Trouble starting after top end rebuild

[Clc021583]

Hi , I have a 1979 suzuki gs 850. I just got done rebuilding the top end When I tried to start it for the first time it backfired trough the carbs and shot out a flame. The muffler was also piping while trying to start. Thanks for any help you can offer.

 

[Guest]

Either cam timing is off or more likely you have the spark plug wires reversed. I believe the left coil powers 1&4, right coil powers 2&3

 

[eddypeck]

I enjoy reading posts like this, knowing I have my first top end rebuild looming this winter :-(

 

[Steve]

Just follow the directions, pay attention to details, ask questions if you are not sure, you will be fine. :encouragement:

.

 

[Clc021583]

Timing was off. Still can?t get it to start though

 

[Nessism]

Carbs clean and airbox installed?

 

[Clc021583]

Yes , soaked carbs and cleaned out everything and the air box is installed.

 

[Clc021583]

Got it to start. Now it won?t stay running / idle. I have to twist the throttle to keep it running.

 

[Nessism]

Did you crank up the idle stop? Vacuum sync?

Be sure to put those new rings under some load right away. Don't thrash it, just ride it with an assertive in-town driving pattern.

 

[Clc021583]

I will try the idle stop. I don?t have a vacuum sync to adjust with. Just wanted to get to where I could ride to a friends house who has one.

 

[Big T]

Timing was off. Still can?t get it to start though

Ignition timing, or cam timing?

Does it still have points?

 

[Clc021583]

Cam timing was off. Got it fixed and replaced the spark plugs. Will run with the choke on but won?t hold idle.

 

[Big T]

Time to clean the carbs per the tutorial. You won't be the 1st person to have to reclean old carbs

Since it runs with the choke on, you have air, spark and some fuel.

You need to get the rest of the fuel

 

[Clc021583]

my carbs are different from the tutorial. Is there another tutorial for other carbs?

 

[cowboyup3371]

Yes, on Basscliff's site where you found the CV carb tutorial is one for the VM carbs which you probably have.

Here's the direct link to it
http://members.dslextreme.com/users/bikecliff/images/vm_carb_rebuild.pdf

 

[Clc021583]

Thanks! Cowboy up

 

[Guest]

You can bench sync the carbs using a pin, feeler gauge or small drill bit. The point is to get all of the butterflies to have the same gap. It is a ball park type of sync, but it will get you riding. You can fine tune the sync later with a synchronizer. Set your idle screw a two full turns from where it just starts to open the butterflies. Not enough or too much will cause a hard start or stalling. Adjust it to 1,100 rpm once the engine warms up.

 

[jdvorchak]

Soaking the carbs probably didn't clean the pilot circuits. I'm afraid you're pulling the carbs again to get them really clean. Don't feel bad. Unless you do a lot of carbs you won't get them clean the first or second or maybe the fifth time. We've all been there.

 

[Clc021583]

I pulled them and cleaned them again. Got a set of air brush cleaning brushes and cleaned every passage out. I got it running and rode it down the driveway a couple times. It wants to die on me after I stop and pull in the clutch. I figure I get the carbs synced and I will be in business. Thanks for all the help guys.