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Old April 10th, 2019, 09:10 PM   #1
NorthernNinja
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Lean Condition After Valve Adjustments

Bike was parked in the fall, wouldn't idle properly at the time but figured it was just carbs, couldn't get it running this spring, checked the valves and they were out of spec so I adjusted them, this was my second time doing this and all went well the first time so it's not a new procedure for me. Well, after getting everything back together it will not run properly at all. Found it had a bit of an intake leak, which i corrected, and the bottom hose of the coasting enrichener was popped off, so i threw it back on figuring all would be good, still nothing. It has all the symptoms of being lean, to me, bear in mind my only experience is with slide carbs (which i believe are far superior at this point). it's hunting for idle, won't really idle right, choke kind of helps sometimes, not so much others. The odd time i could get it to rev up it was crackling and shooting way more flames than usual. but it was pretty much dying as soon as I opened the throttle usually. Figured it seemed lean, pulled the carbs all apart. The pilot jets were a bit dirty, cleaned everything out, clean all jets and passages, reset mixture screws to 2.5 turns out which was my standard and worked before, synced my carbs, checked for good flow out of the petcock, slide operation is good, both rise and fall nicely with compressed air, everything seems to be perfect. Put it all back together and now idle - quarter throttle is a bit better minus still feeling lean (hanging idle, crackling, etc). But as soon as i open it up more it bogs and kills it. The only way I can get it to rev up more is by basically completely blocking off the airbox, then it revs up alright until it starts to just choke. So to me this seems obviously lean, but i have no clue why. The carbs have always been the same setup for the last 45,000km and everything seems perfectly fine. Seems strange that it's all of a sudden after my valve adjustments but it has been sitting for 6 months. Is there ANY other reason why it could be acting like this? I know enough about engines and fueling but for the life of me i can not figure this out and it's starting to piss me off. I just want to ride.
Thanks.

TLDR: Carbs are freshly cleaned, valves adjusted properly, everything set the exact same as it has been it's whole life, and for some reason it has symptoms of an incredibly lean condition. ANYTHING that could be causing this?
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Old April 10th, 2019, 09:13 PM   #2
Triple Jim
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I'd double check the valves before continuing, to eliminate them as the problem.
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Old April 10th, 2019, 11:21 PM   #3
DannoXYZ
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Quote:
Originally Posted by NorthernNinja View Post
cleaned everything out, clean all jets and passages
How was this cleaning done?
As in what was procedure?
What products and machines did you use?
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Old April 11th, 2019, 08:37 AM   #4
NorthernNinja
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I guess I'll recheck the valves. I did set them to the looser side of their specs, whereas last time i set them more in the middle. I have an aftermarket exhaust and de-snorkeled intake, tried jetting it after i did that stuff but it didn't want any more fuel. The only thing i can think of is maybe it's finally breathing enough to need bigger jets, but that seems really strange to me because last time I adjusted the valves it was still totally normal.

And Danno, I just did a basic cleaning. took out all the jets and stuff, sprayed carb cleaner through and blew it out with compressed air. They were pretty spotless for how lean it seems so I didn't really think that would be my problem even. But I could fully disassemble again and run through them with wires and stuff i guess. Also i was careful to try not to get carb cleaner in/around the diaphragms too much.
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Old April 11th, 2019, 09:00 AM   #5
Triple Jim
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Setting the valves on the loose side of spec is fine. Problems occur when they're too tight and don't quite close. I'm not saying that I believe that valve adjustment is definitely your problem, but since you adjusted them in the middle of all this, I do think it would not be a waste of time to double check. If even one somehow got set so it's not closing all the way, you will chase other problems forever.

As Danno is suggesting, the problem is very possibly that your carbs are not yet really clean. If you're confident that your valves are now correct, carbs would be the alternative place to start. Having all the small internal passages clean is critical.
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