Ok, so I'm at my wit's end with this thing.  Backstory is I was working on customizing my '91 500E into a cafe/brat/streetfighter.  Mechanically I changed to ebay pod filters and a ebay slip on exhaust as well as converting to a lithium battery.  I took it for a test ride with the lithium battery before upgrading the rectifier/voltage regulator and the bike rode just fine until about 5 minutes into the ride when I did a highway pull and the bike died and the battery went up in smoke.  Inspecting the bike after that incident I found the left hand ignition coil was melted.  I replaced both coils, as well as the ignition module with used OEM. I got a new ebay voltage regulator and replaced the battery with a new sealed lead acid unit.  All the electronics on the bike seem to work fine now, lights, horn, everything is good, however now when I start it the bike barely runs.  I can get it to idle, but it is very rough and as soon as I give it throttle the slides will start to flutter and the bike sputters and dies. I have taken the carbs off and cleaned them as well as replaced every gasket, needle, jet etc. I've tried every combination of jets, mixture screw settings, needle washers that is listed in the wiki and everything does the same thing, the bike will start and idle roughly for a while but will refuse to rev.  Anybody have thoughts/ideas?   TIA

I couldn't get those dumb pods tuned.  I tried like heck.    Got the lunchbox and much better.  My tiny .02.  You said you had it running and I also had my pods running to where I went around the block, but I threw the towel in and did better with lunchbox.

Quote from: cbrfxr67 on May 03, 2021, 02:11:45 PM
I couldn't get those dumb pods tuned.  I tried like heck.    Got the lunchbox and much better.  My tiny .02.  You said you had it running and I also had my pods running to where I went around the block, but I threw the towel in and did better with lunchbox.

By lunchbox you mean the K&N one right? Not the stock airbox?

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Yea the K&N RU 2970 that clamps onto both carbs.
We (I may have started it) started calling it lunch box eons ago due to the fact it looked an awful lot like a plastic gladware food container.
The funny thing is, I never ran it on my bike. I always used individual pods. I would raid wrecking yards and these were a dime a dozen on the 80's GSXR's, katana's, FZR 1000's etc.
But someone here sourced them from usdieselparts.com back maybe in 2003 or so. No idea if they still have it, or what it was even used for on a diesel motor.

Someone should call them and ask them what diesel motors use it for and some diesel mechanic with a few missing teeth and a cigarette dangling from his lips may come come on and esplain -
Yea we put the diesel in this big holes and the finely atomized diesel comes out of the filter and we put that in the engine and burn it. Y'know diesel doesn't carburete the same as gasoline, that's why we use this lunch box here.

Cool.
Buddha.

Thanks for the clarification Buddah, any thoughts on getting my pile running right?

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You torched a battery or some electrics.
However 91 with K&N pods and slip on would need 150/40/3 turns/1 washer for the carbs.
I dunno from your description what you might have poof-ed. The Li Ion is foreign to me, and I've seen enough horror "brat/cafe/bobber" jobs to not venture a guess without more details and pics to go with it.

Wont rev carbs vent - upper T to the rear of the carb - you have the vent open to air ? It needs to be. Else I'll have to look a bit more into your original post.

Cool.
Buddha.

Yup, top T vent is open. I've got new 40 pilots on the way, previously I only had stock 37.5 and 42.5 to play with

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The pilot jet size is not the problem. Lots will still be wrong even with different main jets. I know Buddha and a couple of others have had some success with the K&N lunchbox but it sucks as an air filter (all K&N do... as do all other cotton/oil filters, they don't filter well at all). But you know, lots of folks are more interested in the appearance than they are with running right or engine longevity.

If the lunchbox does require 3 turns on the 40 pilot jet as Buddha says, then it will likely run better with 42.5 pilots and more like 1.5-2 turns. Gotta tune it in use.

The slides fluttering thing is all about inconsistent vacuum. There's something to be said for that big pressure dampener provided by the stock airbox. Almost like Suzuki & Mikuni engineers knew what they were doing.

BTW the meltdown electric thing was probably the rectifier portion of the reg/rect going south, allowing the voltage to go way too high and trying to charge the battery at 35V and smoking the coil. Probably a lot more melted wiring and connectors in there. You should definitely check every inch of wire and every single connector from the stator all the way to the battery, starter, and coils. You're lucky you didn't wind up with a fire in a very unfortunate spot to have one when the battery went bad. DC and hundreds of amps is a recipe for disaster when something goes very slightly wrong.

I checked continuity on the whole wiring harness as well as resistance on the pulse generator coils. Everything electrical check out with specs in my Haynes manual.  I tried putting the stock airbox back on but the boots that connect to the carbs are too old and stiff to fit anymore.  I can't get them to properly seal on the carb intakes

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by "check" I meant inspect the wiring visually and especially the connectors which can easily melt down. 2 ohms will pass a continuity check but 2 ohms in a connector will cause it to melt and catch fire.

You should sort the airbox. Sure, it's a giant pain to use. I have a '92. Same problems. Still worth it to fix. You can get vaseline to soak into the rubber and it'll recondition it to some extent and make it more flexible. Use a heat gun on low to warm it up to make it stretch to fit.

The stock bike will not run right with 42.5 pilots, no matter what.
I have heard of some flowed and modded heads needing 42.5 and 45's. In reality, 37.5 will let you run almost as well, I suspect the right pilot for that carb on the GS stock motor (filter and pipe are secondary cos the flow rate is so low on the pilot) may be a 39 LOL.
But yes K&N stops mosquitos and not much else.
Cool.
Buddha.