Running very rough on startup

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nachtjaeger13
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Joined: Fri Oct 25, 2019 6:00 pm

Running very rough on startup

Post by nachtjaeger13 »

My vtr has recently started to run very roughly on start up and will only start with the choke.On releasing the choke engine cuts out.Prior to this the engine was revving and performing normally but would sometimes cut out when trying to engage first gear.
It has a K&N air filter fitted on checking it looked ok,unfortunately,I don't know what stage dynojet kit was fitted only that it has been dynojetted,before tackling the carbs would appreciate any advice.cheers
tony.mon
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Re: Running very rough on startup

Post by tony.mon »

No fuel reaching the carbs. Check the vacuum line is connected correctly, to the 9 o'clock position on the fuel tap and not 6 o'clock.
It's not falling off, it's an upgrade opportunity.
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fabiostar
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Re: Running very rough on startup

Post by fabiostar »

did this start at the same time the K&N was fitted? or had the tank of for any reason?
the older i get,the faster i was :lol:
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nachtjaeger13
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Re: Running very rough on startup

Post by nachtjaeger13 »

I bought the bike with the kand n already fitted in October 2019.
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nachtjaeger13
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Re: Running very rough on startup

Post by nachtjaeger13 »

tony.mon wrote: Sun Mar 07, 2021 8:10 pm No fuel reaching the carbs. Check the vacuum line is connected correctly, to the 9 o'clock position on the fuel tap and not 6 o'clock.
Thanks,I had an idea that this may be the problem,but thanks for the vacuum hose position guide.
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cheekykev
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Re: Running very rough on startup

Post by cheekykev »

If it runs with the choke on, it could well be a blocked/gummed up pilot jet, especially if it's been stud for a while.
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