Planet Minis

goku1ab · 04-02-2008, 07:35 PM

For starters I just wanted to say that you guys have great info on your forum. I've been riding my brother's NSR50 for a while now and just purchased an NSF100 for myself. Hope to start racing in CMRRA real soon.

This topic has probably been discussed a bazillion times, but I have an extra NSR frame and an XR650R engine. I want to build a crazy toy

to play with and was wondering what is the largest engine anyone has successfully installed in a mini. I have a friend who owns a machine shop so I can get any parts I need fabricated. Even a frame if need be. And I was also curious about problematic issues due to high horsepower on items such as swingarms, swingarm pivots, steering stem bearings, etc. on bikes with big engines.

fireman_343 · 04-03-2008, 07:41 AM

I think it would be silly to install such a large engine in one... what do you plan to do with that bike?? Lots of R&D fab work goes into something like that and extra money testing what works and doesn't. These are tiny frames, and wheel bases that were not designed for such large motor swaps, they can crack at any weak spot if not braced properly!
With that said... I know of a guy that put a GP250 motor in a YSR that would pull 11's down a 1/4 mile track with the front wheel off the ground all the way down the track! It was so stupid fast that you couldn't control it, due to the short wheel base and small light frame!
I wouldn't go with a large motor, even if I had the money! Stick with a XR100 or 125 motor and you'll be more happy with it! Just my .02!

TEAM QUAZZYMOTO RACING #4

dood · 04-03-2008, 11:00 AM

The XR650 engine has to be one of the heaviest engines on the planet and it's slow too.
You are more likely to get a CRF250F engine to fit in there ( although you will have a fun time mounting radiators )
Although it sounds fun to have a huge engine in a tiny frame, trust me it isn't that fun to ride. I built 2 full size superbikes ( 220hp GSXR1000 and a 210hp ZX10 ) and they are a fukin bear to ride.
I salute you to wanting to build such a monster but because you actually wanna race that thing, I would rethink your plan of action.

shawnbassett26 · 04-03-2008, 11:55 AM

The largest motor iv seen was a YZ426 in a YSR. Its cool to have a HUGE motor..... but if its uncontrolable, it wont be any fun. I did a TON of work to get im XR200 motor in my YSR. Let me tell you on the head in the frame theres a 1/4 of an inch in between the frame and head. I wouldnt try a 650. Too much motor for the frame. I did alot of bracing for mine and it still worries me.... Theres no instruction so but out the welder! Good luck!
~Shawn

reynolds_brad · 04-03-2008, 12:00 PM

husaberg 470cc in a ZB frame.

hpiguy · 04-03-2008, 12:17 PM

^^I wanna ride it!!

stik__boy · 04-03-2008, 12:20 PM

i do too..... with like 16/20 gearing......

goku1ab · 04-03-2008, 07:15 PM

I don't plan on racing a monster like this. I just want it to play with. I'll stick with modifying my nsf100 to race. Regardless, thanks for the input. I do trackdays with my 04 GSXR750 that has a built engine and it's a handful because it's modded so heavily it has a power curve like a two stroke. It feels like a turbo bike with a lot of lag. It pulls like a stocker until about 9500 rpm's and then it's like flipping a light switch. No gradual build in power just BAM! That thing has almost highsided me a couple of times simply because of the powercurve.

Great pics by the way. I love the dual exhaust!!

A little off topic. Anyone in the vegas area do any parking lot racing?

04-02-2008, 07:35 PM	#1 (permalink)
goku1ab PM Newbie Join Date: Mar 2008 Location: Las Vegas, NV Posts: 3	New Member w/ stupid question! For starters I just wanted to say that you guys have great info on your forum. I've been riding my brother's NSR50 for a while now and just purchased an NSF100 for myself. Hope to start racing in CMRRA real soon. This topic has probably been discussed a bazillion times, but I have an extra NSR frame and an XR650R engine. I want to build a crazy toy to play with and was wondering what is the largest engine anyone has successfully installed in a mini. I have a friend who owns a machine shop so I can get any parts I need fabricated. Even a frame if need be. And I was also curious about problematic issues due to high horsepower on items such as swingarms, swingarm pivots, steering stem bearings, etc. on bikes with big engines.

04-03-2008, 07:41 AM	#2 (permalink)
fireman_343 1st Gear Member Join Date: Mar 2007 Location: Blacklick Ohio Posts: 156	Re: New Member w/ stupid question! I think it would be silly to install such a large engine in one... what do you plan to do with that bike?? Lots of R&D fab work goes into something like that and extra money testing what works and doesn't. These are tiny frames, and wheel bases that were not designed for such large motor swaps, they can crack at any weak spot if not braced properly! With that said... I know of a guy that put a GP250 motor in a YSR that would pull 11's down a 1/4 mile track with the front wheel off the ground all the way down the track! It was so stupid fast that you couldn't control it, due to the short wheel base and small light frame! I wouldn't go with a large motor, even if I had the money! Stick with a XR100 or 125 motor and you'll be more happy with it! Just my .02! TEAM QUAZZYMOTO RACING #4

04-03-2008, 11:00 AM	#3 (permalink)
dood 3rd Gear Member Join Date: Sep 2006 Location: Washington Posts: 2,029	Re: New Member w/ stupid question! The XR650 engine has to be one of the heaviest engines on the planet and it's slow too. You are more likely to get a CRF250F engine to fit in there ( although you will have a fun time mounting radiators ) Although it sounds fun to have a huge engine in a tiny frame, trust me it isn't that fun to ride. I built 2 full size superbikes ( 220hp GSXR1000 and a 210hp ZX10 ) and they are a fukin bear to ride. I salute you to wanting to build such a monster but because you actually wanna race that thing, I would rethink your plan of action.

04-03-2008, 11:55 AM	#4 (permalink)
shawnbassett26 2nd Gear Member Join Date: Feb 2008 Location: Orlando FL Posts: 644	Re: New Member w/ stupid question! The largest motor iv seen was a YZ426 in a YSR. Its cool to have a HUGE motor..... but if its uncontrolable, it wont be any fun. I did a TON of work to get im XR200 motor in my YSR. Let me tell you on the head in the frame theres a 1/4 of an inch in between the frame and head. I wouldnt try a 650. Too much motor for the frame. I did alot of bracing for mine and it still worries me.... Theres no instruction so but out the welder! Good luck! ~Shawn

04-03-2008, 12:00 PM	#5 (permalink)
reynolds_brad Advertiser Join Date: Dec 2003 Location: San Francisco, CA Posts: 2,458 Awards Showcase Total Awards: 2	Re: New Member w/ stupid question! husaberg 470cc in a ZB frame. __________________ pecore nere ufficiose Honda50.com Last edited by reynolds_brad; 04-03-2008 at 12:07 PM.

04-03-2008, 12:17 PM	#6 (permalink)
hpiguy 2nd Gear Member Join Date: Apr 2006 Location: North Carolina Posts: 941	Re: New Member w/ stupid question! ^^I wanna ride it!!

04-03-2008, 12:20 PM	#7 (permalink)
stik__boy 2nd Gear Member Join Date: Apr 2005 Location: wisconsin Posts: 829	Re: New Member w/ stupid question! i do too..... with like 16/20 gearing......

04-03-2008, 07:15 PM	#8 (permalink)
goku1ab PM Newbie Join Date: Mar 2008 Location: Las Vegas, NV Posts: 3	Re: New Member w/ stupid question! I don't plan on racing a monster like this. I just want it to play with. I'll stick with modifying my nsf100 to race. Regardless, thanks for the input. I do trackdays with my 04 GSXR750 that has a built engine and it's a handful because it's modded so heavily it has a power curve like a two stroke. It feels like a turbo bike with a lot of lag. It pulls like a stocker until about 9500 rpm's and then it's like flipping a light switch. No gradual build in power just BAM! That thing has almost highsided me a couple of times simply because of the powercurve. Great pics by the way. I love the dual exhaust!! A little off topic. Anyone in the vegas area do any parking lot racing?

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