1984 CR500 Carb Swap Question

[bronc3]

I understand swapping from my stock round slide to a newer flat slide is a big improvement to this bike, but can someone tell me if an 85 carb is a bolt- in affair?

[Turboloader]

18 hours ago, bronc3 said:

I understand swapping from my stock round slide to a newer flat slide is a big improvement to this bike, but can someone tell me if an 85 carb is a bolt- in affair?

I had that very bike and I raced it and enjoyed it. It had starting issues with the stock set up. Race gas works wonders in that zany engine. Id go with the 86 and up carb. Im sure some meathead on here will have the dimensions on the venturi bell diameter and the carbs width. But I expect the 85's might work. I know the pj carb from that time worked better than the old round slide. SDD its the man to see for your carb swap infos. I bet it will run a lot better. I know the cylinder head needed modding to chill out the pinging, so that might be an option also. I miss my 84...

[SlowDinoDog]

The original Keihin round slide PE carb and stock reeds worked fine on my '83 CR480. I recently switched it to a 38mm Airstryker PWK carb from JD Jetting with the recommended jets and needle. I also changed to a VForce reed assy. The bike starts and runs great.

The new PWK Airstryker carb fits in the '83's carb insulator and air filter boot nicely, its a little shorter overall than a PE, but the VForce reeds were wider and I slotted the airbox mount to make up the difference.

I've got a Keihin PJ oval slide carb on my '88 CR250. It works fine in the CR250. Its shorter in overall length than the PE round slide, too. I would guess it fits in the '84 CR500 carb insulator and air filter boots.

Edited February 4, 2022 by SlowDinoDog

[bronc3]

1 hour ago, Turboloader said:

I had that very bike and I raced it and enjoyed it. It had starting issues with the stock set up. Race gas works wonders in that zany engine. Id go with the 86 and up carb. Im sure some meathead on here will have the dimensions on the venturi bell diameter and the carbs width. But I expect the 85's might work. I know the pj carb from that time worked better than the old round slide. SDD its the man to see for your carb swap infos. I bet it will run a lot better. I know the cylinder head needed modding to chill out the pinging, so that might be an option also. I miss my 84...

Thanks, I will be racing it tomorrow. Definitely going to try a later model CR500 carb. 

[DEATH_INC.]

On 2/5/2022 at 6:39 AM, bronc3 said:

Thanks, I will be racing it tomorrow. Definitely going to try a later model CR500 carb. 

Definitely go to the PWK airstriker if you can. They add power and response to all the later 500s (replacing the PJ), should be a huge improvement over the 'ol 84 carb.

[SlowDinoDog]

18 hours ago, DEATH_INC. said:

Definitely go to the PWK airstriker if you can. They add power and response to all the later 500s (replacing the PJ), should be a huge improvement over the 'ol 84 carb.

I think with my '83 CR480, maybe I didn't notice much difference because its also choked down on the inlet side with a CR250 size insulator and reed assy and on the exhaust side with a CR250 size exhaust flange.

The JD Jetting version was super convenient with the right jets and needle. I've just tweaked the air screw.

[DEATH_INC.]

3 minutes ago, SlowDinoDog said:

I think with my '83 CR480, maybe I didn't notice much difference because its also choked down on the inlet side with a CR250 size insulator and reed assy and on the exhaust side with a CR250 size exhaust flange.

The JD Jetting version was super convenient with the right jets and needle. I've just tweaked the air screw.

The biggest advantage of the airstriker is part throttle response, that's what the little fins help. Good on a big bore.

AJ Waggoner (Built 500.com) who pioneered the AF500s did some tests on them, and the power under the curve was best with the 38mm airstriker. Better than the larger 39.5mm pwk from the kx500, and better than a 40mm lectron.

[Babywolf]

Does anyone know what the jets for the air striker were for the 480?

[87' CR 5003]

22 hours ago, Babywolf said:

Does anyone know what the jets for the air striker were for the 480?

Don't know the 480 specifically but all 3 of my 500's took stock jetting with only a drop in the pilot size by 2 steps I think. I could go leaner on the main or needle but not a necessity.

[bronc3]

Will my jets out of my stock carb work in the flat slide carb? Anyone recommend jetting for the flat slide on my 84 500 at sea level and warm climate?

Edited February 11, 2022 by bronc3
added info

[DEATH_INC.]

2 minutes ago, bronc3 said:

Will my jets out of my stock carb work in the flat slide carb? Anyone recommend jetting for the flat slide on my 84 500 at sea level and warm climate?

The main will (the part number crosses over to the later stuff, but I'm not sure about the needle and pilot, the numbers are different, and don't fit the size sequence.

I run pretty much the same as '87, a 175 main, 48 pilot and a stock CGJ/R1368N needle in the center clip on my '87 500 with the airstriker, sea level here too. Should be a close enough starting point for the 'ol air hammer.

23 hours ago, Babywolf said:

Does anyone know what the jets for the air striker were for the 480?

I'm guessing on the 480 with a slightly reduced capacity maybe start 1 size richer on everything and adjust from there.

[87' CR 5003]

43 minutes ago, bronc3 said:

Will my jets out of my stock carb work in the flat slide carb? Anyone recommend jetting for the flat slide on my 84 500 at sea level and warm climate?

168 main, R-1370N needle,middle clip, 48 pilot. 38mm AS, V force 2's.  Buuuuut I'm at 1-1300 ft in the middle of the country

[87' CR 5003]

17 minutes ago, DEATH_INC. said:

The main will (the part number crosses over to the later stuff, but I'm not sure about the needle and pilot, the numbers are different, and don't fit the size sequence.

I run pretty much the same as '87, a 175 main, 48 pilot and a stock CGJ/R1368N needle in the center clip on my '87 500 with the airstriker, sea level here too. Should be a close enough starting point for the 'ol air hammer.

I'm guessing on the 480 with a slightly reduced capacity maybe start 1 size richer on everything and adjust from there.

Death, Did you ever find a website to replace CR 500 riders ? I tried Banned but had to re-enroll twice and didn't really enjoy all the BS they had.

[bronc3]

Thanks all, good info to start with. 

[DEATH_INC.]

1 hour ago, 87' CR 5003 said:

Death, Did you ever find a website to replace CR 500 riders ? I tried Banned but had to re-enroll twice and didn't really enjoy all the BS they had.

No, I signed up for banned, but no-one goes there.

[SlowDinoDog]

On 2/9/2022 at 7:01 PM, Babywolf said:

Does anyone know what the jets for the air striker were for the 480?

I bought the JD Jetting version and they said 175 main and 45 pilot. Works great at 1000ft.

Edited February 11, 2022 by SlowDinoDog

[87' CR 5003]

9 hours ago, DEATH_INC. said:

No, I signed up for banned, but no-one goes there.

Man, I feel for these guys tryna run 500's without that resource. All that experience gone in a flash. ?

[bronc3]

The initial setup on my 84 CR500 with PWK 39 is 175 main, 58 pilot, 1.5 turns, stock needle 3rd groove. Starts incredibly easy and seems to run better than it ever has. I’m sure we will tweak it, but I’m pretty pleased with it so far. 

Edited February 25, 2022 by bronc3

[Turboloader]

Dudes jet according to the replacement carb's chart. The numbers might be different, so it would be wise to follow the chart and only use the jets recommended for that carb. Dont jet that big mutha' too lean or you will gurnade it. Its Aircooled and it will kablam easily! I did my 84' a tad rich or one step rich, to prevent gurnading it. LOL!

[bronc3]

On 2/27/2022 at 7:55 AM, Turboloader said:

Dudes jet according to the replacement carb's chart. The numbers might be different, so it would be wise to follow the chart and only use the jets recommended for that carb. Dont jet that big mutha' too lean or you will gurnade it. Its Aircooled and it will kablam easily! I did my 84' a tad rich or one step rich, to prevent gurnading it. LOL!

The 48 pilot in it was incredibly lean - unrideable. The current setup comes from another member here with the same bike/carb/ elevation. The bike really seems to like the setup, has never started this easily or run so well. Had this bike for about ten years now.