sounds awesome! I'm in.

 

If the AU timing is 10deg more advanced than the US timing,
maybe we could find a source of AU ignition modules.
Craig

 

The US ignition module retails at ~$300. Add shipping from down under and maybe even a higher retail price due to smaller market.

An aftermarket solution (very likely not as robust as an OEM part) better be substantially cheaper. Unless it's a fully programmable gizmo box with a computer application to tune the map etc. (think PowerCommander)

--
Mikko

 

send me an US CDI and ill see if there is a power loss between the two.......

 

Would you do a dyno with both?

 

Ok here to answer a couple question.

A. Cost. There are two routes to go so I can't say exactly. Both alternatives are going to be tunable. One option is going to stray towards $400, yeah alot. the other option may be $200-250.
The more expensive option is going to completely replace the stock CDI unit. The other option will be "in line" with the stock CDI. The "In line" option will take MUCH more time.

B. The question of "How timing works". I really would like you to explore simple engine operation to answer this question. Advancing the ignition means to make the spark ignite closer to top dead center, thus making more power because you are igniting closer to full compression with the most energy possible.

C. Reliability. There are requirements for this type of modification. You are creating MCUH MORE HEAT. You NEED at LEAST an aftermarket silencer. A larger diameter header would be even better. You are going to increase your cylinder temperatures and may shorten maintenance intervals on various items.

D. klx300 R intake. Look at parts site and look at the intake, or on ebay look for a klx300r airbox.

E. Selling my bike. At the moment it looks that way. But projects go on.

This is going to be a self liable product, we can only go so far to give "rough" dimensions of fuel accommodations. Monitoring tools are highly suggested, I finally got an AEM wideband air/fuel ratio installed on my klx today waiting to proceed with this project.

Im very happy with the feedback from you guys, I will continue the project and give my honest opinion after we are done. If i dont see it being worth it, I wont be ashamed to offer that opinion.

 

TNC brings up some very good points of conversation here. Likewise what I'm about to say is not trying to detract from the value of an improved ignition system. However, I do think that the expectations should be clarified, and set in more realistic terms. Generally, potential gains from ignition tuning are similar to potential gains from jetting; while they can be significant and noticable, they will not be earth shattering.

Ideal ignition advance is very much combination and condition specific. That's where the real potential benefit of this project lies: few of us keep our bikes bone stock, and even if we do each one is its own machine and operates in variable conditions. There are certainly gains to be had by tuning ignition to a specific combination, but the effects may or may not be large, and may or may not be easily achieved without detailed dyno tuning.

Just for kicks, here are some additional factory specs.
1996 KLX250R, 5 DEG BTDC @ 1700 RPM, 40 DEG BTDC @ 3000 RPM
2004 KLX300R, 10 DEG BTDC @ 1700 RPM, 40 DEG BTDC @ 3000 RPM
2010 KLX250S, 10 DEG BTDC @ 1300 RPM, 25 DEG BTDC @ 5000 RPM

Now, where we need to get more realistic:
A four stroke engine's ultimate horsepower capability is closely tied to head flow capability (i.e. porting), while torque capability is closely tied to engine displacement. Of course cam profiles play a huge part how the head flows as well, as do the induction and exhaust components, and to a still lesser extent cylinder bore size and piston stroke. We've pretty much seen that the stock KLX head/cam combinations are likely reaching their upper horsepower potential somewhere in the mid 20's. That's why you see bill blue's 351 with similar peak horsepower to a similarly tuned 300, or even 250; while the 351 stomps on the smaller engines in terms of torque. For further illustration, the new KTM350SX puts out about 45 horsepower at around 9500 rpm, and doesn't start into the meat of it's torque curve until after 6500 rpm, peaking at around 26-27 ft-lbs. The BB 351 puts out similar torque(slightly more than 20 ft-lbs) to the KTM350, but the BB351 drops severely after 6500 rpm. Again, all else being equal, engine displacement determines torque potential, cylinder head (and cam) configuration determines horsepower potential.

Bluntly, with stock heads and cams, these KLX250/300/340/351 engines won't likely get too near 30 horsepower (and they don't have a snowflake's chance in hell of getting close to 40).

Going a more positive direction, because dynamically the 351 is such a starkly different engine combination than the stock 250, it very well will benefit from different ignition tuning.

So yeah, like I said before, I'm interested and I can see the potential benefit. I just don't want unrealistic expectations for power improvements out of it. I'll grant that at this point the project is quite vague, so I'm sure the details will fall into place as it develops; and I am excited to see it develop.

 

Possibly could, hadn’t really though about it... would have to ask around to see if any of the mates have a dyno contact so that i could get it for free.

I looked around cause I would like to know what a AU model puts out stock compared to a US model.

I know there will be differences cause the AU has a different exhaust (a smidge more free flowing than the US model), it has a klx300 air box, its jetted differently (i believe but don’t quote me on that) and the CDI is supposedly different.

 

Don't quit your day job.

Good luck in your endeavor.
Ron

 

I wonder if sw0ggd0gg realizes that his description is wrong and wasn't addressing the question. I was asking about how the electronics advanced the ignition timing.

Ride on
Brewster