Hi

toxic · Dec 18, 2011

New to the Forum - but not the bikes !!

Had a 750 back in 1975 and an 850 a year later, somehow got lost for a few years bringing up a family, restoring several MuscleCars and riding bikes without the "Norton" logo on the tank.

Anyhow, now have a 72 Roadster that I've owned for 6 months now. I've yet to ride it any distance as I found a few issues with my new/old pride and joy.

But its getting there, not fussed about originality or winning trophies - just riding and smiling.

toxic · Dec 18, 2011

Still very much "work in progress" but here it is.

rvich · Dec 18, 2011

Huh? What did he say?

The avatar is a bit distracting...but I don't think your photo posted. Or I just didn't see it!

snare1998 · Dec 18, 2011

Looks good to me!

swooshdave · Dec 18, 2011

Well, what are the issues. The bike looks like it was well tended to.

rvich · Dec 18, 2011

Oh! There it is!

toxic · Dec 18, 2011

Might not be issues to some !

But the day I picked it up, wheeled it out of the van one of the rear shocks fell off - the lower bolt near the chainguard had about 2 threads holding the nut on. :cry:
Closer inspection revealed the rear shock on the other side was broken and had been turned around so as not to be spotted.
I decided to spend a bit of time checking it over, found a few things I was'nt happy with - like a home made wiring harnesses with no fuses and bare wires twisted together !

Rewired it with a simple harness, added a Brembo M/Cyl and stainless brake hose, fitted a new set of shocks, replaced the fuel tank - the original fibreglass one leaked the first time I put fuel in it, replaced a few nuts and bolts with stainless too.

Currently got a problem with the carbs, idles but will not rev - waiting to get a #78 drill bit to clear the idle jets, see if that helps. :?

I'll keep tinkering till I get it how I want it.

pete.v · Dec 18, 2011

That is a very fine example. Any evidence of Combat heritage?

What are you going to use as a tail light. I have a 72 with the later type 917. I really really like the period 679 type but the housing are so rare and expensive. I see them once and a while but they can be a little rough. I will find one though.

If you idle but not rev it is something other than the pilot circuit. Sounds like the pilot is working just fine. Check your needle clip. They sometime fall off and the needle drops and produces the symptom you describe.

Welcome!
Peter

rvich · Dec 18, 2011

Sounds like you are getting it sorted out. You should be able to take a can of carb cleaner, dw-40 or basically anything with a straw on it and blast it through the pilot curcuit to see if it is blocked or not. I was doing this on my carbs and discovered the plug on the intake side of the carb (toward the air cleaner) was leaking and allowing it to suck air. If it idles but will not rev I would suspect the needle and needle jet. It might be a matter of repositioning the clip. As the jet wears it is necessary to drop the needle down a notch. But they are not expensive to buy. If you order some up, you might as well get some extra clips. When they get reused too many times they will come loose and allow the needle to float around.

Hobot · Dec 18, 2011

Wonderful avatar, thanks.
Check timing may be too retarded, basic is advance tiny amounts till sense of back fire to kick off then retard tiny amount till it just don'[t. Then get a time light to see where to mark for future but don't think the factroy dial actually indicated degrees until you have indexed by degree wheel, just go by feel. Check for air leaks in carbs and suspect worn slides and bores at some point. I greased my worn ones to verifiy that was an issue to correct. You may also have clogged up internals from dissolved resin form old tank. ugh. I'd try some acetone in gas about an oz per gallon. Floats are set right when idle screw gives best idle at 1.5 turns out.

Its a Combat if low rear breather hose and smaller gap at head junction and wakes up a 3rd piston by 6500 rpm or so. MIne didn't lift front till passing though 6800. ts risky to rev that hi w/o knowing what insides are like or installing better valve train and steel flywheel. Also can check serial number to fall in Combat production zone. Some day try an Interstate tank that Combats introduced, may like its better knee grip and range and area to place big tank bag on and maps and lunch and center folds : )

toxic · Dec 18, 2011

pvisseriii said:
If you idle but not rev it is something other than the pilot circuit. Sounds like the pilot is working just fine. Check your needle clip. They sometime fall off and the needle drops and produces the symptom you describe.

When I first bought it, it was a pig to start, and only idled with one air screw right in and on the other carb screw about half a turn out.
After a while I had it so it was a first or second kick starter, it revved just fine - but the idle/air screws were still an issue.

After being laid up for a couple of months I could'nt get it started, checked everything, decent spark, plenty of fuel.
I was able to start it eventually, but only with a completly closed throttle - it idles real nice but as soon as you touch the throttle it dies/stops.
I hav'nt touched anything in between times, got me a little confused (thats normal !!)

AussieCombat · Dec 18, 2011

Hey toxic,
I hope you realise that now there will be an Avatar competition.
Do you have the front view.
Back to carburetion,... If the mixture screws had to go right in, that is as rich as possible, then perhaps there
is a partial blockage of the idle circuit. Just enough fuel getting through to go with minimal air.
I suppose you are aware of the sloppy slide syndrome, that's more air getting through.
Then check the Needle jets for wear.
Oh yeah, welcome aboard,
AC.

DogT · Dec 18, 2011

Instead of just giving it slow throttle and it dies, try running past that point real fast, like just snap the throttle and see if it will rev. My idle will dip or die by giving it a slow throttle, but once I get past that point, it runs fine and after it warms up, it idles faster and the problem sort of goes away, but the idle still dips giving it a slow throttle. As far as I have understood that's indication of worn slides. Then it could be electrical, ie. timing or points issue. I'm talking original equipment here, Amals and points.

Dave
69S

mikegray660 · Dec 18, 2011

toxic said:
Might not be issues to some !

But the day I picked it up, wheeled it out of the van one of the rear shocks fell off - the lower bolt near the chainguard had about 2 threads holding the nut on. :cry:
Closer inspection revealed the rear shock on the other side was broken and had been turned around so as not to be spotted.
I decided to spend a bit of time checking it over, found a few things I was'nt happy with - like a home made wiring harnesses with no fuses and bare wires twisted together !

Rewired it with a simple harness, added a Brembo M/Cyl and stainless brake hose, fitted a new set of shocks, replaced the fuel tank - the original fibreglass one leaked the first time I put fuel in it, replaced a few nuts and bolts with stainless too.

Currently got a problem with the carbs, idles but will not rev - waiting to get a #78 drill bit to clear the idle jets, see if that helps. :?

I'll keep tinkering till I get it how I want it.

swooshdave · Dec 18, 2011

Take off carbs, clean throughly, reassemble and enjoy.

toxic · Dec 18, 2011

swooshdave said:
Take off carbs, clean throughly, reassemble and enjoy.

That was last weekends job, now very clean inside and out - did'nt make a whole lot of difference.

But - I did'nt have a way of probing the idle jet, I have #78 drill bits on there way.

toxic · Dec 18, 2011

AussieCombat said:
Hey toxic,
Do you have the front view.

I suppose you are aware of the sloppy slide syndrome, that's more air getting through.
Then check the Needle jets for wear.

Sorry no front view !! :shock:

Yeah I am aware of potential issues with the carbs, before I had this problem I had it in mind to fit a single Mikuni.
Still might, but want to figure this out first, not just swap carb and never know the reason.

Tried yanking the throttle open quick to get past the dead spot - that don't work. :evil:
Placing my hand across the rear of the carbs (filter removed) and it'll rev - pops and bangs a bit.

Before this, I was running it around the block each weekend and it ran really nice - pulled like a train.

Hi

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