2003 KX500 137SX Timbersled Build

hwwee · Feb 14, 2017

Gearing

The KX is back up and running!
I am now working on some tuning.

Gearing that I had stock for the KX500 was a 13 tooth front sprocket on the bike going to the oem timbersled 16 tooth sprocket. I left this for the time being and focused on the chaincase. In the stock 2016 SX137 it was two 17 tooth sprockets. I replaced the top sprocket with a 16 tooth and the bottom with an 18 tooth. Riding on Thursday to test!

I am also not spot on with the Lectron yet. Still some fine tuning on the powerjet and the metering rod.

Also seems about time to do the waterpump seals I have been noticing some watery tran oil. Always something!

highflyernick · Feb 14, 2017

If you're looking for more track speed, I think you'll want the 18 on top, 16 on the bottom. That's what I run on my 500 SX

portgrinder · Feb 15, 2017

Couple comments

You could try running more piston clearance. I do it and have recommended to a few guys on here. It likely would have saved you. It helps for hot/cold and if you are making more power. You can also open the ring lands up a bit and when the aluminum smears it has somewhere to go before it pinches the ring and you lose compression

Check your breather first. I bet water is coming in there, not the water pump. You can also shim out your impeller and it will cool much better. Very noticeable.

The big bore won't make any more power. Unless you get a decent pipe, open up the ports and put a bigger carb on it. Im pretty sure to run that big of a piston you need to either weld up the thin area above the exhaust port and mod the power valve or sleeve the cylinder. But again don't expect much for power gains over your stock setup

M5- · Feb 16, 2017

That looks just like the first piston on my Cr500. I thought it was a 4 point cold seize. I rebuilt the top end rode one day hard all good. Next day up the trail same thing seizola. Turns out I had a small hairline crack in my bottom case half where the main crank bearing rides and the crank was walking. On the first rebuild it measured fine but under load it would move enough to pinch the rings. $300 for the first top end rebuild and $1000 for the second one including a new bottom end. I love the 500's but its getting tough to ignore the fact that these motors and parts are 25 years old. If someone built a modern 500 I would be all over that.

M5

Grr · Feb 16, 2017

You can buy billet new cases, billet new crank, pistons, billet new heads, etc etc for a cr500. They are loooong from dead or hard to get parts for

M5- · Feb 16, 2017

Grr said:
You can buy billet new cases, billet new crank, pistons, billet new heads, etc etc for a cr500. They are loooong from dead or hard to get parts for

That's true but new stock CR500 cases are NLA so suddenly you have a $5k billet 2 stroke motor so for the same money there are other options. The day of the cheap 500 is coming to a close.

M5

Grr · Feb 16, 2017

I don't see it that way, if you are like me who has a complete running 500 and need cases I can be into billet for $1700. That's a heck of a lot cheaper than a new bike! Only thing lacking is transmission parts and those are about to be made as well, every single part will be able to be purchased separately.

In fact I can do a complete standard rebuild with stock style reman crank, piston, use my cylinder (which can be resleeved so it should last forever) and head and all other parts and have a completely fresh 500 in billet cases for under $2500. Fact is with all the new stuff coming out for the CR500 they will GAIN in popularity IMO.

Granted when you start talking about a billet Liger 585-625 you are going to be into big money but it is still only the price of a new bike, and there is nothing you can buy that is remotely close in power to weight. Besides the people building them normally have $5-10k in the rest of the bike by then and buying new would be a downgrade, having to start all over upgrading suspension etc.. I only wish they put a balance shaft in the Liger case then it would have been perfect.

hwwee · Feb 16, 2017

Ride

Headed up to Togwotee today and saw a few bikes running around! Sad I will miss the meet this weekend but work calls! Had some good weather. The gearing change made a big difference I am getting closer to this thing being fun to ride. It was warm up there today and I was running in the 170-190s. Stopped twice to keep her under 200. I feel the heated carb and jacket might be messing with my lectron on these 35+ temp days. I took the 130f thermostat out of my avid heater to see what the effect is on operating temps. It seems to be running the best around 80-110 degrees.

More tuning required but getting closer to what I want!

wwillf01 · Feb 17, 2017

You can just put a valuable on the inlet and exit so you can manual stop the flow to the carb heater... For sure if it gets to hot it makes it run poorly... Normally I only needed if I was in submerged powder...

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hwwee · Feb 17, 2017

wwillf01 said:
You can just put a valuable on the inlet and exit so you can manual stop the flow to the carb heater... For sure if it gets to hot it makes it run poorly... Normally I only needed if I was in submerged powder...

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This has got to be my next step. I was up tuning the carb today at altitude and I am not getting to where I need to be. Its gotta be the colar heat messing with the metering rod reading.Do you need a valve on both directions? I was thinking of just putting one in the line to the carb.

I also believe a tunnel cooler like everyone has suggested would be a good idea. I need to find one that will work with the SX platform and width. More research to be done! At least its running!

wwillf01 · Feb 17, 2017

Metered carbs and huge engine temp spikes don't go together.... Tunnel cooler is key ... Turning off the heat to the collar is also.. you fix that you will never touch the rod again... Summer it's never an issue... Once I did that with mine I never touched the rod through the whole season ..... Never and ran 1200s on the egt

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portgrinder · Feb 17, 2017

Shim your impeller out. You won't need a cooler.
Or do it the hard way, your choice.

wwillf01 · Feb 18, 2017

Were you running a long track? I think it has a lot more stress on the engine.. the tunnel cooler for me would keep the engine at 130 constant... Again for me this info is coming off a cr500 so I am sure there are differences plus I am a heavy dude

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hwwee · Feb 21, 2017

Lectron

I have tried just about everything to get my lectron dialed in. I am just not having much luck. The power is hesitant and all over the place. I have adjusted the metering rod both directions from extreme to 1/4 turns. Ive used digital calipers to put it to the dynoed spec they gave me. Ive adjusted the power jet the same. I just cant seem to to get her right! I am currently running the 5-3xl needle and tuning at 7000 feet but for some reason it just hates me. I did purchase an extra dirt rod (5-2XL) and that might be my last resort. I think its being thrown off by the air intake as well. Not using a stock airbox or filter might be allowing to much air in. (I cant use a stock airbox or filter due to the TSS suspension)

Anyone in the WY,MO,ID area have experience dialing in a 40mm Lectron? Im at my wits ends. I know its a carb issue and I just cant seem to get this old girl to run right!

Answ3r · Feb 21, 2017

hwwee said:
I have tried just about everything to get my lectron dialed in. I am just not having much luck. The power is hesitant and all over the place. I have adjusted the metering rod both directions from extreme to 1/4 turns. Ive used digital calipers to put it to the dynoed spec they gave me. Ive adjusted the power jet the same. I just cant seem to to get her right! I am currently running the 5-3xl needle and tuning at 7000 feet but for some reason it just hates me. I did purchase an extra dirt rod (5-2XL) and that might be my last resort. I think its being thrown off by the air intake as well. Not using a stock airbox or filter might be allowing to much air in. (I cant use a stock airbox or filter due to the TSS suspension)

Anyone in the WY,MO,ID area have experience dialing in a 40mm Lectron? Im at my wits ends. I know its a carb issue and I just cant seem to get this old girl to run right!

How long is your intake ? Tuned intake length is a MAJOR thing and I have a hard time believing anyone that got a Timbersled TSS intake on a two stroke making it work properly.

Post a pic.

martin_e_wilson · Feb 21, 2017

TSS intake to small = no hp

martin_e_wilson · Feb 21, 2017

I run pulse intake/carb on mine and it runs great

martin_e_wilson · Feb 21, 2017

I just helped a buddy and the stock carb ran pretty good on stock bike.

martin_e_wilson · Feb 21, 2017

This is mine on kx500

hwwee · Feb 21, 2017

Answ3r said:
How long is your intake ? Tuned intake length is a MAJOR thing and I have a hard time believing anyone that got a Timbersled TSS intake on a two stroke making it work properly.

Post a pic.

current setup I am using. Its really my only option with the TSS. It is not the stock TS setup I have that in the box. This is a one piece from HPS.

I am going to switch the metering rod tonight and see what happens tomorrow.

2003 KX500 137SX Timbersled Build

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