421 MX Ported Serval, which pipes, Snipers or CPI?

[Strm Trpr]

Looking to build a 91 octane MX ported Serval.

I weigh 250lbs with full gear.

I'll be running bored stock carbs, Chariot Intakes, VF4's, advanced timing etc....

There is a stock carbed Serval in the dyno room, but the OP's link to the dyno sheet is broke.

I pulsed him in the thread to no response.

But from what I read, there wasn't much of a gain in power when going to mikuni 38's.

Plus, I plan on riding Glamis and St Anthony's this year, so fuel economy is a huge priority for me.

 

I saw the Redline MX ported Serval throw up a bitchin number running VP110, 33pwk's, Pods, VF4's, CPI's and +6* timing.

I'm not chasing a big number, I just want a powerful mid to top for destroying the Dunes.

 

I like CPI's power delivery and too shabby of peak rpm.

Snipers provide an almost identical power delivery with more peak power and with more over rev.

 

So, Snipers or CPI for this build?

 

Anyone know how long of a wait a set of SBIF Snipers are?

Trying to get long lead items ordered sooner rather than later.

[locogato11283]

12 weeks last I heard. Get them ordered ASAP.

 

You might want to check with Gary though to be sure.

 

He answers his PMs here.

[Strm Trpr]

Damn, thanks for the heads up.

 

Didn't you guys have a 4 mil as cast and ported cub dyno day at redline?

I found the 10mil dyno chart but can't find the 4 mil charts.

 

Is SRP Gary's screen name?

[locogato11283]

Damn, thanks for the heads up.

 

Didn't you guys have a 4 mil as cast and ported cub dyno day at redline?

I found the 10mil dyno chart but can't find the 4 mil charts.

 

Is SRP Gary's screen name?

It's in the dyno section.

 

I think it's titled 4mm Cub Pipe Testing.

 

Yes, Gary's screen name is SRP.

[Strm Trpr]

Excellent thank you Sir!!

[Strm Trpr]

I just got word from Gary at SRP and he's willing to get started on a set of Snipers for me know.

It is a 12 week lead time, but no more!!

$670 shipped!!

[Strm Trpr]

Just got off the phone with Cameron, he said CPI's.

[gusto]

I wonder why? CPI likes the lower port timing maybe?

[Strm Trpr]

He said for what I want to do with the motor, CPI is the better pipe.

CPI's will pull up the face better that Snipers.

CPI's are readily available and they're cheaper.

 

Cameron said he has both pipes at the shop and since I'm having this build dynoed, he could do a back to back test!!

 

I also told Cam that I want to run my bored stock carbs and pods.

He wasn't very excited about that at all, but said he'd run them against a set of 33mm PWK's to see what the difference is.

He mentioned that the stock bowls are small and that I'd be running a lot of fuel through the motor.

I said I know, fuel economy is very important to me but then I said you can't make power without adding more fuel and air.

 

So if there isn't much difference I'll keep the stock carbs and run the Driveline billet bowls.

Should be an interesting build/dyno comparison about the CPI's vs Snipers and bored stock carbs, stock intakes, VF4's vs 33 PWK's, UPP intakes w/cross-over and VF4's.

[ClaudeMachining]

He said for what I want to do with the motor, CPI is the better pipe.

CPI's will pull up the face better that Snipers.

CPI's are readily available and they're cheaper.

 

Cameron said he has both pipes at the shop and since I'm having this build dynoed, he could do a back to back test!!

 

I also told Cam that I want to run my bored stock carbs and pods.

He wasn't very excited about that at all, but said he'd run them against a set of 33mm PWK's to see what the difference is.

He mentioned that the stock bowls are small and that I'd be running a lot of fuel through the motor.

I said I know, fuel economy is very important to me but then I said you can't make power without adding more fuel and air.

 

So if there isn't much difference I'll keep the stock carbs and run the Driveline billet bowls.

Should be an interesting build/dyno comparison about the CPI's vs Snipers and bored stock carbs, stock intakes, VF4's vs 33 PWK's, UPP intakes w/cross-over and VF4's.

I'm looking forward to see the results of cpi vs sniper on a serval

[trickedcarbine]

He said for what I want to do with the motor, CPI is the better pipe.

CPI's will pull up the face better that Snipers.

CPI's are readily available and they're cheaper.

 

Cameron said he has both pipes at the shop and since I'm having this build dynoed, he could do a back to back test!!

 

I also told Cam that I want to run my bored stock carbs and pods.

He wasn't very excited about that at all, but said he'd run them against a set of 33mm PWK's to see what the difference is.

He mentioned that the stock bowls are small and that I'd be running a lot of fuel through the motor.

I said I know, fuel economy is very important to me but then I said you can't make power without adding more fuel and air.

 

So if there isn't much difference I'll keep the stock carbs and run the Driveline billet bowls.

Should be an interesting build/dyno comparison about the CPI's vs Snipers and bored stock carbs, stock intakes, VF4's vs 33 PWK's, UPP intakes w/cross-over and VF4's.

If you are dead set on the stock carbs, get the Driveline bowls. All this talk lately about using stock carbs to support 70-80 hp motors. I'd like to see most of these folks try running wfo accross the dunes on stockers with out melting a motor down from the tiny bowls. Only in the last year or so has there been a way to adequately support the fuel needs of a hungry motor on stock carbs. To my knowledge there haven't been any other Billit bowl options. Hit up BHP.

[Strm Trpr]

That's what I'm worried about too.

If these RB Designs bored stock carbs out perform the 33mm PWK's then I'll grab the Driveline Billet Bowls.

[Strm Trpr]

RB Designs up in Oregon did the mods.

http://www.rb-designs.com/rb_designs_llc_014.htm

 

This is what they look like.

 

 

 

 

From Ron Black of RB Designs:

The carb mod has an oval bore at the slide only and most or the cutting is done at the roof of the bore and only about .5mm on the floor.The reason for the oval bore is the slide is only 26.75 in diameter and if the bore was bigger air would leak around it making problems. The spigot side of the carb is then bored to 28 mm and stops right at the low speed circuitry.

And then the spigots tapered to 30mm from the nose of the carb back in about 10mm. The actual spigot size where it mounts into the reed boot is 35mm in diameter (this is stock size). I also do a little tapering on the air horn (air cleaner side of the carb) to give better entry.

 

So the opening at the spigot is 30mm and that is about what the rubber reed boot manifold is, very minor trimming needed if at all.

 

These carbs flow a ton and give great performance!

[Strm Trpr]

I think the biggest concern is not being able to pull enough air thru the tiny K&N's stock carbs use.

I may have one of my machinist buddies make a billet manifold that'll bolt up to a pro design billet intake and use that massive K&N that comes with the pro design intake.

[gusto]

Your building my kind of engine. Looking forward to the dyno results. I'm more interested in the carb comparisons than the pipes I think.