Back Togather and Back Firing!

[Caterpillarmech]

So, I got it all put back togather today after about six hours of work. Ran like a champ for a while. It starts fine and idles fine but after a good pass is starts popping and dies. I can choke it and it will fire and back fire and run for 30 seconds and then I have to kick the crap out of it to fire again. I let it cool and it fires right up again. Smooth idle and good power. Go to make another pass and it does the sam thing in sixty seconds. I've read several threads on back firing and I don't think it could be the fly wheel keay as it starts and runns fine at first. Help me Obi Wan Kenobie!!!!!!!!!

 

[super noober]

whats your jetting at? i had a stalling problem with mine when i first got it back together and it was due to lean jetting....

 

[blasterfreek30]

possibly bad reeds??

 

[Caterpillarmech]

Reeds are carbon fibre and they looked good when I dropped them in. I don't know what the jetting is as I have not tore the carb down yet. I know, I know I'm going to have to get off my butt and pull it out. With the jetts though, I didn't change any thing with the engine. Should I still have to go through them?

 

[super noober]

Reeds are carbon fibre and they looked good when I dropped them in. I don't know what the jetting is as I have not tore the carb down yet. I know, I know I'm going to have to get off my butt and pull it out. With the jetts though, I didn't change any thing with the engine. Should I still have to go through them?

i wouldnt think so but its still good to check.. you didnt like remove your airbox lid or anything did ya? im not saying it IS a jetting issue i was jsut sharing my personal experiance. but i am currious to hear whats in there..

 

[sicivicdude]

Pull the gas cap off and check the piece of tubing that's on top of it, and the valve in the top of it.

It could be fuel starvation caused by vacuum on the gas tank after a good hard pass.

 

[Caterpillarmech]

K.I.S.S. Keep it simple stupid. I like that, It very well could be the gas cap. I know this sounds stupid but I have been smoked by the time I get off work. I am not hitting on all cylinders when I get to my projects. Thanks for all the help guy's. I'll let you guys know when I pull the carb off and check the cap.

 

[98blaster+4]

now this could be a jetting thing . my qeustion for you is this. why did you rebuild it? for general maintenance reasons or did it blow up and have to be rebuilt??

 

[Caterpillarmech]

This is strictly a freshen up and to fix the cracks in the frame. I had good compression but I bought seal kit so I figured I would just do some preventitive maintnance. I replaced the jug base and head gasket and a few lip seals Shifter, kick starter and blocked off the oil pump. I ran 92 octane on 32:1 mix with Yamalube.

 

[xJust_Causex]

Did you do a leakdown test after you put it all back together? may be an airleak leaning you out.

 

[Caterpillarmech]

No I have not but I will doi it tonight.

 

[Awk08]

how bout re-torque all the head and base bolts after the heat cycles???

 

[Caterpillarmech]

I checked the torque and they all were good. Checked the carb and it still has a 230 main. I did find that I did Not block off the oil line to the carb. Blocked it and it seemed to run better for two minutes. I will do a leak down when I get a chance. Gas cap was good also.

 

[Caterpillarmech]

For any one still folowing. I just started checking every thing again. I found the wire on the key switch was loose. The female terminal was smashed and the male was not seated just graising the outside. I took it for a run and drove it around for half and hour with several hot passes. Thanks for all the help guys.

 

[royalt67]

Always nice to hear when someone gets it figured out!