Back again. 82 GS1100 drive issues

[wilsonsandy07]

So, back again to the forum.

82 1100e

coming off the highway all of a sudden I get some surging, and very boggy throttle input. Gradually got worse. Fairly consistent with a “surge” or “jolt” here and there. Feels almost like running out of gas combined with chain slipping. I did just replace my chain/sprockets, but I immediately verified the slack is well within parameters as soon as I got off the bike. Also made sure I wasn’t actually just out of gas.

here’s the basics covered just also as an fyi

- so new 530 x ring chain, 18/50 sprockets. About 200 miles on them

- no problem idling at all, perfectly steady

- carbs fully dipped and rebuilt/jets verified stock, about 2k on those

- running 93 octane or whatever premium at the pump is where I stop

- no shifting issues at all, before this never lost a gear or anything like that

[rphillips]

UUUUmmmmmm, ?????

[Rich82GS750TZ]

I don't know what you think the sprockets and chain may have to to with your running issues. But I'd be looking at your fuel deliver.

Are you running stock airbox/filter?

Does you gas cap make a whooshing sound when you take it off after a run, especially after you've experienced this "boggy throttle input"? If so, you've got a blocked cap vent. Air has to get in at the top to allow the petcock to allow gas to flow properly.

After that, verify that petcock does flow properly. Should flow continuously on PRIME. Should not flow at all on RES or ON unless/until vacuum is applied by starting/running condition. If there is fuel in the vacuum line from the petcock to the nipple on the front of carb # 2, then petcock needs replaced or rebuilt (iffy proposition according to most).

I'll take your word for it that your carbs are, in fact, clean with all passages clear and no air leaks at the boots behind or in front. If it ran well the last 2K, I doubt there's a problem there. But junk/rust from the tank can get there and clog jets.

Why 93? Never saw any advantage to this. Never-mind, that's going to open up a can of worms like a "what oil should I use" thread.

Or maybe you just got a tankful of bad gas. That happens.

All just my opinions, of course.

[wilsonsandy07]

I don't know what you think the sprockets and chain may have to to with your running issues. But I'd be looking at your fuel deliver.

Are you running stock airbox/filter?

Does you gas cap make a whooshing sound when you take it off after a run, especially after you've experienced this "boggy throttle input"? If so, you've got a blocked cap vent. Air has to get in at the top to allow the petcock to allow gas to flow properly.

After that, verify that petcock does flow properly. Should flow continuously on PRIME. Should not flow at all on RES or ON unless/until vacuum is applied by starting/running condition. If there is fuel in the vacuum line from the petcock to the nipple on the front of carb # 2, then petcock needs replaced or rebuilt (iffy proposition according to most).

I'll take your word for it that your carbs are, in fact, clean with all passages clear and no air leaks at the boots behind or in front. If it ran well the last 2K, I doubt there's a problem there. But junk/rust from the tank can get there and clog jets.

Why 93? Never saw any advantage to this. Never-mind, that's going to open up a can of worms like a "what oil should I use" thread.

Or maybe you just got a tankful of bad gas. That happens.

All just my opinions, of course.

I only mention the chain because I was just having a skipping chain due to not replacing sprockets with a stock set up and a new 630 chain that ended up going bad due to high/low spots on sprockets. But when “surging” or whatever you wanna call it it’s a very similar feeling.

stock airbox and filter. New paper filter and sealed box with weather stripping and new boots


Have not had any gas cap issues like that but I have not been paying attention to it tbh so I’ll see if that makes a weird noise

i did verify petcock operation but I suppose it could’ve failed since or be on its way out now.

did a pretty good tank flush and the tank is sealed inside so hoping it’s not any particles in carbs

idk just thought 93 would be better lol

praying it’s just a bad tank of gas lol

[rphillips]

Not understanding for sure, did it do this getting off the hwy. once, or did it just start doing it getting off the hwy., and is continuing to do it ever since? If it's still doing it, try riding on PRI. for a ways, if it helps I'd say pet cock, if nothing changes I'd say not a pet cock problem

[wilsonsandy07]

That was the first time it happened, its about 30 highway miles and then a few miles off hwy. Just now after the bike sat for 10 or so hours and completely cooled off, it started and ran perfectly fine for the same commute about another 30 miles.

When i got off the highway and got down to lower speeds (40mph and under) the problem started happening again. Something is being affected by the heat of the bike. I do not have the oil cooler mod done so it does run pretty hot.

worth noting my chargin system is verified working and a compu fire regulator

[rphillips]

Very possible, also could point to gas cap vent, 30 mi. gas usage, without ample vent, could slow gas flow drastically, after sitting long enough vent could gradually relieve vacuum and you'd be ready for another 30 mi. Next time it happens, can you pull over, take gas cap off, reinstall and see if it keeps acting up or runs right. If vent problem ON, PRI, nor Res. will flow enough fuel... Just thinking out loud.

[wilsonsandy07]

ill do it just to check the box for sure, although i will say i pulled my cap as soon as i got off and there wasnt any kind of noise or like a vacuum on it

[wilsonsandy07]

brain is thinking something electrical is overheating since its happening after getting off the hwy and losing air cooling. but then again, usually when something electrical overheats its fried.....doesnt work again after it cools off

[rphillips]

It can happen. It's been a long time but yrs. past a coil or condenser would mess up after got hot and do good again when cool... Haven't heard of that in a long time though.

[wilsonsandy07]

gunna throw it into prime next time it happens too just to make sure carbs are getting fuel, and ill probably double check plugs/wires next time it happens too but past that is kind of a crap shoot for me

[rphillips]

Yep, when searching got to try anything, simplest cheapest things first. Remember "IF" tank vent is the problem PRI. won't, help.

[wilsonsandy07]

Yep, when searching got to try anything, simplest cheapest things first. Remember "IF" tank vent is the problem PRI. won't, help.

copy thanks for the reminder

[wilsonsandy07]

Alright after the ride home here’s the latest

completely normal for 35 ish miles hwy, normal start, normal idle.

after those 35 miles hwy. exit, drop a gear and slow down to like 55-60 mph and symptoms begin. Same as before boggy throttle, jerky, slow to increase idle but able to keep going.

throw it in PRIME for a few miles, no change

pull over, kill bike, pop gas cap, bike doesn’t have enough power to start no choke, sounds like nearly dead battery!! Choke on start right away completely normal idle in nuetral

take off and symptoms remain, but able to limp home.

get home and kill bike, grab multimeter, bike starts right back up no choke this time, battery at 12.3 before start then over 13 with bike running.

[rphillips]

????????? Waiting for somebody that knows more than me.