Suzuki 2 Strokes

OK, here goes…. I have a 1969 T350 that I've been working on. It runs pretty decently, but I still have a few annoying issues, therefore some questions.

First: My fuel enrichment levee on the carbs doesn't like to stay locked down. When cold-cranking, as soon as the engine starts, the vibration turns off the fuel enrichment and it dies immediately. I can, very awkwardly, hold the lever down while kicking, but that doesn't work so well, especially since the bike actually has some compression now (head gasket and base gasket replacement) and takers a pretty hefty kick to get going. Is there any way to adjust the detent for the lever so it stays down until it needs to be turned off? If not, I guess I can devise some sort of latch for it.

Second (related): How high should the revs be on cold start with the fuel enrichment on? My neighbors keep giving me stink-eye because it revs high enough to be loud, especially in the carport. I don't really know what the standard is here, but after warm, it idles appropriately with the enrichment off.


Third (related): How long should the enrichment have to stay on before the bike idles on its own? Lately, it seems to need to be on a while, but it has also been particularly cold here when trying the bike. I'm trying to get it ready for when the warmer weather gets here so I can ride it instead of having to piddle with it all the time. Hopefully with some OK dependability. I'm just riding it as an in-town scoot, just so I won't be too far from home if a breakdown occurs. So far I'm finding it difficult to trust this bike completely.


On a good side note, I checked out the pistons/ cylinder bores when replacing the base gaskets… It's had a 0.5 overbore, evidently pretty recently, as the bores look perfect, the pistons fit perfectly and the rings look great. The only carbon in there was a tiny bit atop the piston crowns, and I cleaned that off during reassembly. not bad for a 46 year old imported JDM motorcycle with over 30k miles on it.


Anyway, anyone who could help with advice or pointing me in the right direction will be very appreciated, and if you live close enough,I'll buy you a drink of any sort (alcoholic or non) up to and including a mid-range single malt (probably from my own collection). Cheers.

Had the same issue trying to keep the choke engaged on 500s many times. Not sure if it's the same set up on the 350 having never owned one, but on the 500, there's a little hump on the bottom of the choke lever that rides over a little ridge in a sprung piece of steel. Over the years the sprung steel looses it's spring. I just take it off the body of the carb and bend it a little to tighten things up and it works a treat.......please ignore all this waffle if your set up is different !

The 350 has the same ridge as the 500 to keep the plunger down so look for it and adjust as necessary. The bike will rev with the choke on and in cold weather needs to stay on until it will keep running without it. How long? - as long as it takes to run without it.

In our current hot weather it only needs to be on 2 to 3 seconds before it will run without it.

joethebike wrote:The 350 has the same ridge as the 500 to keep the plunger down so look for it and adjust as necessary. The bike will rev with the choke on and in cold weather needs to stay on until it will keep running without it. How long? - as long as it takes to run without it.

In our current hot weather it only needs to be on 2 to 3 seconds before it will run without it.

It's in the low 50's here right now, and the first crank of the day today it took about minutes of holding the choke down by hand. I went a few places, each time sitting long enough for the bike to get fairly cold, then about 30 seconds of choke each time. This is my first 2 stroke, so theres a bit of a learning curve, but I think I'm getting all the kinks out. I actually ventured away from my neighborhood with the bike today. It ran great, but a bit smokey on hard take offs, and some whispy smoke at traffic lights. I know it's over oiling just a little, as I can't get the lever on the oil pump to line up correctly. It's a little tiny bit past the marks at idle and full throttle, but better than the alternative I suppose. It may be due to the modified 250 throttle cable I have on it. I had to lengthen the cables for the carbs, but figured the oil pump cable would have been the same on both. Anywho, thank you both for the input, I really appreciate it. Cheers.

Also, as an interim fix I've been using one of the fiancé's hair doodads to hold the choke down. Works pretty well….

The oil pump cable has an adjusting screw. The oil pump lever has lines a reference marks on the pump body and a procedure how to set is here -> http://www.oldjapanesebikes.com/mraxl_G ... /index.php" onclick="window.open(this.href);return false;"

I don't let two strokes idle cold. I put just enough choke to start, remove it quick and feather throttle to keep it running. If it's about to stall another quick hit on choke. A few times you can keep it running by feathering. Don't let rpms climb too high for piston and cylinder not yet warmed up even. I immediately take it for a drive and let it warm up easy. After it is fully warm (several miles) the bike should idle. It is easy to foul a plug when the bike is cold and the pug tip is cold not able to self-clean away the fuel and mixed oil deposited.

Too much smoke . A very very common problem with these bikes is the center seals. They may not be worn/damged but simply may be stiff due to age. If true, the smoke is gear oil not 2 stroke injection oil (smell the smoke, gear oil is nasty if you can tell)

Guys are recently now having good luck with seal rejuvenator products like Blue Devil and others. This is the same new technology you see in high mileage oil. This is not the old stop leak stuff that makes rubber into jelly or adds fillers. If that fails you need to remove crankshaft and have the crankshaft disassembled and reassembled to add new seals.

I don't let two strokes idle cold. I put just enough choke to start, remove it quick and feather throttle to keep it running. If it's about to stall another quick hit on choke. A few times you can keep it running by feathering.

That's exactly how I do it -- to the word

Vintageman wrote:The oil pump cable has an adjusting screw. The oil pump lever has lines a reference marks on the pump body and a procedure how to set is here -> http://www.oldjapanesebikes.com/mraxl_G ... /index.php" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;"

I don't let two strokes idle cold. I put just enough choke to start, remove it quick and feather throttle to keep it running. If it's about to stall another quick hit on choke. A few times you can keep it running by feathering. Don't let rpms climb too high for piston and cylinder not yet warmed up even. I immediately take it for a drive and let it warm up easy. After it is fully warm (several miles) the bike should idle. It is easy to foul a plug when the bike is cold and the pug tip is cold not able to self-clean away the fuel and mixed oil deposited.

Too much smoke . A very very common problem with these bikes is the center seals. They may not be worn/damged but simply may be stiff due to age. If true, the smoke is gear oil not 2 stroke injection oil (smell the smoke, gear oil is nasty if you can tell)

Guys are recently now having good luck with seal rejuvenator products like Blue Devil and others. This is the same new technology you see in high mileage oil. This is not the old stop leak stuff that makes rubber into jelly or adds fillers. If that fails you need to remove crankshaft and have the crankshaft disassembled and reassembled to add new seals.

I'm familiar with the adjustment on the oil pump, it just seems my cable is about 1-2mm too short, even adjusted all the way in. Also, the smoke is definitely 2 stroke oil. I was worried about the crank seals at first, especially when my head gaskets and base gaskets were leaking like crazy, but the seals have been ruled out with leak down testing and the fact that, even after many, many miles, the gear box is still the right level on oil. I did put a conditioner in with the oil change as well. Not a leak sealer per se, but a small bottle of Lucas oil conditioner which helps the lubricant stick to the parts and minimize the damage potential on dry starts (after it's been sitting). I now get almost no vibration noise from the gearbox at idle and it shifts extremely smoothly. Also, after several highway rides, it no longer smokes a lot at idle after it's warm, just barely a whisp, but I purposely put a "full smoke" 2 stroke oil in the oil tank just to make certain the pump works well. The color changed in the oil lines, with no leaks or bubbles, so it appears I'm good to go there (plus no engine seizing, so that's also good). The only time I get a lot of smoke (relatively) is on a quick take off or a downshift/ accelerate quickly situation. I can just see a light haze behind me in my mirror, and it also makes cars back off of my tail if they've been too close. I do also get a little bit of oil spatter out of my exhaust, but it's very minimal, and I've been checking spark plugs often, and they are not loading up with oil. Considering the smoothness of my idle, the ease of acceleration, etc, I can't imagine the bike is running incorrectly. I've ridden it almost everywhere I've been for several days now, and aside from it being cold-natured in out fairly cold weather, not a single hiccup out of it. I'm pretty happy with it, unless something crazy is happening inside the engine totally unbeknownst to me. Thanks to everyone that has chipped in on this, as well. You guys are always a tremendous help.

cafe noob wrote:I'm familiar with the adjustment on the oil pump, it just seems my cable is about 1-2mm too short, even adjusted all the way in.

Can you find that 1-2mm by adjusting at the throttle? If not, time to figure out why the cable is short. Are all of the parts, from throttle to pump correct for the bike?