KZ550 powered YZ125 project

She is running on all 4 cyl now. I drilled out my pilots to a 37 and drilled my mains to a 99 (biggest drill i had). Air screw is 1.25 turns out. When I rev it up the rpm seems to hang a little high before it drops back down. Do i need to turn in or out the air screws?

I got to ride her around the block and all the gears are there and the clutch works fine. I'll get some vid of it this weekend if it doesn't rain the whole time.

On a sad note one of the guys (Chris Pollak)that i took the trip to the dragon with passed early this morning from injuries he sustained in a motorcycle accident. He was in full gear when it happened. When ever you suite up remember to keep it safe.

nelson8708 wrote:

She is running on all 4 cyl now. I drilled out my pilots to a 37 and drilled my mains to a 99 (biggest drill i had). Air screw is 1.25 turns out. When I rev it up the rpm seems to hang a little high before it drops back down. Do i need to turn in or out the air screws?

Usually, that indicates an air leak in the manifold boots or the port caps. In your application, all of that should be plugged.

There is a small chance that it's caused by other things. Maybe it's the syncing, or maybe it's the jetting.

With open exhaust, you are probably still lean on the main and the needle. If you add a shim, you probably want a full 1mm shim. I found that adding a shim works better if you add a shim wire to stop the needle retainer form pinching the needle clip/shim. details here:
kzrider.com/index.php?option=com_kunena&...limitstart=20#320816

nelson8708 wrote:

On a sad note one of the guys (Chris Pollak)that i took the trip to the dragon with passed early this morning from injuries he sustained in a motorcycle accident. He was in full gear when it happened. When ever you suite up remember to keep it safe.

When doing some testing, it's easy to get carried away. I find myself going faster than I should, too often. Really sorry to hear about your buddy. Words can't really express it.

Very sorry to hear about your friend. Roy

roy-b-boy-b wrote:

Very sorry to hear about your friend. Roy

Ditto, your next ride on the dragon will have some special meaning.

Thats an AWSOME pic!!:woohoo: The Kawasaki Scrambler!!

MAC

I rode her today to try to work on the hanging idle and after messing with the pilot screw i found my self 1/2 turn out. I'm guessing that means i need to up my pilot jet, no? If so how much bigger should i go (37 currently)? No cracks in the intake boots and every thing is capped off.

Here is a vid of me just rolling down the street.

videos.streetfire.net/video/YKZ550-putting-around_709116.htm

all your missing is a 12" extention on your swingarm a load of alcohol in your fuel tank and a paddle tire and it's off to the hillclimb for you. that is an awesome little bike by the way, how big is your fuel tank.

Really cool video! I think you're OK at 1/2 turn - alot of the bikes have that as being within the normal range. Maybe someone has the exact 550 base setting and can chime in.

One thing I noticed - the carbs sound a bit out of synch to me. If you can synchronize them you'd be amazed at the difference it makes. I did my 3rd set recently and the difference on all 3 bikes was incredible. Of course it's really hard to tell from just a video - just trying to help out. Great job!

I found a guy in my neighborhood who is going to sync them but, he said its better to get the jetting size close before you sync them. If i sync them now and then continue to keep changing my jetting it might get out of sync again.

Gas tank will hold 1.25 gallons.

In that vid she was way lean.....she sounds much better now that i went from 1.5 turns to .5 turns on the pilot screws.

nelson8708 wrote:

I found a guy in my neighborhood who is going to sync them but, he said its better to get the jetting size close before you sync them. If i sync them now and then continue to keep changing my jetting it might get out of sync again.

Yes, very true. Everytime you mess with the carbs the sync can get way off. I've had my carbs on and off several times this year. Everytime requires a sync. If you adjust the needles (on a stock bike it can be done without taking the carbs off) the carbs absolutely will need to be synced again. I've synced my carbs probably half a dozen times, at least, this season. I have to do it again since I shimmed the needles again. (many times, only because I'm doing a study with the wideband o2 sensor to get some data for the 550's using TK's.)

You have a lot of jetting/needle/air-screw adjustments ahead of you, so you will probably want to get some sort of synicing tool of your own.

.5 turns out is not all that bad. You really don't want to do the final adjustment on that yet. It's the one setting that will need to be fine adjusted right after a sync. I wouldn't up the pilot till you know for sure the needles have to be set at .5 turns. (That is, after a good sync). Then maybe go larger so you can get in the 1 to 2 turn range. (Stock is like 1-3/8, I think.)



The reason, if your sync is off, your throttle positiin will be off on several carbs. As the throttle opens the mixture should go leaner up to about 1/8 to 1/4 throttle. If yur idle position is not final, then your air-screw setting can't be final.

Where are your needles at?

Lately i've been busy working on my car (sold my ka swap and going to throw a SBF 302 in there and boost it), but i finally put a little time in on the bike. I went and got some more supplies to finish my sync tool and got a few drill bits so i can increase my main jet size. As of now i have a 40 pilot jet, a 106 main jet and stock needles in their stock location (wont be getting needles for a while). Tomorrow i plan to sync the carbs (attempt # 2) and get the stuff needed to make the choke fast idle adjustable (thanks loudhvx). Earlier today when i adjusted the float level as best i could (time consuming as hell and my first timing do it). After that i took out the plugs to take a look at them and seems like #1 was running lean compared to the others and that is the one i had to raise the float level the most. I hope tomorrow goes well and i should be able to get on her a little bit (past 1/8 throttle) fingers crossed for tomorrow :laugh:

Thanks for the update. Roy