Honda cb175k6, 1972 re-build

[mini-me]

I thang you..........

if you aint old enough refer to arfur askey

[Terrotmt1]

Things getting serious...

All the electrics are up and running after a few 'earthing' issues and a few mysteries, but all works.

Time for petrol and sparks once I get the engine oil into the bike, but the electric starter works a treat.

Now, just what can possibly go wrong as the phrase goes...

[Rex]

Might be a daft question but you're not going to fire it up on the stand, are you?
First starts I always like to have the doors open, the bike on it's wheels and a fire extinguisher to hand, so if there's something nasty involving fire I can push it outside and use the extinguisher.
Bad enough to lose a bike without losing a workshop too..

[Terrotmt1]

Thanks for your concern!
The table is on wheels and the garage is 2 car wide, but it will be run on the table outside on the drive which will have all car there elsewhere.
Keeping it on the table out of convenience to get eye level to th engine timing and carbs.
I did the gold bike on its wheels, and you have made me think again.

[Terrotmt1]

Couldn't resist trying a quick start up.
Rigged the fuel supply up and filled the bowls. Checked for a spark on both plugs, present and correct, but could be fatter.

Pressed the starter button.
Nothing, but did not try very hard or for very long.
One carb bowl leaking slightly so that needs sorting tomorrow, other side OK.

Had a lot of trouble with the gold cb, so here we go again...me and carbs and sparks do not mix well.

[mini-me]

bloody drama queen, here we go again, another 200 pages of why won't it go mister............

[Terrotmt1]

Whoe! Miles off:

One carb leaks from the bottom bowl gasket, so need to replace the rubber seal that has been compressed for 48 years...

Will do both carbs, kit on order.

However, it runs. Lovely Honda Twin rumble, vibrations everywhere (they are all like that).

Some tuning to do tomorrow, but a great kick-off to the last match.

Could this be the quickest re-build on here?

So there Mini, nothing for you to read!     

[TGR90B]

Well done mate. So it's just two smokes  that you're NBG at.

[Terrotmt1]

I've had far more adventures with 2 strokes and 4 than I care to remember.
Strikes me the more complicated the engine the better chance I have of success. over all the years I've spent tinkering I've enough knowledge to be dangerous.
I can almost 'feel' mini's disappointment!

These small Hondas are sensitive to the resistance of the air filters, so tuning needs to be done with them on etc.

My gold cb had some carb issues that took a long time to sort to get the balance right between the carbs, but this is a great design of bike in my limited experience.

[Terrotmt1]

It's getting irritating.
Fresh float gaskets, 21mm float heights, still a dribble every now and then from the overflows.
Brand new coil.

Got it started ok, very hard to get a reliable tick-over, according to the tach best I can get is 1900 or so before it stops.
Air screws do noting, so presume the tacho is reading accurately enough.

Thr rh side that was running cold now runs hot and the left is now luke warm, about 32 deg C, the temperature difference is just touchable at the exhaust tip on the rh side, easy/cold touch on the lh side.
This is exactly how my gold cb was, the hot/cold sides would alternate not during a run on the bench, but between cold starts sometimes.
Bowls are full due to occasional weeping from the overflows.

So, just how do I get these to balance? Any ideas please?

[Rex]

I had a Black Bomber that was a pain for the regular drip from the carb overflow. Two rebuild kits from Japan (utter shite the lot of it, so much for Jap precision!) endless float height checks etc and it still did  it.
Stripped it down for the nth time and inspected the little brass standpipe in the float bowl with a jeweller's loop, and sure enough, on the side nearest the bowl wall (ie the blind side) the pipe was split for about 6-8mm along it's length.
Rather than wait for a new one to turn up I cleaned and sealed the split using solder, and it worked a treat.
Still didn't make it anymore interesting to ride though and it was sold soon after.

[Terrotmt1]

Yes, 'don't trust a thing'!

Going to check everything tomorrow, timing etc while it is all cold. My previous gold cb had this very same issue 5 years back, dammed if I can remember what someone in the USA told me to do but it simply worked...I'm too old for this game!

[TGR90B]

If the idle screw has no effect you've got a blocked fuel or air passageway in the carb body. Probably a tiny drilling in the  idling circuit. Plus check what Rex said as I've no knowledge of Jap bikes. Good luck.

[Terrotmt1]

Thank you, yes, time to backtrack over everything.

[mini-me]

great, now, where to start, mmmm, change carb?, no ...change coils?, no.. change handlebars?, a bit better but not quite,  change spark plug, several grades, no not that either.

change fuel?  amost, now, lets set light to it................thats sorted it.

groundhog day?