Sudden loss of power while riding

Foran · L Plate Warrior Joined: 10 May 2013 Karma :

Hey there. A tad new to the forum so don't scald me if I get it wrong Laughing

I have an AJS Daytona 125, custom cruiser, 2010, and I've been riding for about three weeks now without any issues. Bike's only done 1500 miles and has been fine up to this point during my time with it, with one previous owner.

When I took it out this afternoon I was a tad more hasty than usual in getting it out the garage and didn't let it warm up which I usually do.

I got it on the road for about 2-3 minutes, vastly down hill, until I hit a slight gradient uphill and the bike simply lost power and cut out when it stopped. I geared down straight away, though it was like I had my foot on the brake. I was forced to pull over and wait by the road side as I was fiddling with the choke trying to get it started.

After about five minutes of trying to start it, I managed to get it going again on half choke. Whenever I tried to start it it just wouldn't catch, almost, but didn't. After five minutes I did manage to get it going again and once it was it was fine.

Yet again, this evening it stalled twice, once going up a slight pitch, then about 10 minutes later going up another one on the way back. Exactly the same deal, just lost all power even though I was throttling it up and gearing down.

I did notice, on the third time however, that before I actually lost all power it was starting to pull back, more and more until I hit the hill and I lost power. To get it started again I kept trying different levels of choke, half, more than half, then in the end after a number of tries it started on half, like the other two times.

Does anyone have any ideas? Anything is appreciated. Maybe I need to leave the choke on a bit longer? Maybe I need to warm it up for a bit longer before I get it on the road?

I am a novice but already love riding. Thanks again.

George.

Copycat73 · World Chat Champion Joined: 11 Jan 2013 Karma :

yeah maybe warm it up more..
where you get your fuel from...could you try a different brand or higher octane ?
what happens if you use a lower gear up hill and let it rev. up slightly higher ?
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Foran · L Plate Warrior Joined: 10 May 2013 Karma :

andy_uk · World Chat Champion Joined: 13 Aug 2011 Karma :

What's the acceleration like on the flat?
(thinking compression issues...)
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Aprilia Classic 125, GS500E, ER5-A1, ER5-C4, ER6 & an XJ6 project frame...

Foran · L Plate Warrior Joined: 10 May 2013 Karma :

Scotsman37 · World Chat Champion Joined: 17 Aug 2004 Karma :

If the electrics are working ie lights come on and the horn works, etc, try another spark plug to see if it is starting to fail because that happened to me many many years ago on a 125cc

Another possibility is that your carbs have got crap in them and you're getting fuel starvation because you mention after opening up the throttle to go up hill shortly afterwards you lose power when you open up the throttle ie your engine isn't getting enough fuel when being driven harder! Your bike sits for a while allowing the carbs to refill very slowly, but as you apply hard only throttle not enough fuel filling the carbs in time then the engine starts to die!

Foran · L Plate Warrior Joined: 10 May 2013 Karma :

Ariel Badger · Super Spammer Joined: 02 Dec 2006 Karma :

It sounds like it seized initially, do you have full compression?
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Scotsman37 · World Chat Champion Joined: 17 Aug 2004 Karma :

Fozz · L Plate Warrior Joined: 30 Apr 2013 Karma :

Mine kept doing the same thing..... I filtered all my fuel out and then swilled out the rust and crap that was in the tank, and haven't had a problem since Very Happy

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Ilyin · Renault 5 Driver Joined: 14 Apr 2013 Karma :

I'd start at the beginning:

1. Look inside your tank, tank should be clean and petrol should be clear.

2. I wouldn't bother with supermarket petrol, use good fuel: BP, Shell, Texaco, Murco etc.

3. Check both filters are clean.

And see how you get on, if your still having troubles you'll then want to check your petcock, and then your carbs. But check the simple stuff first.

Foran · L Plate Warrior Joined: 10 May 2013 Karma :

Appreciate all the recommendations!

I've replaced the in-line fuel filter with a transparent one so I can actually make sure there isn't a blockage. I've also spent a bit more time warming the bike up, and leaving the choke on just a bit longer and it seems to have corrected the issue, or at least it hasn't happened since.

I get my fuel from Esso now anyhow, so that might have also had an effect.

Thanks again for all the help.
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AJS Daytona 125, Custom Cruiser

flumpy7 · Could Be A Chat Bot Joined: 31 May 2008 Karma :