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FCR-MX 41 + Dyna Tek FS vs the dyno

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The bottom line in yellow is an average run I had in the past with the 39mm, stock ignition and the current OSHC/Web cams. It peaks at 44.88 hp and 30.17 torque. I've had numbers ranging from 43 to 45.9 hp and 28- 31 torque before during various test using the 39mm, 2047/2048 Hotcams and T4 race fuel.

 

All of the runs today were with the 41, the ignition on the +4 curve and 93 octane pump fuel. I probably could have gotten a little higher number on top with a different curve, but +4 is my favorite and the one I feel is most ridable overall.

 

You can see from the sheet, from 6k to around 10k, the 41 and Dyna combo makes a healthy gain, 2-3 over that range. On peak, I picked up around 2 additional horsepower and ft/lbs an average, and I beat my all time high by 1 hp. The old pull unfortunately cut off below 6k on the graph , but in comparing my old sheets, from 4k to 6k is virtual identical.

 

I just thought I'd share my experience with anyone looking for a little more out of their BB. Beyond what the dyno says, the character has changed significantly vs stock ignition, new style stage 2 Hotcams and a FCR39. The bike is making numbers comparable with 450 MX bikes 10 years ago, and more importantly, it feels like it when riding.

 

Not bad for a bike about to hit 19k miles thats never had a single valve shimming.

 

 

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I hate the peak being @ 8500 rpm, though it is what the motor is .  I wish I had a reasonable access to a dyno for testing ,a cost of living in the boonies .

 

 

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Edited by jjktmrider
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I am still struggling to jet my 470 properly with my 41. Currently has a 42 pilot and 160 main and it doesn't feel great @1000ft. 

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On 2017-08-26 at 3:17 PM, ohiodrz400sm said:


For reference in my 434 @700' I have a 175 main, 48 pilot ,EMR 3rd clip.
I found on a 90 deg. day I need a 45 pilot.

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I just found out now that not all jets numbers are created equal. This absolutely ruins everything about how I thought my bike was jetted when I got it, I thought it was the same shit. 

Do you know what jets have a star on them? I have a 178 with a star... this just got super confusing. Are people always referring to Keihin jets when they list numbers? 

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I just found out now that not all jets numbers are created equal. This absolutely ruins everything about how I thought my bike was jetted when I got it, I thought it was the same shit. 

Do you know what jets have a star on them? I have a 178 with a star... this just got super confusing. Are people always referring to Keihin jets when they list numbers? 

Genuine Keihin jets have the K star you are referring to. Aftermarket jets do not.

In theory they should flow the same but it is not always the case.

 

If people are speaking about the FCR, they are talking about Keihin jets.

If they talking about the stock BSR then it's Mikuni jets. They are a different shape. Genuine Mikuni jets have some sort of box in a box logo.

 

Another thing to consider when looking for jets is each manufacturer makes several types of carburetors. The jet they use don't all have the exact same style/shape.

 

 

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What model of Dyna did you get? There are three listed for the DRZ, I'm guessing the better of the three are the DRZ400 Programmable and DRZ400SM Programmable. Would and S guy need the SM one?

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What model of Dyna did you get? There are three listed for the DRZ, I'm guessing the better of the three are the DRZ400 Programmable and DRZ400SM Programmable. Would and S guy need the SM one?

I bought the DFS3-17P which is listed for the SM.
They also sell the DFS3-16 and 16P for the dirt only versions. P signifies programmable.

I recently noticed that the S and SM have different p/n for the stock CDI box, but I have no idea what the difference is.

They will all interchange. The plugs are the same. The only caveat when swapping the dirt (E) model between the S/SM being there is a extra wire in the S/SM wire harness that needs to be cut or removed before the CDI will power up. The extra wire is the green wire on the big harness. It is a ground wire for the side stand interlock I believe. So with the wire cut, the Dynatek "16" should work on the S/SM as well. As far as the "17" I don't see any reason why it wouldn't be plug n play on an "S" like it is in the SM model.



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Thanks for the confirmation. I figured it would be that one, but I needed to hear it from someone who has one. I am running an E cdi box now so I had to do the green wire trick. Does the Dyna have the ability to raise the rev limiter also? I find I like running up near the limiter when I am on the street and it's nice to have a little more room with the E cdi. I need some Web Cams also! 

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Thanks for the confirmation. I figured it would be that one, but I needed to hear it from someone who has one. I am running an E cdi box now so I had to do the green wire trick. Does the Dyna have the ability to raise the rev limiter also? I find I like running up near the limiter when I am on the street and it's nice to have a little more room with the E cdi. I need some Web Cams also! 

 

It's a pretty cool unit that does a lot. The software is an additional $80-100 though. I ordered it over the weekend and should have it by the end of the week. I did already download the instructions. Programming the rev limiter 1 of many possibilities, although with stock valves, especially if you go to Web's, I wouldn't recommend. There is also the ability to calibrate the tps on the bike and do some 3d mapping changes. The TPS controls the closed, mid and wot throttle curves,which you can edit and specify what throttle percentage activates which curve. Then there is also the ability to program and activate other add-ons such as a launch control, nitrous, or whatever.

 

I'm found experimenting that the + 4 advance is a little too much on top and dulling the power a bit. I plan to write a custom curve with the early advance up to around 40° when back it back down to the stock 36° or less after peak torque. That SHOULD result in the strong bottom and mid and a long feeling pull on top.

 

Again, my bike is not stock. This ignition is only complimenting what I have already done. The changes aren't massive. If you have any experience with a modern FI MX bikes and their tuners, than you should have a pretty good idea what this CDI box does.

 

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