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Ideen zur Wahl der Stoessel bzw. pushrods

Die nachfolgenden Zeilen hat mir Jim Miller von Jesel V-Twin http://www.jeselvtwin.com/ netterweise in einer email geschrieben und mich mal ein wenig aufgeklaert worum es hier eigentlich geht. Lucky und ich stimmen mit einigen dieser Ansichten nicht ueberein, aber es ein intressanter Einstieg in die Materie wenn man so wie ich damit noch nie etwas zu tun hatte.

"............we have found that titainium is a poor choice for a pushrod, as is carbon fiber. Titanium is to springy, carbon to stiff. We have learned that a properly heat treated chrome moly, works best. The pushrod weight is of minimal concern, compared to a pushrod that does not bend and or flex. if you want to lighten valvetrain components, that's good! but focus on the valve [titanium], keeper / retainer [titanium], rocker arms, and lifters and use a pushrod that is strong enough to do the job, don't worry about the weight.

Since you are using a hydraulic lifter, a fixed pushrod would be the best route for you. I would suggest one of our 3/8 straight pushrods, with the .281 ball on each end [you can go with the smaller ball because your rockers and lifter should be a v-cup style] also the smaller ball decreases friction and keeps the pressure in the center of the cups. If you were to go with a double taper I would suggest the .400x7/16x.400. but you may have clearance issues?

Springs and coil bind!!! We have found that you would like to be around .050 from coil bind. Some run less and some run more.

Anmerkung: Any compression spring that is stacked solid, with no space between the coils, is coil bound. It cannot be compressed any further. Usually, coil bind will break lifters.

Here is the reason....lifter loft....every engine has it. Lifter loft is the beginning of valve float, and the only way to control valve float is to minimize the distance a valve can float or a lifter can loft. You do this by putting in strong pushrods as you don't want your pushrods to act like a spring and by tightening up the distance of coil bind.
Valves can float .180, if your coil bind is at .180, if they are at .050 they can only float .050. understand so far?

So if your valve floats .180 the recovery time will be much longer then if they are at .050, this in turn reduces valvetrain harmonics....that evil thing that caused catastrophic engine damage.

As far as not wanting adjustable pushrods, the real reason should be that the conventional screw type adjustable pushrods are only locked down on 3 or 4 small threads and this is a weak, flexing area. we offer a slip fit tip adjustable pushrod, that is adjusted by different size shims.

The springs will be determined by rpm. Springs are very important!!!!!!........................"

Soweit die Ausfuehrungen von Jim, der uebringens auch recht angefressen ist von der ganzen Materie wie man sich leicht vorstellen kann. Anbei ein Bild von ihm, seinem bike und seiner crew von 1998.





left to right - Rich Kita, Bill Garret owners of the HD dealership Jim worked at for 18 years, Jim himself in the orange and black shirt, Don Motley the rider, John Zenneti the crew chief, and Dave Bloom who traveled with us and drove the truck!







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