Bike is making 50% power if that ?

StagHF · L Plate Warrior Joined: 19 Jul 2017 Karma :

So the other day i got a text from my sister to ask if i could deliver her lunch, So i did; On my way home from work I was at the lights and I revved it a little, it started backfiring loads. Then it started to make 50% power if that the bike is a hyosung gt250r, Which has a full size frame which is very heavy. The bike has two cylinders, My guess is that one of them is failing ?
The bike barely made it up the hill where i live. The bike starts up and idles fine, Anyone got any ideas ?

arry · Super Spammer Joined: 03 Jan 2009 Karma :

arry · Super Spammer Joined: 03 Jan 2009 Karma :

Is this the same engine that's already been called out as probably having bent valves?

https://www.bikechatforums.com/viewtopic.php?p=4478205&highlight=#4478205

Rogerborg · nimbA Joined: 26 Oct 2010 Karma :

Yehbut, he get Teffed in the A, so it needs to be asked again.

Quickest thing to check is that both downpipes are heating up, then take it from there. Since it's already been in bits, I wouldn't even like to hazard a guess about how it's been mullered.
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Evil Hans · World Chat Champion Joined: 08 Nov 2015 Karma :

arry · Super Spammer Joined: 03 Jan 2009 Karma :

StagHF · L Plate Warrior Joined: 19 Jul 2017 Karma :

This is literately the most un helpful forum about. No one ever offers any help. No my valves are not bent. I mean it was backfiring when i revved the bike, Whys that hard to understand.

Ste · Not Work Safe Joined: 01 Sep 2002 Karma :

StagHF · L Plate Warrior Joined: 19 Jul 2017 Karma :

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

If it's 50% down on power, is it 50% down on engine?

Are both cylinders firing? Youy would check this by seeing if both exhausts get hot.

Sparkplug electrode condition/appearance will also tell you a great deal about how/if each cylinder is firing.

This was covered by arry in the first reply and Roger in the third reply to this thread.

BCF is helpful while ripping the piss. Choose carefully which you reply to. Had you come back with a report (and preferrably pictures) of the plug electrodes and a report as to if both headers were heating up, I'm sure further advice would have been forthcoming.

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Evil Hans · World Chat Champion Joined: 08 Nov 2015 Karma :

Ste · Not Work Safe Joined: 01 Sep 2002 Karma :

pudder · Scooby Slapper Joined: 04 Nov 2016 Karma :

jakebrownbass · Renault 5 Driver Joined: 14 Feb 2016 Karma :

What years the bike?

There was a recall circa 2008 where there were faulty camchains.

If it's from that kind of era, you could have a bent valve if it wasn't sorted.
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Johnnythefox · Traffic Copper Joined: 01 Dec 2016 Karma :

blockage in brain or carb

arry · Super Spammer Joined: 03 Jan 2009 Karma :

OP flounced over this Shocked

was barely a mild ribbing.

They don't make em like they used to.

Rogerborg · nimbA Joined: 26 Oct 2010 Karma :

Suntan Sid · World Chat Champion Joined: 07 May 2009 Karma :

This is the funniest thread of the year so far, AFAIC!
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