Project bike won't start

[Guest]

I bought a gs650g a while back and I cant get it to start,

here is what I have done and checked:

rebuilt all 4 carbs and cleaned with air and ultrasonic. ( K&L rebuild kit)
all new 4 intake boots and orings
all new spark plugs gapped correctly
changed oil/filter/sping and Oring
I checked spark on all 4 cylinders and it looks to be good.
Checked for air leaks.

I don't have a carb sync tool and I have not yet checked the valves. bike has been sitting since 1987 has 36,000 kms on it.

[Big T]

Well, spark, fuel,air

You have spark, so, are the plugs getting wet when you try to start the bike?

Most probable cause is that your carbs are still dirty, or those junk kits are messed up

[jsandidge]

The valves should definitely be checked. That can cause hard starting. If you bench sync'd your carbs (no special tools required) you should be ok for starting.

Hope you didn't get rid of your original jets and float needles/seats. You should clean them up and use them instead of the K&L stuff. OEM is better quality. That being said, that's not causing your starting issues.

You could also have weak spark issues. What's the voltage at the coils? Have you installed new plug caps?

There's a lot more on your to-do list. Check BassCliff's site and roll up your sleeves!

[jsandidge]

Oh, and check your petcock. You may not be even getting fuel into your carbs.

[gustovh]

Pilot needles 2 1/2 turns out? idle set? as stated before valve check? cables have proper slack?
V

[Sangheraent]

ok I have not checked voltage on the coils I did however just check the valves, Im not sure about the scientific way of doing it I am going to read the manual and get the proper way but I turned the cam knob up on each valve individually and checked clearance and 4 were more then .04mm and 4 were basically touching the valves so I know they need to be adjusted.

There was no fuel tank on the bike I am just using a long peak clamped on to the fuel line and it sucks gas and holds level as needed showing needles work well at least they close.

Spark appears weak in one of the coils now again not scientific but from my past experiences the spark didn't look strong so I will check voltage.

I bench synced the carbs I didn't check floats but from my experience that shouldn't affect starting could cause problems tuning but should start.

I am also going to get a compression tester and see what is going on inside there.

[Sangheraent]

how do I know what shims to buy? there are so many sizes is it trial and error?

[Rover]

Hello
This fellow has answers

http://members.dslextreme.com/users/bikecliff/

[Steve]

how do I know what shims to buy? there are so many sizes is it trial and error?

You need to measure your clearance and see what shims you have in there now.

If the clearance is not correct, you make adjustments by changing the shim by the appropriate number of sizes.

For help doing this, consult your service manual. If you don't have one, get one from BassCliff's site.

While you are there, get the tutorial for 8-valve adjustments.

One last tool can be found in my sig.

.

[Phred]

I had trouble starting my bike after 21 years. It would turn over but not catch. I had installed a new petcock, the carbs were cleaned, electrics were good, so I went over to my neighbours place and got one of his insulin syringes. I filled it with gas and squirted a little bit into the first and fourth cylinder, through the spark plug hole. Just enough to get the plugs to fire and turn over. That did it, and it has been running since then with no problems. It was almost as if there was an air lock in the carbs. that was preventing the gas from flowing or atomizing. I can't explain it other than that, I was a newbie at the time and had spent the previous 2 years rebuilding the bike.

[Octain]

I had trouble starting my bike after 21 years. It would turn over but not catch. I had installed a new petcock, the carbs were cleaned, electrics were good, so I went over to my neighbours place and got one of his insulin syringes. I filled it with gas and squirted a little bit into the first and fourth cylinder, through the spark plug hole. Just enough to get the plugs to fire and turn over. That did it, and it has been running since then with no problems. It was almost as if there was an air lock in the carbs. that was preventing the gas from flowing or atomizing. I can't explain it other than that, I was a newbie at the time and had spent the previous 2 years rebuilding the bike.

I've done that before as well. A teaspoon or so of fuel in each cylinder got me started a couple of times.
If nothing else, it will at least get it to fire.

[Crankthat]

All good advice above!

Do the valve adjustment before trying to start though.
Look for any wear on cam lobes while there.

Make sure the fuel is hooked into the T and not the vacuum line.
Try Phreds advice to get the carbs to start sucking the fuel.

[tom203]

Make sure plug wires are on correct plug. From a cold start .,these bikes need an extra shot of fuel from enricher circuit ("choke")- yours are probably still gunked up. As mentioned,locate those old carb parts.- they are better quality and just need to be cleaned.

[Sangheraent]

Ok so I did my valve clearence check based on this website: http://guglielmo.us/mc/valve_clearances.html

It appears that I do not have .04mm clearence in any cylinder I don't have a smaller feeler gauge so I don't know if it is touching or at .01-.03. But I do know that I am in for some serious shimming. But that is expensive and time consuming.

before I fork out the cash on that is there anyway to test the condition of the cylinders? Can I put the valve cover back on with a few bolts and do a compression test? I want to know that if I spend the money on shims that the rest of the bike is ok.

[jsandidge]

Shims are not expensive. You likely won't need many, as you can swap them around as needed. There is a member here (GhostGs I believe) that runs a shim club. For a small donation, he will swap your unneeded shims for the sizes you require. I've even done this with my local dealer for free! The only real expense is a gasket and rubber half-moons. Since you've already removed your cover to check your clearances, you need them now anyway.