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Discussion Starter · #1 ·
OK here we go!! This was a complete rebuild, it started with a 90 650 trip. Rebuilt by a pro builder with a great reputation!! All new line cleaned recleaned carbs new needle seats set floats carbs are good! The first start up was perfect did the proper break in 3 tanks of gas before I hit the bar! Then all of a sudden the ghost came out of nowhere! plugs starting to foul every ride, mmmm lets redo the carbs ran great then stared all over noticed that the fuel line were sucking air, ok new lines again, fire it up and away we go, now it wont start after sitting for 15 mins, now im scratching my head, now im not getting fuel I need to hold it to the bar pull it over 15 time, fast it starts and runs great! I read your site for all my info. Change the pulse line and fuel pump! Things are good again! Now I have a weak spark on # 2 ok snip off ends of wire and now have great spark!! So go for a ride its running flat, I open the hood in the field and now my wires are arcing all over! back to the garage insulate the wire, try to start it now im not getting fuel again,, I know this is wrong but I shot either in the air box and fire it up running great did a plug chop and it a titch lean not liking this for a new motor! sorry before all this it was running rich, now lean all by itself,, and wont fire just little sputters... like I said I have gone through this forum and read everything I can read before asking for help so this time HELP!!!!!
 

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With no other changes in the mechanicals, you could get a lean condition from a bad crankshaft seal, rubber carb adapters, or debris/varnish/ice in the jets.

Rule out the seal and carb adapters by spraying carb cleaner, starting fluid or even WD40 on the seal or adapters while the engine is idling. If you get a change in idle, you have an air leak. To check the jets will require the carbs off to remove the float bowl to re-clean the jets/passageways.

What color were the plugs (PTO/Center/MAG?)
 

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Discussion Starter · #3 ·
BC dan thanks for reply plugs were on lean side closer to a slightly toasted marshmello,all three of them were the same... did comprestion check on warm motor 128 across all 3.. didnt think of carb boots but i did seal check sprayed with liquid fire!! throttle is less responsive then before but consistant through out, then drops off slighlty at the end!! this motor is playing tricks on me!! so bottom line,, hard start, no fuel until i spray at start up, runs ok, just not snappy for a 650, my old motor witch was very tired!! had more snap!!
 

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Hmm, you have covered everything I would have done. How's the fuel line inside the fuel tank? That pickup line could be collapsing because of age or have a bad check valve in the weighted filter, or have cracks in the line somewhere. That's about all you have left to check!
 

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Discussion Starter · #5 ·
BC Dan you nailed it, even tho i put all new lines on in the begining they must have stretched and was creating an air leak, put new lines on again, and bingo! i have a great running machine! just need to dial in the carbs, im close adjusted the slids for better throttle reaction, and leaned out just a bit to much, reajusted looking better going to drop the clip on the needle! and that should wrap it up,, also i shielded my plug lines and even better spark than before!! thanks for your help!!!!
 
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