Suzuki 2 Strokes

Okay I'm stumped... When I fired up the bike, the right cylinder was running fine, but the left barely fired. I didn't have time to mess with it at the time, so it went back in the garage. A few days later, I pull it out to work on it, and when I fire it up, now it's the right cylinder that's missing, not the left, and the left works fine... Anyone know what would cause that?

As a starting point, make sure you have a fully charged battery, symptoms of running only on one cylinder can be caused by this.

Battery is new and fully charged.

Had what might be a similar problem this spring. The ignition system needed just a little help.

The bike had run fine when I put it away last fall. This spring the right cylinder didn't right run.
It only occasionally fired. Tried again a few days later & the right cylinder didn't fire at all.
Cleaned the points up a bit. (Took two passes with a points file & used an index card to clean them.)
Installed new fine-wire spark plugs.
This got the right cylinder running a bit rough. Took a quick ride to clean the cylinder out & the bike ran just fine.

Fine-wire spark plugs fire at lower voltages -- something that's useful with the weak ignition systems these bikes have.
I'm gradually switching over to them on all of my vintage Suzukis.

Your bike might be in a similar situation.
Check the points & clean or replace them if needed.
Good fine-wire plugs for your bike would be NGK B8EGV

It has brand new B8ES plugs in it now, i haven't checked the points, but the PO said they were just replaced not long ago... I'll check them though, and I'll see if I can get the fine-wire plugs (I feel like they'll likely work better overall anyway). What I can't wrap my mind around is how the problem switched from one cylinder to the other.

jabcb wrote:Fine-wire spark plugs fire at lower voltages -- something that's useful with the weak ignition systems these bikes have.
I'm gradually switching over to them on all of my vintage Suzukis.
Your bike might be in a similar situation.
Check the points & clean or replace them if needed.
Good fine-wire plugs for your bike would be NGK B8EGV

Do you know if the fine wire plug you mention above would be good for a '70 T350? Just wondering because I'm getting near the end of restoring mine, and although I haven't actually run it yet (waiting on expansion chambers to get here), I did notice that I'm only getting spark on one side when cranking. I think it's a bad condenser, because I can see some sparking at the points when I kick it over. I have a set of condensers that I'll swap into it in the next few days and check again, but would be interested in these plugs, too.

NGK B8EGV will not fit your T350 because the thread length is too long.

Your T350 came with NGK B77HC.

NGK plug names can be decoded using:
http://www.ngksparkplugs.com/docs/tech/ ... _plugs.pdf

You need:
thread dimension: B
thread reach: H

Heat range 77 is between heat ranges 7 and 8.

Currently NGK recommends:
1) B7HS, which is a standard non-resistor plug
2) BR7HIX, which is a fine-wire resistor plug

You should use either:
1) non-resistor plugs with resistor caps
2) resistor plugs with non-resistor caps

I use fine-wire non-resistor plugs with resistor caps in my T350:
NGK B7HV or B7HVX plugs & NGK LB05F caps.
The plugs have been discontinued but are available via eBay.

A good choice for resistor plugs with non-resistor caps is:
NGK BR7HIX plugs with NGK LZFH caps

Meanwhile, my issue seems to have disappeared all on its own =)

jabcb wrote:
A good choice for resistor plugs with non-resistor caps is:
NGK BR7HIX plugs with NGK LZFH caps

Thanks for the super detailed info! I already have the non resistor caps on there, so think I'll try a set of the BR7HIX plugs.

For me, right now she's running like a brand new bike, I guess there must have just been something that had to work its way through. For now I'll keep the stock plugs in it, but if starts to get rough I'll make the switch. Trying to save money so I'm only getting what I absolutely need for now (btw... do I really NEED a license plate?)

Hmmm, perplexing. Tonight I replaced both condensers, and am now getting good sparks at both plugs when turning the crank with a wrench. I have the NGK B7HS plugs in there. But, the issue is that now I'm seeing a lot of sparking at both sets of points, too. I know in a previous post you said the B7HS are non resistor plugs, but in a few other webpages they say the are resistor types, could that be a mistake? The plug caps say "NGK" on them, but the truth is that I don't know if they are resistor type or non resistor. Could using a resistor type cap and resistor plug together cause the sparking at the points?
In my limited experience with points setups, the sparking at the points themselves usually means a bad condenser. Or could it be the points themselves? They are what came on the bike, and I did clean them with the usual technique. Thanks again for any help!

Mike1161, take a look at how the NGK plug names are encoded: http://www.ngksparkplugs.com/docs/tech/ ... _plugs.pdf

B7HS plug is:
"B" for thread dimension of 14mm
"" for no construction, so its non-resistor
"7" for heat range 7
"H" for thread reach of 1/2"
"S" for standard center electrode

If it had a resistor, the name would be BR7HS

The NGK plug caps are shown here: http://www.ngksparkplugs.com/docs/Resistor_Covers.pdf

The cap number is printed on the caps. Look closely because its a little hard to see.
NGK uses an encoding for the cap number. You can also figure out which cap you have based on its appearance & dimensions.

Good chance you have one of these caps:
LB05F which has a 5k ohm resistor
LZFH which is a non-resistor cap

jabcb, great info at the NGK pages. I printed out copies of these to take home to the garage for reference. You were totally right about the plugs! Tonight I will check to see which plug caps I have on there, but from the pictures they sure look like the LB series. Any ideas about the sparking at the points? I haven't taken any measurements with the DMM, but could do that.... Should I use the new set of points that I got, too? Or should I just wait until I get the pipes, and see how it runs first?

Have you set the point gaps & timing? Do you have the bike running?
If the settings are right & the bikes runs good, then I'd use the existing points. Then you can keep the new points as spares until you need them.

I haven't accurately set the timing, since I haven't tried a 1st start yet (I'm still waiting on a set of JEMCO pipes, and don't have any other pipes to put on it, since I sent the old ones to be used to develop a fixture to make the new chambers). The timing is fairly close, judging by the timing marks through the little window and using my multimeter to sense the points opening. That kind of backs up what the PO said, that it was running before he started taking it apart, but then lost interest.
Maybe I should just wait to see how it runs, but I thought that if you had a lot of sparking at the points it would burn them up quick, or it indicated bad condensers. The condensers I just put in are new, but they're off eBay, so not sure how good they are. It was a points & condeser kit for a T350, though, so you'd think they were about the correct capacitance. Or at least that's my hope.
Oh, and the plug caps look like the LB05E's, but the dimensions are different than any of the ones on that spec sheet. I looked pretty closely, but just couldn't find any type of part number on them, maybe it wore off? All I could find was a stamped on "Made In Japan" on the top.