KTM 500 - Less is more?

[bill1960]

Originally Posted by empedrado

While this tank is not a huge increase in volume 11.5L vs 8.5L, it does it without adding much additional bulk and it is lighter than the stock tank to boot!! In fact this tank is the same width as the stocker.

So how did they do it. Well a bunch of the volume and the weight must be attributable to DOT vs aftermarket. This tank is thinner wall than the stocker by a significant margin. I can only assume DOT had something to do with that. In addition the indentation on the stock tank where the charcoal canister resided is not present adding probably a quart there alone -- and this is lower cg weight for the same amount of volume. Most of the rest of the volume increase comes from a taller neck on the tank. Which isn't bad as you do not have to fill it all the way up -- meaning with the stock volume of gas this tank is lighter and has a lower cg.

The only snivels I have about the tank are that the fuel pump and shrouds are held on with wood screws vs brass inserts. Could only really see this being a potential problem if one should need to go in and change fuel filters often. The other snivel is the sock gas filter does not fit with this tank. I was having a lot of piece of mind knowing that our crappy gas was getting an extra dose of filtration before mixing with all the FI stuff. Maybe one of the engineer types could figure out how to make the filter fit.

Are these volumes the actual fuel capacity or the total volumes including the space taken up by the fuel pump and filter ?
A 3 liter increase in actual fuel capacity would be worthwhile imo.

[empedrado]

I wish my advancing age would allow me to recall how much fuel the stock tank actually took, but at this point would just be a guess on my part. When I filled the new one it took 2.8 and there was still some room -- I just did not want to fill to the top. A buddy said he put just under 2.9 in his tank. Does anyone recall what the capacity of the stock tank actually is?

Originally Posted by bill1960

Are these volumes the actual fuel capacity or the total volumes including the space taken up by the fuel pump and filter ?
A 3 liter increase in actual fuel capacity would be worthwhile imo.

[neduro]

Originally Posted by empedrado

Does anyone recall what the capacity of the stock tank actually is?

See the earlier post. 2.2 on the button, engine won't start to brimmed.

[neduro]

Originally Posted by Motorfiets

Thanks, with this being said would you recommend them for a big bike for daily use, no interstate, lots of gravel, lots of pavement?

Generally, no. I don't tend to have flat issues dualsporting (gravel/pavement), it's when you're really off-road that pinch flats start to be more frequent.

Why go to the expense of mousses unless it's an acute problem? Are you flatting often and if so, what tires/ pressures?

[tentative_rider]

I have mounted the big (5.3gal) Acerbis tank. Install was very straight forward. The overall width is actually narrower than the shrouds on the stock tank. I did wash the tank out thoroughly and dry it to remove plastic shavings from the manufacturing process. I do notice a bit of "fuel slosh" when it is full, but most rides I just run it with between 3 and 4 gallons. I see very little downside to this tank.

One thing I have noticed is that since the large lobe on the left side of the bike is larger than stock, and that is where the pump resides, that the low fuel light comes on with quite a bit of fuel left. No big deal, since it is very easy to visually see the fuel level on this tank. The plastic is more translucent than the stock tank.

Most of my riding is on double track hard pack, forest road, blm roads with occasional single track. I might pee my riding pants if I came across a descent like the one Ned showed at the beginning of the post.

[Saltydog86]

I like the thought of the Motion Pro rim locks to reduce the need for balancing tires. I see they come in 3 different sizes, what size are you using in the KTM? I believe my 350exc wheels are the same as the 500.

[neduro]

Originally Posted by Saltydog86

I believe my 350exc wheels are the same as the 500.

They are, front is a 1.85, rear is a 2.15. Check the side of your wheel to confirm.

[LukasM]

Originally Posted by neduro

They are, front is a 1.85, rear is a 2.15. Check the side of your wheel to confirm.

You sure about 1.85"? That seems wide, all previous <640 KTMs and Bergs used a 1.6".

[dirtbikeslob]

front is 1.6,rear 2.15

[neduro]

Originally Posted by LukasM

You sure about 1.85"? That seems wide, all previous <640 KTMs and Bergs used a 1.6".

Sorry, my error. 1.6, been around Rally bikes too much lately.

[xr400r]

Ned,

I am curious how many miles you have/had on your Dakar motor before it needed anything or is it still untouched in your trailbike.

[neduro]

Originally Posted by xr400r

Ned,

I am curious how many miles you have/had on your Dakar motor before it needed anything or is it still untouched in your trailbike.

Funny you should ask. The motor has somewhere around 125 hours on it now, and I feel safe in saying they couldn't be much harder. About 2 weeks ago, it suddenly started consuming oil, I pulled the valve cover and saw a lifted intake valve guide seal.

A buddy and I swapped it out by locking the motor, using a compression tester to pressurize the cylinder and thus hold the valves up, and removing/ reinstalling the valve spring retainer. Since put about 15 hours on it and it's back to consuming trivial amounts of oil. Leakdown was about 7%, so rings are at least decent if clearly not new.

Pretty impressed by the beating that thing has taken! Hope the 500 proves as reliable.

[neduro]

An update on steering lock: the left side, where the ECU is, needs some level of protection. I spent some time witha flashlight trying to sort out the maximum amount of steering lock possible.

First, I replaced the 6mm ECU mount bolts with Pan head cap screws:



Then, I screwed around with different combinations on the lock bolt, and wound up at 3 normal thickness washers to allow the forks to brush those bolts, but not firmly contact.



Then, I went riding some more:



This last part was the best in my opinion.

Originally Posted by LukasM

The newer torx head sprocket bolts like the one in the middle are the best because they are even flatter than the old ones.

I liked this concept, but I tried it and it didn't work for me. The sprocket bolt has too much shaft exposed to achieve full steering lock, the sidestand bolt (which is shorter and fully threaded) I couldn't get to the right length for maximum steering but holding the forks from hitting the ECU. A nut underneath was too much, and it wanted to fold washers. What am I missing?

[LukasM]

Originally Posted by neduro

I liked this concept, but I tried it and it didn't work for me. The sprocket bolt has too much shaft exposed to achieve full steering lock, the sidestand bolt (which is shorter and fully threaded) I couldn't get to the right length for maximum steering but holding the forks from hitting the ECU. A nut underneath was too much, and it wanted to fold washers. What am I missing?

If you use a die to thread the shaft of the sprocket bolts like I said it should not stick out any more than your cap screw plus the washers.



On the left side of the Berg frame - which has the regulator/rectifier in the same spot (it used to be the ECU on the earlier bikes) - I even had to use a thin nut (washers would have worked too) to get enough clearance. At full lock the forks now just hit the rads, or rather the BPD guards I now have on there.




Edit: I took this pic when I did mine, you will need a M8x1.25 die and a vise to hold the bolt while you thread it.

[jesusgatos]

Or you could just drill out the threads in the steering stops a few millimeters deep and the run a tap through it to chase the threads.