pop's through carb at,idle

[IXL2Relax]

Originally Posted by brucstoudt

I'd like to replace that vacuum petcock with a Pingel.i have one on my ironhead i drain the gas every winter easily,just open the petcock and let it run out.anyone know the thread size and fuel outlet sizes on my oem petcock?

Here's the Sportsterpedia section on the Fuel Tanks & Petcocks:
http://sportsterpedia.com/doku.php/t...ck_fuel_outlet

All 86-06 tanks (non-EFI EVO engines) use 22mm petcocks. (Some Ironhead tanks use 22mm petcocks.)

There's commentary there about INSTALLING THE PETCOCK that discusses how the dual-threads work.

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[brucstoudt]

Originally Posted by rocketmangb

I still believe the carb farts are a lean misfire caused by hot spots in the combustion chamber which ignite a LEAN mixture when the intake valve is open.
Cool the plugs down one heat range !

i tried 1 heat range cooler today pulled the splitfires and installed NGK DCPR8E. 7E is the oem plug,not much change today,i'll stick with them for a while.still need to do the IDS setting.

[IXL2Relax]

I have been using the Iridium plugs - DCPR7EIX - I like them. For me, I found them to fire more smoothly than the DCPR8E.

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[brucstoudt]

copy that.i noticed your bike has the 883>1200 conversion.still using the 883 heads i assume? reverse dome pistons used on the early oem conversions?

[IXL2Relax]

Originally Posted by brucstoudt

copy that.i noticed your bike has the 883>1200 conversion.still using the 883 heads i assume? reverse dome pistons used on the early oem conversions?

My build was a little more complex - I bought used Buell Lightning Heads (1200) - Bought new 1200 Wiseco pistons (ETA: Flat Top) - Had my cylinders bored specific to the new pistons - Used SE 6800 Ignition Module with a Q-curve (then retarded the plate about 4°). Cranking cylinder compression is 210psi.

Max power was 78HP with 81Tq - But I detuned it off that lean condition and it still produced 75HP with 80Tq. Quickly tops out in 3rd at 95mph.

More build details in My Motorcycle Chronicles.

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[brucstoudt]

thanks i'm trying to verify that 1200 pistons used with 883 heads require the dished pistons.back in the day this conversion could be done at the dealerships.i do see the dished pistons for 1200 bore on Wiseco's website.

[John Harper]

I think there was a template used to grind out the 883 combustion chamber when they did a 1200 conversion to reduce compression ratio. My guess is they used flat top pistons if they went the grinding route, but cannot confirm.

John

[IXL2Relax]

Yes - Dished pistons are needed if using the 883 heads. This helps to make the chamber size 1200cc's and aligns the piston cavity with the 883 chamber.

HD did have a template for grinding 883 heads for use with flat-top 1200 pistons. It came with the flat-top piston kit they offered. The grinding would open the head to make it have a 1200cc chamber. I initially bought such a kit, but when I was able to buy the Lightning heads, I resold that kit. How many guys have the skill to do that modification PROPERLY?

Dished pistons became available as a better alternative. Of course, now with 1275cc kits available, that would seem to be the right direction to go if you're starting from a basic stock 883 top end...

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[brucstoudt]

oh i've been looking at the 1275 kits.i saw Hammer's video where Aaron mentioned not to carve out the 883 combustion chambers to match the larger pistons.better squish i'm assuming the way they are? but too much compression without the dish.