Carb or ignition - which one first?

[Atti2ude]

I have an 05 Chopper w/ VH BR , 650 Woods cam and Super E carb. I need to upgrade to a XXX G carb and Thunderheart ignition but wanted to know which will provide the best performance gains. If you had to choose, which one would you go with first? I've reviewed posts on both topics and seems many have done one or the other with great results. Most of my riding is lower RPM's but want it to be alive when needed.

 

[V]

With that cam I would say "Carb"

 

[RRRUFF]

Carb, I am assuming the heads have been fitted with larger valves and heavier springs.

 

[barhopper]

Carb all the way. I also put in the Dyna Y2K ignition. Carb is awesome.

 

[lee]

I agree - carb. But...those Woods cams are designed for low down torque (mine is anyway - which one do you have?) and the XXX G is a big carb designed to give top end power, so the two don't necessarily go together. As you are going for performance you might want to think about getting a new exhaust too

 

[Atti2ude]

Thanks all for your responses and it's great to tap into everyone's knowledge.

Carb, I am assuming the heads have been fitted with larger valves and heavier springs.

No head work but did go with heavier Woods springs. In hind sight I should have had the heads shaved but the BD tech that worked on the bike said it wouldn't make any difference and I didn't press the issue.

I agree - carb. But...those Woods cams are designed for low down torque (mine is anyway - which one do you have?) and the XXX G is a big carb designed to give top end power, so the two don't necessarily go together. As you are going for performance you might want to think about getting a new exhaust too

Lee, I think we have the same came but can't confirm. When I was at the drag strip the bike pulled great to 90 but struggled after that and I just figured it was the small carb not providing enough fuel. I have traction issues in 1st and 2nd so wouldn't mind loosing a little torque for mid/high end gains. I want performance but not to the point of a 2 into 1 exhaust.

From what I've read, the Thunderheart helps bring out the most in a performance cam so that's why I'm asking about it as well. My goal is to maximize what I have without letting go with a bunch of cash.

 

[lee]

that all sounds fine. The point I am making is that you may be going for a cam designed to give low end grunt and a carb designed to give top end power - you won't get the best out of either. If you go the XXX G route you might gain a bit at the top but lose some at the bottom. Its all a compromise at the end of the day and you can't have the best of both worlds. I actually wish now that I hadn't gone for the Woods 650 - yes it is great off the mark but unless you are racing people off the lights, which I am certainly not, I would rather have a cam that gives a little bit more at a slightly higher rpm range. My max torque is at 2600 rpms and I cruise at a higher rpm than that. All personal preference.

 

[RRRUFF]

The 05 models had the "EPA motors" which has smaller intake & exhaust valves in them. They also had restrictors in the intakes. My understanding was that BDM was trying to meet California emission standards with this. Having the heads shaved or the cylinders will get your compression up. Bigger carb may help some with the cam you have but if you want fully maximize HP, head/valve work to go with your carb is your best bet. Tunable ignition is also a plus.