Suzuki 2 Strokes

We all make mistakes. It's called the human condition and while it does get better over time, we still do it. All that matters is that you are learning and making progress.

Sticky needle valves are quite common.

BTW, I think that the numbers are the diameter in millimeters and not flow rate, but I could be wrong. The best way to check float level is actually to measure the fuel level as that's what we are trying to do anyway. If your float bowls have a drain tube and screw, connect some clear tube to that drain tube and hold it up at the side of the carb and open the drain screw and turn on the fuel tap. Fuel should start to fill the drain tube and should be roughly 3mm below the gasket level on the carb body.

If the drain screw on yours is not connected to the drain tube and just allows fuel to piss out, you will need an adapter like the banjo on the oil feed or a spare float bowl with the fuel overflow tube cut off at the base.

If the fuel rises above the gasket surface, it will weep into the motor and filters. 3-4mm below the surface is normal. Adjust the float tangs to get the same level in both sides and keep a record or photo so if you choose to raise or lower it in the future to fine tune jetting, you will have a good record of where you started.

Then run the bike at idle and adjust the air screws for fastest idle. If you end up less than 1 turn, fit larger jets and if you end up at more than 2 turns fit smaller jets.

Sometimes you will need up screwing the air screws back in 1/8 or 1/4 turn to improve initial pickup which has to be slightly richer than at idle.

Please post and let us know how it works now.

sbaugz wrote:Once again, thank you for the helpful information. I am confident that the idol passageway is clear. Vapor blasting does not use any media whatsoever. It uses high-pressure water.

I believe that vapor blasting is actually a wet glass bead blasting (a form of slurry blasting). I spent some time using different forms of blasting, cleaning components for semiconductor manufacturing equipment. So yes, there could be media in the small jet passages of the carbs.

http://www.arnoldsdesign.com/Vapor-Blasting.html#1.
http://www.restocycle.com/#!vapor-blasting-faq/uev7v

So... How much better is it running with the slides in the correct way.

Don't feel too bad. There have been dozens of posts here, by people who have been bitten by this. Still not as bad as me, who once installed my crankshaft in the cases backwards.

Happy to here your superb machine is getting there, the slide swap is something that easily happens (don't ask me how I know ).

One point, unless vapour blasting is different in your part of the world the water does contain an abrasive component. It is a very gentle one right enough but it is there.

Good luck

Cheers Geoff

If you want to see the coolest blasting (pun intended), I used to use a CO2 blaster to clean anodized parts and quartz. The abrasive was from a block of dry ice, which was pulled into the compressed air line. You needed to put the air gun nozzle just a few centimeters from the item being blasted, but it would clean the parts up very nice.

I use soda as a blasting medium for carbs as its a lot gentler than glass bead and also it dissolves when wet. I always give the blasted bodies a session in the ultrasonic bath and they come out sparkling clean and more importantly with all the jet ways and orifices totally clear.

so back to the topic of getting this bike to run properly.

To summarize my first post:

1975 T500 with UNI pods and Higgy chambers. Shorter early model intact boots. 120 main jets. Electronic ignition from power dynamo.

Since my last post, I now have the slides in properly. I have the carbs sync'd as well.

Starts first kick without choke. Idles great. first 1/4 throttle or so is good. Also full throttle seems pretty decent as well.

Trouble seems to be mid throttle. When I give it between 1/4 and 3/4 throttle, the bike has no power and almost gives a shuttering sensation. Don't know how else to describe this, other than it just doesn't have power. Its not the typical bogging down sensation of too rich, yet it doesn't seem typical to lean either. (I am guessing its not lean because I am using 120 mains).

My take on it suggests this is more a function of clip position on needle. I checked the plugs today and they seem fine- slightly greyish brown. Comparison with all the plug charts out there suggest its running properly. Granted, I have only put about 15-20 miles on the bike so it may be too early to show signs of trouble on the plugs.

Either way, what do you all suggest the next step should be? Move the clip on the needle up or down? Should I try something else first?

Thanks.

Isn't it fun sorting out the jetting on a Bitsa? (bits of this, bits of that...) Between the spannies, pods, short intake on late model engine/carbs, a baseline is hard to determine.

A few thoughts:

-- Be sure that the full throttle is rich enough. While pulling hard up an incline (at a medium-high RPM), rolling off the throttle just a hair should not make it run better. That's a sign that you are too rich. It is always nice to know where "too rich" is, because knowing the main is too lean is much harder to determine.

-- Once you are certain that the Main Jet is correct, you can try different clip settings. The main jet will only slightly influence the 1/4-1/2 throttle, but may be enough to get you confused what is going on (keep good notes on what you try!) The stuttering sounds like you may be just a bit rich (4-stroking). Dropping the needle down a bit may help. A half notch actually makes quite a bit of a change, so you may want to get some shims, to get it set between notches.

so I moved the clip on the needle up one space to the second from top. It made a world of difference. Its actually drive-able now. Only thing I notice is a little bit of bogging down around 3/4 throttle.

I tried the throttle roll of at near full throttle and nothing really happened except engine RPM dropped slowly as expected.

At least now I have a driveable place to start out with and I can start tweaking from here.

Progress is good. 3/4 on is basically all main jet. Try going up 2 sizes to 125 first just to be safe and if that makes things worse, go down one size to 117.5 and if that looks rich, go down another size. Going up it's safe to go with larger jumps than going lean where it's easy to overshoot to end up too lean.

Agree with tz375. Good next step, to confirm Main isn't a bit lean.

(did you mean 122.5?)

Steve....did I read you are using the early shorter inlet manifolds?
On my 75 T500, I use 115 main...35 pilot, and needle middle notch. The bike runs pretty good everywhere. WOT must be rich enough as I have thrashed it very hard with no ill effect. I'm using pod filters.....

titan performance wrote:Steve....did I read you are using the early shorter inlet manifolds?
On my 75 T500, I use 115 main...35 pilot, and needle middle notch. The bike runs pretty good everywhere. WOT must be rich enough as I have thrashed it very hard with no ill effect. I'm using pod filters.....

Yes, shorter manifolds. Does yours have the shorter ones as well?
If so, I might try your setup and see what happens.

No mate.....got the later/longer manifolds on mine.

A little trick, get a small glass and set the carb top on it, then fill through the fuel line until the fuel stops. This way you can actually see where the fuel level is. No special tools.

ja-moo wrote:A little trick, get a small glass and set the carb top on it, then fill through the fuel line until the fuel stops. This way you can actually see where the fuel level is. No special tools.

What a simple but great idea John