1980 GS450E wont start

[pete]

Hmmm I'm a bit stumped at the moment, everything sounds in order...

You did say the airbox is all sealed up now right? Pretty sure you did...

Have you given it some choke maybe?

A valve adjustment certainly can't hurt so worthwhile knocking that off regardless... and you never know it might help!

[CycloneGS]

My top lid has a crack in it. would that cause it?

[pete]

Put some duct tape over it as a temporary fix to see if it helps...

[CycloneGS]

Duct tape didnt help.

[pete]

Bugger! Man I'm reaching the end of my limited knowledge here...

I might be rehashing stuff but I gotta list this stuff out otherwise I'll go nuts thinking about it more...

- Got good spark?
- Got clean carbs?
- Got fuel tap on prime?
- Got fuel leaving the fuel tap?
- Got fuel in the float bowls?
- Got an oiled air filter?
- Got a sealed air box?
- Got kill switch on run?
- Got clutch in or clutch switch bypassed?
- Got vacuum and fuel hoses the right way around? (I don't think they fit the wrong but I'd best raise it in case)

I can't think of anything else right now... I'm really hoping someone more experienced can chip in here!

[CycloneGS]

Yep, everything checks out. I took it to the shop to see what the deal is. There is a super cool vintage bike shop here in town. Pre 1982 bikes only...http://vintagecycledsm.blogspot.com/

[pete]

Interesting... I hope they do a good job! Normally I'd be saying don't take it to a shop, but in this case it looks like it might not be a bad idea...

Don't be surprised if it's something really obvious though...

[CycloneGS]

Yeah, this will be humbling

I hope its not something major, I only paid $150 for the bike.

[pete]

True, definitely let us know what they find though...

[Flaming Chainsaws]

I was going to say check the cam timing then do a valve adjustment. If the valves are out of adjustment, the bike will be hard to start.

And since you have, fuel, spark, etc, it would make sense to me.

Hope the shop does a good job!

[chef1366]

Did you check compression?

[pete]

Good call Chef! I knew there was something I was missing...

[CycloneGS]

I dont have a tool to measure compression, but just plugging the hole with my finger I had some decent pressure. Still waiting to hear back from the shop tho.

[apopleptic]

I have the same bike, although mine doesn't look quite as shiny as yours, and I had some similar issues in getting it started.
I also had to replace my plugs and igniter, but it still souldn't start/run correctly.
I ended up having to fully clean the plugs and then regapped them (manual said .024-.028" the shop insisted .032in), the moment I adjusted the gap to .032in I could tell the bike was about to start, but it still wouldn't run right but it would try to start. turned out to be a combo, #1 the spark plug gap had a speck of something conductive inside the barrel so the spark wasn't happening in the gap, #2 I had routed the throttle cable wrong so it was always giving it more gas than appropriate and it would alternately flood/rev.

[CycloneGS]

Apopleptic, yeah sounds similar to mine.

Shop told me that my spark advancer was broken. I trust these guys for sure, but I dont know what that part is? Does he mean the signal generator?

Anywho, school is crazy busy right now, its a good thing the twin is in the shop.