I am looking into a few more mods for my DS. i was thinking of getting this piston to give me a little more added performance but i have a few questions. If i buy it do i NEED to do anything else? like new cams or rejet or anything like that? i know it would work best with a new set of cams but i really just want a piston right now, cant really afford cams. i also wanna know if i can keep everything else stock on it like i mentioned before. thank you

 

I did that with one of my DS's. Just the 11.5:1 piston. I had a pipe and intake but no cams or bigger carb or anything like that. It was a noticable improvement. It was a torque monster on the bottom end. Great dune setup for cheap and I could run pump gas. I did have a Big Gun rev box also.

Ron

 

Depends on what kind of riding you like, but for just general fun hop up's a 100mm 11to 1 piston is fairly cheap on E bay 150 bucks or I hear that Honda carb for $165.00 helps the DS breath a bit and see if you can find someone to port the intake there should be guys to do for 50 to 75 bucks heck even for free beer, and you could try a counter gear change depending on your riding, cheap bucks. means you still have a few bucks in your pocket left over and thats aways good.

 

ERBE,

What Honda carb for $165?
Sounds interesting, since you know Honda's are a well supported component marketplace.

Where do you find tuning menu's for these carbs and DS's?


Thanks

 

Its on alot threads about the DS but this one seems to have more info :Text Honda 450 carb

 

Thanks ERBE

That really looks like a high tech carb that can be hopped up, versus a cv or a fsc.

After that flashing sign at top of page, I have to buy a Honda something :-)


THANKS!

 

the carbs on the honda 450r are made by Kehein as most of their offraod carbs are. they are slightly smaller bore than the stock DS carb, they are NOT cv vacuum slide, however they do have a butterfly in their throat in frnt of the slide. I have yet to see dyno charts of properly tuned DS's running these carbs to compare to the other larger carbs commonly used on the DS's, but considering their size and the fact they too have a butterfly in the throat, I doubt there is any real significant top end gains over the DS's stock carb. However they do have an accelreator pump so I would assume that trail performance would be better due to better throttle response and easier wheelies that pumpers usually offer.


as DSNUT says the piston alone offers gains for an all stock motor, there's nothing wrong with going one step at a time, be aware that head gasket will cost you $50, and must be replaced when head is removed, but it is not necesary to remove the head to replace the piston, leave the small head bolts intact with head and jug still bolted together and only remove nuts on the 4 main stays and the jug and head will come off together without disturbing head gasket. you will have to tilt the engine forward a bit by removing all but one engine mount bolt, to get the head and jug assembly to clear the upper engine mount because the main stays may not flex enough to clear it ifthe head and jug are still bolted together.

once it is off you need to look in jug to verify spiral crosshatch honing is still apparent on cylinder wall - if its high mileage motor and the crosshatch is worn and you see mostly vertical lines then you really otta seperate the head from the cylinder and have the cylinder honed back to a spiral crosshach for proper break-in of new piston rings. but if the motor is low hours then it will most likely look like new. and don't forget that filing proper ring gap prior to putting the rings on the new piston is paramount, do not use stock ring gap specs, use new piston manufacturer specs, they are different.

 

i would most likely be taking it to a local atv shop that can do all the work, im a little sketchy about doing it all myself, im sure i could do it no problem but i just dont wanna risk overlooking something and trashing my motor. i ride mostly trails, so i was hoping this would add a lot of torque which i need, most of the trails are winding with lots of hills so i need a lot of it. ondunes sells them for 250, so i figured it would be a cheap way of gaining performance. thanks for the help guys

 

Hightower,

That is a viable option I haven't looked at. Keinen 'is' Honda and the largest carb maker, but their non-honda carbs aren't so hot, so honda gets the best of their best carbs, and more r&D than any other carb. The 'not' cv and 'not' fsc seems especially attractive to me due to constraints. If and when I add roller bearing crank etc, I'd like to have high tech design carbs. A pair of 36's like I have would probably work great and add dialajets to them.

With the etg and cht meter data logs and graphs, I should figure something out. I need to buy lunch for a Honda Wrench, lol. Whatever Honda's carbs are on their 600-650cc Supermoto is what I want. Its hard finding that information on the web.

I especially want dual carbs since motorcycles lean and atv's don't, so there is a theoretical balancing factor in fuel delivery into head/valves for max performance; and they should average out better with dual carbs like the engine was originally designed for.

 

yjacket2001 I think DS650powe was just looking for low buck gains for his DS so he can pick some ponies, but heck your idea sounds like a good new tread topic.