Loctite 5910, 598 and Permatex Ultra Black

Valve Cover Gasket Sealants

On my KTM, the corners of the “half circle” parts of the valve cover rubber gasket are supposed to have a little bit of “Loctite 5910” put on them before installation. However, it appears Loctite 5910 is only available in Europe. My web searches seemed to indicate that the closest thing to this in the USA is “Loctite 598”. That can be easily ordered online, but is still not at any of my local stores... they all carry Permatex products instead. It seems “Permatex Ultra Black” gasket maker is the closest Permatex product I could find. I looked at all the tech data sheets, and while I’m not a chemical engineer, these three products did seem very similar to me.

Loctite 5910 (Europe only?)

Loctite 598 (Professional distribution only?)

Permatex Ultra Black (Found at my local auto parts store)

All three of these ar Oxime Silicone, thixotropic paste. All are RTV (room temperature vulcanizing). All are oil resistant. And the properties once cured all seem similar to me.

If anyone knows of a substantial difference between these three products, please let me know!

Steering head bearing adjustment

Adjusted my steering head bearings because I thought they were a bit loose. Then again, maybe my stand was wobbling a bit. Sigh. At any rate, here's what I do.

1- I loosen all the bolts on the top clamp and give the clamp area around the fork a light tap with a rubber mallet to free things up.

2- I loosen the top nut until things are really free and I can feel a bit of a click in the fork legs when I pull them forward and back.

3- Then I tighten the top nut until it feels tight and then I can feel the steering is a bit restricted. Just enough so with the front wheel in the air the handle bars won't fall to the side when I push them. I check there is no play in the fork legs.

4- Final adjustment: I loosen the top nut *just enough* that the handle bar, when knocked up a bit from full lock will fall back down on it's own. If you knock it a bit harder from full lock it will stop at the center. It's not completely free spinning like it is when loose, but there is only a smooth glide when you move the bars, no restriction. At the bottom of the fork legs there might be the smallest click when you push forward and back, but then again it may be my stand. ;-)

5- Lastly, I tighten the clamp bolts, fork legs first. I tighten both bolts on one leg to 10 ft-lbs, then 12.5 ft-lbs, then 14.5 ft-lbs (20 Nm). I do then go back and forth between the bolts at 14.5 ft-lbs to be sure each bolt is up to torque.

Well, that's my way, FWIW.
Carl 

Supersprox vs Dirt Tricks Ironman Sprocket Weight

Being a lightweight myself I like to keep my bikes light. The rear sprocket on a motorcycle is often a heavy steel part. You can get aluminum sprockets, but they often wear out very quickly. So the sprocket manufacturers have been coming up with cool ideas like making sprockets with aluminum centers and steel teeth or making sprockets of super strong spider webbed steel. I was curious which approach might be lighter.
So I weighed one of each! These are both 48 tooth sprockets for a KTM.

Supersprox 48T: 25.1 oz

Dirt Tricks Ironman 48T: 19.6 oz

Supposedly the Dirt Tricks Ironman sprocket approaches the weight of an aluminum one... but I don't have one handy to weigh.

While I was at it I weighed a pair of front sprockets. I had a OEM KTM sprocket and a Dirt Tricks one. Both are 13 tooth.

KTM 13T: 4.5 oz

Dirt Tricks Ironman 13T: 4.3 oz


I put the Ironman products on my bike.

I also heard rumors that it was a good idea to grease the splines where the front sprocket mounts. Supposedly the hammering away of the drive train wears down the splines and proper grease can help prevent this. Google around advrider.com and you will find lots of threads on that. At any rate, normal grease won't do, you want high a high pressure moly grease. Apparently most people use Honda Moly 60 Paste. It's cheap enough. Another recommended fix is the dirt sticks washer on the front sprocket. Its harder and and supposedly holds the sprocket in place better.
Here you can see I've applied the Moly 60 paste to the sprocket. I was careful to use as little as possible. I also put it on the sprocket, not the shaft, hoping that any excess would be pushed to the outside of the sprocket where it could easily be wiped off.

Here's a shot of the installed sprocket. I cleaned the threads with a tap and used new loctite. Note I have marked it so I can see if it ever decides to come loose.

I should also note that I have seen the WASHER turn , while the bolt remains tight. I called dirt tricks, and they said that happens sometimes... I'm not sure what to think of that. But as long as the bolt stays tight I figure things are good.