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Carb Sync Mod

Old 01-03-2005, 03:29 PM
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Carb Sync Mod

Has anyone taken ouyt the vacuum port socket bolt (in the front cyl head) and hooked a line up to it perminatly? To make service easier?

I would like to keep the carb sync adapter on the cyl head but I know that would vibrate loose.

If you permatly mounted it each time that you have to sync the carbs you won't have to pull out that screw with an allen wrench and plug in the carb sync adapter screw.

My big hands have problems getting into tiny spaces.

I went to the auto store the other day to see if they had any speed bleeders (for brakes) that I could use there instead. No luck, I am hoping to get to a bike dealership this weekend to see if they have anything that would work.

In the meanwhile I was wondering what you all have done to make this task easier.

I know that there are many of you that have 100K on yous Shawks, and I would imagine you have gone through this task quite a few times.

Thanks for the thoughts
-D
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Old 01-03-2005, 04:42 PM
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Yes, this is very easy to do. Look at the rear cylinder head in the same area around the intake. You'll see a fitting coming out of the head with a vacuum line attached. This line goes to the fuel petcock. If you order one just like it from your Honda dealer, you can remove the small bolt and replace it with this fitting. Then attach a vacuum line and plug it well. I have some pics and step-by-step for a carb sync on my website.
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Old 01-03-2005, 06:55 PM
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Re: Carb Sync Mod

Here's something I did the first time I sync'd the superhawk about a month ago. I followed Greg's advice about tapping into the rear line with a "T" but I didn't have the proper size fitting for that front cylinder hole and the guage tubing was too big.

I found that the inside plastic clear tube from an old spray bottle worked well. I cut off about 2 1/2 inches of it, cleaned it, and inserted about half of it into the vacuum guage tubing which made it rigid enough to "steer" into the vacuum port. I clamped it with one of the small clips that Honda uses on the vacuum line going to the petcock. Since space is VERY limited this extra rigidity is a temendous help getting it into the hole. :P

The clear plastic tube fit well into the port and the vacuum pulled the hose down tight. The mercury fluctuations were identical (not the readings) which indicated to me that it was sealing well.

Doug
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Old 01-04-2005, 03:17 PM
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What Hawkrider says. I just picked up parts from Honda shop. $4.80 for the screw in adapter and new crush washer. They even gave me a short piece of vacum hose to make a block off plug with. Took 4 days to get it in after ordering.
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Old 01-04-2005, 03:25 PM
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Re: Carb Sync Mod

Thanks for all of the feedback.

I guess that I should have asked: has anyone come up with a good way to permatly mount the "screw in adapter" aka carb sync adapter to the front cyl head.


Thanks all
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Old 01-04-2005, 03:25 PM
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Re: Carb Sync Mod

Thanks for all of the feedback.

I guess that I should have asked: has anyone come up with a good way to permatly mount the "screw in adapter" aka carb sync adapter to the front cyl head.


Thanks all
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Old 01-04-2005, 04:22 PM
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Re: Carb Sync Mod

It screws in hence the new crush washer. Screw out the plug and screw in the adapter. It's not really an adapter. It is the same thing that is on the rear manifold for the petcock. Just leave it in and plug it off after you have done your sync. Use a piece of vacum hose with a screw in one end.
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Old 01-05-2005, 02:55 PM
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Re: Carb Sync Mod

The Honda part# is 16214-MB0-000 About $4 I think.
It's the same part as the rear cyl. I just ran a permanent line from the front cyl back under the carbs to the left side and plugged it - next to another line that "T's" off the fuel valve Vac line from the rear cyl.
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Old 01-09-2005, 06:13 PM
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That's nice. I like it. Great idea!
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Old 01-16-2005, 01:19 PM
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Re: Carb Sync Mod

Thanks for all of the imput!

"The Honda part# is 16214-MB0-000 About $4 I think.
It's the same part as the rear cyl. I just ran a permanent line from the front cyl back under the carbs to the left side and plugged it - next to another line that "T's" off the fuel valve Vac line from the rear cyl."

That is exactly what I was looking for. I went to the dealership this weekend and ordered one of those. That part number is correct, I confirmed it while I was there.

This will make carb sync job easier and hopefuly quicker.

Radar -I like the idea but.....

one thought - you make a hole in the frame. This is a stressed member, could possibly produce a weak spot in the frame. Also you gave rust a great place to start.
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Old 01-16-2005, 06:45 PM
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Re: Carb Sync Mod

Originally Posted by divingindaytona";p=&quot View Post
Radar -I like the idea but.....

one thought - you make a hole in the frame. This is a stressed member, could possibly produce a weak spot in the frame. Also you gave rust a great place to start.
If you look closely, I think Radar used an existing bolt to attach his bracket, the one for the choke ****. Also, the frame is aluminum. It will not rust.
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Old 01-25-2005, 04:37 PM
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Re: Carb Sync Mod

"I think Radar used an existing bolt to attach his bracket, the one for the choke ****"

I looked at my hawk today and took a minuite and looked at the area by the choke ****. You are right. Guess I should spend less time riding the hawk and more time washing it :wink:

Thanks again for all of the suggestions
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Old 04-10-2005, 07:51 AM
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Re: Carb Sync Mod

I ordered a Motion Pro fitting for my synch tool but was starting over again after shearing off the fitting head in the vacuum port. That's a tough little area to work in and I'm sure no one is as foolish as I am to do this. I like the idea of using Honda parts so I plugged the part number mentioned here into BikeBandit.com. The OEM fitting was available and half the cost of the motion pro fitting. I like to support my local dealer but this is a good alternative if you can't get what you need from Honda.
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Old 04-25-2005, 01:18 PM
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Re: Carb Sync Mod

Originally Posted by fred z";p=&quot View Post
Radar,

I am in the process of installing a vacuum line mod like yours, a great idea, by the way. I am having a problem finding suitable fittings to mount on the bracket. Do you have a pic of those fittings or better yet, a source for them, part number, or?

Thanks,

Fred Z.
Fred, Instead of mounting a bracket to place the vac lines out in plain view you might want to consider leaving them hidden, as I did, in the photos I posted in the below thread. They're still very easy to get at when needed.

https://www.superhawkforum.com/viewt...highlight=carb

John
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Old 04-25-2005, 01:47 PM
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Re: Carb Sync Mod

Originally Posted by fred z";p=&quot View Post
Thanks, John, I was going to do that., at least temporarily, until I could find the fittings. Looking at yours, that sure could be a permanent solution. Now all I have to do is find a piece of brake line for the end of the hoses.

Fred Z.
Fred, you can head down to your local auto-parts store and get a small ( 1 ft) piece of 3/16" brake line for about $2. Don't worry about the flare and fittings, just any short length will come in handy. I'm about to post my solution to making a tool to adjust the carb mixture screws. The tool I made up also used some 3/16" and 1/4" brake line.
John
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Old 12-24-2008, 01:48 PM
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are any pics available of the fittings and lines in place?

Hello,
I am ready to do a carb sync. I have most of the bike open and plan on installing the attachments (fittings and lines.)
I am not sure of what was done exactly. I tried the links, but they all say web page expired.
Sorry to be redundant.
Thank you.
Darren
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Old 12-31-2008, 05:54 AM
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please post pics of carb sync mod

Could someone post the pics of:

1. "T" area of the hose connections, and what the hoses connect to
2. How the front hose was blocked off
3.what was used to pinch the line when shutting off the bike (in the manual directions for carb sync.)

Thanks.
Darren
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Old 01-07-2009, 05:09 AM
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easy carb sync modification

I hate to keep asking. I purchased the parts, I am just not sure how to set it up for the EASY carb sync.
Could someone please posts pics or explain differently than above, maybe referencing pics in the manual?
Thank you.
Darren
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Old 01-07-2009, 07:02 AM
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hope this helps:



so you remove the front bolt & install the new fitting & a vacuum hose. secure it with a spring clamp or as i did with a tie wrap.

run the hose across to the left side of the bike.

locate the rear vacuum line that runs back to the fuel petcock. cut that line and install a T fitting. ( the package came with 2 so i used that for the new front line also )



i cut the line and installed the T's so they can get pulled out of the frame to do the sync then tuck them back in when i'm done.

attach your guage to the line and adjust the sync screw if needed... remove the tool and replace the caps on the T's and secure with spring clips or tie wraps.

if you use a dial type ( like me ) guage don't forget to calibrate the guages before adjusting the sync screw.

tim
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Old 01-08-2009, 04:44 AM
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Thank you for the pics. Exactly what I needed.

What did you use to pich the line? per the manual.

Thank you.
Darren
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Old 01-08-2009, 07:10 AM
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Originally Posted by dsevans View Post
Thank you for the pics. Exactly what I needed.

What did you use to pich the line? per the manual.

Thank you.
Darren

the manual states to pinch the line on CA only bikes. pinching the line shuts off the gas flow through the petcock & the bike will stall once it has sucked the bowls dry. i have no idea why they write that as turning the key off will do the same thing. to sync the carbs there is NO need to undo any fuel line.
( unlike your typical I4 bike where it's easier to just remove the tank to access the vacuum ports and adjustment screws ( they have 3 ) ... using a remote fuel bottle )

the only time i pinch the line is if i plan on removing the carbs , that way i won't spill the gas from the bowls all over the garage floor or on the bike.


+ if you drain the bowls it'll be harder to start & you don't want to be reving the engine too high with the mercury stick type guages attached.

tim
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Old 01-08-2009, 09:20 AM
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Sounds good. I'll go back and re-read the manual. I thought that it was for all bikes. Mine isn't CA.
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Old 01-08-2009, 09:30 AM
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If you are guys are too cheap to spend $4 and work at a factory you probably have some 10-32 thread barb fittings around. These are used on small pneumatic devices. The Imperial 10-32 thread is almost exactly the same size an M5 so it will fit just fine. I've had one on my bike (with a vacuum plug I found somewhere) for several years now, works great.
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Old 06-24-2009, 07:20 AM
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if you use a dial type ( like me ) guage don't forget to calibrate the guages before adjusting the sync screw.

tim[/quote]

Tim...what type of dial type gauge are you using. Is it a simple vacuum gauge?
Thanks,
tyronne
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Old 06-24-2009, 07:30 AM
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also make sure that your vacuum lines are the same length, or are at least reasonably close to the same length.
I ran a test years ago with BMW's LCD sync tool where I ran two different lengths of hose to the two cylinders, synched them, and then reversed the lines. The result was that the carbs were no longer synched.
Once I trimmed them to be same length the readings stayed the same.

Kai Ju
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Old 06-24-2009, 07:58 AM
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Originally Posted by tbartley View Post
if you use a dial type ( like me ) guage don't forget to calibrate the guages before adjusting the sync screw.

tim
Tim...what type of dial type gauge are you using. Is it a simple vacuum gauge?
Thanks,
tyronne[/QUOTE]

yes.

something like this:


1 crap'd out & another didn't seem to repeat the readings well... so i sold my I4 and bought a twin

tim
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Old 06-24-2009, 09:03 AM
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Holy old threads!

I also use the dial gauge and they work great, I think i got them for $40 a couple of years ago.
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