Cbr 250 Conversion Found!

[sinewave]

Found a shop that can do the conversion to 250cc's today! Ex HRC mechanic, he let me test a modified yamaha Nouvo that was freaking sick i tell ya. Sounded like a mack truck and pulled like a dragster.

Showed me the race cams for the CBR and explained the process:

stage 1 - change gears 1,2,5,6

stage 2 - cams

stage 3 - cylinder bored, sleeve insert, longer conrod, bigger crank, cylinder spacer (raised to accomodate stroke), bigger piston.

stage 4 - ECU

pipe, silencer, sprockets, NSR carburetor and rejetting somewhere along the line....

after riding that nouvo, there's no doubt in my mind it will destroy a ninja 250 and tiger boxer...its not only a 250 upgrade, it's a full race conversion.

It's on

[dave_boo]

Found a shop that can do the conversion to 250cc's today! Ex HRC mechanic, he let me test a modified yamaha Nouvo that was freaking sick i tell ya. Sounded like a mack truck and pulled like a dragster.

Showed me the race cams for the CBR and explained the process:

stage 1 - change gears 1,2,5,6

stage 2 - cams

stage 3 - cylinder bored, sleeve insert, longer conrod, bigger crank, cylinder spacer (raised to accomodate stroke), bigger piston.

stage 4 - ECU

pipe, silencer, sprockets, NSR carburetor and rejetting somewhere along the line....

after riding that nouvo, there's no doubt in my mind it will destroy a ninja 250 and tiger boxer...its not only a 250 upgrade, it's a full race conversion.

It's on

Information please. I'd like to know how they got it all the way up to 250cc. Biggest I've see was a 66mm bore by a 57.2mm stroke. That totals 195.6cc and costs, as of August 08, 39 500THB. That includes a new head, cylinder, piston, cams, and crankshaft.

Stock is 63.5 by 47.2mm. With the exception of that cylinder spacer and gears you can purchase all the parts from goodspeed for some 47 000 THB. They also have the silencers, downpipes, and transmission gears that you listed. Don't know the price of the gears, but the DBS colour silencer (aluminum designed to look like titanium) is 4 600 THB.

Click here for more information, but turn the sound down or off. DON'T SAY I DIDN'T WARN YOU.

[sinewave]

ehhh...goodspeed is a waste of time, its not a real shop...you have to call in advance and order in advance....the shop isn't on Bangna as stated, it's in Paknam.

I kept drilling him on how he got it to 250cc's, and wouldn't the walls be too thin, and I told him the biggest ive seen is 200cc also...but he said it was possible, what information do you want? it's not like i'm the one that knows how to do it...if you want to go check it out, i'm going to have to take you there, the location is hard to explain...and you would pass it right up

The shop bike was a sonic with CBR cylinder totally tricked out. dam_n clean too.

this is the guy that actually taught my old mechanic, i found out....this guy knows his stuff...The total price is around 40k, not including pipes and silencer

I have to head up there in a few days to rejet my buddies bike, let me know what you want to know.

He did mention something to do with the valve shims, but i haven't seen a pic of the heads so im not sure what he was talking about

BTW-I'm only taking Americans there, British not allowed...j/k

[dave_boo]

ehhh...goodspeed is a waste of time, its not a real shop...you have to call in advance and order in advance....the shop isn't on Bangna as stated, it's in Paknam.

I kept drilling him on how he got it to 250cc's, and wouldn't the walls be too thin, and I told him the biggest ive seen is 200cc also...but he said it was possible, what information do you want? it's not like i'm the one that knows how to do it...if you want to go check it out, i'm going to have to take you there, the location is hard to explain...and you would pass it right up

The shop bike was a sonic with CBR cylinder totally tricked out. dam_n clean too.

this is the guy that actually taught my old mechanic, i found out....this guy knows his stuff...The total price is around 40k, not including pipes and silencer

I have to head up there in a few days to rejet my buddies bike, let me know what you want to know.

He did mention something to do with the valve shims, but i haven't seen a pic of the heads so im not sure what he was talking about

BTW-I'm only taking Americans there, British not allowed...j/k

Are you planning on having this done? I don't want my yellow hornet to be the guinea pig for the forum members!  But I guess perhaps if I have to take one for the team...it would be cool to have a sleeper Ninja killer.  Approximately the same HP in a package that's quite a bit lighter at a price point that's some only 72% of the Ninja's price (warranty issues aside).

God that's so tempting.  Won't be back to LOS until the 10th though.  There's a local out where my house is that has the CBR cylinder on a Sonic; pretty quick stuff but a bit scary at speed.

And that's where the real rub is.  If you're going to be putting a whole bunch more power (assuming an identical compression ratio something along the lines of 10-12 more) is the frame going to stand up to it?  I'd hate to see a CBR shaken to death because there's a big thumper between its spars.

[Richard-BKK]

Hi Sinewave,

This sounds very interesting, and it is remarkable cheap compared to other bore-up kits, which do not include gear modifications, sprockets, ECU and carburetor change. Normally a good race carburetor costs already more then 10,000 Baht.

And I was wondering if the guy does also do this modifications for Honda Sonics, basically the same engine... with the exception of everything what is going to get changed anyway...

[LivinLOS]

Found a shop that can do the conversion to 250cc's today! Ex HRC mechanic, he let me test a modified yamaha Nouvo that was freaking sick i tell ya. Sounded like a mack truck and pulled like a dragster.

Showed me the race cams for the CBR and explained the process:

stage 1 - change gears 1,2,5,6

stage 2 - cams

stage 3 - cylinder bored, sleeve insert, longer conrod, bigger crank, cylinder spacer (raised to accomodate stroke), bigger piston.

stage 4 - ECU

pipe, silencer, sprockets, NSR carburetor and rejetting somewhere along the line....

after riding that nouvo, there's no doubt in my mind it will destroy a ninja 250 and tiger boxer...its not only a 250 upgrade, it's a full race conversion.

It's on

Are you talking about a CBR or a nuovo ??

cos the Nouvo wont have gears 1,2,5,6 etc ?? So assume you now mean a CBR150 ?? Why not just buy a CBR250 ??

I also thought the nuovo max would be the sub 200 kit I have seen done locally.. But that kit also blows bottom ends, rips apart the cvt, totally over rides the braking capacity, just messes the machine with power it wasnt designed for.. By the time you have done all the mods properly you will have spent more than I have on my 900 blade !! And way more than a good 400..

So streetfightered 900 blade.. or unreliable souped up nuovo auto ?? I know which I would ride.

[LivinLOS]

There's a local out where my house is that has the CBR cylinder on a Sonic; pretty quick stuff but a bit scary at speed.

Theres a rusting rat bike downstairs my brother uses.. CBR 150 engine, front forks, and swingarm.. In a sonic frame and rest.. With the 150 headlights zip tied on.. Really ratty but flies..

[Zzinged]

I wasn't aware they sold the CBR250 in Thailand o.O

[dave_boo]

There's a local out where my house is that has the CBR cylinder on a Sonic; pretty quick stuff but a bit scary at speed.

Theres a rusting rat bike downstairs my brother uses.. CBR 150 engine, front forks, and swingarm.. In a sonic frame and rest.. With the 150 headlights zip tied on.. Really ratty but flies..

So your brother has a streetfighter!  Bet your jealous you're spending all your money to make a big 'un.

I wasn't aware they sold the CBR250 in Thailand o.O

There's a few floating around; thaicbr had one.

[LivinLOS]

So your brother has a streetfighter!  Bet your jealous you're spending all your money to make a big 'un.

Rusting rat bike 'thing' that I wish would leave my driveway would be a more apt description

[LivinLOS]

I wasn't aware they sold the CBR250 in Thailand o.O

There was a 250 hornet in the classified recently..

Cost of doing all this to a CBR, or a nuovo.. Then the reliability.. The impossible resale.. Etc etc..

Why not just get a better bike to start with..

[sinewave]

dave, be the experimental lab rat...please...like nike says - "just do it"...i'd get the cams and rejet done first to test the waters since the price isn't so bad, at around 5000 baht.

He recommended doing the gears first, which makes sense because we were talking about how gears 1-2 are too short (agreed), then theres a drop in power between gears 5-6, but I couldn't really agree with the 5-6 statement , since changing the sprockets to 15/44 helped alot...but admittedly, you can still tell 5-6 isn't at its best.

If your a good rider and can shift at the right time, the gears can wait. But doing the gearing will make the bike much more rideable IMO.

If i do...i'll probably get a 2002-2003 model year thats been beat to hel_l and back, and get it rebuilt...heck it'll be getting basicly a brand new engine anyway right? It'll need bigger brakes and stiffer fork springs too as well as wider rubber and if possible wider rims, the chain and sprockets would have to possibly go back to 520, if previously changed to 428....actually you won't need all that stuff, unless you want to be stable and drive like a maniac 24/7.

Not sure on the Nouvo cc's, but it was hectic, I asked him about the drive belt, he just smiled and said it can take it, but if you pound on anything long enough theres going to be damage...I'm pretty sure he did up the bottom end, basicly these bikes were complete rebuilds, from the bottom end up....it's for sale too approx 25,000 baht

Richard, i'm sure you must know some people in the racing scene, this is the guy that taught "Arh racing", when they both worked for HRC in their younger days. This guy is older and is - 'super somchai'.

[sinewave]

if i do it, it's something i'd keep forever.

besides, all the paperwork can be done inhouse at the shop...wink wink wink

[LivinLOS]

If i do...i'll probably get a 2002-2003 model year thats been beat to hel_l and back, and get it rebuilt...heck it'll be getting basicly a brand new engine anyway right? It'll need bigger brakes and stiffer fork springs too as well as wider rubber and if possible wider rims, the chain and sprockets would have to possibly go back to 520, if previously changed to 428....actually you won't need all that stuff, unless you want to be stable and drive like a maniac 24/7.

And this will end up with how much approx cost for this Frankenstein ??

Bearing in my I knew of a ZX10 streetfightered going for 75k recently.. A 1000cc bike with books.. Owener left the country and just wanted whatever he could get to make the sale.

Not sure on the Nouvo cc's, but it was hectic, I asked him about the drive belt, he just smiled and said it can take it, but if you pound on anything long enough theres going to be damage...I'm pretty sure he did up the bottom end, basicly these bikes were complete rebuilds, from the bottom end up....it's for sale too approx 25,000 baht

Ok so the result of that is a bike worth 25k.. And the cost of it is ??

besides, all the paperwork can be done inhouse at the shop...

Whats does this mean.. why would it need any paperwork ??

[Richard-BKK]

Paperwork? If you mean doing this legal, and get book changed to 250cc you will loss you plates directly. By no means you will pass the road-safety tests, and even if you did it will cost you another 35,000 Baht...

[Richard-BKK]

If the total cost of this upgrade is around 40k Baht, I'm surely interested. I did once installed 198cc bore-up kit on a Yamaha Fino and I belief that after one or two weeks the CVT was damaged beyond repair.

As this kit is for a Honda Sonic, which has the same durable engine as a Honda CBR125/150 it would be a less dramatic problem...

[Zzinged]

I wasn't aware they sold the CBR250 in Thailand o.O

There was a 250 hornet in the classified recently..

Cost of doing all this to a CBR, or a nuovo.. Then the reliability.. The impossible resale.. Etc etc..

Why not just get a better bike to start with..

Well, the CBR 250 and the CB250F are slightly different bikes. The CB (Hornet) is an unfaired bike whilst the CBR250 is a fully faired sports bike. At any rate they're both grey imports, so I guess the only option for someone wanting a newer base bike would be to buy a new CBR150 and tinker with the engine.

[sinewave]

I don't think the people who want to do the conversion are worried about that stuff.....Can you imagine the look when you beat a ZX10 off the line up to 140kph?...priceless

the CBR in weaving traffic will wallop on a big bike, and exactly how old are these big bikes that have gone through multiple somchai mechanics hands? 10 years at the least for a bike in the 75k price range.

Someone buy my honda click fast so i can start this!...I can get an extremely ragged out CBR for 18k right now.

im going back to the shop today, to make sure he wasn't pulling my chain about 250cc's.

[LivinLOS]

I don't think the people who want to do the conversion are worried about that stuff.....Can you imagine the look when you beat a ZX10 off the line up to 140kph?...priceless

Your dreaming again right ??

Ever ridden a liter bike ?? Keeping the front end on the ground is the bigger challenge.

the CBR in weaving traffic will wallop on a big bike, and exactly how old are these big bikes that have gone through multiple somchai mechanics hands? 10 years at the least for a bike in the 75k price range.

My blade is a 95 yes.. Doesnt go to somchai, work I dont do myself and then it goes to a farang mechanic to work on it should it need things..

If you think a CBR150 or a nuovo has any hope in any way of even staying in the rearview mirror of a 130 bhp sportbike your out of your mind..

[LivinLOS]

Well, the CBR 250 and the CB250F are slightly different bikes. The CB (Hornet) is an unfaired bike whilst the CBR250 is a fully faired sports bike. At any rate they're both grey imports, so I guess the only option for someone wanting a newer base bike would be to buy a new CBR150 and tinker with the engine.

Different bikes sure.. Just giving options for 250 - 400 cc bikes which have more power than this conversion and even being old probably more reliable too..

And would retain thier resale..

You cant make a silk purse from a sows ear.. You want more power, buy a proper bike and start with something thats got some.

[thaicbr]

'the chain and sprockets would have to possibly go back to 520, if previously changed to 428...'

This statement was good. The Cbr150 as standard is a 428 chain NOT a 520.

I would love to see one of these done then strip the bugger back out again to see what was done. because ALL of this work gears, cams, bore, head, carby and only 40,000baht come on not so believable.

My mechanic (who does not claim to be an ex HRC employee) has told me that cam's, carby with correct jetting and down pipe will yield the best results. he also suggested a reworked cdi BUT only if it still had a rev limit imposed.

[Richard-BKK]

He Thaicbr,

I also have problems believing that it costs only 40k, I not so long ago bought a 32mm flat-slide "replacement" carburetor manufactured in China for the donation of almost 10k. And with "replacement" they mean it looks like original, but it is not..

Then pulling away from Kawasaki ZX10, I belief that this is possible... As the Kawasaki owner will be laughing so loud that he lost the concentration to open the throttle.... (Sinewave, today you win the most funniest posting award...)

[Cromarty]

I don't think the people who want to do the conversion are worried about that stuff.....Can you imagine the look when you beat a ZX10 off the line up to 140kph?...priceless

dude, you are having a laugh aren't you? Yes, I'm sure the baby CBR is pokey, but it isn't in the same universe, let alone the same league as any 'proper' medium to big sports bike.

[sinewave]

LivinLos, I believe the real question is - "Have you ever ridden a full 150cc race bike"....My NSR 150 which was highly modified with stock displacement would KILL bigger bikes up to 140kph....up to 140kph not over, read again please 140kph.

and this next statement you will continue to rip me a new one for also - the stock NSR 150 and stock CBR 150 have the same speeds, the CBR can even pull away up to 140kph...Ive owned both and know the real deal.

I suppose you bought your bike brand new and has never been to somchai before you owned it ehh?

Thaicbr, my CBR came with 520 chains and sprocket. my old mechanic had a picture with him and my new mechanic along with the team honda manager hanging on his wall, with the rest of the team at the track...this was about 7 years ago...BTW 28mm carbs are only 1500 baht.

Dave, I asked him about the actual displacement, it's 244cc but check his math if you don't mind, the bore and stroke are 65-66mm by 73.8mm stroke

Finally Richard, the Sonic because it has a single cam can go up to 275cc, but not recommended only 250cc was recommended for longevity., the shop bike is a sonic at 250cc which he might sell if your interested, he said you were welcome to take it for a ride - i mentioned you.

and the Nouvo was verified at 250cc...25k baht if anyone wants it.

Took my buddy back up to the shop today to revert back to the original throttle opposed to the short throw racing throttle and to remove the resistor inside the sparkplug boot, and we gained another 15%. With a broader powerband with the plug regapped to 0.98mm

he showed me the cam, crank and gears i held them in my hand...if you guys don't believe its 40k no sweat off my back man, but ask youself this, where does he get the parts from? the people actually making the parts get them made for substantially less, think please...he's been in the business for a long time now too.

[Richard-BKK]

Please enlighten me, what is different in a CBR150R engine and a Honda Sonic 125 engine, from the basics what not need to get replaced?

Do you tell, me that the cylinder head of the CBR150R does not need to be replaced? With 100cc bore-up we not talking about a 2mm bore-up, if the head is not replace the piston will surely hit the head... or does the compression drops to a ratio below 8:1? (meaning that the piston is flat???)

Correction: CBR150R pistons are flat, but they have deep spaces for late the valves, meaning that the piston moves extremely high....

This a picture of a 198cc upgrade, the walls of the cylinder are already thin...

[BigBikeBKK]

LivinLos, I believe the real question is - "Have you ever ridden a full 150cc race bike"....My NSR 150 which was highly modified with stock displacement would KILL bigger bikes up to 140kph....up to 140kph not over, read again please 140kph.

Hey Bro,

No offense, but your suggestion that a 150cc "race bike" can somehow beat a 1000cc supersport liter bike off the line, or 0-60 is pretty silly...

[Cromarty]

My NSR 150 which was highly modified with stock displacement would KILL bigger bikes up to 140kph....up to 140kph not over, read again please 140kph.

don't be a wally.

[sinewave]

I don't think the people who want to do the conversion are worried about that stuff.....Can you imagine the look when you beat a ZX10 off the line up to 140kph?...priceless

dude, you are having a laugh aren't you? Yes, I'm sure the baby CBR is pokey, but it isn't in the same universe, let alone the same league as any 'proper' medium to big sports bike.

ehhh i give up, trying to hook you guys up and instead i get dissed, by people with no real hands on experience.

I need a project bike, if anyone with a CBR wants to race me against that modified nouvo...i'll take you on title for title, i lose you get my click, i win i get your CBR...

c'mon its just a nouvo...

[Richard-BKK]

Hello Sinewave,

I agree, you have the idea that you win from big bikes, but what you miss is that big bike riders you race, are worried and go back to look for you.

I not want to call you a joke, but the more you tell the more it sounds you are not telling the truth, even a 250cc two-stroke GP motorcycle cannot win it from a Kawasaki ZX10. And this buddies have actual Honda Racing Freaks working on there bikes... with there help this 250cc 2-strokes come closs to 90 real horses in the real wheel.... But do the calculation 90BHP is nothing close to 130BHP, or some road legal liter bikes doing 180BHP.

[johnwills]

LivinLos, I believe the real question is - "Have you ever ridden a full 150cc race bike"....My NSR 150 which was highly modified with stock displacement would KILL bigger bikes up to 140kph....up to 140kph not over, read again please 140kph.

Hey Bro,

No offense, but your suggestion that a 150cc "race bike" can somehow beat a 1000cc supersport liter bike off the line, or 0-60 is pretty silly...

My money is on the CBR/GSXR 1000, to think that a modified 150 would beat these bikes is a little naive.