Author Topic: First time start after rebuild -- just backfires.  (Read 2207 times)

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Offline Zeke

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First time start after rebuild -- just backfires.
« on: April 16, 2005, 05:39:31 PM »
OK.  Here I am at the moment of truth with my 650.

I probably had too much assy lube in the cyls but I figured that after a few tries it would fire up anyway.

The engine isn't catching -- I get a backfire everytime I try it.

I filled the floats with gas 3 times to make sure they were full.  Choke is on, and I turned in the idle screw a few turn to make sure the throttle was open far enough.  I haven't really gassed it with throttle as I have an accelerator pump and this frequently flooded this bike.

I'm worried about the cam timing the most -- but only because it would take so bleeping long to check it.  But, I put it on and off about 15 times before getting the dot lined up, and I'm positive I did it right because when I did the valve adjust every thing was right, right?  Wouldn't I have known then if it was off?

What else should I check?

I'm gonna do spark check right now as I replaced the plug wires.

I didn't think I'd have to mess with adjusting the timing to get it running since I didn't touch those parts.

Help me guys!!

Zeke

Offline Gordon

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Re: First time start after rebuild -- just backfires.
« Reply #1 on: April 16, 2005, 05:54:14 PM »
Check to make sure you have all the plug wires connected to the correct cylinders.  Seems obvious, but it's a very common mistake.

Offline Zeke

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Re: First time start after rebuild -- just backfires.
« Reply #2 on: April 16, 2005, 07:13:58 PM »
Thanks Gordon.

I checked spark and it was good.  I checked the carbs for gas and #3 was empty.  I was able to remove the bowl and removed the float and bent the tab a bit, and then checked for operation. 

It ran.  Not perfect, but of course the rings aren't seated yet and the carbs are misadjusted.  Pretty proud of myself actually.

Interesting, this was the only carb that I measured and bent the tab when I rebuilt them.  The picture in the manual isn't clear and I figured that if it ran perfectly before I had to rebuild it then I shouldn't monkey with them.  I'll sort this out soon as I will need to remove the carbs again when I get a replacement arm for the choke next week.

OK, it was smoking a bit -- prolly normal in the first 5 mins but a bit more from #1 which has me a bit worried since that's were my rebuild started in november with the #1 exhaust valve guide.  There was a ton of oil in that pipe from the failure so maybe it's still smoking from that?

I'm hoping to warm it up, get it a bit synchronized and take a spin tomorrow morning.  A little bit closer every day!

Zeke