Replace the points? 1975 Suzuki GT-250

[Zechariah]

Hello everyone,

Could bad points make a bike not even sputter when its kicked over?
(it's getting fuel, air, compression and spark (although I'm not sure the spark is strong enough) )

1975 Suzuki GT-250

Thanks,
~Zechariah

[MagicRat]

You will probably find the bike has an electronic ignition in place of points, so there is nothing to replace other than plugs and wires.

IMO for any 2 stroke that does not spring to life (with fresh gas) is to install new plugs. These older Suzuki 2 strokes never seem to produce a big fat spark; it always seems a little weak, so they often do not run too well unless the plugs are perfect.

Also, I would check the other usual suspects, such as a gummed up carb float bowl, bad gas etc.

[kelwa1]

Originally Posted by Zechariah

Hello everyone,

Could bad points make a bike not even sputter when its kicked over?
(it's getting fuel, air, compression and spark (although I'm not sure the spark is strong enough) )

1975 Suzuki GT-250

Thanks,
~Zechariah

Yes, points and condensers can and do go bad, together and seperately. Do you have the points gapped properly @ .016?

Fuel, air, and spark are the main three things you need to get running. Compression can be iffy, and you can still get it running with fuel, air, and spark. What color spark? The color of your spark can tell you the quality of your spark. Blue spark is good, any other color, like yellow or orange is bad. Do you have a battery in this motorcycle as well, or are you just trying to use the kick-start? Do you still have the factory oil injection tank and lines on the bike, or are you mixing the fuel/oil ratios correctly?

[Zechariah]

Wow, it's been awhile, but the weather was bad and I didn't have time to get to the bike.

Does any one know of a how to video/article on adjusting points? or even just explain it here on the forum. I'm new to motorcycles.

Thanks,
~Z

[richtazz]

The points consist of the rubbing block (which is the part that contacts the shaft coming out of the engine case) and the other end that opens and closes to jump the spark. The shaft coming out of the engine is a cam that the point's rubbing block ride on which opens and closes them. Here's the basic proceedure for setting the point gap.
1. Disconnect the power lead from the magneto/ pick-up coil from the points.
2. Roll the engine over until the point's rubbing block is on the leading edge of the high lobe of the point cam.
3. Loosen the screw that retains the points to the engine case.
4. Open the point's contacts and slide an appropriate sized feeler guage between.
5. Tighten the mounting screw and then double check the point gap is still the correct gap (they can shift around as you tighten the screw).
6. Reconnect the power lead to the points and you should be good to go.

There are more technical ways to do it to determine point dwell is correct, but this method should get you close enough for the engine to fire.

[Zechariah]

Okay, thanks for the reply, I'll give it a shot and post my findings.

~Z

[Zechariah]

Well it still doesn't even cough . I was looking at the spark and it look kind of weak, it has brand new plugs and a good battery. The points look good but I don't know... also is 90PSI compression good enough to start? The compression seems kinda weak to me.

Thanks,
~Z

[MagicRat]

90 PSI is plenty for a 2 stroke.
2 strokes do not start to build cylinder pressure until the piston has travelled upwards far enough to cover the ports - about half way up.

So 2 strokes rarely develop as much compression as a 4 stroke engine, which is one reason why 4 strokes are more efficient.

Have you checked the carbs to see if the jets are not clogged and the float bowls are full of clean gas.... and not full of water/stale gas/crap?

Have you checked the ignition timing?

One more thing.... have you tried reversing the spark plug wires? As this is a 2 cyl, if it has 180 degree crankpins (the pistons go up and down alternately,) the plug wires may be reversed.) If it has 360 deg. pins, then plug wire placement will not matter.

[kelwa1]

Sorry about the late reply, I dont frequent this forum much.

What's the condition of your plug wires? I know that the original plug wires were made into the coil(s).

If your spark is weak, you could try removing or unscrewing your plug caps, the thing on the plug wires that goes on the spark plugs. The original plug caps were terrible at allowing the connections to the top of the plugs to corrode. Not good for electrical contact. If they dont come off, you may have to cut the wires flush with the end of the wires and find some replacement NGK plug caps. They're inexpensive and come in 4-6 different styles, just match the design to your original. Trim about 1/4" of the end of the plug wire off. Then screw the replacement plug caps back onto the wires, and try them out. If you still have weak spark, then you should look at your coil. There are aftermarket replacements that you can adapt to your machine. NGK makes some, as well as Accel. There may be more alternatives as well, but IDK, I didn't search. You can.

IIRC, and someone please correct me if I'm wrong, these were 6 volt. If your 6v battery isn't in tip top, or new condition, it's going to be very difficult to get it running if the supporting electrical wiring and connections are crappy. Check ALL of the wiring, and ALL of the ground and connectors, clean them well, and maybe put a dab of dielectric grease to avoid any moisture corrosion on the connections as well. Works the same as a 12v system too, although the 6v systems were much more temperamental.

[Zechariah]

Wow thanks for the info, It's very cold here right now here in Montana (10.9 °F) and I don't have a heated garage hehe, so I'll be waiting awhile before working on it again. I will remember this post and refer back to it when I start work on the bike again.

Thanks,
~Zechariah