1981 Suzuki GS650G - dies under load when throttled past ~1/3

[seinwave]

What do you mean in reference to the mains? I don't think I posted my specs here and I'd have to hunt down the notebook I wrote them down in, but IIRC the mains were the default (110).

[tom203]

Sorry, wrong 650 guy! In the carb forum, there was guy looking for air filter element cage who mentioned using 115 mains. I merged you two together to save brain space

[seinwave]

I didn't want to update too fast -- I've already pulled a Bush Jr. and declared mission accomplished way too soon once. But it's been over a week and a few dozen miles since I've done anything to the bike so I feel comfortable it's fixed. I owe it to future forum trawlers following in my footsteps to bring the story full circle.

Long story short: I didn't *quite* have it fixed after my last post. It started and ran alright, but I quickly realized it was running on only two cylinders - the exhaust pipes for 2 and 3 were ice cold, and I could barely get it to move without the clutch. I confirmed a lack of spark on those cylinders.

The biggest thing I did was bite the bullet and do the relay coil swap; the voltage drops had jumped from one-point-something to two-point something and I was tired of relying on 43-year-old wiring and bullet connectors. $20 worth of parts later I was getting real strong voltage to the coils, and (a visible) spark on 2 and 3 - but still running on two.

Just because I'd already bought them and wanted to leave nothing to chance, I made the third (and hopefully final) swap of coils and hooked them into the (now entirely costume-ized) ignition system. I headed down to the Advance also and picked up four shiny fresh sparkplugs to replace the fouled ones.

I also retarded the timing a little bit - I think I may have had it slightly advanced on initial setup. This was precautionary.

Now it runs and pulls! Before it's properly warmed up I have a tiny momentary stumble the *first* time I pass 4 or 5k revs under load, but it barely lasts long enough for me to realize it's happening before the plant powers through.

Next I'll probably sync the carbs. I also think the #2 airbox->carb boot is misshappen or mis-selected or something, but I can't for the life of me find a replacement, and it's sealing, so... who knows.

[salty_monk]

Congrats!

[dgates1]

Next I'll probably sync the carbs. I also think the #2 airbox->carb boot is misshappen or mis-selected or something, but I can't for the life of me find a replacement, and it's sealing, so... who knows.

There’s a set of all 4 on eBay. Kinda spendy, but they are new.

https://www.ebay.com/itm/275979066905?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=ewfGyMTrQnq&sssrc=4429486&ssuid=5ueBAimr Qo m&var=&widget_ver=artemis&media=COPY

[seinwave]

That price is doable, but I'm a little concerned about buying NOS rubber vs repops; rubber degrades over time whether or not it's installed, though it being out of the sun slows down the process.

The bigger thing is: I don't exactly know what's wrong with the #2 boot! It's not hard or anything, it just... doesn't seem to match the shape it needs to be to fit in the carb. Tried rotating it and it only made the problem better or worse, not fixed. I'll post a picture in a new thread at some point and see if anyone can identify it. It *does* seal, though, so perhaps that's a problem for when next summer's high heat keeps me off the road.