Carb Syncing

[TeamRealtreeHD]

A few guys were discussing the topic. And it is a good one. I was really shocked at how much better my bike ran after I synced the slides at 1/4 throttle. Many guys I know only do it at idle, which helps alot. But it's only half the battle IMO.

 

My bike was synced beyond belief at idle. I used my eyes then the tool. For a long time. Never once did I sunc them at 1/4 thrttle or with the slides open... for one main reason. Every time I tried to do it, the carb sync tool reading would bury itself and bottom out. I couldn't get a reading.

 

So what I did was loosened the throttle cable up to give it more slack. And then I start playing around with stuff laying in the garage.

 

I used a socket tool as seen in the pics below. The kind of tool you insert into a socket head screwdriver. This one here is a socket head allen tool. Anything will work. I inserted this in a point in the throttle housing and since it's 6 sided I believe, it won't slip or move. It stays snug. I got the slides open to the point that I could get a reading on the sync tool. To do this, I played with the slack on the cable coming out of the throttle housing.

 

Slack is a must here... if you have zero slack, your readings will be buried do to the bike revving too much. Or you can simply find something that will work for your current slack in your cable. But finding that perfect something to give you a good reading is going to be tough. But I found the easier way is to adjust the cable so you can get a 1/4 throttle reading/slides open reading on the sync tool.

 

As I said before, I was a firm believer my bike was tuned and synced as good as anyone's. I was wrong however. Not sure which carb was off, but one was opening higher then the other AFTER idle. Yes, at idle it was good. Those carbs were synced at idle like you wouldn't believe. But that's half the battle as I stated above. I am a firm believer this is a must. The bike will certainly run better syncing them this way as well.

 

Here are some pics of my "rigging" I did a few weeks ago. By putting this six sided tool into the housing, it not only allowed me to keep the throttle open around 1/4 throttle, but it allowed for the tool to stay in one place in the small corner you see. Mainly because of the shape of this tool/object. It allowed for me to take my readings and not move.

 

Some may even use the throttle screw in the housing that you can see out the front of my housing. This was to allow so much throttle to open. I couldn't get that to work. Myt ties would always loosen and such. I have that on there so nothing gets in through the hole

 

When I first inserted this in, my idle was too high as stated earlier. But you can account for this by doing one of two things. You can find the perfect match to put somewhere in the housing to hold the throttle open enough where you need to without revving too much and getting off the readings on the tool. Or you can adjust the slack on the cable for the tool you plan to use to allow for the slides to open to get a reading.

 

 

 

 

 

 

And the rest is easy of course. Loosen the carb tops, adjust the carb that is a lower reading on the sync tool to match the carb that is higher on the carb sync tool readings, or simply just make sure both are the same reading, then carefully tighten the carb top adjusters back down. I will then check the carbs readings again after tightening the carb tops down to make sure nothing got out of sync during the tightening process.

 

 

 

 

 

Check your sync at idle again. Nothing should change however... unless there is a problem elsewhere. Note: In the picture, my bike is not running, thus, the reason for no reading on the tool. This was just a picture to help for guidance here.

 

 

 

 

 

 

You're done. Easier said than done of course. This is the way that I do it and what works for me. I am sure there are other ways to do it. I found this to be the best for my application and the things I got laying around though. But I figured for all the help Banshee HQ gave me over the years, this might help out a few. And that's worth it IMO.

Edited August 6, 2010 by TeamRealtreeHD

[ELKARACING_SHEE]

sweet, now i know how to sync my 4 mil, the next time the carbs will need to be synced, oh hey, i have the same carbs as you on my 4 mil lol

[421 OUTLAW]

Pine Grove Yamaha is looking for a mechanic T....

[jbooker82]

Yep like I have said. Take the thumb throttle cover off and wedg something in there so it holds the RPM just above idle. Since it is a socket or scew driver tip it will maintain the RPM the whole time you syncing the carbs.

[SheezFast02]

Thanks for the easy to understand write-up. I'm a noob when it comes to multiple carbs so this will help a lot. Now I just have to order the sync tool.

[spurdy]

Sync tool is second to none when used correctly .

 

Nice write up on the process. Will be good info for the new guys.

 

SP

[RagunCajun]

http://www.google.com/m/url?ei=T0VeTIDrBo6Rtgf2jJkg&q=http://www.youtube.com/watch?v%3D8FDcsojwVxc&ved=0CBEQtwIwAA&usg=AFQjCNGLYYVxOBzco7UZygVud3j8L5HI3g

That's a video how to do it at idle.

 

He also has a partial throttle how to video.

 

 

I thought those were sticky'ed but couldn't find them.

 

As for the part where you need to be partial throttle, it can be any part of the throttle off idle. Lower the more accurate. You can save yourself a lot of time and just use a zip tie to hold the throttle. Zip tie the thumb part to the grip or bar. Have something to cut the zip tie just in case you make it too tight and rev it to hell. I personally like it at 7 or lower on the gauge.

Edited August 8, 2010 by RagunCajun