StromTrooper banner

1 - 17 of 17 Posts

·
Registered
Joined
·
268 Posts
Discussion Starter #1
I have a question.
How much vacuum is normal on a DL1000 at 1200 rpm and is one cylinder or the other supposed to be the control for setting the other?
I mean, on some in-line fours the vaccuum at the #3 cylinder is supposed to be the one you try to match the rest of the cylinders to.

I've got a Morgan Carbtune which works quite well, but I'm having second thoughts about whether or not I'm balancing the TB's in the order they should be.

Any help or comments would be greatly appreciated.
 
D

·
Guest
Joined
·
0 Posts
jomawan said:
I have a question.
How much vacuum is normal on a DL1000 at 1200 rpm and is one cylinder or the other supposed to be the control for setting the other?

Any help or comments would be greatly appreciated.
The manual specifies a particular gap between the front TB idle stop on the fron TB linkage. The screw that you adjust during TBS opens/closes the rear butterfly. I would assume from all of this that the front TB is the baseline reference. What is the actual optimum absolute vacuum? .. good question. I've seen a couple of threads on various forums that discuss this question. In one I recall, the fellow claimed that properly setting the absolute TB vacuum on one TB and then balancing the other against it was the optimum method of TBS. Short of a factory spec (haven't seen one..), the only way to accomplish this is trial and adjust.
 

·
Registered
Joined
·
268 Posts
Discussion Starter #3
Thanks David.
The front cylinder on my engine is pulling about 20cmHg and the rear was pulling about 18. Now according to the Suzuki manual this difference is acceptible. But with my flare for excess I managed to balance both within 1cmHg. The gap you mentioned is between the throttle lever and the throttle lever stopper screw on each throttle body. It's supposed to be .012 inches while synchronizing the TB's.
Riding afterward, there wasn't any noticeable difference in performance or throttle response. But having performed the service myself was a very satisfactory experience . . . although purchasing a bottle of fingernail polish (clear for gosh sake) to lock the screws was a tad embarrassing.
 
C

·
Guest
Joined
·
0 Posts
Apologies for jumping in at the end here, but would a backfire cause the TB's to go much out of sync?

I found I was suffering from the occasional pop up through the intake. This has been vastly improved since the dealer (at the 4k service) richened it up a little at the low end. He did say he had sync'ed the throttles but since then I have suffered from a backfire. Would this put them out? or for that matter cause any other damage/misadjustment?

Many thanks for any advice

Clinton
 

·
Registered
Joined
·
88 Posts
Clinton said:
Apologies for jumping in at the end here, but would a backfire cause the TB's to go much out of sync?

I found I was suffering from the occasional pop up through the intake. This has been vastly improved since the dealer (at the 4k service) richened it up a little at the low end. He did say he had sync'ed the throttles but since then I have suffered from a backfire. Would this put them out? or for that matter cause any other damage/misadjustment?
My DL1000K3 backfired some. I found out that one of the throttle bodies had poped out of its boot. This caused a lean mixture leading to backfires. I guess one of your pops has unseated a throttle body. Since this was fixed on mine no more backfires, and a bit more power.
 

·
Registered
Joined
·
88 Posts
Clinton said:
Apologies for jumping in at the end here, but would a backfire cause the TB's to go much out of sync?

I found I was suffering from the occasional pop up through the intake. This has been vastly improved since the dealer (at the 4k service) richened it up a little at the low end. He did say he had sync'ed the throttles but since then I have suffered from a backfire. Would this put them out? or for that matter cause any other damage/misadjustment?
My DL1000K3 backfired some. I found out that one of the throttle bodies had poped out of its boot. This caused a lean mixture leading to backfires. I guess one of your pops has unseated a throttle body. Since this was fixed on mine no more backfires, and a bit more power.
 

·
Registered
Joined
·
88 Posts
Clinton said:
Apologies for jumping in at the end here, but would a backfire cause the TB's to go much out of sync?

I found I was suffering from the occasional pop up through the intake. This has been vastly improved since the dealer (at the 4k service) richened it up a little at the low end. He did say he had sync'ed the throttles but since then I have suffered from a backfire. Would this put them out? or for that matter cause any other damage/misadjustment?
My DL1000K3 backfired some. I found out that one of the throttle bodies had poped out of its boot. This caused a lean mixture leading to backfires. I guess one of your pops has unseated a throttle body. Since this was fixed on mine no more backfires, and a bit more power.
 
C

·
Guest
Joined
·
0 Posts
Thanks for the reply.

Are the Throttle bodies easy to get to?

On my last bike (an old GT550 shaft) I was happy doing anything but the greater complexity of this engine and the bike in general puts me off a little for fear of creating a greater problem!

I don't have a service manual but the handbook does talk about how to lift the tank. Will this give me access?
 

·
Administrator
Joined
·
17,015 Posts
I don't have a service manual but the handbook does talk about how to lift the tank. Will this give me access?
Yes... this will give you access to your throttle body boots. You probably have to take out your airbox... someone correct me if I am wrong! :wink: This is an awesome engine, it is pretty easy to work on, and really isn't that intimidating! Have you checked the throttle body synch yet?
 
C

·
Guest
Joined
·
0 Posts
I haven't managed to check the throttle body sync. yet. Do I check this with a vacuum gauge or by measurement?

Apologies for my lack of knowledge. I used to balance the four carbs on my old bike with a set of gauges but not sure about this one. Are the vacuum gauge ports easy to get to?
 

·
Administrator
Joined
·
17,015 Posts
Clinton said:
I haven't managed to check the throttle body sync. yet. Do I check this with a vacuum gauge or by measurement?

Apologies for my lack of knowledge. I used to balance the four carbs on my old bike with a set of gauges but not sure about this one. Are the vacuum gauge ports easy to get to?
I have a Motion Pro mercury stick kit that I balance and check with. "Are the ports easy to get to"? I wouldn't say that they are too difficult to reach, but you may want to install some vacuum tubing on each of the throttle body ports, so that you can check in an instant. Just be sure that you obviously cap off the end of the tubing. The difficult part, is actually turning/reaching the adjustment screw to balance the throttlebodies. Do a "search" for throttle bodies or TB synch. Or, just browse around and you will find some great info on how to properly perform this wonderful adjustment. :lol: I would do this checkout/adjustment.. BEFORE doing anything else IMHO!
 
2

·
Guest
Joined
·
0 Posts
I also have Motion Pro mercury sticks. I recently checked the the throttle body sync and by far the toughest part for me was locating/installing the vacuum hoses. I later installed two foot long vacuum hoses to the vacuum ports and they are capped off until the next throttle body check. As noted above, it is very tough to change the adjustment screw to balance the throttle bodies and I bought/used 11' long needle nose pliers to accomplish this task. It was $8.00 well spent. BTW, my throttle bodies were out of sync by about 2" on the mercury sticks after I re-shimmed all of the valves. I have no idea what they were before the 15,000 mile maintenance.
 

·
Registered
Joined
·
3 Posts
How do you know if your throttlebody needs to be synced? I removed the tank to check the air filter witch was clean as a whistle but I noticed the front cylinder butterfly on the throttle body was a little open and the rear one was closed? Do I need to adjust anything or is this normal? It's a 2002 with 26k on it it seems to run out fine but has a little bobble when you rev it not while ridding it just when sitting there.
 

·
Registered
Joined
·
192 Posts
Yes... this will give you access to your throttle body boots. You probably have to take out your airbox... someone correct me if I am wrong!
I was able to tighten my front throttle body boot with a long screwdriver and a flashlight from the right side. Luckily the clamp screw was pointed in the right direction. I had to lift the tank for the rear one.
 

·
Official Stromtrooper.com Sponsor
Joined
·
5,307 Posts
How do you know if your throttlebody needs to be synced?
While there are some symptoms you might notice, such as more vibration at low rpm/low throttle openings, the only real way to know is to test them with a manometer or purpose built tool you can buy.

Throttle body synchronization is always the LAST thing you do when tuning up the bike! Get those valves adjusted, the secondary butterflies adjusted, throttle position sensor adjusted, even get your idle where you want it to be. Then do the TBS. Adjusting valves can change the TBS!
 

·
Registered
Joined
·
1,673 Posts
Throttle body synchronization is always the LAST thing you do when tuning up the bike! Get those valves adjusted, the secondary butterflies adjusted, throttle position sensor adjusted, even get your idle where you want it to be. Then do the TBS. Adjusting valves can change the TBS!
^^^ Absolutely 110% correct.
Actually, synchronization is a misnomer. What you are really doing is equalizing the vacuum between cylinders on the engine side of the throttle plates. The goal here is to make sure the cylinders produce equal power between them. In some Suzuki shop manuals, the cylinders are called "Engines." Engine1 and Engine 2 in the case of a '07 M50 805cc shop manual as an example.
ANYTHING that affects engine vacuum, be it compression, valve adjustment, spark plug gap( a miss-gapped plug), a vacuum leak, can affect cylinder vacuum. These are items that affect individual cylinders. A cam out of time will affect all cylinders.
In a Twin, as just ome example, picture a 2-man rowboat, one on each side. Both rowing with equal force will rum smoother and straighter than one strong rower and one weak rower. You want 2 small engines to behave as one large engine.
The larger the throttle opening, the less effect sync will have--idle and slow speed accel is where the effect is most noticeable. Ive seen bikes exhibit a slight shudder during light-throttle acceleration from a stop due to throttle bodies being way out of sync.
If you have a cylinder low on compression, you can get the reading to equalize--but here you are masking a problem, not compensating for it. Same holds true for valves out of adjustment and anything else affecting an individual cylinder.
Just as in any engine diagnostic path, the sequence of events is Engine Mechanical--> Engine Ignition-->Engine Fuel. Once all those are verified to be correct and within spec, THEN you proceed to a back-and-forth adjustment procedure between idle speed/throttle position sensor/sync.
Never assume anything is correct unless youve checked.
 
1 - 17 of 17 Posts
Top