Never say an unkind word about the Time!

Posted: Mar 27, 2005 03:53 PM  (Msg. 1 of 74)

I got a chance to re-sync my carburetors today using the Morgan Carbtune II I recently purchased.  Compared to mercury sticks, this thing works like a dream without the fear of poisonous mercury be ingested by you or your bike's engine.   The Carbtune uses two clear tubes with stainless steel rods instead of mercury, so no mess and no problems with contaminated mercury.  My mercury sticks were virtually useless after being used about 4 times.  Bubbles would form in the tubes making it impossible to get an accurate sync.

A pic of the tool assembled along with optional carrying case:
Morgan Carbtune II

I recommend the optional case.  This is an expensive tool and this case is custom made to store it properly.

Syncing the carbs on the 1400:

Remove the seat(s) and fuel tank.  (shut the fuel off on the tank) Remove the ignition module from under the seat and reconnect it to the motorcycle.

Under the hood of an uncorked 1400

Seeing as the tank must be off, but the bike must run, you will need a fuel source.  I set my fuel tank off to the left side of the bike on a stand and run 5/16" ID tubing from the tank to the petcock.  I use two lengths of tubing about 4' long.

You will need to remove the allen bolt that secures the petcock to the frame, not only to help you connect the tubing, but it's blocking your access to the rear carbs vacuum port.  I find it's easier to first remove the bottom fuel line to get easier access to removing the top fuel lines.  Some fuel will spill so have a rag handy.  Connect your 5/16" tubing from the subcock on the tank to the top of the petcock and reconnect the bottom fuel line.

The fuel lines are disconnected from petcock....

5/16 tubing run from tank to petcock

BTW, I have found using the 5/16" clear tubing, that clamps have not been necessary to prevent fuel leaks during carb sync.  

After the tubing is installed between the fuel tank and the petcock, turn on the fuel on the tank and the petcock.

Now that we have a fuel source, we have to connect the sync tool to the vacuum ports on the engine.

The front port is found on the right side of the engine on the intake.  My bike is a 1995 model which uses a "boost" sensor.  The vacuum line from the boost sensor is connected to the front port and must be removed.  It's held on with a small spring clamp you can remove with a needle nose pliers.  It is my experience that for the purpose of syncing the carbs, the boost sensor is unnecessary and can be left disconnected.  With the hose removed, you can push on one of the lines from your sync tool directly to the manifold without using an adaptor.

Front Cylinder Vacuum port

The rear port is a bit trickier to get at.  on the rear, the port is on the left side of the carburetor and is covered by a phillips head plug with a copper washer on it.  

Rear vacuum port

Use a GOOD screwdriver to remove this plug.  The first time you take it off it will be tight and if you're not carefull you will strip it!  Be carefull when removing the screw not to lose the copper sealing washer.  An adaptor must be installed where you removed the screw.  With the Carbtune, two sizes were supplied.  Match the threads of the screw you removed to the threads of one of the adaptors.  Screwing the adaptor in can be tricky because it's hard to get your hands in there.  This adaptor only needs to be finger tight, just enough to seal.  Once you have it started on a couple of good threads, you can put a small piece of tubing on the end of the adaptor to help you thread it in easier.

Adaptor with a tube to help with installation

The adaptor installed

In my case, I did not use the adaptors supplied with the Carbtune which are a high temp plastic because I decided I wanted an adaptor installed permanently to make the set up easier in the future.  When done with the sync, I installed a vacuum plug over the sync adaptor.

Once the adaptor is installed, you can attach the other line from your carb sync tool.

Hang the sync tool from your handlebar or somewhere you'll be able to see it easily during the adjustments.

Carbtune on Handlebar

Time to sync:

Here, on the left side of the front carburetor is where the adjustments will be made:

Sync Adjustments


Prime the carbs before starting the engine by pressing the starter button without pulling the clutch.  Start the engine and let it warm up enough to make sure the engine is running smoothly.

The idle sync is adjusted first.  The lock nut for this adjustment is a trick to get at, so I've made a "special" tool to help with it.  I cut a slot in the box end of a 10mm wrench.  This way, you can put the wrench over the cable through the slot and have the benefit of using the 12 point box end of the wrench for loosening and tightening the lock nut.  

Modifed 10mm Wrench

My idle sync is off....

The adjustment is made with the engine running using an 8mm wrench.  Turn the cable either direction as required to even out the reading on the sync tool.  When done, tighten the lock nut.  Re-check your sync after tightening the lock nut to make sure it hasn't affected the sync.  If looks good, the Idle sync is done.

Idle sync is set

In the photo, it appears they may be off a bit, but keep in mind the rods pulsate slightly as the engine runs.  The rods were even after adjustment...

After the idle sync is set, throttle sync is next.  Most of the time, this adjustment can be made at the front carburetor only.  The rear is PITA to get at, so that's a good thing.

Loosen the locknut on the front throttle cable.  Throttle sync should be set at @ 2000 RPM.  Twist and hold the throttle to around 2000 RPM and adjust the front throttle cable either direction until the levels are even on your sync tool.   Re-tighten the lock nut and double check your sync.

Your carbs are now synced.  Put the bike back together.  

Some other notes:
Your air cooled bike is going to get hot running in your garage while these adjustments are being made.  Don't let it overheat.   Setting up a box fan to help keep it cool is a good idea.

I believe it's fairly important to have your jetting as near correct as possible before bothering to sync the carburetors.  That being said, I also believe final jetting tweaks may be more difficult if the sync is to far out.

This might seem like a lot of work, but I completed the sync in less than hour.  After doing it once or twice, it becomes much easier.  The benefit is worth it.  The bike idles more smoothly, power delivery is smoother, as well as  much less vibration at highway cruising speeds .

Hopefully, I at least covered the basics and I hope it can help someone else who wants to try this for the first time.    Writing this post took nearly as long as the entire carb sync process including reassembly...

Never say an unkind word about the Time!

Posted: Mar 27, 2005 07:00 PM  (Msg. 3 of 74)

I'll add that what I described is the same way I would do it using the Motion Pro mercury sticks with a couple of cautions.  

It's my understanding that mercury is poisonous if ingested and while using the merc sticks, I've accidentally spilled mercury on the floor.  I'm not suggesting that I've been tempted to eat it, but my stupid dog would lap it up in a second.  Sweep it up and dispose of it.  A sidenote:  It is kind of neat to look at rolling around on the garage floor....kind of like Terminator 2.  

Also, with the mercury sticks there is nothing preventing your engine from ingesting the mercury but gravity.  A single harsh throttle chop while syncing the throttle cables is enough to suck mercury into the lines running to your carburetors.  Be carefull to let the throttle down slowly while the mercury sticks are connected.


For the 87-88 model 1400's, the procedure is the same with the exception that they don't incorporate a boost sensor on the igntion system.  The front port is plugged off with the same sort of plug as the rear carburetor, which means that the plug must be removed and an adaptor installed.



Edited by kpreis on Mar 27, 2005 at 07:08 PM

I am ...

Posted: Mar 27, 2005 08:29 PM  (Msg. 5 of 74)

I went to the morgan site as I am in need of syncing my carbs too.  Did you read about that Colortune see through plug set to help set the mix screws?  Any thoughts on that tool?

Thanks for the excellent writeup.
Edited by Taylor937 on Mar 27, 2005 at 08:29 PM

You mess with my dad, you mess with me!

Posted: Mar 28, 2005 10:20 AM  (Msg. 7 of 74)

Did you have to cut down the plastic restrictors at all in order for the vacuum to register?  I had to cut mine in half, careful to make sure they were all exactly the same length lest I get false sync readings.

Also, any reason you didn't opt for the 4 cylinder version of the Carbtune, just in case you ever have to sync a 4 cylinder bike?  Was the price difference significant?

Posted: Mar 28, 2005 03:48 PM  (Msg. 9 of 74)

Kevin
Where did you get the adapter for the rear if you didn`t use the the one that came with it.
What size ? etc.

P.S. Great write up!!!!!!
Edited by Spook on Mar 28, 2005 at 03:49 PM

Never say an unkind word about the Time!

Posted: Mar 28, 2005 07:42 PM  (Msg. 11 of 74)

Quote:

I had brass adaptors left over from my Motion Pro mercury sticks.  The Morgan Carbtune comes with adaptors, but they are plastic and I didn't feel comfortable leaving them in permanently.

IF you wanted to buy a Carbtune, I'm almost certain you can order the adaptors only from somewhere like Dennis Kirk.

Never say an unkind word about the Time!

Posted: Mar 28, 2005 07:52 PM  (Msg. 13 of 74)

Quote:

With the 2 cylinder model, I just cut the restrictor in 1/2 per the instructions and installed them in the lines.  Instead of installing them 4" from the end, I installed them at 5" for a little extra room around the rear carb.  It worked great.  

In retrospect, I wish I paid the difference for the 4 cylinder model even though I don't need it right now.  Because the tool is so expensive, I wanted to save some money.  The difference was like $30 I think....Glad I bought the case though.  An expensive tool deserves a nice case.

FYI, it looks to me like the 2 cylinder model is the exact same thing, just minus the two extra tubes inside the tool.

DILLIGAF

Posted: Mar 29, 2005 04:42 PM  (Msg. 15 of 74)

Great write up kpreis!!  Now here is a dumb question, what is uncorking? Do we basically do the same procedure? I have vaccuum gauges, not mercury. I will be pulling my truder out possibly this weekend and finishing her up. Have to sync carbs undoubtedly as they are not the originals (thank you Racine Rider). Everything I can learn about tuning these carbs is very beneficial to me.


TIA

Reno

I am ...

Posted: Apr 20, 2005 04:14 PM  (Msg. 17 of 74)

Kpreis, I must say, this is a most excellent write up.  I used it last night after my carbtune II arrived.  I have a '91 1400 and everything that you described here was right on the money.  After dismanteling and connecting the carbtune i was done my sync in about 5 minutes.  My bike is running wonderfuly again except when i release the throttle.  The carbtune reflected this while it was connected.  The motor will bog down for a moment and then regain its speed back to idle.  Is this where I need to shim my coast valves?

Never say an unkind word about the Time!

Posted: Apr 26, 2005 07:43 PM  (Msg. 19 of 74)

Quote:

The write up mentions how to sync the throttle cables....

Quote:


And yes, while I was performing this procedure, I synched the throttle cables, but it was hard to hold the throttle while making the adjustment and snapping a photo at the same time.