My son and I have a friendly competition going each time we go to the dunes. Round one was at St. Anthonys with a stock DS650 vs a piped and jetted YFZ. The DS won longest jump, but the YFZ won longest wheelie, and drags to the top of Choke Cherry Hill. Round two was at Sand Mountain (UT), and the DS aquired an HMF slip-on, and jetting, for this round. This time the DS won longest jump, and longest wheelie, but still lost at drags to the top of Sand Mountain.

I need to pull one gear higher on Sand Mountain to beat the YFZ, so what is it going to take to get me there? I don't want to have to ride around with rich jetting all the time to compensate for nitrous on the few times I use nitrous, so I think nitrous is out. Can I gain one gear on Sand Mountain with a stock bore HP Research 11:1 piston, cams, and carb; or do I need a big bore? I guess that what I am asking from you folks that have "been there, done that" is what is the best, most direct way to gain that next gear on Sand Mountain. If I need a big bore the kid on his YFZ is going to be able to beat me for a while longer, because I don't think I can spend that much right now. Thanks in advance.

OuterLimit

[edit] I am pulling Sand Mountain in the very top end of second gear now, with stock gearing and 22" nine paddle Rippers. Pulling the hill at a similar RPM in third gear would soundly trounce the YFZ.

 

Get a CDI, Ported intake, full exhaust(Ron woods makes the best IMHO- it really helps the top end, thats where the slip on's and end caps are weak). Then go to a 15 tooth front sprocket and you should be able to easily beat that YFZ.

Sean

 

Well If you are talking about the saddle side then what you are looking to do is about what I have done to mine (non big bore) and I pull the saddle in the top of third and on the NOS I pull it in forth. I am thinking that those paddles are a bit to much for you bike as well If I am correct rippers are a real tall paddle and will put a lot of load on your bike. I run 22" 8 paddle extream haulers and have had really good luck with them running the mountain in UT. I also run 15/42 gearing and that has helped alot with the taller tires.

I guess what I am getting at is of you run a piston, cams, carb, ported intake, and regear you should gain a gear easy on the saddle.

I didn't have to change my jetting at all when we installed my boondocker kit this past weekend so running rich all the time off the bottle would not be a problem with this kit.

If you are down that way anytime soon I could come down and you could see if my bike would beat you boy and then you would know if that will give you what you are looking for or if you need more. You could also check out the NOS set up and really lay the smack down. [img]i/expressions/face-icon-small-wink.gif[/img][img]i/expressions/face-icon-small-happy.gif[/img]

 

What is the stock gearing? 16/?

It sounds like I should be able to gain another gear with a 11:1 or 12:1 piston (on pump gas), with the ported intake, Lectron 46 carb, and Mr. HP cam, and that I will not need a big bore. How will general rideability be with this set up, compared to the stock carb? I could definitely use a bit more over rev capability as well, because I hit the rev limiter bad going through the whoops at the bottom of the hill. But I like the easy going manners of the stock tuning for general dune riding and for beating my kid in our wheelie contest. I rode one "out of the park" this last weekend, it was good enough that my kid just said "you win Dad", and didn't try to beat it anymore.

I would love to try your DS against the kids YFZ DSaholic, unfortunately my weekends will be taken by work until after Novermber 4th [img]i/expressions/face-icon-small-sad.gif[/img] . And hopefully by next spring I will have these mods done. Thanks for the information, and the offer to race your bike.

 

The duneablility would be just fine. I love mine out in the dunes just as much as on the hill. The stock gearing is 16/40. You will definitally want a new rev box with that setup since most of the power will be made above what the stock rev lomit is set at. You will also need new valve springs and stiffer clutch springs with that setup.