500R and its new massive paddle tires

[Billy Golightly]

These are the 25x13.5x9 16 paddle monsters I bought on ebay a while back. They are made by Dick Cepek and are called "Sand Sport's". They came on some kind of big 4 bolt pattern. I was originally gonna swap them over to 9inch honda rims from a 400ex that Ronnie gave to me, but the tire shop couldn't mount em because they said they were to narrow. The original rims were another 2 inches or so wider. Long story short, we ended up drilling them to fit the honda pattern. I then took them back to the tire shop and found out that part of the bead was missing in one tire. I'm going to guess its from when I had the tire shop dismount them to start with but I dont know, coulda happened anytime.

Long story short anyways, it has a tube in it now and the other one is holding air under its own good. I originally had a tube put in it this morning and then came home and rode for about 5 minutes and the tube broke. I took it back into the tire shop and evidently they had not tightened the valve all the way into the rim with the nut, because you could see right where it pulled the valve around the tube and made a hole. They made good on it and gave me another tube and installed it for free. Holding so far. Heres the ride report: I immediatly noticed the difference in ride compared to the pro-wedges. It does not feel near as tippy which I'm sure is associated with the massive footprint these things leave. The ride is predictable, and not wobbly like before with the pro wedges. I'm running about 8 psi in them. I''ll probably take them down to 5 but I'm weary of going less then that or the tube might deflat enough to let the tire spin on the bead. They hook up very, very well. The 500R does still have capacity to spin them but it bogs a little bit if your in some real loose stuff when you launch in first. This is still running the 15 tooth sprocket though. I'm sure if I gear down it'll be able to turn them good. I love the way it sits and looks, like a top fuel dragster. Way high in the ass and low in the front. Not near as prone to wheelie either. I've got a spare topend that should be here tomorrow I'm gonna send off for porting. I'm planning on doing the portwork, and in the near future FTZ's digital ignition system for adjustable timing and less rotating mass. This thing should be quite the monster in a month or two :D

[Billy Golightly]

Oh yeah...I gotta even out that shittin silencer too so its level. Gotta work on the bracketry a little more.

[firefirefire90]

sorry if this is ignorant, but why would you need to do the timing on a 2 stroke when it doesn't have a timing chain or valves? Please explain, because i do not understand.


EDIT: geez sorry for being a retard, i didnt know.

[1984kxtTECATE]

sorry if this is ignorant, but why would you need to do the timing on a 2 stroke when it doesn't have a timing chain or valves? Please explain, because i do not understand.

There are to ways I know of to time a 2stroke, the ignition box offers you to to retard or advance the spark, hence different timing. You can also mess with porting for the exhaust port, it too will adjust the timing. And as he stated he is getting some port work done and getting a aftermarket FTZ box, which will allow him to adjust it.

[Billy Golightly]

Because the factory timing isn't always "spot on" for every machine. It can also be adjusted to take advantage of different fuels your using, IE regular pump gas, high octane race gas, or alcohol. And to tune the powerband a little bit more precisely. Its difficult for me to explain, but heres a quote from the Eric Gorr website that does it better then me:


AFFECTS OF THE IGNITION TIMING

Here is how changes in the static ignition timing affects the power band of a Japanese dirt bike. Advancing the timing will make the power band hit harder in the mid range but fall flat on top end. Advancing the timing gives the flame front in the combustion chamber, adequate time to travel across the chamber to form a great pressure rise. The rapid pressure rise contributes to a power band's "Hit". In some cases the pressure rise can be so great that it causes an audible pinging noise from the engine. As the engine rpm increases, the pressure in the cylinder becomes so great that pumping losses occur to the piston. That is why engines with too much spark advance or too high of a compression ratio, run flat at high rpm.

Retarding the timing will make the power band smoother in the mid-range and give more top end over rev. When the spark fires closer to TDC, the pressure rise in the cylinder isn't as great. The emphasis is on gaining more degrees of retard at high rpm. This causes a shift of the heat from the cylinder to the pipe. This can prevent the piston from melting at high rpm, but the biggest benefit is how the heat affects the tuning in the pipe. When the temperature rises, the velocity of the waves in the pipe increases. At high rpm this can cause a closer synchronization between the returning compression wave and the piston speed. This effectively extends the rpm peak of the pipe.

[Tri-ZNate]

lol those rear tires are MASSIVE compared to the front tire. Looks real good billy. Are you ever gonna get rear plastics?

[nouseforaname90]

Jesus. If you can wheelie while you have those on your machine with the front tire filled with water, you have major problems. Looks nice!! So when is it going to be 100% complete?

[BigGreenMachine]

Love watching your bike evolve Billy. Looks badass with those paddles. So you do intend to gear it down for more grunt?

[Billy Golightly]

Thanks. Yeah, I'm probably gonna go down to a 12-13 and then up a few teeth in the back for running these tires. The gearing setup now is really about perfect with the pro wedges but is a bit tall for these.

[atczack]

Dang Billy, that 500R is looking good! I can't wait to come watch you again at the drag's. Sorry I missed the last one. I bet you really hook up with those baby's...