Yamaha Starbike Forum banner
Cancel

07 v star 650 wont rev past 1/4 throttle..

25534 Views 33 Replies 14 Participants Last post by  james.alan.howard, 
F
Ok, so i have a 2007 V star 650 custom. I have owned the bike since new and have never had issues with it. I parked it two years ago with starts over the first year and then none over the last. This season i pulled it out to sell and i drained the tank, replaced the fuel filter and battery, added new gas and took it around the block. Ran great. Sold the bike basically, brother in law took it to deliver it and get the cash, and as hes riding it for about 10 minutes, all of a sudden it starts bogging and spitting after 1/4 throttle. Brought it home, first thing i thought, carbs. Took them apart, cleaned em out good, everything looked good in them too, seemed very minimally gummed up. Put them back on, did the exact same thing. Next up blew out all the lines, made sure the petcock flowed, and the tank vent was all good. still nothing. Replaced the plugs, nothing. Took the carbs off again, cleaned again, nothing. Took the carbs to a shop to be cleaned better than i could, nothing. changed the oil, changed regulator/rectifier, nothing. Coils seem to be fine. Checked for vaccum leaks, thought i found the issue as the engine reved a bit higher when sprayed at the carb boots, replaced those....not a thing changed. I am seriously at a loss for what it could be...any ideas? Ive been reading the forums on here as well as else were for people having similar issues, and have tried everything... Help!!!
Reply
Save
Like
1 - 20 of 34 Posts
D
Here is a thread on an 1100 with a similar situation.

http://www.starbikeforums.com/forums/showthread.php?t=7338

The resolution to the problem is in the first post. Not sure if your carbs are the same or similar to the 1100.

Best of luck getting it sorted.
Reply
Save
Like
F
also some more info, the bike has just over 3k miles, has hard khrome pipes, but they were installed by the dealer and the cabrs jetted (ran fine for two years after these)
Reply
Save
Like
F
and yeah thank you, i looked at that thread too, i tried to PM tanz45 to see exactly what he was talking about ( not sure what he means to grind down the jet to bypass it)
Reply
Save
Like
B
fueler191 said:
Ok, so i have a 2007 V star 650 custom. I have owned the bike since new and have never had issues with it. I parked it two years ago with starts over the first year and then none over the last. This season i pulled it out to sell and i drained the tank, replaced the fuel filter and battery, added new gas and took it around the block. Ran great. Sold the bike basically, brother in law took it to deliver it and get the cash, and as hes riding it for about 10 minutes, all of a sudden it starts bogging and spitting after 1/4 throttle. Brought it home, first thing i thought, carbs. Took them apart, cleaned em out good, everything looked good in them too, seemed very minimally gummed up. Put them back on, did the exact same thing. Next up blew out all the lines, made sure the petcock flowed, and the tank vent was all good. still nothing. Replaced the plugs, nothing. Took the carbs off again, cleaned again, nothing. Took the carbs to a shop to be cleaned better than i could, nothing. changed the oil, changed regulator/rectifier, nothing. Coils seem to be fine. Checked for vaccum leaks, thought i found the issue as the engine reved a bit higher when sprayed at the carb boots, replaced those....not a thing changed. I am seriously at a loss for what it could be...any ideas? Ive been reading the forums on here as well as else were for people having similar issues, and have tried everything... Help!!!
Click to expand...
WOW only thing left is the air filter, does it run without it? if so, replace air filter. :confused:
Reply
Save
Like
F
thought i added that, air filter was changed out, nothing. I did also try running it with my new spike filter just to see if it was being restricted, nothing. Stock air and open air didnt make a slight change what so ever (i figured a little rejetting would be needed for the carb for the spike, but i will cross that road when i get it running again and actually install the spike cleaner)

i truely cannot think of a single other thing that this could be, does anyone know (and this may be a very dumb question, but i work on cars not bikes) is the rev limited electronicaly controlled? or is it mechanical? i should think electronic as it is different in gear than it is in neutral....
Reply
Save
Like
F
and now that i have taken it to the Yamaha Dealer, and they cant seem to figure it out, i am going to throw this thing into the nearest lake....
Reply
Save
Like
F
ooook, another update, after i took it to Yamaha and they have no idea, and charged me 300 for "diagnosing" and came up empty handed, i took an oscillometer to personally check the coils, computer/etc.... so everything is in working order. I started the bike with the air cleaner off, and the fuel is definatley still going even when the bike cuts out, but the oscillometer says the bike is sparking as it should, and the plugs are new...so why wouldnt it fire? compression should be good since it idles and revs fine up to 1/4 throttle...i feel like i am beating a dead horse here, but does anyone maybe have a little insight? please? anything?
Reply
Save
Like
L
Chargeback the $300...They couldn't figure it out. That's not a diagnostic. Definition of a diagnostic is finding out what's wrong. Which they did not do. I've done this on 3 occassions. Dealerships don't mess with me anymore :)
Reply
Save
Like
F
more updates....and problems...

I am now thinking it has to be an ignition problem.

any ideas how to better check the ignitor unit without taking it in anywhere? while there is spark, the front cylinder under close watch seems to be a little weaker than the back....coils are good as they have been replaced so aside from the ignitor unit, or a frayed wire, which i couldnt find, what else could it be right? i find myself saying that a lot.....:mad:
Reply
Save
Like
Sick Mick
LVNeptune said:
Chargeback the $300...They couldn't figure it out. That's not a diagnostic. Definition of a diagnostic is finding out what's wrong. Which they did not do. I've done this on 3 occassions. Dealerships don't mess with me anymore :)
Click to expand...
That all depends on what you sign when you drop off the bike.

If there is an explicit guarantee that they will fix the problem or it's free, then you might be OK.

However, they will bill you for the diagnostic time they took to try to figure it out unless there is a guarantee of that sort.

I personally don't know of any shop that would spend hours trying to diagnose a problem that they didn't cause on a bike that isn't theirs for nothing.

If you did that to me, I'd take you to court.
Reply
Save
Like
Sick Mick
fueler191 said:
more updates....and problems...

I am now thinking it has to be an ignition problem.

any ideas how to better check the ignitor unit without taking it in anywhere? while there is spark, the front cylinder under close watch seems to be a little weaker than the back....coils are good as they have been replaced so aside from the ignitor unit, or a frayed wire, which i couldnt find, what else could it be right? i find myself saying that a lot.....:mad:
Click to expand...
Did you remove the pilot jets and run a wire through all the holes? That's what that problem usually is. I've seen it many times.
Reply
Save
Like
F
i have not personally done that, but i was told by many the they way the guy cleaned my carbs out there is no way anything could be left (some form of pressurized system)

I am ordering a new CDI...well..semi new...and if that isnt it (the spark will clear a gap up to .250...nothing past that) and if it isnt that..............ill keep banging my head on the wall and try the carbs again
Reply
Save
Like
Sick Mick
fueler191 said:
i have not personally done that, but i was told by many the they way the guy cleaned my carbs out there is no way anything could be left (some form of pressurized system)

I am ordering a new CDI...well..semi new...and if that isnt it (the spark will clear a gap up to .250...nothing past that) and if it isnt that..............ill keep banging my head on the wall and try the carbs again
Click to expand...
If that doesn't solve the problem....clean the pilot jets.
Reply
Save
Like
M
I have the same problem

I have a 2000 yamaha vstar 650 that is doing the same exact thing.
It has sat for a number of years and would only idle with the choke pulled. I personally cleaned the carbs, boiled them, and inspected every detail about them.
It will now run without choke and get about 1/4 throttle. After that it bogs down.

I am at a complete loss. My problem sounds really similiar to yours. Hopefully we can get this sorted out soon.
Reply
Save
Like
M
Not trying to hijack
I removed the tank and fed the hose that went to it to a waterbottle filled with gas. No change. I also put my finger over the hose that feeds the carbs fuel. I can feel a little pressure from the fuel pump but not much. I'm not sure if it needs much pressure or if it just needs enough to fill the bowls. Im assuming the diaphragms in the carbs make the pressure it needs to pump fuel through its jets.
I then dripped fuel directly into the carbs with a squirt bottle while playing the throttle. It revs like a champ if I do that!
I disconnected the wire to the tps sensor and the bike barely runs if I do that.
Have you tried squiriting fuel directly into the carb mouths?
Mine seems like it is a fuel problem, but I dont see why it is happening.
Reply
Save
Like
M
http://www.4shared.com/office/Jrp_qoRp/Yamaha_VSTAR_650_MAIN_MAN.htm
is a link to the service manual for the 650
Reply
Save
Like
F
I have bypassed my fuel pump to make sure that was not the issue (as i blew out all the lines, but didnt want to blow out the pump and break it) so it goes directly from the filter to the carbs. As far spraying gas into the mouth of the carb, i have not done that yet, however i have done carb cleaner in the same fashion (when checking the boots for leaks) and it reved up, but if i keep it below 1/4 throttle it will rev up eventually too.... its too perfect that it cuts out at 1/4 for it to be a carb issue...but i've replaced every and anything electrical/ignition it could have been including the CDI.

must be some magical lump of gump in the carbs...im half debating buying a set off ebay and starting over...
Reply
Save
Like
SSC
They can't charge you for doing nothing if they can't figure it out its their issue I would have been all over the service mangers ass for that. Stupid question when your doing all that how do the plugs look are they wet? This is a trick I learned a long time ago to save spark plugs and prevent fuel going into the oil. Years of piecing holleys together people brought me in boxes. When I have a carb not acting right and im not quite sure it will fly I will hook the feed to a small fuel pump before I bolt the carb on and let the fuel bowls fill up this helps find any leaks be it a warped part or wrong part and will let you know if the floats are to high and if the needle and seat are working properly.

It does sound like a carb issue with 3000 miles I don't think it could have built up enough carbon to plug a feed hole beyond cleaning

Sent from my DROID2 GLOBAL using Motorcycle.com Free App
Reply
Save
Like
M
Got mine fixed!
After all that it was carb related!! It was the PMS SCREWS that I didnt remove because they were behind brass plugs. Check to see if your brass plugs are still intact. If they are than your carb guy missed something.
Besides that I read in another post that a bad regulator caused a bike to stop revving at 1/4 throttle. He connected a battery charger to his bike while it was running to boost the voltage to the CDI box. I tried the same thing as well as unplug the regulator and connect a 10A batt charger to the bike.
Grab a fire extinguisher and squirt some gas down the carb openings. If it revs than it may still be carb related.
Did you clean out the PMS screw holes, and check to see if they were turned out enough. Is your airbox connected?
Reply
Save
Like
1 - 20 of 34 Posts
Yamaha Starbike Forum
A forum community dedicated to Yamaha Star motorcycle owners and enthusiasts. Come join the discussion about performance, modifications, troubleshooting, maintenance, and more!
Full Forum Listing
Explore Our Forums
V Star General Bike Talk New Member Introductions Stratoliner & Roadliner Venture/Eluder
Top