Diagnosing a loss of power

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Hooli
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Diagnosing a loss of power

Unread post by Hooli » Thu Nov 12, 2015 6:51 pm

Can someone remind me. If you flat out at full throttle and the bike acclerates when you close the throttle a bit, is it rich or lean? I'm thinking rich as the pattern filter isn't identical to OEM, it's got a smaller intake and long induction tube inside 2hich the correct one lacks.
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livinginthepast
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Re: Diagnosing a loss of power

Unread post by livinginthepast » Fri Nov 13, 2015 11:24 am

The Amal hints and tips leaflet states Engine goes better if-Throttle is not wide open or air valve is partially closed is caused by weakness

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Zunspec
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Re: Diagnosing a loss of power

Unread post by Zunspec » Fri Nov 13, 2015 1:20 pm

Hello Hooli,

Have you ever considered running the bike on a dyno with a probe up it's exhaust to measure the Air/Fuel ratio etc. A plug chop is not always easy to interpret these days with the ultra clean unleaded petrol.

Cheers Geoff

The "Headless Dyno-Man of Olde Basingstoke Town"
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Hooli
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Re: Diagnosing a loss of power

Unread post by Hooli » Fri Nov 13, 2015 2:45 pm

Zunspec wrote:Hello Hooli,

Have you ever considered running the bike on a dyno with a probe up it's exhaust to measure the Air/Fuel ratio etc. A plug chop is not always easy to interpret these days with the ultra clean unleaded petrol.
Yeah I could, but that costs money.

I know it has to be one of those three things as it happened after the 100k service. I can steal parts of a 'spare 14' in our garden for testing, I'm just wondering which to do first.
Classics ain't built in Metric

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Zunspec
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Re: Diagnosing a loss of power

Unread post by Zunspec » Fri Nov 13, 2015 3:47 pm

It's always useful to have a "spare" 1400 so you can easter egg parts and eliminate the wonky bits :D :D :D

With the impressive mileage you have built up it's to be expected that wear and tear will throw something a bit off kilter. Swap parts to see if a definite solution arises and then replace the pesky culprit(s) with new bits.

Cheers Geoff

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Hooli
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Re: Diagnosing a loss of power

Unread post by Hooli » Mon Nov 16, 2015 2:38 pm

We've got two 'spare' 1400s :lol: helps to have a greedy missus.

Well I've solved it, it's the pattern air filter. I put the old one that's done 45k+ back in & it's running almost right. I'll just have to pay out for a genuine filter as the pattern ones have a lot smaller intake (1.75" compared to 2.25") plus they have a restrictive tube down the throat.

Guess it was rich then.
Classics ain't built in Metric

Willpower
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Re: Diagnosing a loss of power

Unread post by Willpower » Tue Nov 17, 2015 3:29 pm

Digressing a little, but I remember quite well putting on a pair of Daytona pipes onto my T100SS as the lad with the Daytona had fitted swept backs and they were going spare. The pipes on my bike were not the prettiest at the time and as we were going over to the IOM for the TT, I thought I'd pretty it up a little.
Well long story short, my bike kept cutting out every 15 mile or so and took a good 5 minutes before it had cooled enough to start again. Problem was the newly fitted pipes. The Daytona ones were quite a bit narrower than the T00SS and caused loss of power and overheating. As I couldn't afford replacements in the IOM, I had to live with it for a week till I got home and refitted my tatty ones.

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Hooli
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Re: Diagnosing a loss of power

Unread post by Hooli » Tue Nov 17, 2015 3:42 pm

I still get a stutter at about 4-4.5k as I wind the throttle up, that'll be when it swaps from measuring intake pressure to meter the fuel to working on just the throttle position. Meaning at the moment as the air filter is 40k+ old, as it swaps to throttle position it goes a bit rich. I'll swap in an almost new spare filter to prove this.
Classics ain't built in Metric

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