motor question

[hiway6969]

i have a 1989 cr250 motor, is it compatible with the trx250r? if so ill keep it as a spare, if not its ebay bound lol

[wilkin250r]

Nope.

I get what you're thinking, because a lot of ATV engine have dirtbike equivalents. But this just isn't the case with the TRX250R and the CR250. They're radically different machines. Some of the nuts, bolts, and bearing interchange, but the only major component that can swap is the CR ignition can be used on the TRX, that's about it.

[hiway6969]

different jug and cases to huh? total bummer

[hiway6969]

and is the ignition better on the cr than on the trx?

[C-LEIGH RACING]

Originally posted by hiway6969
and is the ignition better on the cr than on the trx?

If the CR engine is a 2000 year & up, yes the ignition system is far better than the TRX250R ignition.
If it is 2000 & up engine, that CR ignition system is what the TRX guys coverting over to & do away with the old anilog CDI TRX ignition.

CR ignition systems below the 2000 year, are anilog CDI just like the old TRX ignition, 2000 & above are Digital CDI.
Neil

[hiway6969]

may be a stupid question but whats so much better about the digital? will the bike feel faster or respond better or is digital just more reliable?

[C-LEIGH RACING]

The old antilog CDI, when it sparks its kinda not alway at the same spot, off timming just a hair one way or the other.

Digital, it sparks same spot every time, no bouncing around.
Neil

[wilkin250r]

Neil, do you know if there is a significant difference in the spark power, or the basic timing curve between the analog and the digital ignitions?

[C-LEIGH RACING]

Originally posted by wilkin250r
Neil, do you know if there is a significant difference in the spark power, or the basic timing curve between the analog and the digital ignitions?

No, dont know anything about that, but I do know the old TRX anilog ignition, you got to spin the engine over at least 750 rpm when starting just for it to produce a spark.

The digital CR ignition, you can take you hand on the kick starter with out the spark plug in & roll it over & it will spark. Very low rpm to produce a spark.
Neil

[troybilt]

Originally posted by C-LEIGH RACING
No, dont know anything about that, but I do know the old TRX anilog ignition, you got to spin the engine over at least 750 rpm when starting just for it to produce a spark.

The digital CR ignition, you can take you hand on the kick starter with out the spark plug in & roll it over & it will spark. Very low rpm to produce a spark.
Neil

Is that why is makes starting the high compression motors so much easier? Mines a beast to start, I hate it... 220 lbs of compression. If would be worth the 500+ for a CR ignition just for that alone.

[C-LEIGH RACING]

Well, it will cause the 250R to start easier, but I dont know if it will have any effect with the compression.

With high compression & old TRX ignition, you realy got to frell on that kick starter to get it up to rpm for a spark.

The CR with the smaller lighter flywheel & the fact it will spark quicker at lower rpms, that is a + right there, but you'll still have to over come the compression when kicking.
It is a difference in going at it like a wild man with that old ignition trying to kick the engine over, but the CR takes less effort.

I tell you Troy, when you ever do get that CR ignition system change, you'll be like, I could kick myself from not doing this sooner, it is that much difference, seriously.
Neil

[troybilt]

Well I'm sold.

I not worried too much about the compression itself, I weigh 225 and can kick like a mule.... its just when that thing kicks back against my foot, it darn near brings me to tears... I no longer try and start it without riding boots... sometimes I want to start it and take if for a quick spin, no go without riding boots... holy cow.

[troybilt]

Along those similar lines, Wilkin you were, I think it was you, mentioned designing a CDI with a CDI reverse? Did you have any more luck investigating that? That would be probably the sickest thing ever on a 250r. I'd LOVE to have reverse on my woods bike. Someone smarter than me would have to come up with that... I don't know much about electrical.

[wilkin250r]

Originally posted by troybilt
Along those similar lines, Wilkin you were, I think it was you, mentioned designing a CDI with a CDI reverse? Did you have any more luck investigating that? That would be probably the sickest thing ever on a 250r. I'd LOVE to have reverse on my woods bike. Someone smarter than me would have to come up with that... I don't know much about electrical.

I got a couple projects kicking around in my head. My first one would be to design a hybrid 250r/CR250 ignition. I'm thinking about rewinding a 250r stator to use the CR250 CDI and coil. You would get the benefits of the CR250 ignition, with lights, and a heavier flywheel (which some people may or may not like).

[troybilt]

I personally like the heavier flywheel, more flywheel effect for touch more low-end, (probably negligible on a 250r though). I've got a perfect stator I probably could donate to the study of and "betterment" of 250r-kind... if you don't have one already, I think Dave (chino886) had one that already needed rewound too, which probably could get cheap...

[wilkin250r]

I'm with you, I like the heavier flywheel, especially on big-bore engines that already have plenty of power to spin it up as fast as you need. If I wanted to rev faster, I'd get rid of my powervalve.

I already tried to put a bug in Dave's ear about that bare stator, my post is still in the thread :cool:

[C-LEIGH RACING]

Oh my goodness, now you guys want to reinvent the wheel.

Everything your thinkings done been done.
Moose has a weight to go on the CR flywheel to get the wheel back just about to the weight of the TRX wheel & then Ricky Stator has the CR stator with lighting coils.

The kick back on the R with stock ignition, comes from as the crank is slowing down when you have kicked it & then a slow built up spark hits the plug before the piston gets to tdc.
Like when you kick it over, piston goes up & back down & has the rotation speed for the ignition to produce a spark & then as the crank rotates another time that piston is getting slower & slower & them pop plug fires before the piston gets to the top.
Neil

[troybilt]

Originally posted by C-LEIGH RACING
The kick back on the R with stock ignition, comes from as the crank is slowing down when you have kick it & then a slow built up spark hits the plug before the piston gets to tdc.
Like when you kick it over, piston goes up & back down & has the rotation speed for the ignition to produce a spark & then as the crank rotates another time that piston is getting slower & slower & them pop plug fires before the piston gets to the top.
Neil

Yea, that's it and it sucks bigtime. The way you describe it makes my foot hurt even more...

[wilkin250r]

I think my quad has only kicked back on me maybe twice. It might be because I'm high altitude, so "high compression" still isn't really high compression, so the motor isn't nearly as likely to stall out during the compression phase.

Dang it Troy, you got me thinking all over again. A reverse-capable CDI will probably have to be microprocessor controlled. At that point, I could make any timing curve I wanted, so I'd probably just copy a CR250 curve (which means I'll need to buy a CR250 ignition, thank you very much).

[troybilt]

Well I hope you get it figure out! I think that would be one of the sweetest things for the 250r since the inception of the PV.

I understand some of the logic, but I don't know how to setup a digital controller... I also don't fully grasp how you stall a motor without completely shutting it off to reverse direction... but that is a really neat idea, and no gears added to tranny..

...next on the list is E-start. I'm too old to kick these darn things...

[wilkin250r]

I'm thinking, wait till the motor slows to idle speed, and then fire a spark so early that the piston doesn't have a chance to reach TDC, it actually gets forced backwards (much like a kick-back). You can then monitor the timing on the pulse coil to make sure the quad did indeed reverse direction, and then adjust the spark timing to keep it running backwards.

Forcing the piston backwards with combustion pressured is probably rather stressful on the engine, but 8k rpms is also rather stressful on the engine, so I guess it's all relative.

You might need a small battery inside the CDI to provide spark energy during the transition from forward to reverse, and you'd probably also want a clutch safety switch as well, to ensure you're not trying to reverse the motor while in gear.