[pkbone99]

have a 07 650 v-star custom 17676 on the clock mostly hiway miles. This thing starts good hot or cold and runs great.......for about ten minutes then as you continue usually about 65 it dies pack to 1/4 power.....sometimes it will even die completely ....crank it back up no prob....1/4 power till the bike completely cools then same again.. I have changed the fuel/ filter/coils/cdi box/ fuelpump/had the tps checked/went thru carbs/checked timing three times (valve timing) bypassed the ais.......hellllpp!!!!!!! any ideas ANY IDEAS profuse thanks will b in order.

 

[ddrumman2004]

Knowing that you have changed the fuel filter and fuel pump.....have you checked to see that the fuel tank itself is venting?
I'm at a loss here but it still sounds like a fuel delivery problem to me.

 

[Sugar Bear]

May be off base here, but it really does sound like a fuel starvation problem, with all you have already done, sure don't sound like much fun right now. The venting would be a good place to ckeck.

 

[pkbone99]

thanks

have visited that situation but as i am desparate i will open the gas cap and ride in the morrow hey! thanks for the ideas

 

[DMTJOY]

another thing you might look at if not fuel starvation is a partially/fully plugged exhaust. this can also present the same type of problem.
good luck.
Doug

 

[pkbone99]

well dangnabit!

stuff a piece of airfilter foam in the tank neck and went for a ride .......same situation bike runs great everything just wonderful than bang yah know it almost feels like a rev limiter but it doesn't know when to quit.....any more ideas pretty please?

 

[DMTJOY]

It could very well be the rev limiters. They (one per carb) shut off fuel 1000 rpm before redling, about 5600. Try disconnecting the wires to them and go for a ride. You will get a check engine light but they will not work. I bought a kit form Maxair that eliminated the rev limiters.
Good luck
Doug

 

[pkbone99]

finally ...........

i think you may have hit upon it ......thats exactly what it feels like. i will take the wires loose and let you know ........oh by the way .......is it going to beer/kisses/hugs/money or what????????? thanks will get back to yah

 

[DMTJOY]

I just did some checking on the Maxair site. It appears that the 650 does not have the fuel shut off solenoids. sorry about that. Do you still have the stock exhaust? I am thinking still it might be plugged exhaust. If so try taking off the mufflers and see what happens. They slide right off. It will be loud but the bike will not suffer any harm for the short time you will be runnig it. Try calling Maxair at 303-362-1336. Another possibility is the AIS could be faulty causing the same symptoms.
hope this helps
Doug

 

[ddrumman2004]

Take the AIS out of the picture by disabling it. A marble in each rubber hose where they connect to the chrome steel lines will shut them off. A couple of golf tees in the vacuum lines from the carbs plus a larger marble in the larger hose on the AIS canister itself.
Stops the popping on deceleration and makes no difference in the way the bike runs. Mine is disabled on my 06 Classic.

 

[pkbone99]

believe it or not!!!!!

believe it or not we are still working on this bike after 6 months.... we have replaced everything on it or tested per the factorys ideas....The bike is a 07 650 v-star custom one owner....the good news is we have isolated it to the TPS sensor ( tho it is in spec's) or the carb start solenoids......the question here is does anyone have a used or aftermarket TPS. they are very very expensive from the dealers and/or does anyone know how to repair/modify the tps circuit????? yamaha seems to be at a loss on this particular bike....but I know this is going to crop up as these bikes age. any help would be greatly appreciated

 

[Sugar Bear]

With all you have been through, Sugar Bear would have had his nails chewed down to the second knuckle and beatin his head against the wall. For what it's worth, a dealer told me the tps is not repairable, a replacement item only, I do not know,(they ARE in the business of sellin stuff and makin money,) just passing along what I can, really hope you getter back to where it is supposed to be! Let us know when and how you get it all back to good. GOOD LUCK...

 

[linerdave]

Throttle position sensor TPS

Checking the TPS.
Tried to paste it here won't work. the book says to remove the TPS. With an Ohm meter pluss terminal on the black lead and negative lead on the blue terminal. The TPS should rea between 4 thousand and 6 thousand Ohms. At room temperature. To adjust, The resistance when throttle is closed should be between 13% to 15% of the full scale reading between the yellow and black terminals. (Example if fullscale was 5k the throttle closed should be 650 Ohms to 750 Ohms.)

I would think if it passes this test then it is OK. I think it is nothing but a variable resistor.

Dave

 

[DMTJOY]

Try taking an OHM meter reading on the TPS and heat it up slowly to maybe around 200deg see if this makes any differance in the readings. you could possibly do the same thing with the carb solenoids.
Good luck
Doug

 

[low budget performance]

My 650 did somewhat the same thing. This may be a shot in the dark, but it did help my bike. I ran some Seafoam thru the fuel tank and then pulled the petcock off and there was some junk in the petcock filter screen. Basically my bike was not getting enough fuel. Like I said, this is just a suggestion. Its a quick check to do and inexpensive. Last idea, have you syncronized your carbs?

 

[pkbone99]

ok guys here goes........ finally fixed this damn 650 v-star hahahahhahah funny the way they get ...... anyway we replaced every electronic component on it (that stuff is outrageously expensive) it always had the same symptoms run fine start fine till you got out on the highway and held it to a highway speed then it would die back as if the rev limiters were stuck on........ when she cooled off everything was fine. So we finally found a matching bike and stole the carbs and tps. the bike ran fine. Soooooooooo we dissassembled the carbs and inside the column of the front carb main jet was a round ball like piece of plastic....maybe 1/2 the size of a pin head. evidently it would drop to the end of the jet and would not cause a problem but under heavy acceleration or prolong running it would suck up into the main jet orfice.......It would stay there till the bike cooled and the pressure released it........maybe a joke from the factory??????maybe just a casting piece off the plastic filter who knows ahhhhhhhhh such is mechanicing.

 

[pkbone99]

Ps Thanks You Guys!!!!!!! Yah Kept Me Going With The Ideas And Such....can't Say How Much We Appreciate It

 

[Sugar Bear]

Thanks for the update, it's been a long hard road for you, Sugar Bear is happy for you! I guess the old saying"little things mean a lot"really holds true in this case!

 

[DMTJOY]

Glad to here it is fixed. Wow it sure sounded electrical.
Ride safe
Doug

 

[TZ750]

Ventilation

Check the carburetor float bowl atmospheric vent hoses for pinching, bends, obstructions, etc...

Fuel will not flow or will flow slowly if the carb bowl vents are not breathing properly.