GS1100E very slow cranking after warmed up

[adam83]

My 83 GS1100E starts up great and drives great. When cold, it cranks pretty normal/quickly and fires right up. After the bike is warmed up and ridden, if I turn it off then try and restart, it cranks ultra slow, and its just barely enough to fire up the bike again.

Does this sound like battery, wiring, or starter? It only happens when the bike is hot. Im going to start doing some testing but if anyone has any input I'd love to hear it thank you.

[rphillips]

I dun'no... I don't remember hearing of anything like that before.

[Grimly]

Have you metered the charging state? Wouldn't be unknown for a weak charging system to not put enough into the battery for a hot start.
I take it you're not charging the battery between outings - overnight, for example? If so, it's starting normally every cold start with no charging?
I'd be suspicious of a loose grounding strap from the engine case to the battery negative and moreso of the positive cabling, check and clean every bolted connection.
After that, all that's left is the starter itself, and heat making it slow to work - perfectly possible it's a bit grunged up inside.

[bonanzadave]

perfectly possible it's a bit grunged up inside.

image.png

Not a bad idea to take it out and clean it. I did it and it can be done without pulling the carbs.

[adam83]

My charging voltage at 1000rpm is around 12.6 V, while at 1500rpm its around 14.1 V. When cranking after warmed up its around 9.5 V.

My ground cable is literally brand new correct OEM suzuki cable, making great connection at engine case and battery.

The starter has never been opened up since Ive owned it (5 years) and likely not by the last owner either, so Im going to buy one of these Caltric starter rebuild kits, looks easy enough to install. might as well.

https://www.ebay.com/itm/280463003847

[chuck hahn]

Just went through this on my 83 KZ750 L3. Same symptoms. Then one day while cranking it started smoking under the starter cover. New starter solved the issue. Hope this helps. Dont wait till the motor implodes like i did.

[adam83]

I removed the starter and used the kit last night. The starter was all gunked up and the Commutator had buildup (brush and carbon residue?) and some corrosion. I cleaned everything with electronic cleaner spray, wiped away the buildup in the case and on the armature. The bearing sounded good but was getting dirty so I cleaned it out and repacked grease. I replaced all the seals and installed new brush plate and brushes. I cleaned the remaining tough buildup and corrosion from the commutator with 2000 grit sandpaper. Some pitting remained on the copper, but overall it was clean and I didnt want to take off too much material. If you do this make sure to note the position of the tab that comes off the stud so when you put the new one in it doesnt hit the brush plate. Also make sure to note how the end caps of the case line up to the case. I greased the thrust washer and new seals, re-installed. Everything is working great now, no problems with hot starts.

Just off the bike. Looks fine from the outside..






Opened it up to discover the truth..












After cleaning with electronic cleaner and wipe down, did about 3 passes with 2000 grit autobody wet/dry sandpaper..








New seals, re-packed bearing, new brushes..








All back together, looks exactly the same as before..

[adam83]

I did not use the new bearing or bronze bushings that came in the kit, mine were in good shape.

[steve murdoch]

Good to see that you got it sorted out.
Thanks for the pics and follow-up.

[rphillips]

Congrats, I love good endings. Am I wrong to think in your dirtiest picture you had already done a loooot of cleaning??? Mine, everything on inside was completely covered and coated with black carbon and suit. A good cleaning and lube got it back in good shape, brushes were still in good shape.