Trip

Any MT parts
Sloppy Link
Posts: 26
Joined: Fri Mar 09, 2018 7:57 pm
Location: Dorset

Re: Trip

Post by Sloppy Link » Thu Aug 01, 2019 2:52 pm

Finally remembered to note the numbers and am returning 38mpg. Strikes me as being excessive, do I need to overhaul/change the carb?
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‘13 KTM Adventure 1190
‘03 BMW F650GS
‘99 Triumph T595
‘85 Armstrong MT500
‘67 Norton P11

Wirralman
Posts: 5499
Joined: Fri Jan 16, 2009 9:45 am
Location: Wirral, Merseyside

Re: Trip

Post by Wirralman » Thu Aug 01, 2019 4:01 pm

Sloppy Link wrote:
Thu Aug 01, 2019 2:52 pm
Finally remembered to note the numbers and am returning 38mpg. Strikes me as being excessive, do I need to overhaul/change the carb?
You don't actually say which engine and which carb

On a 350 with standard carb 60's mpg when running around low 70's on long run 55mph

Unfortunately I have no experience of a 500, but a few questions

What colour are they electrodes on your spark plug?
Plug clean and correct gap ?
Oil age ?
What type of riding- city, open road, off road ?
Which carb ?
Carb externally dry, drain screw shut ?
What jet sizes? Are jets clean ?
Any smoke from exhaust ?
Valves adjusted to spec?
Air filter dry and not clogged ?
Exhaust clear as far as you know?
Chain clean and free running ?
Wheel and sprocket bearing in good condition?
Screen fitted ?
Tyre type off road, road biased?
Tyre pressures?
Brake shoes or pads free , not dragging or running excessively?
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Sloppy Link
Posts: 26
Joined: Fri Mar 09, 2018 7:57 pm
Location: Dorset

Re: Trip

Post by Sloppy Link » Thu Aug 01, 2019 7:55 pm

Phew! A 500. I’ll check the plug when I’m home next.

Errrm....dunno
Errrm....dunno
400kms
Open road
Yep
Original Amal
Errrm...dunno
Nope
Recent top end overhaul by Force so assume so
Dry and clear
Yep
Yep
Yep
Nope
Continental green lane bias
24psi both
Free running.
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‘13 KTM Adventure 1190
‘03 BMW F650GS
‘99 Triumph T595
‘85 Armstrong MT500
‘67 Norton P11

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lardmarc
Posts: 980
Joined: Tue Jun 23, 2015 8:56 pm
Location: Newton Abbot

Re: Trip

Post by lardmarc » Thu Aug 01, 2019 8:41 pm

Sloppy Link wrote:
Thu Aug 01, 2019 2:52 pm
Finally remembered to note the numbers and am returning 38mpg.
Pretty standard I think. If I cane it I can get it down to low 30's.
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“Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so.” (Adams, 2009).

Wirralman
Posts: 5499
Joined: Fri Jan 16, 2009 9:45 am
Location: Wirral, Merseyside

Re: Trip

Post by Wirralman » Thu Aug 01, 2019 9:15 pm

OK , so you need to do a bit of checking to see if the mixture is correct, neither black nor pale

The belief is that the Amal was somewhat forced on Armstrong to increase the UK content of the bike. Whilst some riders stuck with them, the general concensus is that there are better carbs . Quite what 'better' means I don't know but fluff free, smoother, more power I would expect. I feel sure that if you use the forum Search facility you'll find some info, perhaps comments on fuel efficiency.

If you're happy with your bike's performance, my guess is that you'd have to run quite a few miles to recover your cost of a new carb in improved mpg. But then, spending money to make your bike faster might be attractive !

It really depends on what you want to do. Personally I would go through the whole fuel system, fuel cap breather, clean out rust flakes from inside tank and treat it with POR- 15 , strip and clean fuel tap, ensure fuel lines are clear then strip and clean carb, reassemble then play with setting to get optimal performance. But then, I have the time to do that and have done so on MT350s. The quick fix is to go to Sportax and get him to fit and set up a new carb

Whereas the 350 is 22/24 psi in the manual, many run a few psi more than that for road use and reduced rolling resistance which may improve mpg

Green lane tyres but open road riding ? There's certainly increased rolling resistance in green lane tyres, but swapping tyres or even just wheels shod with the right tyres for the occaision is a hassle
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