DS650 Top Speed in Sand
#21
#23
![Default](https://atvconnection.com/forums/images/icons/icon1.gif)
CRTLeech & DSWOLF, You both have hit the rev limit in 5th gear when riding in sand. Were you running stock size rear dirt tires? Stock gearing? Pipe or K&N filter or airbox lid off? Stock carb jetting? Was the drag strip a couple feet deep of loose, soft, dry sand - the kind that is difficult to walk in? Or, was the drag strip surface level hard pack moist sand similar to hard pack moist dirt? The kind of sand drag strip I can't get over 65mph in is the first kind I described, where the DS throws major roost with paddle tires. Also, what are your production dates marked on the frame of the DS? How much distance and time does it take you to wind all the way out and hit the rev limit in 5th gear in sand? With or without a pipe, I can't reach 70mph in deep soft sand.
#24
![Default](https://atvconnection.com/forums/images/icons/icon1.gif)
Hello ScoobyDFW . Have you bought a Ron Woods CDI yet? It of course eliminates the rev-limiter but it also re-curves your ingnition thru high RPM .Ron Woods Racing claims the stock CDI falls off at about 6200 RPM. I bought one for $350. I feel it was well worth the investment because it just keeps on truckin!! I was wanting to re-gear mine for more bottom-end . I wiegh 250 lbs. Have you tinkered with any sprocket changes?
#25
![Default](https://atvconnection.com/forums/images/icons/icon1.gif)
Some racers and distance jumpers can judge speed very accurately. I can get to within two mph or so most of the time. When I started driving I had no speedometer in my van, that must be where it started. You must know exact speeds for jumps. Fumbling around with some speedo would be harder for me.
Our bikes stock top speed was noticably slower in the Imperial Valley sand. The front tires and drag from the sand make a big difference. I felt like the weight of the bike made this effect worse. I have always had much lighter bikes there and did not notice such a drastic difference.
The gear change down 3 teeth in the rear made a big difference. Top speed jumped about 5 mph, but in third and higher gears the bike really worked hard. We noticed clutch burning smell after a couple hours of hard riding. (there is also a click noise from somewhere in the clutch area occasionally.)
Our bikes stock top speed was noticably slower in the Imperial Valley sand. The front tires and drag from the sand make a big difference. I felt like the weight of the bike made this effect worse. I have always had much lighter bikes there and did not notice such a drastic difference.
The gear change down 3 teeth in the rear made a big difference. Top speed jumped about 5 mph, but in third and higher gears the bike really worked hard. We noticed clutch burning smell after a couple hours of hard riding. (there is also a click noise from somewhere in the clutch area occasionally.)
#26
![Default](https://atvconnection.com/forums/images/icons/icon1.gif)
Hey Scooby,
For more top speed all you really need is to run 10% Nitro-propane with some race fuel and gear up. If they are only outrunning you by about 2-3 mph then go up a tooth on the front sprocket and run Nitro. It has much more BTU's than race gas (more violent explosion = increased IMEP = more torque and horsepower) and won't attract water and corrupt your oil like alcohol. The only draw back is this stuff will burn your eyes and throat if you are behind it but hey, that will be the Banshee's problem then.
CT250R
For more top speed all you really need is to run 10% Nitro-propane with some race fuel and gear up. If they are only outrunning you by about 2-3 mph then go up a tooth on the front sprocket and run Nitro. It has much more BTU's than race gas (more violent explosion = increased IMEP = more torque and horsepower) and won't attract water and corrupt your oil like alcohol. The only draw back is this stuff will burn your eyes and throat if you are behind it but hey, that will be the Banshee's problem then.
CT250R
#27
![Default](https://atvconnection.com/forums/images/icons/icon1.gif)
That might be the key, the sand I ride on, the straight flats are typically not soft. It's either wet or in areas that it's kinda hard. That could very well be the difference.
I ride on the coast of Oregon and at Moses Lake in Eastern WA. At Moses Lake, the only straight shots long enough is on the top of a long dune and a straight away in between dunes. There is sage brush and other desert plants on the sides of all the trails and the straight away has a little bit of gravel, dirt and Mt. St. Helens ash mixed in. Some areas where there's ash, it's as hard as cement, though, not on the straightaway. It's been used for twenty plus years as a drag strip, so it's fairly packed down.
In Oregon, the sand is damper and the flat areas are near wetlands or are windswept areas. The straight flat area of Sand Lake is mostly dry, but it's not too soft. Some parts are wet were ponds collect. The same goes for other parts of the Oregon dunes. Any place that the sand is soft, it's usually in an area not conducive to high speed like four-foot hills, edge/crests of dunes and such.
I can't say for sure that I have hit the rev limiter in top gear, but it's been really close if I haven't. I have done this with both stock tires and the Sand Skate II's. My rear suspension I believe is pre-loaded too much and that keeps the back end light. I haven't gotten around to fine tuning the suspension yet. I've only had weekends to ride and I'd rather ride then goof with the suspension.
I believe that I am hitting fifth gear within 100yds, if not top speed within about that distance? I am not 100% sure and I probably won't be able to ride again until spring. I know that I am shifting into third by about 30 feet due to wheel spin and rev limiter, though.
Good luck on getting yours faster!
Laters,
CRT_Leech
I ride on the coast of Oregon and at Moses Lake in Eastern WA. At Moses Lake, the only straight shots long enough is on the top of a long dune and a straight away in between dunes. There is sage brush and other desert plants on the sides of all the trails and the straight away has a little bit of gravel, dirt and Mt. St. Helens ash mixed in. Some areas where there's ash, it's as hard as cement, though, not on the straightaway. It's been used for twenty plus years as a drag strip, so it's fairly packed down.
In Oregon, the sand is damper and the flat areas are near wetlands or are windswept areas. The straight flat area of Sand Lake is mostly dry, but it's not too soft. Some parts are wet were ponds collect. The same goes for other parts of the Oregon dunes. Any place that the sand is soft, it's usually in an area not conducive to high speed like four-foot hills, edge/crests of dunes and such.
I can't say for sure that I have hit the rev limiter in top gear, but it's been really close if I haven't. I have done this with both stock tires and the Sand Skate II's. My rear suspension I believe is pre-loaded too much and that keeps the back end light. I haven't gotten around to fine tuning the suspension yet. I've only had weekends to ride and I'd rather ride then goof with the suspension.
I believe that I am hitting fifth gear within 100yds, if not top speed within about that distance? I am not 100% sure and I probably won't be able to ride again until spring. I know that I am shifting into third by about 30 feet due to wheel spin and rev limiter, though.
Good luck on getting yours faster!
Laters,
CRT_Leech
#28
![Default](https://atvconnection.com/forums/images/icons/icon1.gif)
Agree on using a GPS, I'm using the Garmin 3+, with mount on the handlebar, most and best toy I've used in the woods.
How can you be lost when you know how far and which way?
I've crossed my own trail once and didnt know it until I got to looking at the GPS, we all had a big laugh when we returned to the crossing and took the short cut back to the pickup & trailer.
Ya gotta try it.
How can you be lost when you know how far and which way?
I've crossed my own trail once and didnt know it until I got to looking at the GPS, we all had a big laugh when we returned to the crossing and took the short cut back to the pickup & trailer.
Ya gotta try it.
#29
![Default](https://atvconnection.com/forums/images/icons/icon1.gif)
Wyo,
Just curious where you heard or why you think radar is tuned with a tuning fork? I'm not bashing, I'm just curious.
Radar works on the basis of a frequency (a very very high frequency) X band radar is around 1.5GHz. Basically a radar gun knows the speed of this signal / frequency and calculates the time it takes for it to return (after bouncing off an object) giving you the rate and time, as the distance of the object changes (usually as it moves toward the signal origin) and speed is derived.
Just curious where you heard or why you think radar is tuned with a tuning fork? I'm not bashing, I'm just curious.
Radar works on the basis of a frequency (a very very high frequency) X band radar is around 1.5GHz. Basically a radar gun knows the speed of this signal / frequency and calculates the time it takes for it to return (after bouncing off an object) giving you the rate and time, as the distance of the object changes (usually as it moves toward the signal origin) and speed is derived.
Thread
Thread Starter
Forum
Replies
Last Post
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)