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Featured Yamaha Vstar 650 spluttering & bogging down under load

Discussion in 'Technical and Troubleshooting Torque' started by vince650, May 11, 2015.

  1. Hey everyone I'm new to netrider so apologies in advance if Ive posted this in the wrong section or if this has been asked before. I own a 650 vstar i got my L's today and took it for a ride. 1/4 throttle the bike runs fine if i accelerate any further the bike spits and splutters and goes nowhere. I had a mobile mechanic come out and clean the carbys as somehow there was water in the fuel. Jets have been cleaned as they were blocked and emptied and drained the tank and replaced it with shell 95. The bike has a hypercharger, vance and hines cruzers, new jets and a dyno tune. As all the work was done by previous owners im not too sure on specifics. If anybody could help me that would be much appreciated. Thankyou in advance.

  2. Start by changing the fuel filter and checking/clearing the fuel lines.
    Check/replace the plugs and leads next
    Is there shite in the petrol tank?
    Who did the dyno tune, how long has the bike sat between use etc.?
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  3. Push the choke in. Its under the seat on the left hand side. If not its on the righ hand side.
    • Agree Agree x 1
  4. I replaced the plugs today cause when i checked them they were black. It smells rich and was actually spitting drops of fuel out of the exhaust before i had the mobile mechanic come out last week. That seems to have stopped. Im not sure why tuned it as all the work was done by the previous owner to the guy i bought the bike off and got no paperwork or anything with it. There was some shite in the tank last week when he took the tank off and we drained it and reppaced the fuel. Apparently thats why the jets were clogged but he cleaned them for me. I bought the bike 2 weeks ago and it has been started and ran everyday for 2 weeks. I got my license this morning and took it out for a ride.

  5. Push the choke in when??? I start it with the choke on full and let it warm run for about 5mins then push it all the way in. Is there something else i should be doing with the choke??
  6. It should idle without the choke pretty quickly after a cold start. Like under a min quickly.
    No need for 5 mins of choke.

    Sounds like it's starving for fuel at higher revs.

  7. So its possible to be running rich down low and lean up top???
  8. Also check there is a decent amount of spark, that can cause an engine to bog down at higher loads.

  9. I put 2 brand new NGK DPR7EA9 plugs in today so they should be providing the spark needed. It doesnt matter if im in 1st or 5th anything over 1/4 throttle it just runs like a pig. Quite devastated actually lol.
  10. If there is not enough spark, changing the plugs won't help. Also worth checking your battery voltage when its running.

  11. Ok thanks for that. Think i might just bite the bullet and take it to a reputable mechanic and pay the $$$$
  12. Yeah as Darrin said, it could be spark breaking down under load as well.

    My money is still on fuel starvation though.

    It's probably not a major fix, just have to track it down.
  13. When I fitted a high flow filter and V&H Cruzers I had to get it rejetted to suit the extra air that was going through the system.
    The first place that looked at it ( a Yamaha dealer ) couldn't get it right at all. 3 hours of playing with very little improvement.
    I ended up taking it to a dyno tuner and they had it fixed in short order.
    They actually had to increase the idle jet rather than the main jet to ensure that it was getting enough fuel at all stages of throttle.

    Same symptoms as you describe, just crap at full noise.
    It may have been tuned to suit the the stock exhaust.

    I'd take it to someone who can actually sort the issues and ensure it has been set up properly the first time.

  14. Thanks man. It has had the jets done which jets i have no idea and i have no idea who tuned it. I spoke to a mechanic today who straight away said he thinks its because the jets are too big just from telling him the mods and symptons. Guess ill just have look around for a decent tuner in sydney and see how we go.
  15. Good luck man, Id be +1 on a fueling issue.
  16. So problem is solved. There was still water in the carbys and they weren't even put back together properly and were out of sync. Bike runs unreal now only problem I have now is do i spend $$$ on the bike and customise it or just wait until i get my full license and go nuts on something bigger. Thanks to everyone who replied.
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  17. If you're set on upgrading, I'd leave it as is and save the dosh for the next ride.. if you're happy to continue riding it/ keep it in the collection, Mod away! (y)
    • Like Like x 1