Snap test

[Dr.n2o]

Looking for some input guys. I just rebuilt my carbs and cleaned everything down to the jet blocks. I put them back on and did not move any screws regarding sync during rebuild so they would hopefully stay close. Float levels are good, 2 1/2 turns out on a/f screws, new manifold boots and carb boots. I have a stage 7 w/ no vboost just so you guys understand my setup. Problem is when I snap the throttle open to @ 5000rpm and let off, it takes a little while longer for the r's to come down than it used to. Kinda like it's hangin up just a little longer than it used to. Also some food for thought- When I re synced them after rebuild, I had the guages on it and I cranked all the sync screws ahead about 2 turns matching all the banks and i'm wondering if when the throttle snaps shut that there might be a little too much throttle plate vacuum(being that I turned them all forward a bit) That could be "hanging" up the idle. ------Sorry for re writing the "Illiad" here but That's where I'm at guys. Any input from past experience appreciated :ummm:

 

[MaxMidnight]

If you have no V Boost (open boost tubes?) how can you synch the carbs?
I would have though that the vacuum gauges would read the same for the pair of cylinders on each side (i.e. the average of the vacuum)

Wouldn't you need to blank off the V Boost tube so that you had a reading for each carb?.....or am I being a bit thick here?

 

[Dr.n2o]

If you have no V Boost (open boost tubes?) how can you synch the carbs?
I would have though that the vacuum gauges would read the same for the pair of cylinders on each side (i.e. the average of the vacuum)

Wouldn't you need to blank off the V Boost tube so that you had a reading for each carb?.....or am I being a bit thick here?

I guess you would be correct sir. I'm going to back the sync screws off equally today and see if that does anything. I will also start seacrching for the Weber sync tool seeing as how that's the only way it seems.

 

[one2dmax]

You should be able to hear the throttle snap shut when you blip it (and bike is off). Make sure it's not binding. Then check for vacuum leaks (WD40 sprayed around parts works well).

 

[Dr.n2o]

I appreciate the help guys. All the stops are clicking shut but I notice that if I just tickle the throttle open(bike off) that the left bank begins to open just a very little bit before the right bank. I'll try and loosen the idle thumb screw and back them out (sync) and try to even everything up. Best I can do till the Weber sync tool gets here. Can't do it till my 2 year old wakes up from his nap :biglaugh:.....I'll try the ol' backyard temporary sync for now. The annoying thing is that it's not far off just so friggin tedious

 

[shicks16]

Once you get the sync tool you won't know how you did without it, one of the best tools I've purchased for the bike, it's paid for itself 10 time over by now!

 

[Dr.n2o]

Once you get the sync tool you won't know how you did without it, one of the best tools I've purchased for the bike, it's paid for itself 10 time over by now!

Does the Weber tool hook directly to the carb opening or do I have to fab up some velocity stacks ?

 

[Redbone]

Does the Weber tool hook directly to the carb opening or do I have to fab up some velocity stacks ?

Check with Rovic (Tugla), when I watched him use his he pressed it onto the carb body (individual filters removed of course) to get the readings.

 

[Rusty McNeil]

If you mean rpm is hanging up, and then slwoly returning to set point, and you're sure it's not a mechanical hangup in the plates or throttles, then that is usually indicative of a lean idle circuit.

I run no vboost either, but left the butterflies in place and the short cable with a throttle stop screw (like a go cart or lawnmower cable pincher thingie) so it can be left open, or closed for synching...

 

[Dr.n2o]

If you mean rpm is hanging up, and then slwoly returning to set point, and you're sure it's not a mechanical hangup in the plates or throttles, then that is usually indicative of a lean idle circuit.

I run no vboost either, but left the butterflies in place and the short cable with a throttle stop screw (like a go cart or lawnmower cable pincher thingie) so it can be left open, or closed for synching...

Yeah Rusty, I've been kinda playin it by ear a little this afternoon and I have to wait for the weber sync tool to come in the mail. I'm pissing in the wind right now. The idle is at 1800rpm and it's not even on the thumb screw. I'm just guessing the throttle plates are cranked to far open by the sync screws. Just did an awesome carb rebuild and the funny thing is it was running "JUST FINE" before I went through em'. Something is way off and I had to step away from it :bang head:. I think i'm gonna go have a cold beer now.

 

[99 MAX]

A slight hijack here, would you mind sending me a link on your weber tool please, I have to know what I've got going on with mine as well, Thanks.

 

[Dr.n2o]

A slight hijack here, would you mind sending me a link on your weber tool please, I have to know what I've got going on with mine as well, Thanks.

http://www.ebay.com/itm/140784622741?hlp=false#ht_3746wt_1118

 

[dannymax]

Looking for some input guys. I just rebuilt my carbs and cleaned everything down to the jet blocks. I put them back on and did not move any screws regarding sync during rebuild so they would hopefully stay close. Float levels are good, 2 1/2 turns out on a/f screws, new manifold boots and carb boots. I have a stage 7 w/ no vboost just so you guys understand my setup. Problem is when I snap the throttle open to @ 5000rpm and let off, it takes a little while longer for the r's to come down than it used to. Kinda like it's hangin up just a little longer than it used to. Also some food for thought- When I re synced them after rebuild, I had the guages on it and I cranked all the sync screws ahead about 2 turns matching all the banks and i'm wondering if when the throttle snaps shut that there might be a little too much throttle plate vacuum(being that I turned them all forward a bit) That could be "hanging" up the idle. ------Sorry for re writing the "Illiad" here but That's where I'm at guys. Any input from past experience appreciated :ummm:

Did you clean everything down to but not including the jet blocks? Or were they removed, dismantled and cleaned also? :ummm:

 

[johnpclynch]

Yeah Rusty, I've been kinda playin it by ear a little this afternoon and I have to wait for the weber sync tool to come in the mail. I'm pissing in the wind right now. The idle is at 1800rpm and it's not even on the thumb screw. I'm just guessing the throttle plates are cranked to far open by the sync screws. Just did an awesome carb rebuild and the funny thing is it was running "JUST FINE" before I went through em'. Something is way off and I had to step away from it :bang head:. I think i'm gonna go have a cold beer now.

Sounds like some of the plates are hanging open OR there's air getting in somewhere between the carb and the head (check the carbs are seated fully & vaccum ports at the head are capped)

Try idling the engine (at 1800 :biglaugh and block each carb with your hand, when the idle drops most you know you've found the culprit

 

[Dr.n2o]

Did you clean everything down to but not including the jet blocks? Or were they removed, dismantled and cleaned also? :ummm:

Did the jet blocks too Danny. New manifold and carb boots. Checked it with propane to see if idle would raise....nothing. Gonna recheck the push/pull setup and wait for the Weber.....this sucks

 

[Dr.n2o]

Sounds like some of the plates are hanging open OR there's air getting in somewhere between the carb and the head (check the carbs are seated fully & vaccum ports at the head are capped)

Try idling the engine (at 1800 :biglaugh and block each carb with your hand, when the idle drops most you know you've found the culprit

Brand new vacuum caps...All I need to do is get this situation worked out. Just did the Gannon C O P mod to and throttle response is unreal. Can't wait to ride it...:bang head:.....I appreciate all the help fellas....tryin to get this ironed out

 

[Dr.n2o]

Small update. I was just eyeing around the sync screws trying to find a visible problem before the weber gets here and my left sync screw is in about 1/4 of the way the right side for 3&4 and left and right bank sync are cranked in about 1/2. I would imagine they should be relatively close :confused2:. I guess I just didn't realize how far apart they were after I reassembled the banks and refit the springs. total brain fart. I can't fix this thing fast enough. Such a great running bike when she's healthy.

 

[dannymax]

Small update. I was just eyeing around the sync screws trying to find a visible problem before the weber gets here and my left sync screw is in about 1/4 of the way the right side for 3&4 and left and right bank sync are cranked in about 1/2. I would imagine they should be relatively close :confused2:. I guess I just didn't realize how far apart they were after I reassembled the banks and refit the springs. total brain fart. I can't fix this thing fast enough. Such a great running bike when she's healthy.

It doesn't matter where the screws are in relation to each other, they can be all over the place as long as the throttle plate openings are the same. The Weber readings will tell you if some plates are opened more or less than the others.

 

[tugla]

what you can do in the interim is take the carb rack off and sync by eye held up to a light. i always do this when have the carbs off and it gets it just about right. just have to be anal about it and take your time. should help you get it somewhat close to running better, 1800 is way out as you know........unless you start from a dead stop into a nice john force burnout :biglaugh:

 

[Dr.n2o]

Well the weber just got here :clapping:...What do you guys get for Hg readings on you're bikes ? Or should they all just be relatively equal...Tryin to research a spec here.....