What are the symptoms of a bad carburator sync?

Well, my question is pretty much all in the topic.

 

Bad sync results in rough running and really bad throttle response. When it is spot on the throttle feels light and crisp. Performance is also better of course.

Doing the job right takes a lot of time and generally starts with a full teardown on the carbs for a good cleaning. A good carb sync tool is made by Motion Pro
http://www.motionpro.com/

and they have the 90deg tool for adjusting the screws while the engine runs.
http://www.motionpro.com/motorcycle/tools/90_degree_1-4_hex_driver/
I invested in both to make mine purr.:biggrin:

 

lousy idle for starters, and as stated an all around not running very smooth, thou if you never felt the dif, would be hard to explain but the idle isn't hard to tell..

 

Thanks for the replies!
The thing is that I'm getting (verry slight) vibrations around 6000rpm when riding. I was just thinking is it normal for this bike, or should I be looking into it?

 

Same problem here

I hope someone knowledgeable answers your question re vibration at about 6K rpm. I have the same problem, and was about to try a throttle body sync (pay to have it done) as a last resort - '99 VFR

 

I have a carb syncer i have used a bunch. bikes for the most part take a LONG time toget out of sync.you could buy a syncer and do it urself for the cost of the joker at the dealer to half ass it.And u still have the syncer to do ur buddies bikes(for beer)

 

better yet, make a carb sync tool out of some aquarium tubing mounted with zip ties to a yardstick and filled with two stroke oil for fluid.

Use a long piece of tubing (20-30' or whatever you can get at the pet store) so you can hang it off the rafters, connect in order to the carb pairs (ie tune 1/3, 2/4, then 2/3 or whatever the manual says). You just need them to match between the respective two to get a perfect balance, rather than an absolute number. Just loop it around the bottom and connect one end to each carb....

Mine cost less than $5 and works like a charm. Tuned all my friends bikes for beer. Just keep in mind to fill it with something like 2 stroke oil b/c after the friends feed you a few beers and you pull one hose off with the bike running it will suck the oil out of the tube and into the motor. If you use two stroke oil no big deal, ask me how I know '

 

The 93 and the 99 are very different animals under the skin so the cause of this vibration at 6k on either bike may be different. Keeping the engine in tune (fuel mixture and sync) will be a bigger challenge on the 93 as carbs have more moving parts that can get gummed up etc. Modifications to the intake and exhaust could also induce vibrations due to changes in mixture and power delivery. This is a complex issue that I cannot (not that I'm an authority on anything) state will be improved with a sync of the throttle bodies or carbs although it will never hurt.

Suprisingly one of the mods that resulted in smoother handlebars (significantly) was the change from stock steering head bearings to tapered rollers! Why? Who knows, perhaps less slop in the steering head reduced the potential for vibration. The bike felt really different in every way, smoother, more composed at speed and at full lean. Best $30 I ever spent on e-bay! I got them from All Balls Racing if you want to check them out.

 

Now you got my attention Jethro, I have a slight vibration in the handlebars, My bike is perfect in every way except when I take my hands off the bars at 30 mph, then I get a slight shimmy. I've always thought this was bearing issue and just checked e-bay for those tapered rollers you speak of for my 99, if you ever see some, please PM me...

 

RW:

You don't have to wait for e-bay to have the tapered bearings. You can get them from the Dennis-Kirk Street cataloge. Or go to www.denniskirk.com. Same price as the ones on e-bay (or close to it).

BZ

 

Ivan:

Just out of curiousity...what's riding like in your country? Roads in good shape? Are there many people who ride motorcycles? Do you have a dealer in St. Petersburg?

BZ

 

can you post some photos please? :target: