The MegaBomb is waiting at the house. I should be able to get home long enough to do the dyno testing within the next month. I am open to suggestions on this testing as I'm going to be spending money with the intention of providing the forum a creditable comparison of stock header vs MegaBomb.

Here's my plan so far -
Do roll-on, SAE corrected, 4th gear tests.
Ride to Dyno, run it while at operating temp. Get HP/TRQ and AFR chart.
Install MegaBomb on site.
Dyno again and overlay data onto the first run to get a chart comparing both runs.
I should end up with a HP/TRQ, AFR chart that shows the differences.

Thoughts ;
If the Megabomb causes the bike to go leaner, I will not be able to install a larger main jet - I'm using the largest now, DJ#132... So I won't know what to do, in that case, to richen the WOT AFR.
I have port matched my header.. Is that going to be a problem ? I personally don't think the bike benefited at all and may even have lost a little performance.

 

Maybe you could tug on the choke a little if your Megabomb leans it out? Or look up the Keihin/DJ main jet interchange chart and take Keihin jets with you if you have access to them

Here ya go: http://www.jetsrus.com/FAQs/FAQ_miku...ihin_sizes.htm

 

Thanks Richard. That web site is great. I really do not want to re-jet at the dyno shop. I an hoping the MegaBomb won't radically change the AFR. But if it does, that information is valuable in itself.

It is a fact that my bike gained 1 hp when I went from 14.5 to 12.9 AFR so I may have no choice but to dyno a third time, after a rejet, if the AFR goes lean.

 

Well you can assume if you go REALLY lean (not damaging lean) that you need a bigger main jet which in turn means you gain power.

 

Yes that's the way I see it too.. If I go lean all the way back up close to 14.5 then I know at least one more HP can be gained with a re-jet.

 

Is this the Chinese Megabomb or the US version btw?

 

If you do run lean you could always put the airbox lid back on sans snorkel for the test. Just a thought. Looking forward to your results.

 

Richard, it is the actual FMF Megabomb. I had my peeps check it out at the house... It has "FMF" stamped in it and the paperwork states it as an FMF MegaBomb....

2veedubs, I don't expect the AFR to go way up BUT I really hope it does. If so, I assure you I will re-jet and re-dyno to get the full benefit on paper.

 

I think people had weld issues, I'm not sure if fmf cleared it up, but just in case watch for weld breaking by the expansion chamber

 

While you're fiddling around on the dyno, take the seat off under power and see if the a/f ratio changes. (but hold it down until you're ready)