classic motorcycle forum

Motorcycle Discussions => British Bikes => Topic started by: toz on July 24, 2011, 06:24:48 PM

Title: 1972 T120R
Post by: toz on July 24, 2011, 06:24:48 PM
Bike been laid up for 3 weeks as I have been away. Just before I went I noticed her popping back through the carb now and again but nothing serious.

Today she ran like a pig, ok one min then failing, then ok, finally she stopped and for the first time I had to push her home.

Fuel or ignition I thought and went for ignition first, spark looked ok but maybe a bit weak sometimes, it has a Boyer on. Plugs not black but a nice colour.

Checked the carb and noticed her leaking fuel out of the tickler on an intermitant basis, flooding out sometimes. Float seems ok but main jet did have a bit of something in there, blew it out. Got her going again but difficult to start and when I do she is popping and farting like a good un. Runs ok once going at a good pace but stops when I have to slow down, difficult to keep her going.

Im thinking carb. Any offers please.
Title: Re: 1972 T120R
Post by: Rex on July 24, 2011, 08:46:50 PM
Low battery voltage.

Give it a good charge and try again. Bet it's fine.
Title: Re: 1972 T120R
Post by: toz on July 24, 2011, 09:43:29 PM
It did cross my mind Rex, dismissed it though. :-[

Will give it a go,

Thanks.
Title: Re: 1972 T120R
Post by: toz on July 25, 2011, 07:18:50 PM
Hmmm, charged battery over night, only reads 10.7v on newly bought volt meter this evening.

On charge again and gone up to 11.7 in an hour.... not holding charge I would say. Will pop it back on bike later and see if it runs ok for a bit when just charged.
Title: Re: 1972 T120R
Post by: toz on July 25, 2011, 09:07:50 PM
Yup Battery is goosed, bike ran but dies as soon as I put lights on, battery soon went to 7v.

The one on is a 12N9 4-B-1  Is that ok?  If so I will replace with the same.

Good call Rex.
Title: Re: 1972 T120R
Post by: Rex on July 25, 2011, 09:22:00 PM
Ah well, even a broken clock is right twice a day..... ;)

That battery sounds like the typical Triumph twin battery and should be OK.
Title: Re: 1972 T120R
Post by: toz on July 31, 2011, 11:18:28 AM
Well, the new battery sorted the running out and she goes fine. I then noticed the throttle sticking on,.... just a bit now and then.

Carb off, cleaned the slide and everything, put back together and it was stuck solid. As I loosened the manifold bolts to take it off again I heard the slide drop down. Weird, but if I over tighten the manifold bolts the slide is stuck and if I just nip them up its fine. I can only assume that the tightening of the bolts distorts the body of the carb somehow,....... strange I think.

I have to say, its been a lot of years (30) since I tinkered about with bikes. Loving it though, its almost as good as riding them. :D
Title: Re: 1972 T120R
Post by: raptorkev on July 31, 2011, 02:26:17 PM
yes dont overtighten the the flange bolts you will distort the carb ;)
Title: Re: 1972 T120R
Post by: rogerwilko on July 31, 2011, 08:56:07 PM
You must be the last pommy bike owner on earth to find out about Amals distorting!
Title: Re: 1972 T120R
Post by: toz on August 01, 2011, 03:13:06 PM
Maybe so, new to these old bikes. learning is the best bit though.

No one likes a know it all do they :-*
Title: Re: 1972 T120R
Post by: Bomber on August 01, 2011, 04:46:33 PM
I'm with you on that Toz! Funny how we Brits get labeled poms.. I thought it stood for 'Prisoner Of his Majesty'
Title: Re: 1972 T120R
Post by: johnnyboy-wonder57 on August 07, 2011, 10:20:35 AM
I used to get WOT on my BSA single, through the Amal mono-bloc being very sensitive when bolting back onto the cylinder head. I used to road test the bike on a 3- lane road called Euxton Lane, downhill one bend sweeping to the left and the dead straight, everyone used to test their top speeds on this road in the locality.
Got a shock some years ago when I returned to find that the said road had not just the  round-about for the New village, but now traffic lights and a 40mph restriction on it, the Royal Ordnance factory is all but gone, where my Dad's Father, Mother & Brother worked and guess what its now a huge housing complex, where you are not allowed to grow vegetables in the gardens!
Speed cameras everywhere and inane speed restrictions which would make the most modest of us a law breaker & speed criminal. No chance of WOT any more.

Oh! I always thought POM referred to the red-colour Brits went on the beaches in Australia,  a comedian once said Australians were the most balanced people in the World, they have a chip on each shoulder!  As we do not like Poms they do not like being referred to as Colonials, having said that you could be deported for stealing a loaf of bread, in the old days,
Title: Re: 1972 T120R
Post by: johnnyboy-wonder57 on August 07, 2011, 10:25:16 AM
Post disappeared, but I had  put Aussie & Brit are better terms & keep any relatives I have out there happy!

Cheers

JBW