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Discussion Starter · #1 · (Edited)
Can someone tell me the procedure for syncing the throttle bodies and setting the CO% on my 1198. I think I have everything I need to perform it, but I'm not sure what the CO% should be set to. I'm doing this because I've cored the exhaust, removed the carbon cannister and put in a high-flow air filter. I'm also just curious how the readings are currently, since I live at 6000 feet. I'm sure it was never set at the dealer, the covers were still on the air bleed screws. Thanks
 

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Can someone tell me the procedure for syncing the throttle bodies and setting the CO% on my 1198. I think I have everything I need to perform it, but I'm not sure what the CO% should be set to. I'm doing this because I've cored the exhaust, removed the carbon cannister and put in a high-flow air filter. I'm also just curious how the readings are currently, since I live at 6000 feet. I'm sure it was never set at the dealer, the covers were still on the air bleed screws. Thanks
Set the sync via the air bleed screws then adjust the CO.The CO should be whatever feels best,in other words were not looking for a specific value here but how the engine/throttle response feels.
ciao
 

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OK. Here you go. Synching the TB's means adjusting the TB plates so both read the same vacuum at idle. (That's the easiest way to do it). Airscrews have nothing to do with it. They're for adjusting the CO or A/F at idle and usually will give different vacuum readings to get the same CO or A/F.

Assuming the 1198 is the same set up as the 1098 you adjust the rear TB to match the front. This is done by turning a screw on the left side of the front TB linkage which adjusts the link rod to the rear TB. You have to do it with the airscrews fully closed so that they have no influence on the vacuum.

The vacuum for each TB can be accessed from the two hoses that come from the TB's and "T" into the line going into the evap cannister.

If you're going to fiddle, and I strongly urge you to do so as it's the best way to learn the bike, get the shop manual and read, read and read it.
 

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Discussion Starter · #16 ·
Looks like the goading is starting to work :naughty:

What tools do you have exactly Tangelo ?
I have a gas analyzer and carb balance tool. I also have the VDST on order, hopefully it'll be here this week. Maybe you know, can I adjust the idle with the VDST or is that done with the bleed screws? I thought the tb's were balanced with the screws and not the linkage. I thought the linkage adjustment pertained to the 999 and others. I know jack about injection!!!:D
 

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Airscrews have nothing to do with it. They're for adjusting the CO or A/F at idle and usually will give different vacuum readings to get the same CO or A/F.

If you're going to fiddle, and I strongly urge you to do so as it's the best way to learn the bike, get the shop manual and read, read and read it.
From the manual

If the cylinders are not balanced, turn the bypass screw (20) of the cylinder with the lowest vacuum level (the highest value)
backing it off slightly (a 1/4 turn at a time) until the two lines on the graph coincide, or until identical numerical values are displayed,​
if numerical display is selected.
Also from the Manual

If the CO value is lower than 0.7, close the bypass screw (20) of the relative cylinder by a 1/4 turn and wait 15 seconds before​
taking the exhaust gas reading again.
Ciao
 

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Interesting - I know Lee aka Cloudrider & LuckyPhil have been up to their armpits in motorbike motors longer than most of us have had hot meals so it's interesting to see the differences.

I'm not familiar with these new fangled bikes but I would have assumed the same basic process should apply.

No one has mentioned yet starting with a TPS check as a baseline upon which everything else is built upon.
I just had a skim through the 07 1098 service manual and in reference to the TPS check/set it doesn't state that the throttle stop screws should be backed out in order to have the plates fully closed. Shouldn't this be the case? If not, how does that work?

Edit: So it's all electronic and when the bike is switched off the plates are actually fully closed? Is there a stepper motor on the throttle bodies operated by the ECU?
 

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Interesting - I know Lee aka Cloudrider & LuckyPhil have been up to their armpits in motorbike motors longer than most of us have had hot meals so it's interesting to see the differences.

I'm not familiar with these new fangled bikes but I would have assumed the same basic process should apply.

No one has mentioned yet starting with a TPS check as a baseline upon which everything else is built upon.
I just had a skim through the 07 1098 service manual and in reference to the TPS check/set it doesn't state that the throttle stop screws should be backed out in order to have the plates fully closed. Shouldn't this be the case? If not, how does that work?

Edit: So it's all electronic and when the bike is switched off the plates are actually fully closed? Is there a stepper motor on the throttle bodies operated by the ECU?
The air bleed screws essentially just bypass air around the throttle plates which has the same effect as adjusting the linkage to get both cylinders to pull equal vacuume.
No the plates are not fully closed when on the stop screw.
Ciao
 

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If the throttle plates are not synchronized, that is to say at the same angle in the bores, then it will throw off the vacuum readings when adjusting the airscrews. Furthermore the airscrews are most effective at idle/off idle and at higher throttle openings don't do anything. But the angles of the plates will affect the amount of airflow through the TB's and if not set the same will result in more/less airflow between the two cylinders. Just as if you had two separate throttles opening each throttle. In an extreme case if you were to open one cyl 1/4 and the other 1/8 what do you think the result would be.

The process of tuning involves the elimination of as many variables as possible leaving only constants to deal with. In my book equalizing the TB plate angles is a primary step in achieving that.

It can also be done mechanically by holding the throttle open at various positions and measuring the clearance between the edge of the blades and the TB bores. A bit more involved which is why using the vacuum method is preferred.

Setting the CO with the airscrews per the book is fine, and I don't disagree. But it should be done after the blades are synched.

It is what I do and have always done whether carbs or TB's. Doesn't make it right or wrong. Just my choice.

As for the TPS check. The voltage reading with the throttle plates fully closed (slightly catching in the bores and off the idle stop screw) is the baseline figure that the ECU uses to calculate fuel at all other throttle positions. I do not know what the figure is for a 1098 as the TPS can't be tweaked by hand. On my MV it can be and the figure is 150mv fully closed for the 16M ecu. 1200 rpm idle is 345 mv. That doesn't concern anyone here but if you can find the closed voltage figure for the Duc you can "back probe" the tps and read the mv on a multimeter. Or you can set it with the analyzer.

There is nothing mysterious or complicated about EFI. All it does is regulate fuel and timing. Same as carbs and points. Just a different way of doing it. It's all the other crap that they throw in there that makes it so interesting.
 
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