Heres the deal. I already have the V-Force II reeds, HPD trail pipe and clutch kit plus Uni-Filter/air box mod and Weico piston.
I was thinking of getting the trail porting and billet head. Does this seem like the next logical step? What exactly does the billet head do? I am looking for much more all-around power, not just top.
Any other sugestions???

 

Xplor,

You could try a bigger carb too. Once you've got all that flow, the only thing slowing it down will be the carb. If you have a pre concentric drive model you'll be stuck with either carb boring or a 38mm Mikuni TMX. With the concentric drive, you can use the either the 38mm TMX or the 39mm Kehin PWK. Out of the two the 39mm PWK is the easiest to jet.

 

Mike,

What do you think of the following all together:

39mm carb
Porting
Billet head...what exactly does this do?

Is this what I need?

 

Xplor,

The simplest way to answer this is what happened last weekend. Jim Malone and I lined up last weekend. His only mods were a pipe/clutch kit, a 39mm PWK carb and lots of lightening modifications. From a standstill I let him take the lead as I slowly brought the Sport into the powerband. It isn't wise to just nail the throttle on mine, you could wind up with the quad on top of you. After the Sport kicked into "hyperdrive" (as I call it), it was all over for him. I passed him like he was standing still and left him about 5 quad lengths behind at the end of about 300 yards.

The "coolhead" will make your machine much more efficient in terms of both cooling and raising the horsepower. You have your choice of 12:1 or 14:1. I prefer the 12:1 because:

#1 I hate to pay $1.70 for premium (but I do)

#2 I would hate even more to pay $4-$5 for race gas for the higher compression 14:1 head

#3 It has as much horsepower as I need or can handle at this point

The carb is needed to flow more air into the crankcase. The woefully undersized Mikuni 34mm VM just ain't up for the task. Plus, with the flatslide carbs, you will have less turbulance when opening the throttle. Less turbulance means quicker throttle resopnse.

In the last paragraph I said the carb will flow more fuel/air mix into the crankcase. You will now need to get that fuel air mix into the cylinder to do any good (besides lubricating the engine). This is where a port job comes in. Rick Ritter cleaned up the ports of any casting flash, and then removed metal from the ports top side to open them up a little. The result is VERY noticeable. The larger carb you put on will now be usable. At full throttle there is more flow into the cylinder from the crankcase.

Also, get a Wiseco piston. There are larger holes on the piston's intake side to flow more fuel/air mix. Not to mention the fact that the forged pistons are much softer than the stock cast ones and are less prone to breakage. I'd recomend this mod to ANYONE who gets their motor ported.

This should set you up nicely!

 

Thanks a lot Mike!

I already have the Weisco piston and the V-Force reeds, so thats one step in the right direction. Do I really need the spacer and the cage? (I don't even know what a cage is?!)
I love the way my Scram rides now but with porting, billet head, 39mm carb...will the differnce be radical? 100% better maybe??? LOL

Do you suggest to go with Rick for the porting...or stick with Darrel at HPD?

Thanks again.

 

Xplor,

If you bought the Delta 2 reeds then you bought the cage too. I've heard of people just putting reeds on the stock cage. The cage is what the reeds mount on. The Delta 2 system is about the best out there. No, you really don't need a spacer, I've got by without one for years. Besides, on my non-concentric drive machine, space is at a premium.

Oh yes, one more thing. If you get the larger carb, you will nees to either do some serious air box mods or just run a filter and outerwear. The compromise is to get a White Bros. air box. It protects against splashing, but doesn't make it water tight. This is what I've done.

 

I thought I had the cage...They should just call it the "dark grey plastic thingy holder"...I would have understood. LOL
I have already done the air box mods. I added an extra 1 inch 1/4 hole from the boot to the box along with a 2 1/2 p.v.c. for greater intake on the boot. Uni filter of coarse. Is this sufficient? Last week when I added the hole, I could really feal a difference.

 

Mike, your statement on the 39mm PWK carb earlier.
Is there a major problem fitting one to a non-concentric drive 97 Sport ?
Or is it just that I will have to fabricate my own
aluminum air box ?
Thanks
Andrew Hills
97 Sport 400 ( in 400 pieces ! )
Perth - Western Australia

 

I just got home from the hunting camp with the Scrambler and I'm going to start tuning on it now that it's broken in. The porting work that Rick did was for mid range really made a difference in the way that it runs. It runs a lot stronger in spite of the extra rich jets and extra oil in the pre-mix. I'll start leaning it out and making some real horsepower. I rode it the last time up there and recorder a 70+ MPH blast on the paved road with a 12 channel GPS.
I was running around in hilly terrain with a 100lbs of feed on the back rack and it still ran strong.
I rode a 1999 Grizzly 600 up there and wasn't that impressed. That thing is a behemoth... It's almost the size of a Jeep...

 

if you read my signature I think you will see your 400 is on the way to being like mine in the mod dept.since I had a HPD pipe,clutch,carb,ect... it only seemed right to have darrel do the porting as well.rememder he made all this trail mod stuff to work together and I felt that is why I havent had no problems with my 400 every thing bolted on and worked the frist time,
But RCR's work is good and his porting is is top notch,but will it work good with your HPD spec 400....hopefully,like I said HPD knows there trail porting works with there trail pipe it was made to.If you do go with RCR make sure he knows what pipe you are running