Carb issues

[dzwarrior]

Hi guys,
Been looking for a while with a lot of great info. I have a 87 warrior that has been a total beast since 98. Best 500 I ever spent. Recently I decided it's time to show some love to the old girl. First thing was a new clutch. Afterwards I realize it was running lean. Backfires when letting off throttle. I upper the main from 145 to 147 then to 150. Raised and lowered needle. Finally I had a 152.5 ran ok. Ok as in it would run decent at times then at times would pull hard like it should. But it was intermittent. Its stock with the air box lid drilled and stock pipe with guts removed from tail pipe. I pulled carb this weekend soaked it and reassemble it with the 152.5. Still lean, even with air box holes tapped up. So for the hell of it I took the stock 145 and drilled it to 3/32 Still lean. Went to 7/64 and it was fat as hell. Played with needle no luck. Today I took another 145 and drilled a 3/32 and played with needle again. Still fat.

Intake boot is good, I've had that before. New petcock on tank. Spark seems good. Can't tell on compression, don't have proper adapter. But it is or feels tight. Hell I can almost pick up the whole thing trying to pull start it.
Am I just going to far from 152.5 to the drilled out jet?? Could I have a week coil?
Plan on getting some larger jets. 160 range I guess. Any thoughts?

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[Warrior1996]

I'm assuming you are still running the stock air filter as well? It sounds like you are getting way to big with your jets. On a stock air filter and gutted pipe, I would think the 152.5 would be on the rich side. Have you checked your spark plug? what color is it?

 

[dzwarrior]

It was black around the oitside, electrode was whitish

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[dzwarrior]

Yes stock air filter

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[Warrior1996]

Something else is wrong then imo. There is no reason you should be lean with a 152.5. Have you changed your pilot jet? and you might want to check your carb boot better. A good way to check is by running the engine, and then spraying starting fluid on the boot, if the RPM increases, you have a leak.

 

[dzwarrior]

I agree, I used carb cleaner on the boot with no change. Pilot is the same, 22.5 I think. But definitely something else I think also. Before it would run crappy then the next pull it would pull awesome.

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[dzwarrior]

Hmm...I just put a 150 back in, needle on low setting. Running decent. WTF

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[Warrior1996]

I have a larger pilot jet in mine to get rid of the bottom end hesitation. 25-pilot/147.5-main I believe. I only have a k&n air filter, stock exhaust with baffle. Is your air filter in good condition, and is it sealing against the airbox properly? Any exhaust leaks around header area?

 

[dzwarrior]

Air filter is a aftermarket k&n type that I think is sealing up ok. No exhaust leaks until the header meats the slip on. However it's been slightly leaking since I have had it. The muffler has a few pin holes forming. That is on the to do list. I'll run it again tomorrow. So it is 150 with needle low as it will go. Had minor pops in the exhaust when I let off the gas. Prob. Put it to middle position. Still don't know why I'm chasing this. Or maybe I'm over thinking it

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[dzwarrior]

That is my plug, used starting fluid with no notice in speed. 150 jet needle is low placement and it runs shitty.

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[dzwarrior]

Another question? What is this diaphragm do? Is it a enrichment valve like a Holley? Or is it something else. I am way lean. Looking at all intake stuff now

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[lbjamm]

Deceleration Enrichment Diaphram

 

[dzwarrior]

Will that cause back fire when letting off throttle? Plug looks good. Its running good with a 152 main. Way to much I know.

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[lbjamm]

Will that cause back fire when letting off throttle? Plug looks good. Its running good with a 152 main. Way to much I know.

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Maybe. It will cause it to run lean on deceleration if not working properly.