Chriochris,

With those mods you will breathe better, and are probably 3-5 HP over stock. Your peak power is probably somewhere between 8000 and 8500 RPM. It's cool to be the fastest in your group! Certainly, the Bomber was made for wide open spaces, and I bet its a ton of fun! When you are ready to move up, there are several things you can consider. First of all most people look at the CDI, the Carb and the exhaust. You already have the exhaust down. So, its only natural that you were thinking about the CDI. There is already plenty of info on this thread about CDIs. There is also plenty on this forum about the two most popular carbs currently out there. 1) The Mikuni TM45 and 2) the Lectron 46HV by MrHP. I suggest you study up on those - again, there is plenty of info out here on both of those. Hightower is probably one of the best unbiased experts on the TM45. and I believe Blackhawk is also an unbiased expert on the Lectron 46HV. For open fields, you will be racing wide open, so, my opinion would be to go ahead and shift somewhere at your peak horsepower - somewhere between 8000 and 8500 RPM. There's not much benefit of risking engine damage above 8500RPM if you dont have a finish line. You are probably racing for top speed; and therefore may want to consider gearing changes to improve that aspect of it. A taller gear and or taller tires will help with top speed. But you do give up some in terms of low end.

Later, after gearing, CDI and Carb changes, you'll want to consider new valves and springs. I would probably suggest a cam with specs similar to these: Lift .425 in. intake / .395 Exhaust with duration 287 degrees intake and 284 degrees exhaust. These cams provide a good boost in Low end power and increase in high end power over stock. Dual Performance valve springs required. Shim Under Bucket springs can also be used with them (which is what I suggest). You also want to consider a piston at the same time as the valve springs. Consider if you want to run race gas, or not. A lighter piston will rev up faster. Higher compression will give more horsepower. To much compression will make the piston heavy - which is probably good for torque and horsepower, but not quickness.

I hope that helps!

 

when you say 3-5 hp's, is that with the ported intake or just the cap and k&n with jet...

i am going to stay away from internal mods but a cdi(still not sure which) and a carb sound good.

i am really trying to get more snap and acceleration, not so much top speed..

how will a 15 tooth front sprocket with 22's on rear for more clearance in trails affect my plan?

 

I run 22'' with the 15t front sprocket. thats not much of a gear change. but you will have more rear axle clearance. wich is why I changed to that set up.

 

If you like your quickness, and not top speed, you wont want to make the tires taller unless you compensate with, as Busmechanic says, with a lower gearing ratio with your sprockets. Taller tires will give you more rubber on the ground and more hook up. But they naturally make your gearing higher. So you may want to go down one tooth (from 16T to 15T) on the front sprocket or a combination of front and rear.

 

chirochris,

go with the vortex cdi, it's a good one. IF you don't want to spend the money, the only other unit I would consider is the procomm, but I'm pretty sure you don't like that one. If you really have money, go with MSD.

Now that your CDI is done, buy a 15 tooth front sprocket - be sure to get the good one that is sold by ron woods and marketed by other companies. The cheap $12.99 sprockets don't last very long at all. Also be sure to spend the extra $5 for the locking ting. Even if you don;t need it now, the deal will charge you like $8 or 9 so save yourself money.

You can also go with 22" tires, I have the 22" rear and 23" front holeshot XCTs - they are great. The Razr 2s are great ( they look mean) and the Bandits are said to be a good tire as well.

Now your are looking at a new fuel device. You have three options: TM45 (least expensive) works great. No problems. Lectron 46HV if setup according to Mr. HP, it works great and in my opinion is a little faster than the TM45, however costs more. Lastly you have EFI - yep Electronic Fuel Injection. No one has done any public dyno testing or comparison of this next to the TM45 or Lectron - so we can't say for sure how it performs. Technologically, it should out perform the other two and also adjust itself properly as it has a coolant temp and exhaust temp sensor which it alters it's operation based on those and I'm sure other readings. The EFI is relativly new to the market, but of the people running it, no one has had any problems that have gone public. Kelly of KMS has been able to fix any problems customers have had over the phone. Also buying the EFI puts you close to half way to a Turbo system, just another $2500 at the current price. Who knows, maybe the price will go down in the future?

Your hardest decision will be the fuel delivery device, and it should be - it's probably going to cost you the most and bar none it WILL make the most difference.

Hightower Loves his TM45, and he wouldn't give it up, I love my Lectron and wouldn't give it up either, BigDogAZ has a turbo EFI system and I know he enjoys that as well as Crackerjack. It seems right now no one is running just the EFI (at least no forum members.) I'm fortunate enough to have two DS650s, so after I buy a house, I'm going to buy EFI for my second DS650.

Good luck!

 

Stock DS650 horsepower range is from 6000 to 7000 rpm. Power is falling off by 6500rpm. The endcap does not move the power range up, it just increases power, (mostly bottom and mid range with some peak and overrev). At best, the K/N air filter added nothing to the power (and can be argued to lose 1/2 hp depending on the dyno run).
Cams: I'm not telling[img]i/expressions/face-icon-small-smile.gif[/img] but I will say this- I've never seen bottom end or mid range gains by adding 50 degrees of duration!! In fact, never mind...

High compression Pistons: the good ones have been lightened and/or special designed to stay lightweight. The best ones have less surface contact with the cylinder wall and reduce the biggest horsepower robber: friction.

The 44mm Lectron and tm45 are approx the same price.

222

 

222,

Basically, I understand where you are coming from, the DS curve just starts flatten after 6500 RPM. Thats not to say that it falls off at 6500 into the negative. If I understand your point, you would want to try land your next shift somewhere between 5100 and 6500 RPM (where the most agressive advance power curve is). That makes sence. The curve does not totally flatten on the stock motor until about 7600 RPM and then begin into negative territory. Folks just have to be able to land the next shift between 5100 RPM and 6500 RPM. I just don't know off hand what your pre-shift RPM would need to be to land there. I always thought it was around 8500 or so RPM, but I could be wrong on that - its been a while since I've had my motor stock.

You bring up a good point; That you really shouldn't shift into the next gear soley by looking at where your power curve starts to flatten downturn (like 8000-8500), but more along the lines of what RPM to land in on your next shift.