1993 vfr 750 carbs.??

motocrossscott62 · 07-20-2008, 09:39 AM

Are the carb. vacuum pistons supposed to all open when the bike is reved through the rpm range???? #4 carb. vacuum piston is the only one opening up. This 1993 vfr 750 hasn't run strong since it was put back together after 12 years of down time.It doesn't miss,skip or run rough,just week throgh the rpm range. It has a Two Bros.full exhaust,K&N air and dyno jet kit.Plugs look nice light brown. Please!!! Any Help Would Be Greatly Appreciated!!!!!! Scott M.

Sye · 07-20-2008, 10:59 AM

Do they move freely using slight finger pressure?

If not then you have grit in the slides. If they do, then you have two possible solutions.

1) The diaphragms are holed or split.
2) The sub filter is clogged and stopping the passage of air as the slides are pushed up.

HTH and good luck.

ChatBox (No new messages since your last visit)
Loading...
Message...
Ask your questions in the forums. The ChatBox is for small talk. Lamps to everyone!

07-20-2008, 09:39 AM	#1 (permalink)
motocrossscott62 Junior Member Join Date: Oct 2007 Last Online: 08-09-2008 09:23 PM Location: Northern Florida My Ride: 2007 YZ 250 2006 YZF 450 1993 VFR750F Posts: 12 Thanks: 0 Thanked 0 Times in 0 Posts	1993 vfr 750 carbs.?? Are the carb. vacuum pistons supposed to all open when the bike is reved through the rpm range???? #4 carb. vacuum piston is the only one opening up. This 1993 vfr 750 hasn't run strong since it was put back together after 12 years of down time.It doesn't miss,skip or run rough,just week throgh the rpm range. It has a Two Bros.full exhaust,K&N air and dyno jet kit.Plugs look nice light brown. Please!!! Any Help Would Be Greatly Appreciated!!!!!! Scott M.

07-20-2008, 10:59 AM	#2 (permalink)
Sye Member Join Date: May 2008 Last Online: Today 12:20 PM Location: Wirral UK My Ride: 1986 750FG 1991 750FL 1997 750FV Posts: 51 Thanks: 0 Thanked 5 Times in 5 Posts	Do they move freely using slight finger pressure? If not then you have grit in the slides. If they do, then you have two possible solutions. 1) The diaphragms are holed or split. 2) The sub filter is clogged and stopping the passage of air as the slides are pushed up. HTH and good luck. __________________ www.tom-yehya-racing.co.uk

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Re: vfr Digest, Vol 52, Issue 13	Steve	VF/VFR Mailing List	0	07-18-2008 03:17 PM
1993 VFR 750 week on power	motocrossscott62	Mechanics Garage	5	06-23-2008 06:53 PM
RE: vfr Digest, Vol 43, Issue 8	Andrew Bertsch	VF/VFR Mailing List	1	10-04-2007 04:05 PM
For Sale 1993 VFR	Gabriel Ronk	VF/VFR Mailing List	3	04-24-2007 07:13 PM
No Subject	Jeff	VF/VFR Mailing List	0	08-09-2006 05:14 PM