Honda-SOHC

Hi

I just had to do the same with mine. After blasting it was absolutley full of holes and leaked at the seam. I used the Frost kit to seal the inside and patched up some of the larger holes on the outside too. It has worked a treat for me and I have no sign of leaks. 78 F2 also.

http://www.frost.co.uk/por15-motorcycle-fuel-tank-repair-kit.html

Hope this helps,

Cheers,

Magnus.

Hi, I have cleaned it out with compressed air and am pretty sure the seals are the right way around.
The more I dig around on forums it looks like in that blocked cavity there should be a tiny return hole.
I have tried clearing it with pins and guitar strings but it is solid. Have read elswhere that I could drill it with a 0.4mm hole so I think that will be my next effort.
Thanks, Magnus.

The seals are new, I did wonder if they were sticking. They push in by hand relatively easily, but I can't push them both back at the same time even with a clamp.
Thanks, Magnus.

I will check some of these out too. Unfortunately, your local is the extreme opposite end of the country from mine (Orkney Islands, Scotland) but I am not sure if that matters.
Cheers, Magnus.

Thanks for that but I think I have just discovered the problem.
I had the spark plug caps reomved and when I was turning the engine over I saw the spark jump fully 10mm from the end of the cable to the cam cover.
I tried them all off and got a big spark from every one.
I assume it must be the plug caps. These were new a few months ago and I have had the bike running so unless they have gone faulty it must be the wire to cap connection being poor.

Thanks for taking the time to help me.

Cheers,

Magnus.

Thanks for the info.

I checked the condenser wires and sure enough I had pushed them on a bit too far and the connector was just touching the bracket.
Success I thought. Checked for sparks and was getting them on 2 and 3 but not 1 and 4. Double checked timing redid connections for 1 and 4 and tried all again. No sparks anywhere.
Must be something going on at the timing side. I should probably buy new points and condensers and set the whole thing up again.

Thanks for the comments.

Magnus.

Hi all, if any of you happened to see my intro I have just about completed my F2 cafe racer build.
It has not had a proper run yet as it has been running mainly on 3 cylinders. I was trying to narrow it down today and all plugs and checked sparks again which I knew I had before but after removing them and cleaning them I discovered I was only running on 2 and 3.  No spark on 1 and 4. Checked points and timing was ok although they were sparking not sure if good or not. Tried swapping condensers around as they seemed to be identical. Then no spark whatsoever! Swapped back again nothing. I am not sure how to test condensers but read up on how to check coils.
Checked voltage at coils black and whites 12v getting there. Checked resistance of primary coils b/w to yellow and b/w to blue and around 7 ohms at both ( ok I think?)  but no secondary  whatsoever. I gather I should be on 20k and should be able to use either wire to ht end but nothing at all. I am very close to ordering a couple but would like to check I have not done anything stupid. I have gone from a bike running on 3 mostly to 0 in the space of a day.
Would switching condensers have killed the coils? I guess it is nearly 40 and hasn't been run in 20 years but I was under the impression coils rarely actually failed.
Any help appreciated
Cheers, Magnus.

Hello everybody,

By way of introduction I live in Orkney. I have returned to bikes after a lengthy absence and was looking for a project so I had my first proper experience of one last year when I got an XT350 as a box of bits with only around 70% there. I enjoyed the experience very much and did almost everything myself. When approaching the end of that build in April last year, I was offered an old CB750 on a chance conversation. I paid very little money for it as I thought it might be on its way to the scrapyard but here I am just trying to get the finishing touches.

The engine was seized, the carbs were off and it had been standing for nearly 20 years in a damp shed. I thought I would remove the engine and see what I could do with it before attempting anything else with the rest of the bike.

Over the next few months I got the engine unstuck and cleaned up and repaired what I could. Giving the top end a refurb and eventually got the engine running in a stand before attempting the rest of the bike.

As it was too far gone to restore, I thought I would try to make a café racer.
I have probably gone for every cliché in the book but I am quite pleased with how it looks so far.

I probably should have joined before now as I have lurked on a few of these forums and found really helpful information, so I must thank you all for that.

Anyway I will post a few pics before I say any more just now. I do have a few questions but will hold back on them just now. See what you guys think, constructive criticism welcome.

Oh by the way it’s a 1978 CB750F2 SOHC (or was anyway).

I also have an XT350 as mentioned and an FZS600 Fazer. The bikes date from 1978, 1988 and 1998.

Cheers, Magnus.