Carb Sync Idle?

[ken]

I've got a set of vacume gauges ordered to sync the carbs on my RSV. All the help threats say to set the idle at 1000rpm. How is this done without a tach?

[SilvrT]

I've got a set of vacume gauges ordered to sync the carbs on my RSV. All the help threats say to set the idle at 1000rpm. How is this done without a tach?

 

I take a wild guess. Normal idle is what... 6-700? So I just crank it up some.

 

I think the idea is that you need a bit higher rpm to get a decent vacuum reading and also to prevent stalling whilst you're mucking with the sync.

 

(works for me) but then again, maybe I should use a tach.

[MiCarl]

1000 is normal RPM. Sync is done at normal idle speed.

 

As you sync it the idle may change and you'll have to adjust it up/down to keep it at the proper speed.

 

Ideally you attach a tachometer, but you can do it by "ear" too.

[Freebird]

I agree...I actually keep my idle at around 900 and I have a tach on mine but it's really not a big deal that the carbs be synced right at 1000. Before I got the tach, I just cranked up the idle till I could just hear it come up a bit and figured that was good enough.

[N3FOL]

I did a search for you and found this website that has the exact type of tachometer I am using everytime I carbtune. On my bike, my idle is set at apx. 1000 rpm everytime I synch my carbs. http://www.ntxtools.com/network-tool-warehouse/ESI-325-p-ESI.html

[kyle]

As far as the 1000 rpm idle thing goes i have done this with same results, synced at 1000 rpm idles smooth runs smooth , synced at 2500 rpm runs a tad smoother on the hiway . trying it at a higher rpm where the engine is running seems to make it run better. IMHO i still get about 40 mpg a gal. but it runs so smooth.

[jer878]

I did a search for you and found this website that has the exact type of tachometer I am using every time I carbtune. On my bike, my idle is set at apx. 1000 rpm every time I synch my carbs. http://www.ntxtools.com/network-tool-warehouse/ESI-325-p-ESI.html

 

I have this tach also. It's a tight fit to clip on the plug wire. I'd like to have one with the pick up separate from the meter. I haven't found one yet. Kinda stopped looking after getting the 325.

If anyone has other tach suggestions I'd be glad to listen.

[N3FOL]

I have this tach also. It's a tight fit to clip on the plug wire. I'd like to have one with the pick up separate from the meter. I haven't found one yet. Kinda stopped looking after getting the 325.

If anyone has other tach suggestions I'd be glad to listen.

 

In order for me to reach a plug wire, I simply remove the seat and clamp it to the right rear cylinder - I think that is plug wire #3. The tach is very easy, IMO.

[Seaking]

I installed a Drag Specialties Mini Tach on mine.. I synch my carbs often enough it makes it easier.. Unfortunately, I just to replace mine with a spare I had because the guts dropped out of the tach.. so odd.. A call to Drag Specialties about warranty replacement indicates that I can only get an RMA through the shop I purchased it from..

 

My memory isn't that good.. erk!

 

I originally had a black faced one to match my Midnight RSV but you really couldn't see the tach needle at night. the back lighting didn't make it stand out.. but the spare one I installed is white faced and isn't glaring in your face bright, just the right amount.

 

Idle set at 1,000 rpm..

[uechi kid]

I bought this tach for tuneup purposes. It works good for carb sync.

 

http://www.ntxtools.com/network-tool-warehouse/ESI-328-p-ESI05.html

[BigBoyinMS]

As far as the 1000 rpm idle thing goes i have done this with same results, synced at 1000 rpm idles smooth runs smooth , synced at 2500 rpm runs a tad smoother on the hiway . trying it at a higher rpm where the engine is running seems to make it run better. IMHO i still get about 40 mpg a gal. but it runs so smooth.

 

The last time I sync'ed mine I did it at 2500 rpm and it seemed to run much smoother. Then again it could have just been out and the sync just smoothed it up some. But I sure don't remember that big of a difference when I did it at 1000 rpm last time.

[N3FOL]

Same here...after reading a thread about synching at different rpm, I couldn't really tell the difference. So from now on, I've just been synchronizing my bike at idle. That reminds me, it wouldn't really hurt if I synched my carbs again. The last time was last summer.

[Seaking]

When you make your adjustments on the screws, do you notice a change in rpm or sound if you happen to push too hard against the screws with the screw driver? It doesn't take a lot of pressure..

 

Next time you synch your carbs, just press a little against the adjustment screws.. I often wondered how much that affects the overall synch process and perhaps that's why some of the shops have such a hard time synch'ing up these bikes..

[Marcarl]

IMHO it doesn't matter so much what the exact RPMs are, so long as it's somewhere around the 1000 mark, so 900 to 1200 or so. If it's too high it's get harder to get an honest reading and too low it fluctuates too much. The important thing to keep in mind is that at the end all cylinders read the same, at the somewhere near the 1000 rpm mark. Morgan Carb Tune makes this easy.

[N3FOL]

...and the best time to synch your carbs is after a nice ride when the engine is up to temperature.