When I put the high compression piston in my ds build it was a noticable differance in torque. and I was running the stock cams and just had the K&n filter and the ron woods pipe and I loved it but soon got the itch for more speed and did the porting and cams and the shim under bucket and big carb. Just make sure when doing mods that you get things that are proven and work together.

 

Just to clarify, I am not trying to argue with you Vic, and I know very well the amount of time with Test and Tune and trying parts you have done. I know we have both ripped our hair out once or twice lol..... But yes, I agree. The biggest thing I wanted to let our new guy know is that no single part will be the end all save all of your HP gains. IT is always going to be the sum of the parts. Well other then maybe the 730. But that is another story.


As to the "to shim under or not to shim under" question. My thoughts are this. Very few times in this kind of sport will you come across an item that all the builders agree on. They will all tell you the shim under kit is needed for agressive cams. And some of these guys cannot even agree to disagree. That being said, does that still mean they know everything. Not always. But that many agree on something that could potentially save you thousands in repairs...... Do you need it or not? I do not know. But I can tell you that not 1 of our 3 DS's will run a cam bigger then the 109 with out them. Consider it a form of insurance.

That is my opinion.

Swaie. as for what Cams to get depends on you riding, what mods you plan to do, and what exactly you want out of your bike.

Give us some ideas

 

Ace,
It does not suprise me that your cams made the biggest improvement. Your prior mods (larger carb and CDI) contributed greatly to that. The question from Swaie was in regards to putting a set of aftermarket cams on a completly stock DS. THe point Dragon and I are trying to make is that aftermarket cams ALONE on a stock carb, stock CDI DS will not produce much. Cams in my opinion should not be the first mod someone should be looking to put on a stock DS.

 

<div class="FTQUOTE"><begin quote>Originally posted by: DSengineer

Ace,

It does not suprise me that your cams made the biggest improvement. Your prior mods (larger carb and CDI) contributed greatly to that. The question from Swaie was in regards to putting a set of aftermarket cams on a completly stock DS. THe point Dragon and I are trying to make is that aftermarket cams ALONE on a stock carb, stock CDI DS will not produce much. Cams in my opinion should not be the first mod someone should be looking to put on a stock DS.</end quote></div>

I agree 100% that the cams should not be the first mod. I was just letting him know that for me they seemed to make the largest gain of all of the aftermarket items that I had applied.
I would recommend a higher comp piston before the cams anyway, although I haven't installed mine yet. I did drop an 11.5:1 into my sons bike and it also made a very noticable difference. His bike already had a TM45, K&N, Big Gun CDI, and Big Gun Race Series full exhaust.
I'm getting prepped for DS Days here shortly and I have the cams for my sons bike and the piston for mine. I'm trying to hook up with Big Mike and have him do some porting work for me. I know with 100% certainty that I will never get the full potential of the cams and pistons without some porting work. But both items on their own do account for some better power.

 

It would simply appear, that we are all agreeing from different sides of the coin. We all agree the quarter is worth .25 we just made it differently [img]i/expressions/face-icon-small-smile.gif[/img]

 

LOL

 

True, but if you had done the cams first and carb later you probably would have said the carb gave you the biggest increase[img]i/expressions/face-icon-small-smile.gif[/img] When in actuality it was the combo of both...

The porting is definately worth it. My HR3's really came alive after I had my head ported. Nothing extreme (stock valves w/trail porting) but the difference was very noticeable. IF your going to port I would highly recommend going to shim-unders. THe porting will really make it want to rev on top and you sort of playing with fire when you get into that RPM range using shim-overs.

 

Okay, now we're getting into all of the gory details... so all of this high end reving, when does it actually take place? Again, I'm a duner, not a racer or hill shooter. If I'm just cruising around the dunes following Big Ray on his 800 am I really at that high of an RPM to where I would NEED shim unders? Even on the occasional run up Comp, Banshee, Olds, China Wall, Brawley Slide, Lizard Hill, Little Sahara, or any other of a number of hills that we frequent, am I at that screaming range where a valve would float??? I've missed a shift of two in my time and I know that is the highest rpms I've hit and I've yet to have one of my shims come out of their baskets. Just curious.

 

I know I am not qualified to answer that question. Too bad all the builders were ran off... Vic, I would say that is a great thing to post somewhere Mr HorsePower would actually see it and give his insight as to the pros and cons and all that.. I know I would like to know it.

 

I'm leaning towards his answer being that under normal duning conditions the shim unders may not be required. Some of the revs that I see during these races may need them because they (the high rpms) are maintained over a longer duration of time.
Of course I'm just putting words in his mouth, but I don't think Eric would really try and sell us something that we don't really need.
I may adress this over at the other site. The answer will be for you guys because I can't afford the under buckets anyway.
Do you see what I'm saying though about the amount of time that you are at such high rpms? In the dunes it's very rarely.