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bmw4life
04-27-2009, 12:37 PM
After completing the valve job on my R1200rt I proceeded to do throttle body sync. As simple as it may sound I am confused. I followed JVB instructions to do this. I have not did not make any changes to the throttle cables or disconnect the stepper motor. I just wanted to get a baseline read out.

This is the procedure I followed.
1) After the valve adjustment I ran the engine for about 10 minutes.
2) I used the twin max hose and plugged it onto the vacuum hose nipple on the engine heads. Here were I had my first issue. The hose from twinmax fits very loosely on the vacuum nipple (especially on the right side of the engine). And depending on how the hose is moved/wiggle the reading varies. Did others have the same problem?
What I did for this issue was use a zip tie to tighten (I took care not to over tighten the hose the vacuum nipple). I could still pull the hose out from the nipple without the need to cutting the zip tie. I made it hand tight.

3) Next with the engine shut off, I moved the twin max knob to high sensitivity setting and centered the zero as suggested by JVB. I started the engine and let it run at idle. The needle was swinging back and forth between 1-2 -3 on the A side. I had plugged the hose from twin max side A to the right side of the engine and B to the left side of the engine where the hose attaches to the carbon canister.
According the JVB at idle the needle should be swinging at 1-0-1. Prior to zip tie the end of the hose the reading was 1-2-3 on the B side.
I am not sure if the reading is correct at idle? Any insight
4) I can manually center the needle between 1-0-1 when the engine is running at idle. Then I raise the rpm to 2000, 3000 and 4000 and the reading shows that I am of the center of zero towards the B (0-1). I did not make any changes to the throttle cable.
5) But now when I shut the engine off and with the twin max is in on position the needle is pointing at 1 on the B-side.

Am I doing something wrong that gives me all these varying read outs or do I have a problem with my idle? Please advice.

Thanks

Semper_Fi
04-27-2009, 03:56 PM
Hope this helps


2) I used the twin max hose and plugged it onto the vacuum hose nipple on the engine heads. Here were I had my first issue. The hose from twinmax fits very loosely on the vacuum nipple (especially on the right side of the engine). And depending on how the hose is moved/wiggle the reading varies. Did others have the same problem?

On my Twin Max it came with a small piece of plastic which is an id reducer and a short section of hose that has a smaller diameter than the ones connected to the unit. With the small tube reducer and the smaller id tubes they fit very snuggly on the air ports. There should be no air (vaccum) leaks as this will throw off your measurments


3) .......A to the right side of the engine and B to the left side of the engine where the hose attaches to the carbon canister.
According the JVB at idle the needle should be swinging at 1-0-1. Prior to zip tie the end of the hose the reading was 1-2-3 on the B side.
I am not sure if the reading is correct at idle? Any insight

I may be mis-understanding you but i connect the twin max to the highlighted point on each intake


4) I can manually center the needle between 1-0-1 when the engine is running at idle. Then I raise the rpm to 2000, 3000 and 4000 and the reading shows that I am of the center of zero towards the B (0-1). I did not make any changes to the throttle cable.

I would adjust for 1-0-1 balance



5) But now when I shut the engine off and with the twin max is in on position the needle is pointing at 1 on the B-side

Engine off - no vacuum?

bmw4life
04-27-2009, 04:42 PM
Hi SemperFi,
Thanks for your response. Let me help clarify myself. My twin max that I purchased did not have the smaller diameter tube. So therefore I opt to zip tie the hose to the end of vacuum nipple as shown in your diagram. This is done for both the right side and left side of the engine before I start the engine up.
According to the JVB procedure prior to starting up your engine you set the sensitivity level to max and dial the zero knobs to set the needle at zero.
You then start the engine, let run at idle and the read out in your twin max should be 1-0-1. This is how I perceived the procedure to be. Please correct me if I am wrong.
When I do the procedure as described above at idle, my read out is 3-2-1 on the A side of twinmax. At this point either my set up is incorrect or at idle my engine is off.
Now while the engine is running at idle I can dial the zero knobs to place the needle to be between 1-0-1. (I donÔÇÖt think I am supposed to do this as per JVB procedure, I am supposed to set the needle at zero prior to starting the engine). And then rev up the engine to 2000rpm, 3000 rpm and so forth to see where the needle is pointing. When I do this for all the varying RPM, the needle is pointing slightly off the 0 mark.
Can you please walk me through the steps? I think I might be screwing up in the procedure.
I live in Lake Orion Michigan. I wonder if there is someone from this forum who lives close by to walk me through this procedure live. Just asking.
Thanks

Semper_Fi
04-27-2009, 05:02 PM
BMW4Life - sound about right. I will check my notes - will get back to you

Just to eliminate any measurement issdues i would see about getting smaller id tubes to connect to the intakes.

A quick call to Twin Max might either have them provide it to you or get the information of the diameters from them and then go to McMaster-Carr for the items.

marchyman
04-27-2009, 08:24 PM
My twin max that I purchased did not have the smaller diameter tube. So therefore I opt to zip tie the hose to the end of vacuum nipple as shown in your diagram. This is done for both the right side and left side of the engine before I start the engine up.


Apparently twin max removed the reducing adapters from the current version of the stock kit. You need them, IMHO. I would not trust the cable ties made for an air free connection.



According to the JVB procedure prior to starting up your engine you set the sensitivity level to max and dial the zero knobs to set the needle at zero.


Correct.



You then start the engine, let run at idle and the read out in your twin max should be 1-0-1.


I hope you turned the twin max off before starting the bike and reduced the sensitivity before turning it back on. Startup can cause the needle to bang around quite a bit, throwing off your adjustment. I do not know if it can damage the unit. The procedure should be something like:


Turn off twin max
reduce sensitivity to zero
start bike
turn on twin max
increase sensitivity while observing the needle. Do not increase sensitivity so much that the needle is bouncing off of one stop or the other. If the bike is adequately balanced you'll be able to use full sensitivity.

The allowed offset side-to-side on the hexhead at idle is 25 mbar. The twin max doesn't help you there. Also, I think that offset is with the BMW diagnostic computer parking the idle stepper motors, not sure. If your balance is worse than that BMW says to check for air leaks and make sure the valves are adjusted properly. Yep, you adjust idle balance by adjusting your valves.

The allowed offset side-to-side off idle is 15 mbar. Any offset should be constant as you slowly adjust the throttle position.

// marc

deilenberger
04-28-2009, 02:58 AM
After completing the valve job on my R1200rt I proceeded to do throttle body sync. As simple as it may sound I am confused. I followed JVB instructions to do this. I have not did not make any changes to the throttle cables or disconnect the stepper motor. I just wanted to get a baseline read out.

This is the procedure I followed.
1) After the valve adjustment I ran the engine for about 10 minutes.
2) I used the twin max hose and plugged it onto the vacuum hose nipple on the engine heads. Here were I had my first issue. The hose from twinmax fits very loosely on the vacuum nipple (especially on the right side of the engine). And depending on how the hose is moved/wiggle the reading varies. Did others have the same problem?

Nope. Normally if you buy it for use with a BMW it comes with the reducing nipples and smaller hoses. Doing it like you are is going to give you errors - no if, and or but about it. It won't work that way..

What I did for this issue was use a zip tie to tighten (I took care not to over tighten the hose the vacuum nipple). I could still pull the hose out from the nipple without the need to cutting the zip tie. I made it hand tight.
Get the reducing nipple and hoses and try over again.

3) Next with the engine shut off, I moved the twin max knob to high sensitivity setting and centered the zero as suggested by JVB. I started the engine and let it run at idle. The needle was swinging back and forth between 1-2 -3 on the A side. I had plugged the hose from twin max side A to the right side of the engine and B to the left side of the engine where the hose attaches to the carbon canister.
According the JVB at idle the needle should be swinging at 1-0-1.
Perhaps in a perfect world, but I've never seen a hexhead that idled perfectly. Mine is a tad off at idle - has been since it was brand new, and since I don't ride at idle, it really makes no difference, especially since there is no adjustment at idle. I simply would ignore idle.


Prior to zip tie the end of the hose the reading was 1-2-3 on the B side.
I am not sure if the reading is correct at idle? Any insight
Ignore idle.

4) I can manually center the needle between 1-0-1 when the engine is running at idle. Then I raise the rpm to 2000, 3000 and 4000 and the reading shows that I am of the center of zero towards the B (0-1). I did not make any changes to the throttle cable.
NOT how it should be done. You should NOT change the offset on the TwinMax once it's centered based on an idle readout. It should be centered with the engine off, then turned to MIN sensitivity to keep from pinning the meter, then once the engine is started brought up to MAX sensitivity being VERY CAREFUL not to change the offset (centering adjustment.) It would be nice if the centering adjustment had a 10-turn pot on it with a gear-drive, but it is possible to set it and have it keep the adjustment if you're careful.

Whatever you measured after changing the centering is meaningless..

5) But now when I shut the engine off and with the twin max is in on position the needle is pointing at 1 on the B-side.

Am I doing something wrong that gives me all these varying read outs or do I have a problem with my idle? Please advice.

Thanks
Yup. Guess we'll have to do a TWIN-MAX TB Balance DIY. I might even get some time in the next week or two to do it.

You adjust cable balance at around 2,000 RPM. This is the most sensitive point for the balance since the throttle plates are not open very far. The idle bypass passages make no real differerence once off idle - so the idle balance can be ignored (especially since there is absolutely nothing you can do about it - there is no adjustment.)

The other important point to make - if the bike is tuned up accurately (valves done very carefully), chances are excellent the balance will be PERFECT on the TB's above 2,000 RPM. That's been my experience with my bike over 24,000 miles.. I've never touched the balance. Adjust the valves and the balance falls right to "0" (actually -1,0,1 on the Twinmax.) at 2k RPM, and it stays at 0 up to 6,000 RPM (I don't race an engine faster than that with no load on it..)

I'll think about starting to take the photos for a DIY...

deilenberger
04-28-2009, 03:02 AM
I hope you turned the twin max off before starting the bike and reduced the sensitivity before turning it back on. Startup can cause the needle to bang around quite a bit, throwing off your adjustment. I do not know if it can damage the unit. The procedure should be something like:


Turn off twin max
reduce sensitivity to zero
start bike
turn on twin max
increase sensitivity while observing the needle. Do not increase sensitivity so much that the needle is bouncing off of one stop or the other. If the bike is adequately balanced you'll be able to use full sensitivity.


// marc
One difference I have with your procedure - I just turn the sensitivity to min before starting the engine. Turning the TM on and off always seems to change the 0-centering. It won't bang the needle at minimum sensitivity when starting. Other than that.. exactly how to do it.

bmw4life
04-29-2009, 10:57 AM
Thanks all for the tis and advice.
I will try it out over the weekend and let you all know the outcome.