Throttle Sticks Until Shifting to a Different Gear

[Guest]

Hello,

I think I've got my bike almost together. I was happily riding around yesterday, and suddenly I noticed when I let go of the throttle, it continued to rev/accelerate at the rpms I left it at. In a moment of confusion, I shifted down, and the rpms dropped.

The weird part about this is that it felt like the throttle returned. I'm going to open it back up tomorrow, but I was just wondering if anyone has any suggestions or insight. Recent things I've done to it is completely torn down and cleaned the carbs, bench synced, checked point gaps, valve clearance, changed shims, oil. It currently backfires a bit on acceleration. Thanks in advance.

[tatu]

Are the carb-head boots/rubbers all good?

[tom203]

Are the carb-head boots/rubbers all good?

Yes, sounds like some sort of air leak here- new o-rings at boot/cylinder interface??

[giganticflying]

I did install new o-rings on the cylinder boots. The rubber is still flexible.

[Steve]

Both throttle cables connected to the carbs?

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[giganticflying]

No, it appears there is only one. I've seen on diagrams where there should be another but when I asked a shop in town they said that since there is a return spring it wasn't necessary.

[JTGS850GL]

Stop listening to that shop. The VM carbs had a two cable system for a reason.

[giganticflying]

Time to go cable shopping then. Thanks

[Steve]

Time to go cable shopping then. Thanks

That part is easy.

Apparently, they are the same cable, so get two of #8, for about $20 each.

How is your clutch cable? It's item #7, and is just under $28.

When you get to the checkout page, enter the word "BANG" in the promo box, you will get free shipping.

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[giganticflying]

Rad! Thanks Steve.

[giganticflying]

Wait, quick question: do you think there is a huge quality difference between those on partsoutlaw.com to the cables sold on ebay/d2moto.com for half the price. It says they're made by Volar.

[Brendan W]

Double check the clutch cable routing. On my bike if it isn't secured forward by a clip as it drops down between the intake boots it will prevent the throttle closing fully.

[Steve]

Wait, quick question: do you think there is a huge quality difference between those on partsoutlaw.com to the cables sold on ebay/d2moto.com for half the price. It says they're made by Volar.

Not acquainted with Volar, but most people agree that any new cable is going to work well, the question is how long.

All cables have a plastic inner liner that guides the cable and reduces friction. Many (most?) of the aftermarket cables use a softer plastic that does not last as long. When the plastic wears, the cable will cut a groove. Those grooves form on the inside of a curve, which means that the cable will take a slightly shorter path, giving the illusion that it has "stretched". Yes, an OEM cable costs more, but it usually lasts longer. The cost per mile might average out the same, but you will spend more time changing cables with the cheaper ones.

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