Swapped a 92 motor into a 2009. Running the 09 carbs and ignition jetted with a kit from Buddha.

This is the build thread: http://gstwins.com/gsboard/index.php?topic=71018.0 
There is a video there of the first start up after the swap.

With the real gas tank set up and the fuel lines running through the frame petcock, I couldn't get the bike started like I had in the first video using the temporary tank. So I decided to go back to that setup and see if I could get it started again. The only change I made was running the fuel directly into the main fuel line.

The bike started up immediately on full choke and ran up to around 4k. I eased the choke down as the revs climbed trying to find an idle point around 2k. I was getting quite a bit of popping through the intake and some backfires. The bike ran with a bit of an erratic idle for about 60 seconds before the revs dropped and the motor stalled out.

I re-started the bike but it wouldn't idle without half choke and some throttle. After stalling I tried starting again a few times without success. On my last attempt I heard a pretty large clunk. This video is filmed after the bike had cooled down a bit. You can hear the clunking sound again a few times.

How should I proceed from here? Could a starter gear problem cause this sound?

 

Hi Agno,
listened to your video and it seems to me, with that sound, that it is the starter gear is slipping on the magneto drive.  The holding nut may have lost just enough torque to slip on occasion.
You'll need to have your or someone elses ear next to the left side of the crankcase to hear it correctly and locate it as this when you start the bike. You'll hear the clunk.
It is easy to fix if it is this.
Adidasguy goes through it in detail on this youtube video.
https://www.youtube.com/watch?v=GxS5yZ44AHU

Hope this helps you or someone else can confirm this or offer you another opinion.. 

Quote from: Numewsm on April 08, 2019, 05:40:05 AM
Adidasguy goes through it in detail on this youtube video.
https://www.youtube.com/watch?v=GxS5yZ44AHU

Thank you for the link. I found the video pretty interesting.

I am pretty sure the starter and starter gear is doing its job at the moment. With the bike completely cold it will crank via the starter 20 times without firing. It is definitely turning over. If I apply throttle I get some popping in the exhaust, some cycles where it sounds like it wants to fire, and some clunking and spitting through the throttle body.

I am guessing it is a valve issue. Either timing or sticking. The part that gets me is that it fired up after getting everything put back together and ran for a bit. now it wont even do that. Cant get my head around what would cause that kind of situation.

Going to do some basic motor health checks and see if I can zero in on the issue. probably compression check, valve check/adjustment, maybe leakdown too.

Any other suggestions for hunting down the issue?

Hi Agno,
Bummer news..   

Firstly whip the cam cover off, remove the spark plugs and the timing cover.

Check 1: Set it to right top dead centre.  Look at the right side cams - exhaust cam should show arrow 1 facing the front of the engine. count 18 links on the cam chain from no.2 arrow on the exhaust cam to number 3 arrow on the inlet cam

Check 2: Do a compression test on both spark plug holes.  if you haven't got a tester use your thumb as a pressure guide.  No/low pressure = valves or piston issue

Check 3: Check your valve shim gaps. should be 0.03 to 0.08mm.  See youtube for easy guide (GSbaltimore does the main valve check and timing video!) Too tight is a problem, too loose 0.12 and above may be an issue

Check 4: check your shim buckets move freely.  If sticking remove and clean or get new ones

Check 5: remove the cylinder head and do a full internal check, may be burnt/cracked valves, holed burnt piston.  the head comes off on the bike, no need to remove the engine!!

process of elimination i'm afraid.....   

Do the checks in this order so you can progress through the engine.

Did a quick compression check.

Left side was 130psi dry and 162psi wet.
Right was 145psi wet and dry.

Pulled off the signal generator cover and found that the center bolt holding the timing assembly together had backed out!

Must have been correct on initial startup and rattled loose causing the bike to run progressively worse. Gonna get the timing sorted out and give it another go!

After securing the signal generator bolt, she fired right up.

Heated up under choke and I rode up and down the street a few times. After warming up I was having problems maintaining idle without some throttle input. Onto the next problem I guess!

Quote from: Agno on April 29, 2019, 02:06:14 AM
After securing the signal generator bolt, she fired right up.

Heated up under choke and I rode up and down the street a few times. After warming up I was having problems maintaining idle without some throttle input. Onto the next problem I guess!

so glad it was something simple!!!  lesson for me too on that one!!   

If it starts cold on full choke ok at about 4-5k, it will be a carb issue, blocked jets or fuel idle mix screw/ idle screw.  The engine will need to be warmed up/ridden for at least 20 mins to reach its full operating temperature to check fuel mix idle screw or idle screw.
if it starts cold on full choke at less than 4k revs you'll need to look at your valve clearances first and if they are ok the actual valve condition.