Kawahara Bore up kit 250>300

[mania]

I searched but can find no info on this.
http://layz-motor.com/product/body-k...ja-250-300-cc/

Was curious if anyone here had ever heard of Kawahara or the quality of their products? I guess a Japanese company Kawahara Racing I see being sold in Indonesia.

The other thing is I am on a 2013 250 special edition sold the first half of 2013 in Asia before the 300 released here
Would have to check if applicable etc.
But initially I like the idea of bore increased to get the 300 rather than stroke like the Kawasaki 300 did
Should be perky

This kit is advertised as being just under $400 USD once converted from Indo dollars

[Racer x]

Great I have not finished my 282 cc engine and now there is a 68mm kit.

[mania]

Originally Posted by Racer x

Great I have not finished my 282 cc engine and now there is a 68mm kit.

Isn't that always the case

I know how you feel as I bought the 2013 250 & 7 months later
the 300 with slipper clutch came at only a bit more price.
Ah well eh?

[quarterliter]

I wonder if it will work on a pregen.....

[Racer x]

No. The tensioner is different.

[mgentz]

increasing the bore by so much will slow down the motor. This happens on dirt bikes when you go too big the motor just doesn't spin up as fast.

Also, with such a large change in piston weight, you WILL need to balance the rotating assembly.

[Somchai]

Originally Posted by mgentz

increasing the bore by so much will slow down the motor. This happens on dirt bikes when you go too big the motor just doesn't spin up as fast.

Also, with such a large change in piston weight, you WILL need to balance the rotating assembly.

The increase in bore must not necesssarily be the main problem, you're right the main factor to look for is the weight.
With a mod like this the stroke-to-bore-ratio changes from 0.66 to 0.61 and when we compare this with the 600 Gixxer which has 0.63 and is reving up to 13500 rpm for its power output.
Also I think with this mod you would need the TB's from the 300 with the 32 diameter.
At least it would be worth a test...

[mgentz]

when I say slow down, I meant in rev quickness not total speed. My DB will still go to 12,000 rpm but it feels like it gets there slower.

[bruce71198]

Where did you see them advertised? Are they in the USA or being shipped from overseas?

[dcj13]

Originally Posted by quarterliter

I wonder if it will work on a pregen.....

The website only mentions the new-gens (in dutch or some other non-english foreign language).

If they made a kit for the pre-gen, I'd be be buy-curious...

[Racer x]

My thinking is this is 50cc worth of power. Time to get a 300 engine and put this kit on it to make a 350cc ninja.

Don't know if it will work. But that is my thinking.

[kitt0y]

i think this bore up kit is the same size as the stock block of the ninja 300...

i think this is for the 250's so that they can have the 300cc power...

this is just my 2 cents..

[oblivion007]

Originally Posted by kitt0y

i think this bore up kit is the same size as the stock block of the ninja 300...

i think this is for the 250's so that they can have the 300cc power...

this is just my 2 cents..

If the kit only changes the diameter and not the stroke then there is a 300/250 increase in area and when applied to a 300 that's stroked for the extra 50cc's you get a 360cc motor!

[mania]

Originally Posted by bruce71198

Where did you see them advertised? Are they in the USA or being shipped from overseas?

I saw them where the link takes you.
Layz motors
A Indonesian shop so yes shipping would be overseas if your in the USA

Also as Kitt0y said This could be possibly done because here in Asia
we also had the 2013 250 special edition
So I am not sure about block changes thru the years for other Ninjas

Which is basically exactly the same as the 300 except 41.2mm stroke instead of
49mm but both have the 62mm bore.

The 300 also has the slipper clutch & 32 instead of 28mm throttle bodies

But all else is the same. Well the 250 did not offer ABS which was fine for me too

[sharky nrk]

Didn't follow the link cause I am lazy lol but was CR stock?

[mania]

Originally Posted by sharky nrk

Didn't follow the link cause I am lazy lol but was CR stock?

Yes as far as I know CR ( compression ratio? ) was stock
but I am not positive as I have not contacted them.
Also to note CR is already higher on the 2013 250 than the 300

250 was 11.3:1 & the newer 300 runs at 10.6:1

[sharky nrk]

May not be a bad idea for those who need a refresh on a race motor and are in class allowing 300s

[ForceofWill]

Anybody take a look at how to buy this kit from the US?

For $400 it'd be worth a shot

[kitt0y]

Any updates with this? anyone take the bore up kit?

Im also Interested with this..

[micoulisninja]

ok guys I have all the info you want on this kit and even more that you will find either interesting or just dissapointing....
there is quite a lot to say to be thorough and answer all of your questions so I will do it one at a time so that others can work on the data input....

a couple of things I have to mention before I set off with this is and that you should keep in mind:
1. A friend of mine had this kit ordered here in Greece and had a chance to make a full and thorough inspection and measuring on it (the 68mm kit)

2. eventually I decided to buy the 67mm kit instead which they make
having full knowledge of what to expect and what kind of precedures I was going to go through...I am still working on it and about to put together my 345cc engine...

[micoulisninja]

Originally Posted by mania

I searched but can find no info on this.
http://layz-motor.com/product/body-k...ja-250-300-cc/

Was curious if anyone here had ever heard of Kawahara or the quality of their products? I guess a Japanese company Kawahara Racing I see being sold in Indonesia.

The other thing is I am on a 2013 250 special edition sold the first half of 2013 in Asia before the 300 released here
Would have to check if applicable etc.
But initially I like the idea of bore increased to get the 300 rather than stroke like the Kawasaki 300 did
Should be perky

This kit is advertised as being just under $400 USD once converted from Indo dollars

I had never heard of them before but since I am a modaholic I had to get one of these on my hands... luckily another guy bought it for his 08 FI 250 and decided to just bolt it on....so he told me all about it and asked me to help him...
the kit is quite cheap to buy but what you pay for is what you get in terms not of quality but in machining precision and other details that are hard to see and notice but so crucial for engine performance and reliability...

now my friends, have a really good close look at those pistons and at the head gasket please....
the answers are there but so hard to notice through a photo...
I want tell you everything all from the start just to help you make your own observations and conclusions...

as far as the pistons are concerned they are cast and allegedly of a base CR of 13,2:1 (it is also hard to find the kit details on the site...)
BUT
1. notice the valve reliefs/pockets and their angle... 25 degrees or more off vertical for each side intake and exhaust it is, nothing to do with our 15-16 angled heads... so one thing is you either use stock camshafts so that you have no valve to piston contact and let the engine strive to breathe in the higher rev range and have the extra heat and CR stress with gains only in low to mid rev range torque OR you have to change the valve relief angles (which can be easily done) on those pistons because of their shape and thickness so that you are able to use wilder camshafts - a must do- with those kit if you want power on the high rev band and less heat being wasted in the engine...

2.now let's turn our attention to the head gasket... it looks indeed nice and is of great quality... there is an outer sticky layer just like on some stock factory gaskets. It is of better quality than the stock part by far BUT if anyone of you believes that with such a tiny piece of metal between those two high comp pistons going up and down our engine is going to hold gas pressure within the chambers, oh well he should drop the modification business or have a big fat bank account... nope, sorry guys, biggest problem there... nice pics though, huh? A sight for sore eyes !! oh, let me give you a number.. 5mm (less than 0,2" that is) and that is the clearance between the two cylinders which by its turn means that you will have two reciprocating big, fat, heavy, high comp pistons that close...how much heat do you think a close deck cylinder block can dissipate before it gets fried and warped ??

well there is more to say but I am keeping it for later on... there is some good news to it though but I thing you are getting the big picture now

[micoulisninja]

Originally Posted by Racer x

Great I have not finished my 282 cc engine and now there is a 68mm kit.

hope you are relieved as if there wasn't one Eric...in fact if you are not as dedicated to tuning as we are I think it is as it really isn't there....so don't think about it, you are on the right (and reliable) track !!

[micoulisninja]

Originally Posted by quarterliter

I wonder if it will work on a pregen.....

do not wonder... it definetely cannot fit for more than one reasons...

[micoulisninja]

Originally Posted by mgentz

increasing the bore by so much will slow down the motor. This happens on dirt bikes when you go too big the motor just doesn't spin up as fast.

Also, with such a large change in piston weight, you WILL need to balance the rotating assembly.

well, yes !! but... not exactly....you see that depends on piston weight mostly and extra friction from the extra contacting surface of the piston skirt AND the common practice mistake to use bore-up kits without using wilder camshafts or at least alter their timing so that the extra incoming mixture can also leave the chamber that fast....

in this case you are right about two out of three factors you mention, so you win !!
piston weight is a ridiculous 158+ grams without piston pins and rings and they are not of the exact same weight because they are cast...
along with the 40 gram pin, 7 gram rings and 2 gram pin safeties we have a total of 207+ grams on top of the con rod while same total weight for 250 is less than 167 grams for the 250 and less than 155 grams for the 300 and that is a huge difference since each extra gram is an extra ton of streching force when spinning at 13K+...
just for comparison, a 67mm ZX-6R stock piston weighs less than 140 grams (180 with pin, rings and safeties)
and JE 66mm forged piston is 148 grams

however I need to mention that the skirt is a bit wider but much shorter and has a total contacting surface just a tiny bit less than stock piston's....

[micoulisninja]

Originally Posted by Somchai

The increase in bore must not necesssarily be the main problem, you're right the main factor to look for is the weight.
With a mod like this the stroke-to-bore-ratio changes from 0.66 to 0.61 and when we compare this with the 600 Gixxer which has 0.63 and is reving up to 13500 rpm for its power output.
Also I think with this mod you would need the TB's from the 300 with the 32 diameter.
At least it would be worth a test...

Roland you know I respect you and your expertise and you know more about these things than most of us here (all over the world) do... so I'd expect you of all people to be a little bit more cautious when suggesting even a test...
this kit needs much more than a simple TB upgrade and is definetely not worth the test by anyone who is not willing to throw money away unless they have the time and means to do all the rest that is necessary to make this kit work and we are talking big bucks here....

[micoulisninja]

Originally Posted by bruce71198

Where did you see them advertised? Are they in the USA or being shipped from overseas?

Jakarta, Indonesia and you get a big tax to pay to get that over there... forget about that Bruce... what you need to do is get some 300 rods, leave a bit more squish clearance, a new gasket and off you go with your excellent choice of dropping them into your 250...how is that going by the way ??

[micoulisninja]

Originally Posted by Racer x

My thinking is this is 50cc worth of power. Time to get a 300 engine and put this kit on it to make a 350cc ninja.

Don't know if it will work. But that is my thinking.

That is why I love the way you think Eric !!!
Like I said....
I am working on it !!
damn !! it takes time to go through every little tiny detail to make it all come together... be patient !! in amonth or so I will start posting pictures...
I have bought the 67mm kit, going through an entire upgrade modification on upgrade modifying bore-up kit to fit in my 300cc, 33 (yes, upgraded that too from 32mm to 33!!) TB for a 345cc little wasp...
is anybody paying attention to my signature or what ??

[micoulisninja]

Originally Posted by sharky nrk

Didn't follow the link cause I am lazy lol but was CR stock?

like I mentioned earlier kit base CR is an alleged 13,2:1...

[micoulisninja]

I believe you must have what you need to get an idea of what this kit is all about but to be just I will provide some more data and comparison figures for food to the mind...

the 68mm kit is of the same quality, craftmanship and machining as the 67mm kit I chose for my engine but there are some details between those two that make a huge difference. the 67mm kit is NOT on the site but is being sold on ebay on auctions...
current link is: http://www.ebay.com/itm/Kawasaki-Nin...item4adc1f95e7

so what I can tell for both is
1. the cylinder block is of good quality, cast aluminum close deck with alumil coating
2. head gasket of very good quality and other gaskets for the block are provided in the kit to be able to alter base CR...
3. pistons are of good quality (but not very good), cast, with a poor quality (gets scratched pretty easily) graphite coating and they are (will say it once again to emphasize how ridiculous) ridiculously heavy and thick bottomed. Most importantly they are definetely not designed especially for the 250/300 engine and are of some universal form that just happens to fit in the 250 with no clearance issues for stock camshafts with stock camshaft timing
4. piston pins are of good quality but also much heavier than stock(41 grams while 35,1 for 250 and 31 for 300) , adding up to the total of reciprocating mass...
5. pin's safety are throwaway pieces...
6. rings look of good quality, will know once I get mine working

now for some difference between 68 and the 67 kit...
1. piston pins and safeties are identical but 67 pistons weigh less(152 grams while 158+ for the 68)...
2. 67 kit has more coolant space, head gasket is wider of course between cylinders and their in between distance promises better heat dissipation and less chance for warp
another major advantage for the 67 kit is you can use stock '08 ZX-6R pistons (if anything goes wrong) which are lighter... piston pins are identical to 250's !! you will need to work on piston surface a bit though and adjust choice of gasket to get the desirable CR...

will update as I go through the building process...
so now it is time for you to dissapoint you all if I haven't managed to already....

[micoulisninja]

when I got kit in my hands my friend had not opened yet his engine so I only went through figures and measurments on the kit itself... I checked on upper and bottom surface flatness and they were within a stunning less than 0,001 warp !! so was the roundness of the aluminum sleeves !! indicating that the machining process of the cylinder block is being done correctly... too bad they pack along with pistons off some shelf for any bike...

anyway I couldn't imagine that a kit advertised as a bolt on would have such major fitting issues
anyone wishing to fit the 68mm kit will have to take the bottom end apart and carve off at least 2mm of metal off the top case for them to fit in, a little less for the 67mm kit...
what is funny about the whole thing is that while being advertised for the 250, the bloody thing fits perfectly on a 300's casing !!!
well there you will have other obstacles to overcome mostly because extra CR is gained by smaller squish clearance (more distance from pin to top of piston) but that is another whole different story... will be happy to share too if anyone interested... for two weeks I have been upgrading the "upgrader"...lightened and balanced the pistons and pins, altered valve relief angles and some other stuff and have yet to go...
any more questions guys or have you had enough yet ??

[bruce71198]

Originally Posted by micoulisninja

Jakarta, Indonesia and you get a big tax to pay to get that over there... forget about that Bruce... what you need to do is get some 300 rods, leave a bit more squish clearance, a new gasket and off you go with your excellent choice of dropping them into your 250...how is that going by the way ??

Got my squish set at .041" and a copper head gasket. Resurfaced the cylinder block and a 300 head. The .041" setting seems to be the magic number for bike engines according to the engine builders I talked to. Will be at the dyno some time this week.

[micoulisninja]

Originally Posted by bruce71198

Got my squish set at .041" and a copper head gasket. Resurfaced the cylinder block and a 300 head. The .041" setting seems to be the magic number for bike engines according to the engine builders I talked to. Will be at the dyno some time this week.

well...kinda... depends on if you want to go full compression and have no valve to piston clearance issues and if pistons are light enough-compared to stock- to be ok with that margin... when using heavier pistons (like 66mm JE is....) I would prefer to scarifice just a bit of that base CR and stick with .05" squish clearance... of course I am doing that calculating two factors you probably don't have to worry about (although I would keep in mind the second even at stock rpm limit)... 1) extra revving 2) con rod bolt stretching at those extra rev range
I am expecting you to show us a whopping 45hp dyno sheet and watch us all drool in envy...

[bruce71198]

Originally Posted by micoulisninja

well...kinda... depends on if you want to go full compression and have no valve to piston clearance issues and if pistons are light enough-compared to stock- to be ok with that margin... when using heavier pistons (like 66mm JE is....) I would prefer to scarifice just a bit of that base CR and stick with .05" squish clearance... of course I am doing that calculating two factors you probably don't have to worry about (although I would keep in mind the second even at stock rpm limit)... 1) extra revving 2) con rod bolt stretching at those extra rev range
I am expecting you to show us a whopping 45hp dyno sheet and watch us all drool in envy...

The squish issue seems to be a gray area with every one I talk to. The rule seems to be the tighter the squish the more torque the engine will produce. Why? Mixture concentrated in the center of the combustion chamber near the spark plug? Mixture/combustion occuring directly over the connecting rod? Both answers I have heard. However .040" seems to be a thresh-hold that if crossed unstable combustion conditions occur. One builder said at that point the mixture will pre-ignite, due to compressing it that tight, from the outside towards the middle as the spark plug lights it off in the other direction causing a huge, sudden increse in cylinder pressure. I think this is what my over heating issue stemmed from as the gasket wasnt physically "blown", combustion gas actually pushed past the gasket forming a air pocket in the cooling system.

[micoulisninja]

Originally Posted by bruce71198

The squish issue seems to be a gray area with every one I talk to. The rule seems to be the tighter the squish the more torque the engine will produce. Why? Mixture concentrated in the center of the combustion chamber near the spark plug? Mixture/combustion occuring directly over the connecting rod? Both answers I have heard.

I totally agree on what you mention up to here just because so it is...

Originally Posted by bruce71198

However .040" seems to be a thresh-hold that if crossed unstable combustion conditions occur. One builder said at that point the mixture will pre-ignite, due to compressing it that tight, from the outside towards the middle as the spark plug lights it off in the other direction causing a huge, sudden increse in cylinder pressure. I think this is what my over heating issue stemmed from as the gasket wasnt physically "blown", combustion gas actually pushed past the gasket forming a air pocket in the cooling system.

I totally agree with that one builder too... that is why I suggest you go for the SAFE clearance of .050" instead of .041"... this little difference is just about the difference of a stock head gasket... this way you will not lose valuable compression=torque especially in the low end but your pistons will keep a safe distance from the head while spinning at 13k+rpm and stretching the rods and the rod bolts...and guess what...compression will rise while rpms rise due to this stretching (which is inevitable to some point) and when reaching redline revving that squish difference originally set at 0.05" can become 0.01" or less !!!
the rest you mention about the gasket is probably what indeed happened since I've been through that same scenario myself chasing that .041" squish on my ZX-12R...
anyway I am looking forward to hearing from you having fun at the track with that engine being bulletproof from now on...

[micoulisninja]

I am wondering though... this topic was on fire a few days back...
where is everybody gone ? no more questions, no more posting...
Have I rough landed anyone interested ? Oh, come on guys... it's not that bad...
In conclusion what is to remain is that it can work IF a LOT of precise measuring, miling, chiping off, lightening, balancing etc is to be done by you (if you have those necessary precision tools and expertise) or a specialist with a ton of patience (even better both working together if possible)... It definetely is NOT a bolt-on kit if you want it to perform and last....
Go for the ebay 67mm version kit, it is easier to work with, more reliable and less PITA to bring to your preferences...

[bruce71198]

Another thing ocured to me this morning, When I first put this engine together I jetted it by feel and plug color. It turns out I was way on the rich side. No harm, better being safe than sorry. I ran it at Road America tuned this way and had no issue with it over heating. RA is a long, horse power track and no over heat. Came home, dyno tuned the engine, leaned out the mixture, made good HP. Next outing at Blackhawk Farms and the over heating started. Thoughts?

[micoulisninja]

Originally Posted by bruce71198

Another thing ocured to me this morning, When I first put this engine together I jetted it by feel and plug color. It turns out I was way on the rich side. No harm, better being safe than sorry. I ran it at Road America tuned this way and had no issue with it over heating. RA is a long, horse power track and no over heat. Came home, dyno tuned the engine, leaned out the mixture, made good HP. Next outing at Blackhawk Farms and the over heating started. Thoughts?

what AFR was it while being rich and what AFR did it end up on the dyno... It has occured to me more than once to have to let an engine run rich to avoid such issues sacrificing a couple of ponies up high and a bit of extra consumption but still a blast on the street compared to the feel it had on the dyno...that is why I prefer fine tuning on the street with O2 sensors(and FI)...
try sth around 13:1 and I guess it will be even better running 12.9:1 than 13.1:1 even if not optimal theoreticaly....

I've also seen great AFR changes on the dyno because some dyno tuners use an AFR reader stick placed into exhaust can, which in turn raising exhaust fume back pressure diversified AFR reading compared to what it would have been if the reading were through a built-on-exhaust sensor...
What's more there are reading differences when using different sensors...

I would suggest starting rich again... try dynoing the thing and if much leaner on dyno, rich it back just a bit for safety and cooling the chamber... will lose just a tiny edge but will run just fine when in top gear and/or holding throttle fully open for a long time...

[Somchai]

Originally Posted by micoulisninja

Roland you know I respect you and your expertise and you know more about these things than most of us here (all over the world) do... so I'd expect you of all people to be a little bit more cautious when suggesting even a test...
this kit needs much more than a simple TB upgrade and is definetely not worth the test by anyone who is not willing to throw money away unless they have the time and means to do all the rest that is necessary to make this kit work and we are talking big bucks here....

Thank you very much for that honor Nick, but please keep me a little bit more under the carpet
But let me confirm that you're absolute right with everything you said

[mania]

Just saw this as have not been on forums much lately

Well as you said you get what you pay for I guess
For these types of things better to go with a well known name brand.

To tell you the truth Indo is not far from here for postage etc. but I have never bought anything from that country as I was always afraid of fake brands & also doing business with them always seemed hard. One time I wanted a brake caliper they had but they only accepted bank transfers in their currency & at the end of the day it was just not worth the hassle & for a unknown product

I think their plastic parts that some sell on Ebay may be ok but machined parts I would be hesitant....same as the USD forks they were selling at various Indo shops.
Just dont know the quality

[pingels]

Originally Posted by micoulisninja

Go for the ebay 67mm version kit, it is easier to work with, more reliable and less PITA to bring to your preferences...

So would you recommend the 67mm version with a set of (much lighter and higher quality) zx-6r pistons? I would imagine from what you said that would be the best of both worlds. I'd be down for this mod in about a year if it: 1) gets the kinks sorted out or 2) some one sorts the kinks out and re-sells kits.