Post by: Grewth on May 17, 2025, 05:07:56 PM
It was cheap.
For a good reason, it's a total wreck.
47 years of British weather have not been kind to the black coating that Honda applied to the engine unit, it's festering and lifting off in places, and TBH, I think natural alloy looks much better anyway.
From my experience with Yamaha's, it's an absolute pig to get off.
I'd be interested to know if anyone has successfully stripped an F2 engine back to bare alloy with a presentable finish ?
Post by: Grewth on May 17, 2025, 05:09:32 PM
Post by: Bryanj on May 17, 2025, 05:46:48 PM
as to the black coating how about nitro-glycerine?
Post by: royhall on May 17, 2025, 07:21:08 PM
Post by: Laverdaroo on May 17, 2025, 08:43:43 PM
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Post by: Laverdaroo on May 17, 2025, 08:53:40 PM
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Post by: Grewth on May 17, 2025, 10:30:43 PM
I was sort of hoping someone had found a miracle solution to stripping the stuff.
Oh well, it looks like my wallet will be taking another hit.
I'm not keen on those late type carbs either, I'll hopefully be moving them on at some point.
I've found the early ones a cinch to work on.
Post by: Johnny4428 on May 18, 2025, 07:34:06 AM
Post by: Grewth on May 18, 2025, 05:17:06 PM
Worth in to keep those big valves
With the barrels and the crankcases, it's probably going to be cheaper to swap in F1 or K model items, especially if I'm going to re-shell the crank anyway.
Post by: SumpMagnet on May 18, 2025, 09:30:10 PM
As far as removing paint goes, I used to have an XS1100 1.1S with a black finished engine. I was able to remove that by...er...washing the bike. Honda finished their engine cases a little better.
Post by: Laverdaroo on May 18, 2025, 09:56:03 PM
That’s a lovely transformation on that engine Roo! Interested to see how you get on with yours Grewth.Cheers Johnny, I saw it after basting all the bits and kinda liked the blue ‘hue’ it had. Clear corrector to fix it and ta da! It’s a huge difference to the 550 which I did in a silver but this finish kinda suited what she, (who shall remain nameless) wanted. Still live it though.
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Post by: Grewth on May 21, 2025, 05:08:38 PM
It did occur to me for a moment that someone had sold me a F1 or K series head just painted black ( I haven't had time to check the valve sizes yet), so I tried the pan scourer on my other F2 engine with exactly the same results
Post by: royhall on May 21, 2025, 05:15:26 PM
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Post by: Spitfire on May 21, 2025, 06:55:49 PM
To get into the fins I used lolly sticks and stirrers from McDonalds with the aforementioned wet and dry wrapped around them.
Lots of sore fingers and broken nails and it was not fast but I was retired.
(https://imagizer.imageshack.com/img924/4720/qq0QVJ.jpg)
Cheers
Dennis
Post by: K2-K6 on May 21, 2025, 07:29:16 PM
That's in comparison to previous iteration.
Post by: Grewth on May 22, 2025, 12:43:59 AM
For identification purposes, doesn't the F2 head have notably extended top fin arrangement on front fins of head ?Thanks for that.
That's in comparison to previous iteration.
As soon as I get chance (likely to be Friday) I'll compare the front fins on the four heads I've got.
There's a complete F2 engine, the loose (allegedly) F2 head I've just bought, a complete F1 engine, and loose K type head of unknown vintage.
Post by: Grewth on May 22, 2025, 01:14:11 AM
Head Drain-Back Hole: The F2 head has a common head drain-back hole, unlike earlier models, which eliminated the middle drain-back holes.
I have to confess that I'm not quite sure exactly what I'm looking at, but I'm sure I'll be finding out very shortly.
Post by: K2-K6 on May 22, 2025, 07:19:59 AM
Apparently the F2 head can be identified by having different drain back holes to the earlier heads -
Head Drain-Back Hole: The F2 head has a common head drain-back hole, unlike earlier models, which eliminated the middle drain-back holes.
I have to confess that I'm not quite sure exactly what I'm looking at, but I'm sure I'll be finding out very shortly.
Yes, correct. They were struggling with development (without big changes) on this last iteration. The objective looked to keep more oil at that level by restricting drain volume is my view of it.
The bigger valves were moved further back upward into the combustion chamber to give clearance at their head diameter, both between them and bore periphery naturally.
The angle between them often quoted as changing by some sconces, incorrectly as for example I've worked with.
But it did put the top of valve stem higher in relation to the arc of movement in tappet face, which ultimately put more side load on the valves from that arc of interaction geometry. It's primarily this that affects wear on valve guide, exhaust predominantly.
The F2 has to use higher dome piston to maintain compression in that bigger chamber too. Valve springs stepped up in rating, higher rpm ceiling etc.
Also std F2 has an oil "cooler" plate fitted between filter housing and crankcase, extra fins etc and longer filter bolt to accommodate (I think) but worth checking.
Mounting F2 head on F1 or K bottom you'd have to consider and check oil return path etc. Or the opposite swap likewise.
Post by: Grewth on May 22, 2025, 07:30:09 AM
I'm beginning to realise just what a can of worms I've opened here, but I suppose that's the only way that you truly learn anything.
I think you've just explained why the F2 has a reputation for valve problems at 30-40,000 miles, while the earlier engines do not.
I've had the foresight to purchase both the F/F1 parts catalogue and the one for the F2.
Without checking, I think that the cam carriers remain the same, but the rocker arms change for the F2/F3.
That makes perfect sense.