4 x 2.8           1
F2   286   91319-300-000   L main oil way O-ring 13 x 2.5           1
F2   282   91314-220-000   F main oil way O-ring 16.4 x 2.4           1
H1   213   35751-333-003   Neutral switch O-ring 11.2 x 1.8           1
A2   285   91317-703-000   Camchain adjuster O-ring 6 x 1.7   1
C1   30   12905-333-000   Oil pipe holder                                   2




.

[SandyRob]

Thanks, to you all for your help, I'll work out what I need to do, it seems to be leaking from the middle to front on the right hand side of engine.
Thanks, Rob.

[SandyRob]

Took the cam cover off and checked the head nuts/bolts, all seemed ok, but two or three of the cam cover bolts were loose/stripped, so next job is head off, don't fancy doing that. Anybody got a good engine for sale?