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turbo dan

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About turbo dan

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    Male
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    New Mexico
  • Interests
    Two stroke motocross

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  1. turbo dan

    Cheap eBay wheel set?

    It's pretty easy to cut costs when the Chinese think R&D stands for Ripoff and Duplicate. The cost of building a bike comes with the cost of development. The best chance they have of producing a competitive bike is by outright stealing someone else's design. Without the same production methods, quality control and metallurgy I don't think they will be able to produce an equivalent product, but they will be able to come up with something convincing enough to steal significant market share from the companies that have been developing and building real bikes for decades. Not good for the sport, all things considered. The Chinese are into it for a quick buck. You won't be able to get parts for your knock off Yamaha, for example, in five or ten years unless genuine Yamaha parts happen to fit.
  2. For a 250 two stroke, air cooled single cylinder. 12" header constructed of 2" straight walled pipe 14" divergent cone starting at 2" and opening up to 4" at the end 7" belly section of 4" pipe 12" baffle cone starting at 4" and tapering down to a 1" inner diameter stinger I'm shooting for a 7000-7500 RPM power peak with approximately 180 degrees of exhaust duration. I figure I can adjust the belly length to dial in the power characteristics once I have the pipe fabricated if it isn't quite right. Should be close as I have done some of the math. The rest of the dimensions are also based on how much room I have available. Any thoughts?
  3. turbo dan

    Fork Oil After Racetech Upgrade

    I like motor oil because it is designed to be slippery. ATF is designed to work with clutch packs.
  4. turbo dan

    Yz250

    I used to run ATF in two stroke gearboxes. After having two bearing failures on two bikes I switched to Rotella T4. I've had used oil samples analyzed after running them through gearboxes and the Rotella came out looking great. I've been riding for over 20 years and I've only ever had gearbox problems with ATF. Can't recommend it after that.
  5. turbo dan

    Fork Oil After Racetech Upgrade

    They do vary quite a bit. In practice you'll find that it doesn't make a tremendous difference in a cartridge fork.
  6. turbo dan

    Fork Oil After Racetech Upgrade

    Been running it for years in my 48mm KYB's. Kawasaki owners manual also states SAE 5w20 as an alternative to the KYB 01M. The action is good and my seals and bushings last a very long time.
  7. turbo dan

    Fork Oil After Racetech Upgrade

    There is always 0w20 motor oil. It doesn't have the same viscosity index as fork oil but I am certain that it is slipperier. Most people don't ride in cold enough weather to notice a difference.
  8. turbo dan

    Kx125 MODS!!

    7 tooth countershaft sprocket
  9. turbo dan

    2006 KX250 Shock

    I hate to come in here and offer a contrary opinion so regularly but I question that diagnosis. Any consequential defect on the shock shaft will cause oil loss, not air loss. Air pressure is confined to the bladder itself. Oil loss will cause the bladder to distend and even rupture but if you had no oil leakage that can't be the issue. Air does migrate through the bladder into the shock oil over time which is why you have to service these things somewhat regularly to maintain optimal performance. The result of this is low bladder pressure and air in the oil, which can occur in as little as a few months if you're riding a lot. Did these rebuild kits you were using contain a new bladder? Were they KYB parts of one of the aftermarket companies? In any case, as long as it is fixed it's all good. For the record you can use the 04-05 KX250F rear shock on the 05 KX250 and many other models as well. The valving is different but the shock itself is the same unit. The 03 and earlier bikes also used a similar shock but with a shorter clevis. When the linkage change in 04 they switched to a longer clevis to accommodate this. Even newer bikes like the aluminum framed 250F still use a similar shock though I have noted clearance issues with the airbox and shock reservoir when mounting these to the steel frame bikes.
  10. turbo dan

    hone every time?

    Pro-X just repackages other peoples products. They didn't manufacture anything. Somebody at Pro-X decided to put that note in there to help shoot down warranty claims. I know I've never seen such a warning included with any other ring or top end kit from any other manufacturer. Many manufacturers also use synthetic as a factory fill. You know how lots of people say you can't switch between conventional and synthetic oils? That's BS too.
  11. turbo dan

    hone every time?

    Were you just looking for someone to tell you what you wanted to hear? Synthetic or not doesn't matter. The person at Pro-X that decided to include that note doesn't know anything nobody else does. The probably put that same note in four stroke top ends too since it is supposedly common knowledge that synthetic oils inhibit ring seating in four strokes. In fact, most synthetic oils are actually mineral based but more highly processed than standard conventional oils. They behave similarly in many ways when compared to a true synthetic oil and are legally allowed to be marketed as full synthetic oils but in terms of chemical composition and lubrication properties they are the same.
  12. turbo dan

    hone every time?

    I don't do anything to mating surfaces unless there is a problem. If the head gasket leaks, you should look into it. If not, don't worry about it. Don't sand anything as you will almost certainly make it worse. It is very difficult to properly surface a cylinder deck or head with sandpaper. It can be done but the only time I do it is if I am adjusting deck height or cutting down a head. Honing a plated bore just takes hundreds of hours off of the service life of your cylinder. Honing cannot restore a worn bore to proper dimensions, it will only make any existing wear even worse. Honing a stock electrofusion cylinder can destroy the plating in seconds. Nikasil holds up a little better but you're still screwing it up. Ordinary hones will rip chunks of carbide out of the nickel substrate and scour out the nickel underneath. They also loosely embed chunks of abrasive in the cylinder wall which prematurely wear your new top end. The only time to hone a nikasil cylinder is during the final step of the plating process to crosshatch the cylinder wall. Replaters use a diamond hone which cuts clean through the carbide particles in the cylinder wall leaving a smooth, very hard but non abrasive finish. All you need to do to a running engine that just needs a fresh top end is take it apart, replace parts and put it back together. Work on a clean bike, make sure as little debris as possible gets into the motor during the process. Clean is critical. Clean everything before you put a wrench on a cylinder head or base nut.
  13. turbo dan

    hone every time?

    I have never honed a plated cylinder and I strongly advise against it. Deglazing is not necessary unless you're running castor oil. I take them apart, replace the top end components and put them back together.
  14. turbo dan

    I'm back in the vintage club again: 1978 KE250

    I would have gone for a rotary valve if one came up. There was a 250 bison in Nebraska but it would have cost too much to ship. There was a 350 bighorn in southern CA too but I did not hear back from the seller. Piston port induction is okay. It is much easier to change carbs, if I want to install a PWK it would be a breeze. The 250/350 rotary motors more or less require the stock carb. What will be interesting is measuring port timing. I know this thing is conservatively tuned. I'm looking forward to pulling the head off and getting some specs.
  15. Like it only wants to make power way up top. Weak power in the midrange but it revs like crazy on top. Hard to describe but that's the best way I can explain it. You aren't likely to be running lean if you start with stock jetting, stock is almost always on the rich side.
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