New rps magician 250 - getting to 80mph

slithica · 01-13-2021, 11:49 PM

Original post beneath this.

In the end I got to about 70 without porting the heads or doing what I consider major engine work and the vibrations/wobble started to scare me.

I ended my journey to 80mph, I'm afraid to go over about 65 on this thing.

Basically, it wobbles too much at high speeds and vibrates terribly. Don't try to go faster than about 65.

Original post.

I got a new one, from killer motor sports.

My goal is to get this bike to 80mph.

this will be my post regarding that and my eventual success or failure.

This may take a while, and I won't have much to update after this for around a week or two, but check back later to see how it goes.

The plan so far.

Larger front sprocket - 17 tooth

Smaller rear sprocket - 40 tooth

Aftermarket carb

High flow air filter

135 main jet - maybe need bigger?

45 idle jet - will adjust as needed

tracker installed with backup battery.

cat de-restriction

Based on my math, the top speed of the stock bike is about 62mph at redline.

With the new gear ratio it should be closer to 85mph theoretical max speed, so with the gear ratio making it possible to go faster, I just need the power.

Maximize air in and air out, i put on a high flow air filter and I'll make it so air can get out of the exhaust, probably by removing the catalytic converter element or replacing it with a better one.

Heat: With all that power you'll have more heat, air cooling won't cut it, time for liquid cooling! Installing a largish (125ml) oil cooler, with fan for idle.

So far, that's the plan and I'm 80% through the modifications right now.

Once that's done I'll take it for a drive and see how fast it goes, I'll update it when that comes around.

What if it's still not sonic though? (gotta go fast)

I have more plans if it's not fast enough!

NO2 : that's right! I'll put an NO2 can on the bike and flip that switch for a little boost, I didn't say it had to maintain 80 forever, but with a low flow one it should be enough to last a while and give it 1 extra horse or so for a bit.

Tires: lighter, less knobby tires. Right now it has all terrain tires, swap those for slightly lighter and smoother street tires to lessen friction and go faster

Lose weight: I'm not fat by any means but I could lose like 10-15 lbs and still be healthy!

lol, no but I could lighten the motorcycle a bit if I need to.

Aluminum rims, remove the cargo rack on the back, yeah... not much to lessen weight. It's a light bike. Maybe like 5-10lbs that I could take off.

Porting the heads:

I don't want to do that, it's a fair bit of work, but if I have to.... I'll do it

That's all I've got for now, I'm certainly open to ideas though.

I welcome you all to my journey to reach 80mph.

I did change both sprockets as I wanted, the intake, the carb, the tires, oil cooler, and a bunch of other small changes and additions.

01-13-2021, 11:49 PM	#1
slithica Join Date: Jan 2021 Posts: 38	New rps magician 250 - getting to 80mph Original post beneath this. In the end I got to about 70 without porting the heads or doing what I consider major engine work and the vibrations/wobble started to scare me. I ended my journey to 80mph, I'm afraid to go over about 65 on this thing. Basically, it wobbles too much at high speeds and vibrates terribly. Don't try to go faster than about 65. Original post. I got a new one, from killer motor sports. My goal is to get this bike to 80mph. this will be my post regarding that and my eventual success or failure. This may take a while, and I won't have much to update after this for around a week or two, but check back later to see how it goes. The plan so far. Larger front sprocket - 17 tooth Smaller rear sprocket - 40 tooth Aftermarket carb High flow air filter 135 main jet - maybe need bigger? 45 idle jet - will adjust as needed tracker installed with backup battery. cat de-restriction Based on my math, the top speed of the stock bike is about 62mph at redline. With the new gear ratio it should be closer to 85mph theoretical max speed, so with the gear ratio making it possible to go faster, I just need the power. Maximize air in and air out, i put on a high flow air filter and I'll make it so air can get out of the exhaust, probably by removing the catalytic converter element or replacing it with a better one. Heat: With all that power you'll have more heat, air cooling won't cut it, time for liquid cooling! Installing a largish (125ml) oil cooler, with fan for idle. So far, that's the plan and I'm 80% through the modifications right now. Once that's done I'll take it for a drive and see how fast it goes, I'll update it when that comes around. What if it's still not sonic though? (gotta go fast) I have more plans if it's not fast enough! NO2 : that's right! I'll put an NO2 can on the bike and flip that switch for a little boost, I didn't say it had to maintain 80 forever, but with a low flow one it should be enough to last a while and give it 1 extra horse or so for a bit. Tires: lighter, less knobby tires. Right now it has all terrain tires, swap those for slightly lighter and smoother street tires to lessen friction and go faster Lose weight: I'm not fat by any means but I could lose like 10-15 lbs and still be healthy! lol, no but I could lighten the motorcycle a bit if I need to. Aluminum rims, remove the cargo rack on the back, yeah... not much to lessen weight. It's a light bike. Maybe like 5-10lbs that I could take off. Porting the heads: I don't want to do that, it's a fair bit of work, but if I have to.... I'll do it That's all I've got for now, I'm certainly open to ideas though. I welcome you all to my journey to reach 80mph. I did change both sprockets as I wanted, the intake, the carb, the tires, oil cooler, and a bunch of other small changes and additions. Last edited by slithica; 12-26-2021 at 09:29 PM.
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