I was looking to buy a Big Gun rev box for my 03 DS650 Baja. K&N filter and a Trinity Stage 4 full system are my only mods. I would have already bought it but when I read about it on the Big Gun site it claims to raise the rev limiter by 750 RPM's but it does not specify Baja or not. If I understand right there is a different rev limit on the Baja model. My qusetion is the 750 RPM is that based on the Baja? Also is the rev box worth the money? I ride with a guy on a Predator that is piped and jetted who beats me every time up comp hill at Dumont by about a bike length. I need to get a little more out of my bike. And to answer any questions about the Predator, I'm sure those are the only mods he has, we both weigh about 280lbs, and I beat him off the start every time till about a 3rd of the way up that's when his bike passes me. Any info about the rev box would be great.

Thanks,
Andy

 

I think the general feeling for many people around this forum is that the only way to go is the Vortex. Many of the other models cause damage to the starter. Do a search for sprag clutch, and you will see many of the common problems.

 

As far as low end ignitions, the Big Gun is quite good. Of course, the best on the market in my opinion is the Vortex. There are TONS of threads on these boxes, you should do a search to find out more.

 

My son runs the latest Gig Gun CDI and for the last 9 months have had no problems.
Like all new electronics, sometimes a few have problems.
You have to keep your battery charged when using these cdi's.
They draw more voltage and even though the starter is turning, they will not fire until a certain amperage is met. If motor is turning very slow when the cdi fires, it may cause a backfire that is hard on the sprag clutch. If you have an 04 or newer, they have improved the overal electrical system and this problem does not seem to affect these newerr models.

The bottom end torque is better and you will gain about 2 hp on top.
You will win the race to the top of hill.

 

Did a secrach on CDI's and I see that the MDA and the Vortex are good, but I don't want to spend the cash. I did the search on the sprag clutch and could not find a connection to Big Gun so I think I'm going to get it. Thanks for the info.

 

When my OEM box went out I got the Big Gun. I would like to of had the Vortex, but like you I did not have the cash to put into it at that time. After researching the forum I saw that a few of the guys were running the BG unit with no problem. I got mine and have been very happy every since. Even when I let my battery set without a trickle charge for over a month , and yes it was a little weak, the Ds started right up. No kick back, maybe I am one of the lucky ones but I am sold on this unit. I have read that the BG unit has a slightly different curve than some of the other units built by the same company, for this reason they have not had the problems the other units suffered.

 

Well we can't have a Predator beating you up the hill. Get with Oldmanracing about maximizing your carb potential. I guaranty you he can improve your performance. You are losing some torque with the trinity system. At 280 lbs it is harder for a lower torque motor to make horsepower........ especially if you race on a hill. How do you compare on the flats? Install your rev box, that will help. Since you will be increasing advance with the CDI, make sure you run premium if you don't already.

What tires and gears are you running? How long is the hill and how steep? (Never been to Dumont).

The guys on this forum should be able to help you gain at least an average bike length if these items have any room for improvement. There are a lot of BIG DS riders on this forum who have dialed in the tires and gearing and they haul a$$!

It will be reward enough to me at least to hear back from you about how your buddy is going out to spend more money on his Predator because you keep beating him up the hill with your current mods.

Seriously though the torque of the DS should have an advantage over the Pred for you guys that make a habit out of shopping at the Big and Tall store! [img]i/expressions/face-icon-small-wink.gif[/img]

Ron[img]i/expressions/face-icon-small-happy.gif[/img]

 

Uh......just to clarify, when I referred to a lower torque motor I meant lower torque with the Trinity than with a Yosh or a Topgun or Big Gun exhaust. I didn't mean lower torque than a Predator. Trinity makes a good pipe, it just seems to make good horsepower at the top end with less gains down low.

Ron

 

The hill is about 200 yards long (I think) and is about 350' tall. I have 20" sand star tires and everything else is stock. I bought the bike used about a year ago and I don't think it has ever had its valves checked, so I'm going to tackle that when I put on the new CDI. I also need to check the jetting, when I pulled the plug it looks lean so I question if the guy I bought it from ever re-jetted for the pipe and filter, but no telling for sure till I take it apart. I only ride about one day every two months or so. Does anyone know approx what size main jet I should have for my limited mods?

 

20" tires aren't the best. I always buried the backend with 20's and had trouble launching out of the hole when racing. If you could find a way to get some 22" Sandstars or 22" 9 or 10 paddle haulers this will improve how your bike handles on the sand.

What gears are you running? Front and back sprocket?

You do have more power to be had with the carb. PM Oldmanracing and talk with him about your stock carb.

Ron