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Converting a ktm 525 to 450

Yes, you can convert it to a 450, it will be the EXC model. The 450 SX and I believe XC had a shorter stroke with the 525 piston and cylinder. 400 EXC parts will also work, they are the 450 EXC top end with the SX shorter stroke crank. I’d imagine the heads are different but I’m not positive. Other things to look at would be the intake boot, header, etc. The best thing to do would be to get on an OEM parts page like Rocky Mountain ATV and check part numbers.

You may be able to tame it with ignition mapping also, some of the later models had on the fly switches to tame them down.

Just looked it up, the head is the same. https://www.rockymountainatvmc.com/oem-schematic/2
 
As has been said there isn't that much power difference between a 450 and the 525.
Neither bike wil be the best bike for tight woods trails.
To combat the heat you can change to a colder plug, richen up the mixture to the fat side and add some water wetter to the coolant.

You never said if it still has the factory exhaust. If it doesn't, you could probably find one cheap and it will drop the power.
 
montrose818 said:
Brother, I am not going to cook the bike. You ever hear the phrase I mentioned, better drive slow bike fast than fast bike slow? Yeah you go take your cr500 in single track on side of the hill, but I will pass thank you.

I dont want to sell it because new frame design, first year street legal, and last year of RFS engine make this is rare bike, especially in this condition. Plus my buddy sold it so I could ride it, it would be a dick move for me to turn around and sell it.

Guess Im on my own. Its going to boil over riding single track, even more if I gear it down, so maybe get a smaller bike for dirt and sumo this sucker then
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Where are you going riding at?
 
Rowher Flats by Agua Dulce is the closest place to me, the tracks are tight in some places but mainly they are all on the gill sides so if you go off, its NOT going to be fun, so I rather stay on the the trail.

I have to check the exhaust. Havemt thought about a colder plug, will research that. If not for the heat, I could probably make it work with low gearing, but not if I am going to cook the bike.

Really I need to just a smaller bike for dirt.
 
I used to have a KX500, I thought it was too much. I was a 145lb scrawny kid at the time though. I thought the 300 2-stroke was about perfect.

A richer fuel setting should be a pretty quick and easy way to tune it down. I have ridden a 450 of that vintage, still a lot of bike. Seems like a lot of trouble for the end result.
 
Thanks, Ill try a colder plug and richer mixture. If not then I suppose Ill leave this bike as is, and think about somethinf else I can thrash in the dirt.
 
montrose818 said:
Thanks, Ill try a colder plug and richer mixture. If not then I suppose Ill leave this bike as is, and think about somethinf else I can thrash in the dirt.
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Do you work nights? Drunk dumb ideas in the morning. Sleep all day, then wake up and realize how retarded the idea was? :lmao:
 
If you plan on getting more into the woods, check out at WRR.
 
Reminds me of when I was a kid.

I was rocking a CR125 and dreamed of having the Bad Bay, the CR500

I one day met a guy on one.

I was so excited.

I asked him how great it was?

He told me it pretty much sucked.

I didn't understand, it made no sense what he said.

He explained it had so much power it wasn't fun to ride, it was diffacult to ride, besides riding on one wheel going straight there wasn't anything great about it.

I get what the OP is saying.

I think Supermoto is your best idea for it.
 
crispins said:
Reminds me of when I was a kid.

I was rocking a CR125 and dreamed of having the Bad Bay, the CR500

I one day met a guy on one.

I was so excited.

I asked him how great it was?

He told me it pretty much sucked.

I didn't understand, it made no sense what he said.

He explained it had so much power it wasn't fun to ride, it was diffacult to ride, besides riding on one wheel going straight there wasn't anything great about it.

I get what the OP is saying.

I think Supermoto is your best idea for it.
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This is the opposite of what I would expect to read from this site.
I've had a cr500 in the past and now have a lt500 and the 250s are no longer fun for me to ride. Imo if he gets out and rides the 525 more and buys a smaller bike the smaller bike will just sit around.
 
M92PV4U said:
This is the opposite of what I would expect to read from this site.
I've had a cr500 in the past and now have a lt500 and the 250s are no longer fun for me to ride. Imo if he gets out and rides the 525 more and buys a smaller bike the smaller bike will just sit around.
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When I was nagger rich, I spent $10k on a motor build for my ZX-10r

I think I put under 200 miles on it before i parked it.

I still have it, not fun to ride, will kill you.

I have the dyno sheet for it 230 HP on a under 400 lbs bike
 
I had an old, 1980s Honda XL250. My cousin has a CRF250. Did a day trip together. Got to the pavement and wanted to race through the valley. Tucked up, wide open, 6th gear, we raced. I felt like Rossi. That motor was SINGING. I won. At a blazing 64mph.

Probably the best time I had on a bike. That was hilariously fun.
 
crispins said:
When I was nagger rich, I spent $10k on a motor build for my ZX-10r

I think I put under 200 miles on it before i parked it.

I still have it, not fun to ride, will kill you.

I have the dyno sheet for it 230 HP on a under 400 lbs bike
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See that is Awesome. How much to rent it for an hour? Pics?
 
Currently have a KX500 and a KTM 690. It's all in how you ride the bike you don't have to grab a huge handful of throttle, just roll into it nice and smooth. If you just grip it and rip it you will spin the tire or pull up the front
I have big bikes, because I am a big fat guy.

I can certainly understand having fun wringing out a smaller bike, but the OP said that this is the bike he has and is "stuck" with.
To convert it to a 450 would be expensive, and have no positives except maybe running cooler, but there's no garentee on that.

Riding a 125 and having to keep the thing in the screaming rpm range gets old quick. With the bigger bike you can lug the engine down without stalling it.
 
I'll be punching out my DR650 to a 790 next year most likely.
 
montrose818 said:
Its going to boil over riding single track,
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Have you actually gotten it to boil over yet? What PSI cap?

I have ridden with a lot of KTM guys down in Baja doing single track. Tecate in the summer is and technical. Didn't see any over heating issues. A lot of guys had the add on fans though.
 
Taller gearing (smaller rear sprocket) or try riding it in a gear higher than you think. You'll be keeping it out of the meat of the power band that way. As long as you're not abusing the clutch and its not stalling out all the time it's fine.
 
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