CR480 Carb Upgrades

[Tahitian_Red]

I'm going to upgrade the carburetion on my '83 CR480.  I have two carbs I am going to try, the first is an class legal Mikuni TM 38mm and the second is a more modern style Keihin PWK 39mm.  I will be running a V-Force reed and an aftermarket pipe.  Does any one have a baseline jetting setup I could use for either of these carbs? 

Anyone running the PWK on their CR500?

Thanks!

[Tahitian_Red]

Well I now have all the parts.  I will jet the PWK like a stock CR500 PJ Keihin, as a baseline.  Anyone running a PWK on a "modern" CR500?  Does the pilot jet need to be smaller in the PWK?

I'm not sure about using the 250 reeds in a 500, but will test them out and try reeds from a CR500 V-force if needed.  Anyone have experience with this?

[Enginerd]

Well I now have all the parts.  I will jet the PWK like a stock CR500 PJ Keihin, as a baseline.  Anyone running a PWK on a "modern" CR500?  Does the pilot jet need to be smaller in the PWK?

I just tossed the stock PJ from my 1997 CR500, and installed a 38mm Quad-vent PWK airstriker from a 97 KX250.  The bike starts so much better now! Main jet will be close to what the PJ used.  You are right in thinking the PWK will like a leaner pilot jet than the PJ did.  I'd start with 2 sizes smaller pilot in the PWK than what you were running in the PJ. You may still have to go smaller on the pilot, but 2 sizes smaller than the PJ is a good starting point.

I live at 5000' above sea level in the US. I was running  a #50 pilot in the PJ. I initially tried a #45 in the PWK, but it still started hard and was way too rich when the bike was warm.  I ended up going to a #42, then a #40, and I've finally settled at a #38 pilot.  The bike now starts with 2-3 kicks cold, and will idle within about 60 seconds of starting if the temperature is above 60 degrees F.  When warm, the bike still idles great and has smooth, responsive low-rpm power.

Hope this info helps! 

[Hoony]

T-Red have you checked out http://www.cr500riders.com/ lots of info on there for you.

[Tahitian_Red]

Hoony,

I did a Google search on CR500 PWK jetting and found a few threads on that site.  I am just going with the stock CR500 PJ jetting with a few steps leaner pilot.  Hopefully that will be close. 

[Tahitian_Red]

I am going to install everything tonight and hopefully get to test it soon. 

[John Orchard]

Wish I was there to test ride it  ;-)

[Tahitian_Red]

I'm fixing the forks next, so she will be waiting for you when you come back. 

[Tahitian_Red]

Started the bike up for the first time yesterday and it does start easier! 

It may be a little rich on the pilot though, but it was also 104 degrees F here.  I am looking forward to the first test/jetting session when it cools down a bit.  LOL

[Tahitian_Red]

Here is what it looks like mounted.  I need to loosen the clamps and wiggle it a bit to make it fit perfect in the air boot and add a fuel filter, but it was a pretty easy install.
 

[sa63]

was the ohlins shock hard to find ? and is that a standard kick lever or some other? but back to the topic anyway!

[Tahitian_Red]

Bought one of the last ones the East Coast (USA) Ohlins guy had, but you may be able to get one from VMX Racing (they were the last place I saw selling them.) 

Kicker is from a 90's Honda TRX Quad.  I think they are still available form Honda dealers, but I wouldn't use one without the compression release setup on the head.

[sa63]

ok. good info!
Are you running a flywheel weight as well?

[VMX Andrew]

How did you go with the setup on forks ?

[JohnnyO]

Sean, Derrick Redding has one of those quad kickstarters on his 480 and an Ohlins shock. You'll see it at conondale.