WHOOOOAAA outta sync carbs - SV650.org

07-08-06, 07:18 PM

(I found the loose wire preventing my bike from starting, thanks everyone by the way)

So I am in the middle of the carb sync. And it my carb tool told me my carbs were way off, and that was what i expected. However they appear so far off that even with the butterfly adjust screw all the way in, they are still just a little bit off at idle. When i rev it up to 3000rpm the reader says the carbs are dead on. Is it bad that my screw is all the way in?

TSM · 07-08-06, 07:31 PM

Its possable that you have an air leak, check that the carbs are fitted correctly and that they are correctly secured.

07-08-06, 08:11 PM

You should always have the bike off idle when you try to synch. The dead closed position response varies from carb to carb. 2K to 3K RPM is a good synch point.

07-08-06, 08:15 PM

Quote:

Originally Posted by Torn-Thorax

(I found the loose wire preventing my bike from starting, thanks everyone by the way)

So I am in the middle of the carb sync. And it my carb tool told me my carbs were way off, and that was what i expected. However they appear so far off that even with the butterfly adjust screw all the way in, they are still just a little bit off at idle. When i rev it up to 3000rpm the reader says the carbs are dead on. Is it bad that my screw is all the way in?

As TSM said, check for leaks/seals. If this checks out then it might be worn valve seats that are causing the lack of vacuum at low RPM, try a compression test, or better still a ‘leak down’ test

Sid Squid · 07-08-06, 08:19 PM

When balancing run the engine at the slowest speed at which the gauges will give a stable reading, on an SV this shouldn't need to exceed 1800-2000rpm, but of course depends on your gauges as well, the slower you balance the more accurate it will be.
There is no benefit whatsoever in the fallacy that you should balance at some sort of running speed, the throttle position at, say 5000 rpm, on the stand is enormously different from that at which it will be under even the smallest load when riding.

07-08-06, 08:39 PM

I had this problem when i synced mine, i traced it to the bar that moves the rear carb butterfly via the front (its on the left of the carb)

There was some play in the brass washers which made syncing a nightmare, i replaced the bar, butterflys and the bit where the cables attach and no probs again (til next time

)

07-08-06, 10:09 PM

What is the drip leak test?

08-08-06, 02:07 AM

OK. I checked all around the carbs for loose, wrotting, or otherwise leaky tubes. I also checked for any loose parts on the carburetor. The bike seems to run much better now, it doesnt stall out at low RPMs. I just am still a bit concerned about the butterfly screw being all the way in

07-08-06, 07:18 PM	#1
Torn-Thorax Guest Posts: n/a	WHOOOOAAA outta sync carbs (I found the loose wire preventing my bike from starting, thanks everyone by the way) So I am in the middle of the carb sync. And it my carb tool told me my carbs were way off, and that was what i expected. However they appear so far off that even with the butterfly adjust screw all the way in, they are still just a little bit off at idle. When i rev it up to 3000rpm the reader says the carbs are dead on. Is it bad that my screw is all the way in?

07-08-06, 07:31 PM	#2
TSM The Sick Man Mega Poster Join Date: Nov 2004 Location: Peckham.SE.LDN Posts: 4,768	Its possable that you have an air leak, check that the carbs are fitted correctly and that they are correctly secured. __________________ OTR: KTM 690 Duke R 2015 Full Akro SIDELINE: Kwak ZX636 A1P 2002, Red, R&G's, Yoshi, Double Bubble Screen GONE: Kwak ZX-7R P1, Full Akro, Undertray, Screen GONE: SV650S K2 Very Bruised & Without Fairing, Motovation Frame Sliders, R&G Ally Sprocket Toe Protector, HEL 2 Line Setup, GSXR K1 600 RWU Forks, Barnett Clutch & Springs, Penske 8981 Shock, Gilles Ti Rearsets, Steel Barends, Scottoiler, AFAM Chain & Sprockets, Twin FIAMM Horns, Skidmarx Bellypan, Full Micron Zeta Steel System, Cut down undertay. Forum Problems & Information / Site Suggestions

07-08-06, 08:11 PM	#3
andyauger Guest Posts: n/a	Always synch off idle You should always have the bike off idle when you try to synch. The dead closed position response varies from carb to carb. 2K to 3K RPM is a good synch point.

07-08-06, 08:19 PM	#5
Sid Squid No, I don't lend tools. Mega Poster Join Date: Jul 2003 Location: Skunk Works, Nth London Posts: 8,680	When balancing run the engine at the slowest speed at which the gauges will give a stable reading, on an SV this shouldn't need to exceed 1800-2000rpm, but of course depends on your gauges as well, the slower you balance the more accurate it will be. There is no benefit whatsoever in the fallacy that you should balance at some sort of running speed, the throttle position at, say 5000 rpm, on the stand is enormously different from that at which it will be under even the smallest load when riding. __________________ If an SV650 has a flat tyre in the forest and no-one is there to blow it up, how long will it be 'til someone posts that the reg/rec is duff and the world will end unless a CBR unit is fitted? A little bit of knowledge = a dangerous thing. "a deathless anthem of nuclear-strength romantic angst"

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07-08-06, 08:39 PM	#6
svrash Guest Posts: n/a	I had this problem when i synced mine, i traced it to the bar that moves the rear carb butterfly via the front (its on the left of the carb) There was some play in the brass washers which made syncing a nightmare, i replaced the bar, butterflys and the bit where the cables attach and no probs again (til next time )

07-08-06, 10:09 PM	#7
Torn-Thorax Guest Posts: n/a	What is the drip leak test?

08-08-06, 02:07 AM	#8
Torn-Thorax Guest Posts: n/a	OK. I checked all around the carbs for loose, wrotting, or otherwise leaky tubes. I also checked for any loose parts on the carburetor. The bike seems to run much better now, it doesnt stall out at low RPMs. I just am still a bit concerned about the butterfly screw being all the way in