Advanced Idle Timing?

[burgurboy]

I thought i remember reading somewhere that the idle timing can be advanced to help smooth out idle & help cure the "throttle blip cough"

What do you guys think about this? I can't seem to source the documentation where i read that at...


I wanna say the rear cyl timing was advanced to 9 deg and the front cyl was advanced to 6 deg.

I played with it earlier but, i don't like seeming with timing... i don't want to leave anything permanent.

any thoughts?

 

[burgurboy]

bump... somebody must know something about manually setting up the idle timing

 

[wolfo68]

never heard of it, sorry

 

[uly luigi]

Static timing has been discussed before, thats's the mechanical side, but all of the spark timing is done thru the ECM, I have seen a lot of people with a lot more experience than me say "Unless you have a dyno, and a lot of experience with advanced timing tuning, you will grenade your motor very quickly", I trust the engineers at EBR to set up my timing

 

[newyorkbuell]

Iv done this, for me made no difference but my bike always has the cough. I relate mine to the open airbox that I want to get rid of.

 

[burgurboy]

hmmm.... so, you don't like your open air box? I was thinking about doing the mod soon. What all don't you like about it?

 

[uly luigi]

The biggest complaint I've heard is the noise, and not a good grumbly growl noise, just a rather aggravating mechanical noise, doesn't really improve the performance an appreciable amount

 

[newyorkbuell]

Exactly what is stated above, I had a jardine muffler that was so loud I never knew the airbox was that loud. When I went to my Buell race pipe the airbox noise became very annoying quickly. I'm still running it currently and the reason I relate the cough to it is due to 2 years ago when I hacked my stock box apart I did not to a good job and the top doesn't seal 100% to the air filter. So there is some ruff running and popping for me at low speed. I'm going to fix it this winter with a 07 + airbox with a little modding.

 

[jimijeans]

The throttle body has an Velocity Stack mounted on the top for better performance plus the sound is loud! yes the noise is much greater when opened up. The throttle BLIP as I guess it's called has to be tuned through the ECM. A preprogrammed unit such as the ECM needs to be individually tuned for each bikes Engine, As far as the Timing you might want to keep it close to stock for A Stock Engine due to tolerance levels on machined parts. Timing on Any Standard Vechicle unless you are Racing on a track needs to be set for best starting and riding Also Dependability along with fuel . That being said The cough is not going away on a Stock ECM completely. You can lessen the cough with some tuning on the preprogramed ECMs. If thats not your thing then there are other options. Such as sending off the unit to be done for you and so on. You can Blip the Throttle with no changes to Bike at all if you learn to do it right. I only do it [slightly] sometimes on downshifting really just for the effect with the Drummer SS sound . It does at times get some of the foreign bike riders looking and asking Questions here and there. You can get Octopus to give you some tuning lessions if you like and this will help you get the bike to where you need it. Check on that before you change the timing . This way you are more informed and able to decide if thats the best for your Engine. Good Luck. *Jimi[confused]

 

[burgurboy]

Thanks for the tips!

I've done quite a bit of tweaking under the "other maps" tab. I've bumped the accel enrichment and things like that (as per xopti mike's instructions) but, still cant escape the "blip cough".

I see people all the time on the forums saying "it's a big air cooled v-twin, you just cant blip the throttle or it will choke on itself"... I've gotta call bs. I rode my buddy's 1100 V-star this weekend and I purposely tried to get it to "cough" when blipping the throttle. no dice. It revved perfectly.

A guy at my church rides a big 90ci harley. my buell was idling in the parking lot the other day. He walked over and blipped/revved the throttle to hear the exhaust... of course the bike coughed and sputtered before revving up. "oh man! you've really gotta get these carbs cleaned out"

^^ although there are plenty of things wrong with his statement... the point is, His big air cooled harley does not have the same problem.

Also...I took my airbox off this weekend to inspect my breather re-route after 2k miles. Well... one thing led to another and I now have an open air box.

I agree with the previous posts... It is VERY loud under WOT but, unlike some others, I noticed big performance increases.

It has a lot stronger top-end pull and it also seems to have helped the infamous midrange flat spot. I do, however, think I may have lost a small bit of low end torque.


In case anyone is wondering..

my current setup:
-04xb12s
-breather re-route
-K&n Air filter
-Buell race exhaust
-Buell race-mapped ecm
-Open air box

I'm gonna stop by my local sound system shop and see if they have any extra sound deadening material laying around. I think I can quiet it down a little bit by covering the underside of my "tank plastic" with some dynamat.

 

[wolfo68]

I didn't notice a difference on my airbox

 

[burgurboy]

Did you guys add any fuel to your maps after Modding the air box? More air calls for more fuel!

 

[Iamarchangel]

Throttle blip cough is lag and perfectly natural on a large v-twin, or single which is why most advocate against blipping.

Learn not to fidget.

But, if you want to get all scientific about it, compare several bikes. Compare small displacement singles to inline fours (which are actually small displacement singles in a row) to large singles and large twins (which are large displacements twinned).

The reason for multis and twins was to get rid of that cough by having another cylinder fire through it.

(Don't ask why engineers made '60s twins that fired at the same time, those bikes were like artillery pieces to anybody behind them.)

 

[captain chaos]

It's one of the MANY design limitations of the Harley twin. I managed to lessen the "cough" on my Buell and my Sportster but getting rid of it entirely proved to be all but impossible. It's generally caused by the narrow cylinder angle (45deg is an AWEFUL angle for a smooth running engine) and the shared intake. Wider cylinder angles or separate carbs/throttle bodies (one per cylinder) tends to eleminate the off idle sputter when you crack it open. I suspect stroke pays into it as well as my XB9 didn't seem to cough as easily as my 12 did.

Honestly, this is why I gave up on my Buell. The chassis was INCREDIBLE but the engine had so many stupid design flaws like this I just couldn't "mesh" with it.

 

[Mike Van V]

burger -

Yes, it does smooth out the idle nicely. It also makes the engine run a little cooler when the timing is set where the engine is happy.
The "book" setting is not always where the engine wants it to be for the most effective work. Every engine is a little different and will run differently with the same timing values.

As has been mentioned, be very carefull when adjusting the ignition timing. You can get very nice results, you can also get "holed" pistons.
Unfortunatly....there is a fine line from holes in piston decks to running as well as it can run.
The little Harley engine seems to like a fair amount of timing....but as I say it's easy to go overboard.

Adjusting/changing this carefully....will increase power, driveability and fuel milage and also the engine heat once you get over a little hump in the lower/mid rpm areas of the map.

My timing map changed from the idle area all the way to around the 5000rpm area, from there up it seems to like the factory settings best.

Mike

 

[burgurboy]

thanks mike,

I knew there had to be something out there...

Thanks everyone for the replies. I understand that the 45 degree v twin wasn't the best of ideas but, as i had stated earlier, i have ridden similar (or even bigger) sized twins and didn't have this problem. Shoot, my buell blast never had this problem (as a 500cc single). i'll keep at it and see what i find out.

hey mike, if you don't mind me asking... what are your current idle values?


oh and for those of you who don't like your loud/open airboxes....

http://www.buellxb.com/Buell-XB-For...CityX-XB12Scg/tired-of-your-loudopen--air-box
thanks again guys!