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Big Bore Kits

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I was reading Ramz site and noticed he has the first 283cc big bore kit that was produced. :cool:

He mentions a larger kit is in the works too. :banana:

I'm guessing since the head isn't shown in the big bore pictures that it is getting ported too... :excuseme:

Then he posts picture of 2 packages that look like new cams... :thinking:

He has something special up his sleeve.... :smirk:

Details would be great. :D

Thanks

:cheers:

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Hi MG, and everyone here !

I'm registered here too ;)

Ramz's blog is quite impressive, as he makes all possible mods/installs, to say the last :thumbsup:

BB kit is a radical way to give more (or enough) muscle to this kind of bike, i guess, but i had never owned or installed one.
Do one have to modify the cranckase too to install new cylinder (due to larger diameter of sleeve) or is that a straight bolt-on ? In this case, i could consider buying one.

Saw also a 304cc kit that fit the CBR250R, so it could also be suited to the CRFL which shares the same block.
http://www.automotiv...0cc-BORE-UP-KIT
10_img.jpg

L

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Welcome,

I found the new home for my CRF250L posts and threads. :thumbsup: I'll be following and posting the CRF250L topics at this site only from now on. :smirk:

It's much easier to follow and find information here. I've been busy working on posting tech here.

You should be able help get things organized and up to speed. I like the atmosphere better here anyways and always have. :)


I don't know for sure but I'd bet the 283cc BBK is a straight bolt-on kit.
 

The 283 or 305 BBK is probably the best way to add more power IMO, but i will require a fuel controller and some other supporting modifications.

You can find fuel controller details at this site.

:cheers:

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Welcome to the "other side" Krono :thumbsup: TNT/a.k.a/ MG is right on the money saying how it's easier and better atmosphere, little slower pace but I like it!! Sure you will too.

Wow...a big bore kit (my mind just kicked into another dream mode,and the credit company's smiling).. may be a few yrs down the road before I get into this, but glad to be part of this experience and am looking forward to RamZ's review and we got TNT here to help us out to better understand it.

OK TNT, you mention above about needing a controller and other supporting mods. Would you say that the current EJK on the market now would be adequate enough for this build? The reason I ask, is because as I order parts and mods for this bike, I wanna be able to reuse parts and such, without having to order more of basically the same thing (same as exhaust,I realize the header pipe diameter/exhaust opening shouldn't be affected, or would assume not..) you may have already touched on this above , when mentioning the head may not change :excuseme: ..my bad if so :D

I'm sure RamZ's build will be tried/tested and true, with a great write up, long before I even put more thought into this..until then, it's on my wish list. ;)

Thx

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I'm looking forward to this too. I'm on the fence about a pipe right now, I usually get a new bike and mod it to death as it's part of the fun but for me having a quiet dual sport is a plus. I'm now getting a EJK and would consider a big bore later if needed.

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I remember my old xr250 with a 280 kit, was a big improvement over stock for little money! I preferred riding it over big bores because it was so much fun! really good for woods and trails that get boggy and muddy, that small amount in cc's makes a big difference! :rolleyes:

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I just talked to engine builder that is going to building my engine. First time I've ever had anyone do that for me....

After talking with him I'll be send my engine to him. He knows what I want and I have 100% faith in his abilitys. We covered the basics, I'm leaving the details up to him.

We also discussed the CRFL engine and bike. We also talked about the CBR. We agree there is tons of potential power left on the table.

He will be looking into it and may post here since is a member.

If you can imagine it he can build it from what I have seen. I have also seen things I didn't imagine...

Keep your fingers crossed. He is in the USA and builds his own pistons, rods, custom cams and way more.

I figured an update was needed, details to come.

Edited by TNTsXR
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Cool :thumbsup: ..Do you remember this posted by Bake at the other bar? May be of some help, not sure if you were on Vacation then:

Bake

adventurer

Stock piston. This engine has about 200 miles.

stockpiston2-S.jpg

Anti seize coating on the skirt

stockpiston-S.jpg

Valve cutaways on the stock piston

stockpiston3-S.jpg

stock iron bore

stockbore-S.jpg

stockbore2-S.jpg

Cylinder head showing combustion chamber and valves. Intake are the large ones. Tiny little sparkplug

valvehead-M.jpg

Pickle forks, cam journals

picklefork-S.jpg

Shims are on top the valve stem, under the pickle fork. Forks uses large needle bearing as the roller that is pushed by the cam. Cams are single lobe, which lightens the rotating mass in the valve train.

shims-S.jpg

A look down the intake ports, looking at the valve stems and guides. About average looking ports.

cylinderporting-S.jpg

Oxygen sensor shown in the exhaust port

O2sensor-S.jpg

Single lobe cams. The journals are very large, as long as there's good oil pressure, it's very unlikely these will ever score up and fail.

cams-S.jpg

280cc big bore cylinder ready for installation

CrF250BigBorecylinder-S.jpg

280cc big bore piston in place

bigborepiston-S.jpg

We have the first new 280cc big bore kit installed.

280installed-S.jpg

bigbore2-S.jpg

Bill Blue is going to be testing the 280 kit for a bit, and is in development of the bigger kit.

(my guess is it will be 300cc or more)

Bill developed and has manufactured the Kawasaki 250 KLX351 kit for several years. His motorcycle experience goes well back to the '60's, he is involved in cycle restorations and our real passion, the smaller enduro bikes like the CRF250L.

He says stay tuned for the testing of the big bore kits.

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I just found this thread, so I don't know if anyone has already mentioned it; but is everyone aware Honda is coming out with a 300 kit for this bike? Supposedly, it's gonna a fairly inexpensive kit (hard to figure coming from the factory). Some people probably can't wait for more power, but I'm gonna wait and see what they come out with, before I make my decision. I know if it's coming from Honda, it will definitely be reliable, and after having 9200 miles on it in one year, that's something that's going to be especially important to me.

The CBR300 will be coming out soon, so I'm sure it will be released around the same time as that.

 

morepower.png

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I just found this thread, so I don't know if anyone has already mentioned it; but is everyone aware Honda is coming out with a 300 kit for this bike? Supposedly, it's gonna a fairly inexpensive kit (hard to figure coming from the factory). Some people probably can't wait for more power, but I'm gonna wait and see what they come out with, before I make my decision. I know if it's coming from Honda, it will definitely be reliable, and after having 9200 miles on it in one year, that's something that's going to be especially important to me.

The CBR300 will be coming out soon, so I'm sure it will be released around the same time as that.

 

morepower.png

 

The CBR300 is a longer stroke engine, so it should be a stroker kit.  Add a big bore kit to it and you'll have about 350cc's. Add some head work, a cam and a oversize throttle body to that since neither were designed for that much displacement and air flow.  Then you'll be talking.    :smirk:

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I just found this thread, so I don't know if anyone has already mentioned it; but is everyone aware Honda is coming out with a 300 kit for this bike? Supposedly, it's gonna a fairly inexpensive kit (hard to figure coming from the factory). Some people probably can't wait for more power, but I'm gonna wait and see what they come out with, before I make my decision. I know if it's coming from Honda, it will definitely be reliable, and after having 9200 miles on it in one year, that's something that's going to be especially important to me.

The CBR300 will be coming out soon, so I'm sure it will be released around the same time as that.

 

morepower.png

 

CBR300 is not a big bore motor so if Honda come out with a big bore kit it will be totally unrelated to the CBR300 motor.

Just so there is no confusion the CBR300 is stroked to 286cc not 300cc

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CBR300 is not a big bore motor so if Honda come out with a big bore kit it will be totally unrelated to the CBR300 motor.

Just so there is no confusion the CBR300 is stroked to 286cc not 300cc

 

And that's why you take anything a salesman says with a grain of salt!

 

That makes sense. Now I really have to question his source. He was dead serious that they were coming out with a 300 kit for the L. I'll wait it out and see what happens. Plus, if I'm gonna tear apart the motor to throw a new head on it, it'd make sense to do a cam upgrade and any other modifications to the motor (that are gonna help you maximize your gain from the big bore) all at one time. And maybe by that time, some dude will have these motors figured out as far as what it needs for more....... .......................................................powerTG.jpg

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And that's why you take anything a salesman says with a grain of salt!

 

That makes sense. Now I really have to question his source. He was dead serious that they were coming out with a 300 kit for the L. I'll wait it out and see what happens. Plus, if I'm gonna tear apart the motor to throw a new head on it, it'd make sense to do a cam upgrade and any other modifications to the motor (that are gonna help you maximize your gain from the big bore) all at one time. And maybe by that time, some dude will have these motors figured out as far as what it needs for more....... .......................................................attachicon.gifpowerTG.jpg

 

They might come out with a big bore 300 kit. I am pretty sure Kawasaki use to offer a 300 kit for the KLX250.

They might offer a stroker kit too but these are more time consuming to install which means more money if you are getting a mechanic to do it.

I would be interested to see whether they have redesigned the head on the CBR300 with bigger ports and valves.

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My 305 was rockin and rollin today ...  :thumbsup:  I have all kinds of faith in it and believe it will run a very long time ...  :prof:

I had 3 different people today at the trails come up to me and say .... what the hell is that thing ? .....  :lol:

 

These were guys I did not know and were not riding with either .... my guess is they heard it and saw it move thru the woods ...  :p  I think the plate thru them off a little too  ...  :goofy:

 

My bike is becoming a beast and even kind of hard to hold on to in the woods  ...   :ride:

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I would be EXTREMELY surprised if Honda actually offered a big bore kit for this bike.  Then theyed also have to use some kind of fuel programer or more likely reflash the ECU also which I just cant seem them doing.  It would just be more risk than reward for them.  And if they did it wouldn't be designed to perform with any aftermarket exhaust or intake mods because it would still have to conform to all the emissions and noise regs and bs stuff like that.

 

I hate to be a negative nancy, but I just cant see it happening. 

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I would be EXTREMELY surprised if Honda actually offered a big bore kit for this bike.  Then theyed also have to use some kind of fuel programer or more likely reflash the ECU also which I just cant seem them doing.  It would just be more risk than reward for them.  And if they did it wouldn't be designed to perform with any aftermarket exhaust or intake mods because it would still have to conform to all the emissions and noise regs and bs stuff like that.

 

I hate to be a negative nancy, but I just cant see it happening. 

 

I agree, there is more money to be made by making and selling a new crf350L than a big bore kit which is already available

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So I've thought over everything really good now; especially trying to take into consideration Honda's track record (especially of recent) and going with my gut feeling (of salesmen being full of poop). I'm thinking Honda's not coming out with a 300 big bore kit for the L. However, think about this. If the CBR "300" is gonna be a stroker and there's currently a 305cc cylinder, then theoretically they could be combined and you'd have a bored and stroked bike that would probably be a monster. Might have to upgrade the clutch assembly and all but man I bet that would be sweet.

 

Just something to think about :cheers:

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I really like my B&B 305 big bore and am so glad I just pulled the trigger and went for it ...  :prof:

 

I'll be honest and I was very scared to replace my piston and cylinder at 1200 miles ...

I mean really scared and full of doubt and looked for every excuse I could find not to do it.... Tracin my mechanic said it best ..... "Gary we can always go back to what it was" ... So based on his comments ....  I was in !!! 

My particular bike runs very strong and I feel as tho it will run a very very long time .... Tracin said he could not see why it would not run for 25,000 miles or so ... I said ... lets do this .... 

If you want to talk bang for you buck .... the 305 is it !!!  :smirk:  $1,000.00 dollars for a real no BS full to the wheel 7 hp gain is a bargain ...  :ride: If I can find a place to do head work that I trust and believe in .... I would spend another $1,000.00 to get 3-5 more HP ....  :p  That would put me at 32HP and that is strong for a 250 ...  :thumbsup:

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I really like my B&B 305 big bore and am so glad I just pulled the trigger and went for it ...  :prof:

 

I'll be honest and I was very scared to replace my piston and cylinder at 1200 miles ...

I mean really scared and full of doubt and looked for every excuse I could find not to do it.... Tracin my mechanic said it best ..... "Gary we can always go back to what it was" ... So based on his comments ....  I was in !!! 

My particular bike runs very strong and I feel as tho it will run a very very long time .... Tracin said he could not see why it would not run for 25,000 miles or so ... I said ... lets do this .... 

If you want to talk bang for you buck .... the 305 is it !!!  :smirk:  $1,000.00 dollars for a real no BS full to the wheel 7 hp gain is a bargain ...  :ride: If I can find a place to do head work that I trust and believe in .... I would spend another $1,000.00 to get 3-5 more HP ....  :p  That would put me at 32HP and that is strong for a 250 ...  :thumbsup:

gnath9, you suck :D You're making me want a BB more and more. It all comes down to what's left over after taxes haha. Suspension is first, then maybe the BB if funds allow. I'm really happy with my stage one and 13/42 though. But between you, and my buddy picking up a DRZ400 this weekend, and another buddy looking for a KTM, I might just have to go BB (and not tell them lol).

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