Higher Rpm wall/cutting out

[suzukigs1100ez]

So for the last 2 weeks been fighting this issue on my 82 gs1100e. Did not have this issue last year just this year. But history on the bike. The bike I had gotten from the father-in-law. He bought it in around 2001 and left it sit. I took it over 3 years ago to get it running again. He had lost the title for it and never transferred ownership. So I had found a titled frame from another 82 gs1100e. This last spring I decide to swap frames since I had been running the plates on the wrong vin tag. So to be more legal I decided to change that. Last summer bike started and ran good. Just seems to be under powered but would go to red line.

So the bike has the everything from the last year except the Ign. switch and the frame. Everything else was swapped over. Engine stock as far I know with the valves adjusted to spec. Stock air box with stock filter. Unknown brand 4 into 1 header pipe is the only Mod that it had when I got it. Carbs were dipped twice for 24 hrs each. Has new O rings and boots between the carb and head. The carbs are also vac. sync to the same.

Now the issue. When your riding the bike it goes awesome till about 6500 and feels like you hitting a rev limiter. You can hear it cutting out. I thought it was a vac leak which I did find some and sealed them up but still doing this. Check voltage at the coils and found it low so I did do the coil relay mod with no change to out come. The plugs where changed when the bike was first got running for the road so that was 600 miles ago. I can bring the revs up in the driveway and get it cut out so I checked the charging voltage and at 5k it was at 14.1 and idle is are 13.6. It stays steady until the throttle let go. Brand new battery this last spring also. Have extra grounds off battery to frame and use box. Trimed all 4 wires from the caps on the plugs. 2-3 didn't look very good but 1-4 looked fine but did anyways.

I thought it was possible fuel issue but I changed the jets from 110 to 120 and the bike runs and pulls alot better with those but still hits that wall

Sorry for the long post just trying to bypass what I know so far. Below is the bike in question

[tom203]

So last year, the sorta illegal bike ran ok to redline.......but parts moved to new frame this year,but now
bike struggles at 6500?

Were the carbs cleaned for this transfer , or done previously?

" I can bring the revs up in the driveway and get it cut out" .... in neutral, no load? Do you have a spare ignitor to test ?

[salty_monk]

I would bet on the ignitor....

[suzukigs1100ez]

carbs were clean twice before last year and were removed for winter and drained I've had the bowls off twice this year with no signs of crud in them.

I originally was thinking the igniter but was reading in the search that they work or they don't it seemed. No way of actually testing it with just trying it with different one?

[John Park]

If it has a mechanical ignition advance mechanism - electronic came out in '83 - check that the advance is opening up properly and not rusted in retard.

[salty_monk]

82's run electronic advance in my experience...

[suzukigs1100ez]

So still messing with this. Did some more testing. I check the pickup ohms and it in spec. Made a jumper to tee into the coil while the bike runs. Found at idle the bike is getting pulse signal and flashes faster with increase rpms. Even when the rpms are raise till the point it starts to cut out. So I think the ignitor is working like it should. But other thing I had notice is at idle. I can remove the #1 and #4 caps off and engine does not change sound. I had clipped the wires before so I know the connection was good on that end. I ohmed out the caps and there reading a hair over 10. So there not the 5 it calls for.

When caps are off I do not see or here spark jumping unless I kinda put a screw driver into the boot to assist it. I reved the engine with 1 and 4 off and the engine would raise but wasn't very fast. So I know that 1 and 4 are kicking in with rpms increased so I'm wondering if there cutting out on higher rpms too.

I bought 4 new caps from the Suzuki dealer in town since 2 were high. Changed them in the parking lot and bike still cut out when I left. But this morning ride to work it only hiccup once (at 8500k) other than that it ran the best the bike ever ran.

Going run it on lunch see if I get the same results

Ran on Lunch seem to go back to hitting that wall again and won't rev past.

[Rob S.]

That's a pretty frustrating situation. Wait until Steve chimes in, he's one of the go to carb guys. I' m sure he'll have an opinion.

[tom203]

"morning ride to work it only hiccup once (at 8500k) other than that it ran the best the bike ever ran."

I wonder if this could be charging related....after bike warms up, maybe a high voltage situation is giving the ignitor's advance curve the fits.

[suzukigs1100ez]

I work 2 miles from home but I know there a little more warm up time in the morning before I hop and go. But last night after work I pulled the take off and redid the ground connector on 1/4 coil since I didn't like the fit. Let run with tank off and started up and went for a ride out town to try go and it back to being the worst even been. It 6k and just stopped revving past. So turn around put in the garage.

I did test to see what would happen if I pulled #2 off when running notice the same no sound of spark sign spark leaving the boot but the engine almost stalled when it got removed vs no change on the 1&4. I going pull the carbs off and dip them once more I guess I can't find any issues else where.

I can ride with volt meter on it and see what the voltage would be

[Brendan W]

But other thing I had notice is at idle. I can remove the #1 and #4 caps off and engine does not change sound.

That generally means that 1&4 are not firing. Are there temperature differences between the headers?
Maybe you are looking at a lazy coil? Is there enough lead to swap the coils over and see if the problem moves to cylinders 2&3?

[suzukigs1100ez]

1 and 4 are colder if just idling. If I bring the rpms up the temps even out. I try and swap them out as I got the tank off so I can get to them

[suzukigs1100ez]

Last night switch wires on the coils and swap caps around. Started bike pull 1 & 4 same no change on the engine. So I tried spraying starter fluid to see if the 1 and 4 would fire. The rpms came up so I pulled the wire off still no change with the coils still swapped. Thought if it was fuel issue that there be change in the engine if wires were pulled.

[suzukigs1100ez]

So decided to start working on this since it winter here. Took the carbs off to reclean them but might of found the issue. #3 carb diaphragm boot was not fully set in the carb the boot doesn't look damaged but there a good 1.25 of open gap were it wasn't seated. Going to soak the carb anyways since I'm that far torn down. Will post up any updates.

[suzukigs1100ez]

Soak carbs and bike is running better at times. Notice it cuts out if still partly choke but clears up if choke is pushed off till get to higher rpm. Does this if riding or sitting in the drive way. In the driveway seams to cut out at about 8500 or 9000. But riding seams to start around 7500 mark. Sometimes it does it and sometimes it doesn't.

Also took and measured ohms of the pickup sensor and that in spec. Notice that plate the sensor is mounted to is adjustable so I adjusted it to the middle of the hole. It was all the way to one side before. I got get my hands on timing light to maybe set it properly. The cam is free to move and springs are all intact and moving. Clean the connector for the pickup sensor to ignition module. All this with really no change to the core problem.

Thoughts?