Carb Gremlins? - SV650.org

Sir Zuki · 25-03-26, 08:25 PM

Noswaith dda fellow bikers,

Ever since i got my SV the throttle response wasn't great. Off-idle the engine stumbled and popped. On the highway it always felt a little "tame".
Given the Dynojet sticker on the airbox i figured there could be some adjustment error....

Carbs removed, easy.
What i found was surprising: there was play in the link system between the carbs. This caused the rear throttle valve to lag (is that the right word?) the parts that make up the sync-adjustment on the rear carb didn't fit well on the throttle valve shaft. It took a small file to remove burrs and make it fit. Strange... This solved the excessive play in the linkage.

Pilot screws were 2 1/4 turn (front) and 2,5 turn (rear) out in stead of the 3 turn required by the Dynojet manual. Main and pilot jets were ok. The jet needle was too low, 2nd clip, not 3rd. hmmmm.......

carbs reinstalled & synced. Cold start is eeeeaaaaasy. Idle is steady. Off-idle problems are gone (wheelie alert!) and full throttle @ 100 kph is great fun.

Lesson learned: Don't trust a cheap 2nd hand bike. Now, whats next ?

Sir Trev · 25-03-26, 09:03 PM

Did you balance the carbs as well? That always made my Curvy run much better.

garynortheast · 25-03-26, 09:14 PM

Yes, carb balance makes a big difference to performance, vibrations, and mechanical noise.

25-03-26, 08:25 PM	#1
Sir Zuki Junior Member Join Date: Jan 2026 Posts: 17	Carb Gremlins? Noswaith dda fellow bikers, Ever since i got my SV the throttle response wasn't great. Off-idle the engine stumbled and popped. On the highway it always felt a little "tame". Given the Dynojet sticker on the airbox i figured there could be some adjustment error.... Carbs removed, easy. What i found was surprising: there was play in the link system between the carbs. This caused the rear throttle valve to lag (is that the right word?) the parts that make up the sync-adjustment on the rear carb didn't fit well on the throttle valve shaft. It took a small file to remove burrs and make it fit. Strange... This solved the excessive play in the linkage. Pilot screws were 2 1/4 turn (front) and 2,5 turn (rear) out in stead of the 3 turn required by the Dynojet manual. Main and pilot jets were ok. The jet needle was too low, 2nd clip, not 3rd. hmmmm....... carbs reinstalled & synced. Cold start is eeeeaaaaasy. Idle is steady. Off-idle problems are gone (wheelie alert!) and full throttle @ 100 kph is great fun. Lesson learned: Don't trust a cheap 2nd hand bike. Now, whats next ? __________________ '01 SV650S Ride, Wrench, Repeat

25-03-26, 09:03 PM	#2
Sir Trev Member Mega Poster Join Date: Jun 2005 Location: High Wycombe, where the chair factories used to be Posts: 1,505	Re: Carb Gremlins? Did you balance the carbs as well? That always made my Curvy run much better. __________________ We are the Goon Squad and we're coming to town, BEEP BEEP!

25-03-26, 09:14 PM	#3
garynortheast Member Mega Poster Join Date: Mar 2010 Location: Mid Wales Posts: 2,802	Re: Carb Gremlins? Yes, carb balance makes a big difference to performance, vibrations, and mechanical noise. __________________ https://teulu.bandcamp.com/releases Blue Curvy S with over 113,000 miles and still going strong.

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