KTMonda CR500 450sxf conversion

[team ftb]

Jar944 - I always love your build threads as they do a lot of what I wish i had the skills to take on. Congrats on putting together some fun projects

Very interesting to hear that there was not that much real weight savings with this project over the RFS. I always complain about my 4 strokes seeming a lot heavier than the two strokes I used to race. +1 on the CR500's not being scary but just huge torque monsters. I'm a girly 140 pounds and raced one in an enduro twice and it was so torquey it was like cheating. For 3/4 of the race i thought it was all peaches and cream, not until I got tired in the last 1/4 of the race did the cr500 become too much.

Can I ask how much of a real world improvement you found in your RFS hybrid projects in terms of handling? Did it flick side to side (like threading it fast through 1st and 2nd gear tree's) any better? What were the key benefits you found to doing that upgrade? I've got a 2010 set of forks to bolt on the RFS if I want and wondering if the frame contributes that much additional benefit to the overall package? Or maybe the later model suspension is the key component providing the benefits.

I'm asking as I've got a TR570 like you and wondering if its worth the bother to do it or just take it in the ass buying a 2nd hand 500exc in a year if all the FI problems can be dealt with enough for me to ride it on long multi week rides in a third world country like my RFS does.

Again great job on the build!!

Justin

[jar944]

Originally Posted by team ftb

Jar944 - I always love your build threads as they do a lot of what I wish i had the skills to take on. Congrats on putting together some fun projects

Very interesting to hear that there was not that much real weight savings with this project over the RFS. I always complain about my 4 strokes seeming a lot heavier than the two strokes I used to race. +1 on the CR500's not being scary but just huge torque monsters. I'm a girly 140 pounds and raced one in an enduro twice and it was so torquey it was like cheating. For 3/4 of the race i thought it was all peaches and cream, not until I got tired in the last 1/4 of the race did the cr500 become too much.

Can I ask how much of a real world improvement you found in your RFS hybrid projects in terms of handling? Did it flick side to side (like threading it fast through 1st and 2nd gear tree's) any better? What were the key benefits you found to doing that upgrade? I've got a 2010 set of forks to bolt on the RFS if I want and wondering if the frame contributes that much additional benefit to the overall package? Or maybe the later model suspension is the key component providing the benefits.

I'm asking as I've got a TR570 like you and wondering if its worth the bother to do it or just take it in the ass buying a 2nd hand 500exc in a year if all the FI problems can be dealt with enough for me to ride it on long multi week rides in a third world country like my RFS does.

Again great job on the build!!

Justin

Justin, Thanks for the compliments on the builds. I've always enjoyed the fabrication side as much as riding. Since I moved out of the country and into the suburbs I have a lot less riding opportunities, so i spend more time in the garage building.

Regarding the RFS hybrids, no they are not any more flickable than a std RFS. I think that flickability has to do with the motor placement and gyroscopic effect of the engine. Neither of those change on the hybrid. The area that really improved was the turning & handling of the chassis. It goes exactly where you point it, never washes out and generally inspires more confidence for me than the RFS ever did. The suspension action is considerably better than anything on a rfs, but most of that is likely the improved forks and shock.

I was thinking of a 500 myself, but like you the FI issues and lack of ability to unlock the ecu made me change my mind.

-Jared

[team ftb]

Jared - Thank you for the feedback on the projects. Great to see you squeaking the most out of bike ownership getting not only the joy of riding but also fabbing up the special rides.

What made you want to stuff the CR500 mill into a KTM chassis as opposed to a CRF 250?

[jar944]

Originally Posted by team ftb

What made you want to stuff the CR500 mill into a KTM chassis as opposed to a CRF 250?

I had a spare KTM roller just sitting in my garage when I saw a thread on a ktm/honda conversion. I just happened to check craigslist a few days later and there was a cr500 posted for $500.

I liked how the chassis handled and since that I already had a few KTMs with the same chassis it made the decision easy. With multiple bikes it's nice when they all share parts.

[jar944]

2nd real outing

http://www.youtube.com/watch?v=ks4VM...ature=youtu.be

[jar944]

Pulled the head to cut the squish and add a decomp. Unfortunately it's too big to fit in my 4 jaw. Looks like I need to make a fixture to hold it

Looks a little rich (only about 4 hours on the motor)

[jar944]

I drilled and tapped the head (8x1.25) for a decomp. The valve was 10x1.0 and I thought could get away re-threading for use w/o a adapter. Needless to say I was in a hurry and didn't think it through. I'll be turning an adapter when the new decomp arrives.

[Research Rat]

Great build! What year cr500 motor did you use? And can you provide detail on the magura clutch?

-Scott

[jar944]

Originally Posted by Research Rat

Great build! What year cr500 motor did you use? And can you provide detail on the magura clutch?

-Scott

thanks. The motor is a 91.

What would you like to know about the clutch? I'd have to check the box but I believe it's for a 07 crf250r

[Kawidad]

Thanks for sharing. I think. See stuff like this makes me hate father time even more.............

[Research Rat]

What made you decide on a 91 vs. other years?

Re the clutch, is it a hydraulic unit?

Thanks,
Scott

Originally Posted by jar944

thanks. The motor is a 91.

What would you like to know about the clutch? I'd have to check the box but I believe it's for a 07 crf250r

[jar944]

Originally Posted by Research Rat

What made you decide on a 91 vs. other years?

Re the clutch, is it a hydraulic unit?

Thanks,
Scott

91-2001 are basically the same with some very minor differences (color & trans ratios) & Yes the magura is hydraulic.

[Research Rat]

I'm keeping my eyes peeled for crs.

With the magura, is it as simple as plug and play or is there more involved with the install? Have you thought about adding a rekluse (if there is even one available for the cr motor.)

Originally Posted by jar944

91-2001 are basically the same with some very minor differences (color & trans ratios) & Yes the magura is hydraulic.

[jar944]

Originally Posted by Research Rat

I'm keeping my eyes peeled for crs.

With the magura, is it as simple as plug and play or is there more involved with the install? Have you thought about adding a rekluse (if there is even one available for the cr motor.)

yes it'a a simple bolt on. as for the rekluse i'm personally not a fan.

[Research Rat]

Jared,
Do you know if the 2008 450 EXC frame would work as well for the conversion as the 450 sxf/xcf? From the fiche I can tell they are different part numbers.

Thanks!
-Scott