Full Tilt CR250 Build - MXA Two Stroke Hall of Fame

7/26/2016 8:30am
kawi448 wrote:
This looks sweet! What suspension are you gonna run? And what did you do to the motor? I can't wait to see it all done
KYB kit suspension based off the latest Honda version of the SSS forks and a 2015 CRF style rear shock. [img]https://p.vitalmx.com/photos/forums/2015/12/22/116440/s1200_20151121_033602.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2015/12/22/116441/s1200_20151218_221926.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2015/12/22/116442/s1200_20151218_220413.jpg[/img] [img]https://p.vitalmx.com/photos/forums/2015/12/22/116443/s1200_20151120_160049_2.jpg[/img]
KYB kit suspension based off the latest Honda version of the SSS forks and a 2015 CRF style rear shock.









How did u get the triple clamps to work on the frame like what mods did u have to do to make it bolt on thanks
(((what)))
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7/26/2016 8:33am Edited Date/Time 7/26/2016 8:35am
JW381 wrote:
Can you elaborate a little? I'm running a 172 (170 when the Temps go above 85) 42 and a JD red needle on the 2nd from...
Can you elaborate a little? I'm running a 172 (170 when the Temps go above 85) 42 and a JD red needle on the 2nd from the top. Very lean compared to other settings. I'm running a blend of 97 and 110 with Super M at 40:1. 04 with a 00 CR PWK. I suspect I have weak spark or not enough air flow.
Is the bike having a specific problem of some sort?
JW381 wrote:
Well I'm only at about 600'-800' elevation, wondering what is causing my bike to need such lean settings. It won't pull without the 170 main above...
Well I'm only at about 600'-800' elevation, wondering what is causing my bike to need such lean settings. It won't pull without the 170 main above 85 degrees. The 110 race fuel is made by renegade, and the 97 is just a higher octane non-ethanol premium. I'm not sure if the 110 is oxygenated. There is a hesitation in the middle, whenever I try the middle clip position it barely runs from being so rich. But I have not tried with the 170/42 combo yet. So when I see guys at similar elevation talking about 48P and 178M, I scratch my head a little. My plugs never indicate lean. They do, however, get uneven coloration. On half of the plug is coffee brown, the other is black.
Your stator is on its way out. The stators on those motors don't just quit, they slowly piddle out and manifest themselves as jetting issues.

What page is the mammoth video on
JW381
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7/26/2016 9:32am
Is the bike having a specific problem of some sort?
JW381 wrote:
Well I'm only at about 600'-800' elevation, wondering what is causing my bike to need such lean settings. It won't pull without the 170 main above...
Well I'm only at about 600'-800' elevation, wondering what is causing my bike to need such lean settings. It won't pull without the 170 main above 85 degrees. The 110 race fuel is made by renegade, and the 97 is just a higher octane non-ethanol premium. I'm not sure if the 110 is oxygenated. There is a hesitation in the middle, whenever I try the middle clip position it barely runs from being so rich. But I have not tried with the 170/42 combo yet. So when I see guys at similar elevation talking about 48P and 178M, I scratch my head a little. My plugs never indicate lean. They do, however, get uneven coloration. On half of the plug is coffee brown, the other is black.
(((what))) wrote:
Your stator is on its way out. The stators on those motors don't just quit, they slowly piddle out and manifest themselves as jetting issues. What...
Your stator is on its way out. The stators on those motors don't just quit, they slowly piddle out and manifest themselves as jetting issues.

What page is the mammoth video on
I've been saying/thinking that for a while now. Thank you for validating me! I'll get on that.
cslacker
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7/26/2016 10:16am
JW381 wrote:
Well I'm only at about 600'-800' elevation, wondering what is causing my bike to need such lean settings. It won't pull without the 170 main above...
Well I'm only at about 600'-800' elevation, wondering what is causing my bike to need such lean settings. It won't pull without the 170 main above 85 degrees. The 110 race fuel is made by renegade, and the 97 is just a higher octane non-ethanol premium. I'm not sure if the 110 is oxygenated. There is a hesitation in the middle, whenever I try the middle clip position it barely runs from being so rich. But I have not tried with the 170/42 combo yet. So when I see guys at similar elevation talking about 48P and 178M, I scratch my head a little. My plugs never indicate lean. They do, however, get uneven coloration. On half of the plug is coffee brown, the other is black.
(((what))) wrote:
Your stator is on its way out. The stators on those motors don't just quit, they slowly piddle out and manifest themselves as jetting issues. What...
Your stator is on its way out. The stators on those motors don't just quit, they slowly piddle out and manifest themselves as jetting issues.

What page is the mammoth video on
JW381 wrote:
I've been saying/thinking that for a while now. Thank you for validating me! I'll get on that.
My 03 likes similar lean jetting to yours. I swapped all of the wiring, stator etc.. last year and it had no effect on the need for leaner jetting than most. Don't get me wrong, feel free to try a stator swap yourself, just thought you should know you are not alone.

The Shop

blackdiamond
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7/26/2016 10:50am
Yeah I was trying to mount the cdi in the middle of the bike since I'm putting the 2015 forks on the front with the stabilizer...
Yeah I was trying to mount the cdi in the middle of the bike since I'm putting the 2015 forks on the front with the stabilizer like u did. And how hard was it make the coil bracket mount.
The clamps are an easy swap, just replace the steering stem with one from a CR250 (they are a slightly different length if I remember correctly)

The coil mount is a modified coil mount used on a shifter Kart. They can be found on eBay and there are a few good images of it in the beginning of the thread.
blackdiamond
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7/26/2016 10:58am
JW381 wrote:
Well I'm only at about 600'-800' elevation, wondering what is causing my bike to need such lean settings. It won't pull without the 170 main above...
Well I'm only at about 600'-800' elevation, wondering what is causing my bike to need such lean settings. It won't pull without the 170 main above 85 degrees. The 110 race fuel is made by renegade, and the 97 is just a higher octane non-ethanol premium. I'm not sure if the 110 is oxygenated. There is a hesitation in the middle, whenever I try the middle clip position it barely runs from being so rich. But I have not tried with the 170/42 combo yet. So when I see guys at similar elevation talking about 48P and 178M, I scratch my head a little. My plugs never indicate lean. They do, however, get uneven coloration. On half of the plug is coffee brown, the other is black.
I would have to agree with some of the others and I would definitely test the stator.

In regards to the fuel, for future reference make sure you know the oxygen content of the fuel because oxy fuels make a huge difference in jetting the bike especially when cutting them with pump fuel (also oxygenated in most cases)
7/26/2016 11:37am
Thanks for the info im glad I saved my cr250 triple clamps. Did u get any pics of how u mounted ur CDI box thanks
JW381
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7/26/2016 12:03pm Edited Date/Time 7/26/2016 12:18pm
(((what))) wrote:
Your stator is on its way out. The stators on those motors don't just quit, they slowly piddle out and manifest themselves as jetting issues. What...
Your stator is on its way out. The stators on those motors don't just quit, they slowly piddle out and manifest themselves as jetting issues.

What page is the mammoth video on
JW381 wrote:
I've been saying/thinking that for a while now. Thank you for validating me! I'll get on that.
cslacker wrote:
My 03 likes similar lean jetting to yours. I swapped all of the wiring, stator etc.. last year and it had no effect on the need...
My 03 likes similar lean jetting to yours. I swapped all of the wiring, stator etc.. last year and it had no effect on the need for leaner jetting than most. Don't get me wrong, feel free to try a stator swap yourself, just thought you should know you are not alone.
I hear ya, but mine has gotten progressively leaner over time, plus it's inconsistent and erratic. I've done top ends, clutches, reeds, carb rebuilds, main seals. It doesn't have symptoms o an air leak or failing right side seal. It could be a vacuum leak. I remember a day about 3 years ago when I had it dialed (175M and 45P), bike was scary fast. Fingers crossed for the stator
JW381
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7/26/2016 12:11pm
JW381 wrote:
Well I'm only at about 600'-800' elevation, wondering what is causing my bike to need such lean settings. It won't pull without the 170 main above...
Well I'm only at about 600'-800' elevation, wondering what is causing my bike to need such lean settings. It won't pull without the 170 main above 85 degrees. The 110 race fuel is made by renegade, and the 97 is just a higher octane non-ethanol premium. I'm not sure if the 110 is oxygenated. There is a hesitation in the middle, whenever I try the middle clip position it barely runs from being so rich. But I have not tried with the 170/42 combo yet. So when I see guys at similar elevation talking about 48P and 178M, I scratch my head a little. My plugs never indicate lean. They do, however, get uneven coloration. On half of the plug is coffee brown, the other is black.
I would have to agree with some of the others and I would definitely test the stator. In regards to the fuel, for future reference make...
I would have to agree with some of the others and I would definitely test the stator.

In regards to the fuel, for future reference make sure you know the oxygen content of the fuel because oxy fuels make a huge difference in jetting the bike especially when cutting them with pump fuel (also oxygenated in most cases)
http://www.renegaderacefuel.com/fuels-2/fuels/

The 98 octane I mix is stated as non-oxygenated. It doesn't specify about the 110 octane. Since I've switched to this mix I've noticed it burns way cleaner at least. Before it was non-ethanol 93 with either 25% or 50% 110 and it would load up like a bitch. Couldn't let it idle for even a few seconds. So at least I've got that going for me.
blackdiamond
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7/26/2016 4:29pm
Thanks for the info im glad I saved my cr250 triple clamps. Did u get any pics of how u mounted ur CDI box thanks
I haven't, I'm going to be out of town for another week I'll try to take some pics when I get back
7/31/2016 2:32pm
Did the rear shock bolt right up? Or was modification needed? Great build!! Love it
blackdiamond
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7/31/2016 3:11pm
Not even close, it had to be shortened and required a KYB kit shock shaft and a works seal head to get the spacing correct. I thought it would be easier but I soon realized it wasn't going to be easy to do it the right way. If Graeme Brough wouldn't have had the spare A-kit KYB parts laying around I would have been forced to go to plan B.
pgd
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Scottsdale, AZ US
7/31/2016 4:28pm
Is the carbon fiber ignition cover a Light Speed product, and if so could you advise where you purchased it? Thanks.
blackdiamond
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7/31/2016 4:51pm
Yes, it's Lightspeed. The last time I talked to Willie over there he only had a couple left, they don't actually produce them anymore for the CR250. If you want one you better hustle.
pgd
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8/3/2016 11:56am
Yes, it's Lightspeed. The last time I talked to Willie over there he only had a couple left, they don't actually produce them anymore for the...
Yes, it's Lightspeed. The last time I talked to Willie over there he only had a couple left, they don't actually produce them anymore for the CR250. If you want one you better hustle.
Thanks BD, I was able purchase the last one from LS.
blackdiamond
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8/4/2016 1:05am
Yes, it's Lightspeed. The last time I talked to Willie over there he only had a couple left, they don't actually produce them anymore for the...
Yes, it's Lightspeed. The last time I talked to Willie over there he only had a couple left, they don't actually produce them anymore for the CR250. If you want one you better hustle.
pgd wrote:
Thanks BD, I was able purchase the last one from LS.
Sweet! They are a really nice piece, you will be stoked.
rostocker
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8/4/2016 3:15pm
Hey BD, have you ever considered JD racing ignition? I don't know how and why it would be better than what you got now, maybe a little simpler to use or something. It's made for motocross and not go-cart at least... Wink You are usually quite knowledgeable regarding these things and so it would be interesting to hear your thoughts
/D
blackdiamond
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8/4/2016 10:18pm Edited Date/Time 8/4/2016 10:24pm
rostocker wrote:
Hey BD, have you ever considered JD racing ignition? I don't know how and why it would be better than what you got now, maybe a...
Hey BD, have you ever considered JD racing ignition? I don't know how and why it would be better than what you got now, maybe a little simpler to use or something. It's made for motocross and not go-cart at least... Wink You are usually quite knowledgeable regarding these things and so it would be interesting to hear your thoughts
/D
I have used the JD unit in the past and they work quite well on the CR 250, especially if you're trying to squeeze a little more over-rev out of it.

The biggest advantage to the Zeel ignition is the fact that you can tune the power valve mapping and that's what helps us achieve the "four stroke like" linear power curve that is almost too good to be true.

The same types of ignitions are used in karting that are used in motocross including Vortex, JD and Zeeltronic and a few others.

The ignitions are just tuned differently for different applications, but there is no kart specific or motocross specific designation. It all comes down to dyno time and custom maps based on fuel, altitude, pipe spec, porting, jetting, etc.

At the end of the day its just an electronic box that does what you tell it to do. It doesn't know what its connected to or what type of racing it's doing, the box is just following orders (if that analogy makes any sense)
rostocker
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8/7/2016 3:42am
Ok I understand. Man you have some knowledge! Much appreciated to be able to learn from your CR wisdom Woohoo
I actually found that the zeeltronic was cheaper than the JD ignition. Wink
Maybe its somewhere in this mega thread, but how is the zeeltronic out of the box? plug and play or is a call to MR cable guy necessary to get it to work? is there a pre-programmed map that is usable or do you need to set it up to get it to work? and finally does it support the power jet (if used) or do i need to specify that i want it when ordering?

blackdiamond
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8/7/2016 2:11pm Edited Date/Time 8/7/2016 6:05pm
They do not provide a base ignition map and the ones they suggested were not even close for mt application. The biggest problem is that this ignition and PV controller have been largely used by the Kart and road racing community and there is very little information available for the MX arena.

They sent 6 different PV maps and we didn't use any of them. I tried all of them and basically all they were useful for was learning what the engine liked. We ended up with a full custom map on the PV. It is extremely sensitive to that adjustment. You can move the opening at a specific RPM point 2% and see it on the dyno. For example: at 5500 RPM it might be 57% open instead of 55% That's all it takes to see a difference, it's mind boggling how sensitive it is.

I did my own baseline ignition map based on a ton of info gathered from several different data sources, tuners and theories and ended up with a 1.5 HP gain at peak over the OEM system. More importantly we were able to get the PV map dialed in which eliminated the holes on the front side of the dyno curve and created an extremely linear and broad (almost 4 stroke like) powerband.

I am going to be dyno testing again this week and expect to find some more HP at that time. I would be willing to do custom mapping once I feel this package is as perfect as I feel it can be for $100 if you are interested.
blackdiamond
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8/7/2016 7:01pm Edited Date/Time 8/7/2016 7:03pm
blackdiamond, where did you mount the CDI box in your bike? I noticed that there is not enough space for it behind the number plate
The only reasonable location for it is at the very rear of the air box because of its size. I fabricated a removable tray that pops...
The only reasonable location for it is at the very rear of the air box because of its size. I fabricated a removable tray that pops in and out allowing easier servicing of the air filter. I'm out of town for work for a week but when I return I can post some pics. It's tricky, I tried mounting it in the middle of the bike earlier in the build but it's just too complicated to do correctly in that area. The cleanest, coolest and most waterproof area is in the air box.
Here are a few pics of the tray inside the airbox that holds the ignition. Velcro strips hold it to the tray so it can be removed and swung out of the way for easy airbox access without tools. I designed it so that when the seat is installed it sandwiches the electronic box perfectly and makes it impossible for it to move. This is the setup we ran when Ryan Surratt won the Mammoth MX with my ignition and carb.










rostocker
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8/8/2016 6:14am
They do not provide a base ignition map and the ones they suggested were not even close for mt application. The biggest problem is that this...
They do not provide a base ignition map and the ones they suggested were not even close for mt application. The biggest problem is that this ignition and PV controller have been largely used by the Kart and road racing community and there is very little information available for the MX arena.

They sent 6 different PV maps and we didn't use any of them. I tried all of them and basically all they were useful for was learning what the engine liked. We ended up with a full custom map on the PV. It is extremely sensitive to that adjustment. You can move the opening at a specific RPM point 2% and see it on the dyno. For example: at 5500 RPM it might be 57% open instead of 55% That's all it takes to see a difference, it's mind boggling how sensitive it is.

I did my own baseline ignition map based on a ton of info gathered from several different data sources, tuners and theories and ended up with a 1.5 HP gain at peak over the OEM system. More importantly we were able to get the PV map dialed in which eliminated the holes on the front side of the dyno curve and created an extremely linear and broad (almost 4 stroke like) powerband.

I am going to be dyno testing again this week and expect to find some more HP at that time. I would be willing to do custom mapping once I feel this package is as perfect as I feel it can be for $100 if you are interested.
I would be happy to buy the settings youll get when you are done. Smile
Will you use the map switch?
How do you think the map will work on a bike with no motorwork and TMX carb (apart from HGS pipe/silencer, Rad valve, VHM head ("standard" insert) )?
blackdiamond
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8/8/2016 4:01pm
rostocker wrote:
I would be happy to buy the settings youll get when you are done. :) Will you use the map switch? How do you think the...
I would be happy to buy the settings youll get when you are done. Smile
Will you use the map switch?
How do you think the map will work on a bike with no motorwork and TMX carb (apart from HGS pipe/silencer, Rad valve, VHM head ("standard" insert) )?
What fuel are you running? Also, have you checked the squish?

I don't run the bar mounted map switch here in So Cal because the tracks are typically very well prepped and consistent. Once I find a good setting I tend to just stick with it and ride so I didn't feel the need for the map switch but its easy enough to set up if needed.

The map should work really well, especially with the HGS pipe.
rostocker
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8/8/2016 10:40pm
rostocker wrote:
I would be happy to buy the settings youll get when you are done. :) Will you use the map switch? How do you think the...
I would be happy to buy the settings youll get when you are done. Smile
Will you use the map switch?
How do you think the map will work on a bike with no motorwork and TMX carb (apart from HGS pipe/silencer, Rad valve, VHM head ("standard" insert) )?
What fuel are you running? Also, have you checked the squish? I don't run the bar mounted map switch here in So Cal because the tracks...
What fuel are you running? Also, have you checked the squish?

I don't run the bar mounted map switch here in So Cal because the tracks are typically very well prepped and consistent. Once I find a good setting I tend to just stick with it and ride so I didn't feel the need for the map switch but its easy enough to set up if needed.

The map should work really well, especially with the HGS pipe.
The fuel Im running now are Pump gas PON 92 or something similar. The head have a squish of 1.5mm and a volume of 20.20cc
blackdiamond
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8/9/2016 11:06am
Is there any way you can get your hands on higher octane fuel?
rostocker
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8/9/2016 12:46pm
Is there any way you can get your hands on higher octane fuel?
yes I can, What should I run?
blackdiamond
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8/9/2016 1:15pm
rostocker wrote:
yes I can, What should I run?
Depends on the compression, what is the cranking PSI?
8/9/2016 9:06pm
Out of curiosity, what do you think how Zeeltronic would run with no TPS information? I read somewhere that original Honda 05-07 CR250 CDI changes the mapping from 3D to 2D, if there is no TPS information available?
blackdiamond
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8/9/2016 11:34pm
Out of curiosity, what do you think how Zeeltronic would run with no TPS information? I read somewhere that original Honda 05-07 CR250 CDI changes the...
Out of curiosity, what do you think how Zeeltronic would run with no TPS information? I read somewhere that original Honda 05-07 CR250 CDI changes the mapping from 3D to 2D, if there is no TPS information available?
It would definitely hurt performance at low to mid throttle openings because you would sacrifice the ability to run more advance at those lower RPM points. You have to give to get. Why would you want to do that?
8/10/2016 1:26am
It would definitely hurt performance at low to mid throttle openings because you would sacrifice the ability to run more advance at those lower RPM points...
It would definitely hurt performance at low to mid throttle openings because you would sacrifice the ability to run more advance at those lower RPM points. You have to give to get. Why would you want to do that?
Just speculating, thanks for the reply.

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