Oil pressure issue / motor rebuild

[MrDavo]

Ian got it out by jamming a twist drill in it, I'd tried heat but only suceeded in burning myself. The pump is rebuilt, primed and back in place with all the new seals and springs which you sent me.

The barrels are back on (I couldn't resist fitting the new damper rubbers I bought from RGP750 too), and the clutch cover, I was going to put the mousetrap that changes the gears back together last night, but the stop plate that goes on first is missing the tag that goes into the selector rod to stop it turning. I ordered one from DS today, he gets them to order.

Next I'll have a look at the head, more gasket scraping off to do, also I want to whip all the valves out for a check, number 3 exhaust has been running hot, I want to see if the seat is OK, though I suspect the old rock hard carb rubbers as the cause (I've got new ones). I'd like to measure all the springs for length too, although they might all have been new when the motor was originally rebuilt, I wonder what 10 or 20 years standing might have done to the ones that were compressed.

I'm posting to make a quick query, I know that NOS Honda head gaskets are preferable to pattern ( which explains all the single Athena head gaskets on eBay), but where the *&^% do I get one? If you don't want to reveal your source publicly, you can always pm me

[JamesH]

Should be able to get genuine Honda head gaskets from CMSNL. But be warned, they're almost £80 a pop...!

[MrDavo]

Ye Gods, one hundred and two of our earth pounds with VAT and carriage.

Suddenly the US ones with horrendous postage seem worth checking out. Are the Athena ones that bad?

[JamesH]

Graham's the man to ask....

[MrDavo]

I did that, and rather than skimp on a job I only want to do once, I have bitten the bullet and ordered the real thing from CMSNL.

Ouch!

[MrDavo]

Out of sequence, as it's going back together now, but here's the layer of paint that killed the crank by stealing the clearance - I took this after scraping away half the paint off the journal, having softened it with the evil stripper, and yes, I was wearing a mask. I had to be very careful not to remove any alloy or otherwise b*gger up the original surface, but I think I did a good job.



Here's what was going on in the kitchen yesterday, while the wife was away, more gasket scraping going on here. The teaspoon made a good scraper for the carbon in the combustion chambers, after I softened it with the gasket remover. Later I put the valves and springs back, after lapping them in. Ive still got to have a go at getting the oil jets out, or Trigger will tell me off, but then the head can go back on once they are cleaned out.



The genuine Honda head gasket just turned up from Holland, via UPS, in a huge box. As Trigger said, it's strangely sticky, but I've put it back in the packaging for now, as it looks very fragile around the middle camchain slot. I don't want to mess it up, I assume from the price it has a layer of 24 carat gold in the middle.

[JamesH]

Yeah I've had 4 of the genuine Honda Head gaskets in as many months. Bloody bloody expensive....and bloody bloody sticky.

[Bryanj]

 Thats why they are a bugger to scrape off

[Greebo]

Another very good tip for anyone doing a rebuild, or just doing any head work.

The genuine Honda rubber "O" rings in the head that create the oil seal were found to be to thin, hence many of these bikes had leaks from the head...to stop this happening you can buy the same Diameter O rings that are slightly thicker [1mm]
So that when you torque the head down it does create a proper seal where as the stock O rings did not , this was a fault Honda never cured or modified.

[MrDavo]

Well, the motor went back in today, no pics yet until I'm on the desktop PC.  the same two mates that helped me get it out came round, it was fairly straightforward. I won't get a chance to do any more till Sunday, my first priority is going to be getting oil pressure before carbs, pipes etc go on.

I'd had a drama with the ignition timing yesterday, the new Honda points on pots 2-3 would not gap small enough, and setting 1-4 correctly would not let me get the other pair opening properly. I remembered reading that there are two OEM suppliers, and wondered if I was mixing a backplate from one with points from the other. Anyhow I refitted the original points, which were in as new condition, and it timed up a dream! 

Once I'd got the engine bolts done up and the oil filter on, I put her on the side stand (still an alarming angle) took the oil gallery plug out and squeezed half a litre of oil in. That will put some oil the crank's way and give me a head start filling the filter when I start kicking her over, once I have the tank and oil lines back in place. Of course the proof of the pudding will be getting the oil light to go out, then starting her for the first time. I remember how nervous I was firing up the Sportster after her crank change earlier this year, but once run in I set off for the North coast of Scotland, no worries.

It does look good, at least I've got a polished cam cover now, and some oil pressure, hopefully. Thanks to all that have helped, especially Ash and Graham.

[Trigger]

Another very good tip for anyone doing a rebuild, or just doing any head work.

The genuine Honda rubber "O" rings in the head that create the oil seal were found to be to thin, hence many of these bikes had leaks from the head...to stop this happening you can buy the same Diameter O rings that are slightly thicker [1mm]
So that when you torque the head down it does create a proper seal where as the stock O rings did not , this was a fault Honda never cured or modified.

If you use a O ring 1mm thicker it will not fit in the recess or the hole in the gasket as it is a 16mm hole. The OEM O ring is 11ID x 2.4mm, 1mm thicker will give you a overall measurement of 17.8mm

[Trigger]

Maybe he meant he still uses a 16mm but it's a 3.4mm thickness rather than 2.4mm thick? That would result in the 11mm ID being reduced slightly as when it squashes down it will spread a little more, don't expect that the ID is that critical though.

Very critical, as it is a oil way. On the F1 Honda still used 16mm ID but, put dowels and sleeves to update the gasket seal.

[AshimotoK0]

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[Trigger]

I think you time machine to get part number 12020-300-305 Ash

[AshimotoK0]

I think you time machine to get part number 12020-300-305 Ash

Just buy quad rings . in Viton