Why Won't You Start!!!

[resjudicata]

Sounds to me that you reassembled the carbs wrong in some way. The tiniest mistake could prevent the carbs from operating correctly.

How many times have you rebuilt these type carbs? Anybody local that could go over them with you to make sure you get them assembled right?

Oh, BTW, adjust the valves.

Chris

[mike10]

won't start

Did you take the carbs,compleatly apart and follow the instructions for carb cleaning from this web site? I didn't hear you complain about getting the Air screws out most people do. You said the time it did start idle was high that's a sign of a air leak. I think you have some combination of problems. Recheck what you know is right, it might be wrong. Happened to me. When you do the valves, on the GSTWIN site there is a video of a Guy adjusting valves on a GS 500. Basically the same operation it was good help to me on my first time. I built a 1980 GS1000 from scratch my very first try at it. With a lot of help from this site. Now the bike screams down the road trying to get me a speeding ticket. It's not magic stay with it brother, it wants to run. Once it doe's, don't even sit on it without all you gear. Good helmet ect..

[Adler]

Did you take the carbs,compleatly apart and follow the instructions for carb cleaning from this web site? I didn't hear you complain about getting the Air screws out most people do. You said the time it did start idle was high that's a sign of a air leak. I think you have some combination of problems. Recheck what you know is right, it might be wrong. Happened to me. When you do the valves, on the GSTWIN site there is a video of a Guy adjusting valves on a GS 500. Basically the same operation it was good help to me on my first time. I built a 1980 GS1000 from scratch my very first try at it. With a lot of help from this site. Now the bike screams down the road trying to get me a speeding ticket. It's not magic stay with it brother, it wants to run. Once it doe's, don't even sit on it without all you gear. Good helmet ect..

Yup, followed the VM carb rebuild guide on BassCliff's site and redid all the o-rings courtesy of Robert Barr. Im not sure what air screw troubles you're talking about though, maybe the broken bits of airscrew some people have stuck in the hole? Thank goodness, these carbs didn't have those troubles.

I'm almost done with the valves, switched around some shims and now I'm up to ordering some shims to fix the few trouble valves. Here is where the clearances are as of now;

[CODE]
Cylinder Shim In Shim Ex Clearance In Clearance Ex
1 2.70 2.67 <0.0015 0.0025
2 2.70 2.70 0.0025 0.0025
3 2.70 2.70 <0.0015 0.0030
4 2.75 2.65 <0.0015 0.0020
[/CODE]

On Sunday I plan on going over everything, and maybe even switch the carbs for a spare set.

[Adler]

Alright! Update!!
Took me a long time but my valve clearances are DONE!!!

Here is where they are now;

[CODE]Cylinder Shim In Shim Ex Clearance In Clearance Ex
1 2.62 2.67 0.0025 0.0025
2 2.70 2.70 0.0025 0.0025
3 2.65 2.70 0.0030 0.0025
4 2.60 2.65 0.0025 0.0025[/CODE]This is how they started;
[CODE]Cylinder Shim In Shim Ex Clearance In Clearance Ex
1 2.70 2.67 <0.0015 0.0025
2 2.70 2.70 0.0025 0.0025
3 2.70 2.75 <0.0015 <0.0015
4 2.65 2.70 <0.0015 0.0015[/CODE]Thanks to Ghostgs1 and the valve shim club for making it easy.

Anyhow, I will shortly try to run this thing again and see if my issue was just the clearance, though somehow I dont think so....

[Adler]

Update again... I tried to run it again... no dice... VERY frustrating. I think my next step is to pull the carbs (AGAIN!!! ) and investigate... If that still doesnt work, its on to points and condenser.


EDIT: Anyone know how to test the points and condenser? That would be helpful...

[tom203]

Update again... I tried to run it again... no dice... VERY frustrating. I think my next step is to pull the carbs (AGAIN!!! ) and investigate... If that still doesnt work, its on to points and condenser.


EDIT: Anyone know how to test the points and condenser? That would be helpful...

You have double checked coil wiring to make sure that spark plug leads didn't get switched? Valves ok, fuel to carbs- all it needs is spark at RIGHT time .

[Adler]

You have double checked coil wiring to make sure that spark plug leads didn't get switched? Valves ok, fuel to carbs- all it needs is spark at RIGHT time .

Yup pretty sure about the plug leads, I even tried with them switched just in case...

It WILL run on quick start (I know, I know, bad idea) which indicates to me that either the spark is too weak to ignite the fuel or its not getting fuel from the carbs.

[spyug]

I share your pain....been there and now....back again....sort of. Back last fall and winter I rebuilt my 82 Katana project. The engine had been seized but I got that sorted and the carbs were completely redone as per the standing rules and regs of the GSR. The bike would not run. There is a huge long thread on this topic buried somewhere in the archives. The bike did eventually run and i had it tuned like a Swiss watch.

After languishing 5 months this summer I'm back on the project now and I can't get her to run on cylinders 3 and 4 ( there's a help me thread on here now too). now it will run on choke only. If I blow into the overflow hose , 3 and 4 will kick in but then die so gas is getting to the carbs. There is lots of engine vacuum and spark. Gas is not flowing through the carbs however. I pulled, recleaned and rebuilt the carbs yesterday but saddly no change.

Originally back in the winter I tried everything to get it to fire and nothing until someone suggested a novel approach. Disconnect or remove the airbox or pods and cover the mouths with "clingfilm" ( i.e. Saran Wrap etc). Poke a tiny hole in the center and with choke on crank her over. Once warmed close choke. I did this and it ran perfectly. Once running and warmed I removed the film and it continued to run fine and start and run there after. I don't know the whys and hows but it did work.

It did take a bit of cranking so I added a deep cycle auto battery in parallel for some extra cranking amps.

I just remembered this overnight so haven't got to try it again on the Kat but I will later.

You might try this too.

Good luck,
Spyug.

[resjudicata]

Yup pretty sure about the plug leads, I even tried with them switched just in case...

It WILL run on quick start (I know, I know, bad idea) which indicates to me that either the spark is too weak to ignite the fuel or its not getting fuel from the carbs.

If it will run on starting fluid then most likely you are not getting gas for some reason. You need to pull the carbs and check them over carefully to see what is preventing the carbs from delivering fuel. You may not be filling the float bowls for some reason. Or, if the float bowls are full them your jets aren't transferring fuel from the float bowls to the throat of the carb at the proper ratio.

BTW, if you question whether you are getting spark you should use a timing light to check. Simply connect the light and turn the motor over while watching the bulb of the timing light. A regular pulse to the light shows spark. Do this for each cylinder. Also, pull the timing cover and use the light for the timing marks to make sure you have the right leads on the right cylinders.

My bet here is the petcock not delivering fuel to the carbs, or the float valves not allowing fuel into the float bowls, or pilot jets that are dirty again and/or not fully cleaned.

Chris

[Adler]

Today I had a burst of motivation so I pulled the carbs and cleaned out the tiny holes in the bottom of the float bowl (that lead to the enrichment circuit) then I transferred all the things missing from my spare rack over to the spare rack and I reinstalled the spare rack.

Filled it with gas, flicked the switch and tried kickstarting it (the battery is weak, didn't want to stress it too much with starting) nothing happened... (besides the engine turning over... obviously...). So I did what noone on here likes, I sprayed one or two seconds of quickstart in the airbox, it fired up and much to my amazement it stayed ON!!! I adjusted the idle and it hums pleasantly around 1500, I could maybe turn it a little lower and Ill try that later.
Now I just wonder if my other rack of carbs is the problem or if the float bowls was the problem. A question for another day!