How do I go about doing that? Is is like a carb sinc with the floating *****/vacuum gauge thingy?

 

Mine has started this little temper tantrum. I suspect bad gas ( being in the Ga gas crisis) has not helped the situation. I havent really fucked with it yet though. Pulls great on the street but idles like anus. Could be a bad ground, bad gas, vacuum leak, etc. The 636 pulls like a tank, if it doesnt then its not running right.

 

if it was the tps sensor it would also effect w.o.t so i doubt thats it.....check the vent lines also that the gas fill cap is vent properly.....next time it occurs stop the bike and open then tank.....there shouldnt be any hiss sound when you do..if there is the tanks not venting.....did you dent the tank yourself? the internal vent line might be pinched or clogged........also lift up the tank and rev the bike and listen for a snake like hiss which would mean a vac line is disconected also i would replace your plugs to start from a fresh plate so to speak also make sure the bike doesnt run any differnt with the tank up or down if it does you could be pinching a vent tube when you put the tank down

 

actually it is possible but very very very unlikley

 

Motionpro sells a sync tool (http://motionpro.com/motorcycle/tool..._trade___sup_/)
I had a cheaper version and basically followed the f4i manual. I was gonna do it on the 636 but never did. (For the 636 just follow the manual. The main thing is to get the baseline #1 locked. For 636 it could be different design.)
On the f4i, the throttle body air adjuster, Cyl #1 is locked. Adjust the air/vac inlet of #2, #3, & #4 to match #1. The f4i manual (or 636) tells you which four vac lines to unplug and attach to each individual hose (sync). The gold pieces in the pic join vac lines to hoes lines. With the airbox removed and crankcase vent blocked (per f4i manual) crank the bike over and let it idle. (bike should be already warm before doing this). The fluid (mercury or other) will bounce around in the sync tool cylinders. Turn throttle body air adjusters of 2,3, & 4 to match #1. When I did mine they were, at first a couple inches apart in height!!! Get them all to match in height(#1) and your throttle will be smoother/crisper reving.

Not having this done, I dont think, will give you serious bog, hesisitation. On my F4i it still had a serious bog with no idle. What fixed mine was a new fuel filter & fuel pressure regulator.
Wheres your fuel pressure regulator? If on rail/throttle body, nevermind.
replace Fuel filter?
Emission lines?
Fuel lines?

 

Mine is doing the same thing now. Not sure what it is. I havent really messed with it to find out. Tomorrow I will check the vacuum lines and swap the plugs and see what it does. Its driving me crazy! Idle takes forever to rev back up to where its set once you get on the brake. Its chugging!

 

that sounds like a vacuum line,bad plugs, or wide open/dirty injectors.

 

Thanks. I'll look into that.

 

Fixed? What did it end up being?

 

Im checking everything over today and swapping out my plugs. Ill see if that fixes anything and let everyone know. If not next on my list is a throttle body sync. Damn I hate this ****.

 

I was looking at my throttle bodies that I let skinny try out on his bike.
I can see the air adjuster screws. I think that doing that sync adjustment with the motion pro tool is a great idea and may fix the problem. I want that tool.

Another idea (skinny) why don't we take my t-body out of my lot thrasher 636
and put them in your bike. At least I know my motor runs perfect now and the idle pulls awesome. Then if it fixes your problem we will buy the tool.( I want to sink all my 636's anyways) If it don't fix it then we know you got other issues and we can keep trying things out.

 

Did synching the throttle bodies work?

 

I haven't touched the bike in over a month.

Anyone else who posted in this thread get theirs to work? I know greggy got his fixed with spark plugs and manually adjusting the air mix screws on the throttle body.

 

my f4i has 39xxx miles on it and was doin the same thing

-clean the throttle bodies and those little sucking holes that suck air on the top of the throttle bodies
and check all the vacum lines to be sure they are hooked up...
and the bike should be fine

 

I sync'ed the throttle bodies today and it still idles like crap

 

And you checked/changed for fuel pressure reg and fuel filter?

 

the only thing left is ignition timing. check the cam chain tension. get an APE tensioner and a new cam chain...and if your running any kind of power commander..get rid of that ****.

 

I am gonna see if I can get another fuel pump to try. other than that, there is no fuel filter, and the reg is built into the rail i believe. And i have already tried numerous throttle body assemblies.

There is no power commander. How do i check the timing on these things? Do I need a light?

How would the cam chain tension affect this?

 

if the cam chain is loose the timing will be affected.

 

yeah but he would have heard some ticking. I mean, f4i can have a bad cct and run fine. I think its more related to fuel.