RB-Designs carb mod or PowerNow?

[AZRickD]

Bike: 2005 DE 250 (12 oz FWW), LTR carb kit and LTR PV extender, FMF pipe and silencer

This summer I'm going to do a top end R&R and send the head to RB-Designs for a squish mod. I'm also considering sending in the carb (even though I have PowerNow on both sides).

I asked Ron that given my PowerNow, would it be worthwhile to ditch them and go with his mods. He kinda blanched at me ditching $100 worth of P-Now (even though the former owner bought it). I feel that the PNow in front makes the throat smaller and the PNow in back is kind of a slop-fest.

Any thoughts on the RB stuff squish and carb ?

Thanks,

Rick

 

[Treesmacker]

I had RB do the squish on my 04 DE300 and it made the jetting better for
different temps. and more low end also. Before the head mod my bike would
run terrible when it was hot and humid.

 

[AZRickD]

Here is the info on the RBD carb mod for the 250/300 Gas Gas...

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

Carburetor Modification for the gasgas 250 and 300 includes;

Boring carb to 39 mm (gives you a better top end)

Installing divider plate (gives that low end response, like a smaller carb)

Modify slide (do not forget to send your slide with your carb)

Install new needle (gives the carb that personality)

Change jets (if necessary)

Modify jet block (helps with the over all performance)

Modify low speed circuitry This part of the modification along with the other mods really brings the air mixture screw into play. With only very small adjustments, you can keep your bike running at its peak as you change altitude or with weather changes during your ride.

Price is $165.00 US Funds and includes return shipping & Handling in the USA

 

[joey11]

I just rec'd my RB modded carb back from Ron, but I have yet to get my bike back together so I can't say if it is any better. What I can say is that Ron is a class act and he was upfront with me. I felt the carb was not right during last race season, and when he tore into it he found the choke was shot and several other gaskets and seals were shot as well. He contacted me and broke down my options and I chose to replace the parts. I just had to send him the additional cash. He also has fully modded carbs available for purchase if you don't want to change your stocker. His turnaround was quick too. I'll report back when I get it up and running and let you guys know what I think. It's just been too cold to work on bikes.

 

[Eric K]

RB designs work is superb.

The head mod is at the top of my list for engine mods. It is the best bang for the buck. It significantly increases low and mid power while improving fuel economy.

The RB designs carb mod is a nice package. It is great for those that just want to install and ride.

The power now in the air filter side of the carb does not do much. Take it out and see how much difference it makes.

If your current jetting is well dialed in with the power now, I would not expect a significant improvment with the RB designs carb mod. If your current jetting does not work well then the RB designs kit will help.

 

[PEB]

I thought the carb mod added top end? MY new 07 revs like neither the 99 or 02 would, I attribute it to the RB bored carb, It also jets almost flawlessly from sea level to about 3000 feet.

 

[GMP]

Paul, I'm sure the carb has a lot to do with it, but my '07 250 also revs out higher than either my '00 or '03. I know the pipe and CDI map are different, and I'd bet the porting has been tweaked over the years as well.

 

[PEB]

That new FMF pipe is very nice. My bike has a SPES pipe on it now. Looks cool with its bare metal and all but does not seem to want to rev like the FMF did. Seem like it hits earlier and sign off earlier as well. When I switch back I will have to try and ride the bike right away to make a better comparison.

 

[nick790]

I'd like to do the RB designs squish and carb' mod's but there's no one here in the UK doing it and the shipping makes it to expencive.

Any idears?

 

[2 strokes 4 life]

That new FMF pipe is very nice. My bike has a SPES pipe on it now. Looks cool with its bare metal and all but does not seem to want to rev like the FMF did. Seem like it hits earlier and sign off earlier as well. When I switch back I will have to try and ride the bike right away to make a better comparison.

Thats funny because on my 2002 EC250 I found the FMF did not do well past the huge mid range hit where as the Messico was softer on bottom and mid but had alot more top end.

 

[PEB]

The 07+ pipe is an SST type pipe supposedly similar to the Doma and OEM pipe. You are right the older FMF pipe had a huge hit and abrubtly signed off.

 

[2 strokes 4 life]

The 07+ pipe is an SST type pipe supposedly similar to the Doma and OEM pipe. You are right the older FMF pipe had a huge hit and abrubtly signed off.

That makes sence. I cant wait to try my DOMA out, should be much better in the open stuff.

 

[AZRickD]

My jetting is pretty good. I have jets to take me from sea-level in winter (southern latitudes) to at least 7,000 feet in Flagstaff.

What doesn't work so well is the airscrew. Not much difference no matter how much I spin it. The current set up has pretty nice, linear power delivery. I'd say the motor signs off a little earlier than I'd like it (on the rare occasion I do MX) -- on single-track it's not an issue.

 

[Eric K]

The later year models seem to rev out a bit higher. However, I don't have any tach data to verify.

The pipe is by far the biggest contributor to top end performance.

For reference, I have run the RB Designs carb, the stock carb with many different setups, including the Power Now and the SLP Power Pack which is similar to Power Now.

 

[gasIdaho]

The carb mod was money well spent for me. I ride mostly at 6000ft and above. Adjusting my air screw(for temp, elev, etc)now has a profound effect on performance whereas before turning it full in or out had no effect. The one thing that surprised me was the effect on the top end.....it screams! This is especially nice when out riding in the desert. Overall, I'm running much larger jets than I did prior to the RB mod. I'll go one size larger only on the main and I can run safely at 2000ft in the desert