Suzuki 2 Strokes

Trying to get my inherited GT250 on the road for longer than 10 miles. The hard-to-find mechanic got the bike up and running. We picked it up and started our long trip home and the bike just stopped running at about 10 miles in. It would stat again but wouldn't move without stalling. After a 20 minute cool down it starts fine and goes again. Everything seems fine with the carburetor, petcock, fuel cap, plugs. Now the mechanic says I should shop for ignition coils and points so he can see if that's the issue. Any thoughts on why the sudden loss of engine power after running for 10 miles - 15 ish minutes at speeds under 55mph?

Should I pursue the coils and points? If so, where do I shop for them?

Thanks!

Don't forget condensors.

I have a gt 550. Had the same problem when i bought the bike. It was a sticking diaphragm in the petcock. Try switching to prime and see if that cures it.

GTandcbr wrote:I have a gt 550. Had the same problem when i bought the bike. It was a sticking diaphragm in the petcock. Try switching to prime and see if that cures it.

That happens to the Stihl weed whacker all the time! Clean it out and the thing runs great.

I'm pretty sure he did something like that. But I'll check to be sure. I read that the diaphragm is not replaceable and I'd need a new petcock assembly. And then I read that someone simply flipped over the diaphragm and never needed a new petcock. Thoughts on trying to do that?

Just purchased the points and condensers. I can't find a reasonably priced ignition coil. So I'm hoping that the other parts solve the problem. Hoping, hoping, hoping.

If you go to the back of the petcock and remove the 6 screws. Carefullly take off the cap you will see there is a thin rubber membrane. Careful as its fairly delicate. Watch out for the spring which goes from the cap to it. In the middle is a plunger. Gently ease the membrane and plunger out. Give it all a good clean with carb cleaner. The plunger and the pipe it fits into in the petcock. There is a rubber o ring on the plunger. I smeared the membrane with a bit of silicon grease. When reassembling be sure to match the hole in the membrane and the hole in the petcock as it is a vent. Put it all back together. May save you buying a new one! Good luck
Ps the diaphragms are available but really expensive here
http://hard-to-find-parts.de/epages/aff ... 51Membrane" onclick="window.open(this.href);return false;

A link to help you service the petcock
https://youtu.be/qWNyvjaWfz8" onclick="window.open(this.href);return false;

Thanks for the tips. The mechanic feels that we need to focus on ignition coils and points. So that's where we are right now. Got a used stator but a quick multimeter test of it seems like it might be dead. But it has points and condensers on it, maybe they are still useful.

Well, I wish I could tell all you future readers what fixed this problem. But ignition coils from a different make and model two stroke were modified and installed. "New" points and condensers were put in. The petcock was bypassed and two valves were installed after the petcock. And it runs for longer than 15 miles now. Haven't put it to a longer ride test, but there really isn't a need as it's just not really that comfy I'm told. It vibrates and shakes and is just strange. It's a nice unique ride and sure does get looks and waves. But we'll be putting it away for the winter soon and try to start it every few weeks over the winter to keep it happy. A lot of money went into it, but it was my dad's bike for a while. Maybe we'll take it to shows for some fun. I don't know how shows work, or if it's worthy being at the tank was painted and there are some not original parts on it. But it sure looks pretty.

Thanks for all of your input and suggestions!

Another update - In November we went on vacation and tucked the bike in the basement for 6 days. When we got home the whole house smelled of gasoline. Luckily (maybe), the boiler has an undiagnosed electrical issue and shuts itself off every week or so when the heat is cranking. So when we walked in the smell was awful! Opened all the windows and doors, used fans to help. Fired up the boiler again and nothing exploded. Since we have always stored three other bikes down there over the past 10 winters and none of them ever let any gas fumes "escape" we knew it was the Suzuki and the bypassed petcock. There was no puddle. Just fumes. So we removed the tank and put it in the shed for the winter. I am afraid to go check it. The lining of the tank was peeling a bit at the top. I don't know if anything got in there. And I am not sure where to take the gas if we dump it. The kids have moved on to dual sport and street bikes now. We can't keep seven motorcycles. I have come to terms with the fact that something must go. And while this was my dad's bike, I think he would want it to get some use. I cannot ride it because (so my kids have told me) I don't know how to really ride because my little Ninja is forgiving of my shifting shortcomings. I wish I could justify keeping it, other than it was my dad's and I spent over $1200 getting up to riding condition. And I am sure it's not worth that to anyone but me. I have some thinking to do. In the meantime, I don't see any on Ebay right now. And there are none near me in NH on Craigslist. Any thoughts of the best place to sell this sort of bike?

one thing that comes to mind is a blocked fuel cap vent- had a GT380 that used to do exactly the same - next time you go out just latch the cap down loosly and see if it makes a difference
Mal.

beachboysnh -

I had the same issues. Easiest fix is to get a pingle petcock - I'm not a fan of vacuum style petcocks. If you go that route, you'll just need to get a rubber vacuum cut-off nub to slip over the carb nipple where the vacuum line used to run from the original petcock. I think I got mine at napa.

Take a look at the top post on my blog site in my signature below (it'll tell you the petcock model I got, and describe the same gas smell I came home to).

Thanks for the information. That petcock might be the way to go. The kids say that the new petcock bypass doesn't provide enough fuel for strenuous rides...we live in the mountains and that's an issue since the most fun ride is over a windy mountain road.

Here's a pic of the set up the only guy in the area willing to touch it did...
http://i53.photobucket.com/albums/g51/j ... ophorj.jpg" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

Although, I am not sure we're going to get it out of the basement this summer. Many other motorcycles to ride that don't cause trouble...except the '86 Concors. Now that is a stumper as to what wrong. It's for sale but it's something that someone would need to be specifically searching for...like a GT250.

MarkH loved your blog photos of the motorcycle junk yard! My son was drooling and asking where it was. Sadly, it's a bit too far. He'd have gone to get everything to make a Frankenstein's monster bike. My basement can't handle that.

For now, we're hanging on to the bike. Sentimental and all that...but if I stub my toe on it one more time...well, I wouldn't know where to sell it anyway.