Ok, New development

[bighamms]

I decided to check for spark one last time. This time I took out the right plug, grounded on engine and turned it over. At first, i had no spark, then I let it crank for for about 10 seconds and started getting spark. It looked weak to me, but there was spark. SOOOO, i put it back in the bike and tried the Left plug also letting it turn for 5-7 seconds.....and low and behold, it fired up. the bike just started and ran as long as i kept pressing the start button. So i let it die, then tried it again, and got the same result, but this time I gas it, and it responded well.

so, what would make the bike run with one plug out???? Help...

 

[Dave8338]

Bad plug, coil wire, coil ground, weak coil, poor connections, battery that is low on charge...

 

[Billy Ricks]

Have you checked the voltage going into the coils? Have you checked coil resistance? You should get 3-5 ohms on the primary side, the side the wires from the igniter go to. The secondary side should give you 25k-50k ohms if they are stock coils. You measure secondary resistance by removing the plug wires and inserting one probe into each plug cap that comes off of the same coil.

 

[BassCliff]

Hi,

Check the "Electrical Odd and Ends" section of my website for a fairly comprehensive article on ignition troubleshooting by Mr. Matchless.

What about the rest of the maintenance? Valves, carbs, etc?


Thank you for your indulgence,

BassCliff

 

[bighamms]

Progress...I think???

Progress...I think???

I decided to go out and wrench a bit more today (it's about 98 degrees here and the combination of a non running piece of equipment and extreme heat will not end pretty). I read the ignition check instructions that Basscliff sent me. I'll have to read it a few more times because it did not totally sink in.
I decided to take off the coils and check for broken wires and clean up connections. put everything back together and the bike fired up again. Ran for about 6 seconds than stalled out. This sequence repeated 4-5 times. So it is running, just not very good. I was able to give it a bit of throttle and it rev'd but then died.

on two occasions, it backfired rather loud. I've taken the carbs back off and am thinking that maybe i need to adjust some jets. my bike is fitted with the BS34ss carbs. Main/pilot setup is: 115/17.5. I don't have an air screw, but do have another small jet on the intake side. Currently, I have all jet securely seated in their respective slots. Should I adjust these out a bit?

 

[hampshirehog]

I'm guessing but GS1100? You can't adjust the jets by screwing them in and out. The only adjustment you've got is the mixture screws (head side of the carbs) and balance. Is everything 100% clean (I mean 100%)?

Is your fuel tap working properly - could be that you're just managing to fil the float bowls enough to start then they're not filling quick enough to keep the bike running.

 

[bighamms]

@hampshirehog.....No, a gs450s (1981). Carbs have been rebuilt (chem dip, new o-rings and gaskets).

I also rebuilt the petcock. seems to function fine when I test it buy sucking on the vacuum. It opens the petcock and the fuel flows freely.

should all of the jets be securely seated in their slots?

 

[Billy Ricks]

@hampshirehog.....No, a gs450s (1981). Carbs have been rebuilt (chem dip, new o-rings and gaskets).

I also rebuilt the petcock. seems to function fine when I test it buy sucking on the vacuum. It opens the petcock and the fuel flows freely.

should all of the jets be securely seated in their slots?

All except the idle mixture screws on top of the carbs. Adjust them for the highest idle you can get out of them.

 

[salty_monk]

Yes they should. Only the air mixture screws have any adjustment

 

[hampshirehog]

should all of the jets be securely seated in their slots?

Yes. Tight but not overtightened (you'll strip threads or heads).

Not sure if you've got a prime on that bike - if you have set the lever to that position. To check if it is the tap remove the tank, blank off the vacuum hose (a bolt or pencil etc will do) and jerry rig a fuel supply - even a funnel that fits inside the fuel pipe will be enough -don't spill any petrol!

 

[Dave8338]

How about an inline filter, other than the one on the petcock, inside the tank??? :-\\\

 

[bighamms]

More progress...

More progress...

I was able to get the bike to run last night for more than 6 seconds. I had submitted a post asking about jet settings. Anticipating that I may have to adjust the settings, I took the carb back off. I backed the air jet (on the intake side) out a full turn on both carbs. Several guys replied to my post and told me not to adjust the mains & pilots so I put the carbs back on. Decided to call it a night and put the bike back together. Hit the starter one last time and the bike turned over 2-3 times then fired up and stayed running. I gave it gas, it responded. Was so excited I hopped on it and road it around the hood a time or two ( i know i shouldn't have, but I had a temporary lapse in judgment). I made sure to keep it gassed because it sounded like it wanted to die if i let the throttle go. It was really sluggish, but that's my fault. Realized after the fact that I forgot to hook the throttle cable in the bracket....YEAH, ROOKIE MISTAKE. As i was pulling back onto my street, it died (i wanted to see if it would idle on it's own.).

couple of take aways from this bit of progress....I'm thinking that I may replace the coils for good measure (any suggestions on NEW coils would be great), may also replace the petcock to eliminate a lack-of-fuel issue. May sound unnecessary to just replace stuff, but it is far cheaper than buying a new bike. Also, when it was running, the engine didn't sound like other 450's i've heard, so I'm definitely going to do a valve check/adjustment.