August 16th, 2015, 05:27 PM | #1 |
ninjette.org member
Name: what
Location: Canada
Join Date: Aug 2015 Motorcycle(s): 2013 Ninja 300 Posts: 37
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JE High Compression Piston Kit (13.5:1 compression, 356cc displacement)
Hi everyone,
I was wondering if it's possible to install Ninja 250R piston on our Ninja 300 but I could not get a definite answer from Ninja 300 Forum. http://www.kawasa***************/for...placement.html Anyways I decided to come here and see if anyone knows anything. Looks like piston ring is the problem? **EDIT** I just tried to link the thread that I was referring to, but this forum won't let me. |
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August 17th, 2015, 05:37 AM | #2 |
dirty boy
Name: Joe
Location: Johnstown, PA
Join Date: Sep 2012 Motorcycle(s): I don't even know anymore?? Posts: A lot.
MOTM - Apr '14
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I am not 100% certain but I think that the 250 and the 300 pistons have a different wrist pin to top of piston measurement. So no they will not work.
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August 17th, 2015, 04:54 PM | #3 | |
modaholic junkie
Name: Nick
Location: Athens, Greece
Join Date: Sep 2012 Motorcycle(s): 2001 ZX-12R, 2009 ninja 345cc and plenty of others in the past... Posts: 438
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Quote:
first of all the 250 has an aluminum block with iron sleeves while the 300 has an all-aluminum block with nikasil coating, which is expensive to replate if overbored and very few companies are able to do it reliably. The kind of work you are looking for would be custom-only, so even more costly... you would also have to fit rings made for nikasil-plated aluminum, the ones made for iron sleeves would scratch the block to destruction... second is the fact that con rods are same thickness but not the same length, the 300's being quite shorter... piston pin is same OD but quite narrower... like subxero said, pin to piston deck is different, head gasket on 300 is a triple "sandwich type", almost 5 times the thickness of the 250's single metal leaf... apart from those major differences and difficulties to overcome, there other details that also need special modding... I am not saying it is impossible, I am saying it would cost you more than a new 300 for a result that would still be much less than... half a ZX-6... I was about about to go for that kind of build but soon realised that it was a mistake all along, mostly because the 250's casing cannot take larger, stronger studs, the oil cooling is inadequate and there was the head with its tiny valves and soft springs and the TBs and so on... So, since I am a modaholic, I got a 300's engine, the 32mm TBs, and ordered an overbored all-aluminum 67mm aluminum block (by the way JE or wiseco make up to 66mm, that is +4mm on either 250 or 300, the +6mm is simply a mistake at their site, so if put on a 300 crank it would be about 335cc...) The financial crisis thing going on over here has put me to a stop at the moment but I am about to catch up by early September... needless to say that this is not cheap, it could be used to buy me a 300 with several extras, since there is much head work, springs, modded rods, pins and pistons off a '09 ZX-6R... garth285 who was really close to building a turboed 250 helped me choose the springs and gave me ideas... https://www.ninjette.org/forums/showthread.php?t=223351 cuong-nutz is the master of information... you will verify most of my writing there and get very useful data... https://www.ninjette.org/forums/showthread.php?t=180069 Somchai is always inspiring and his huge experience is precious, contact him or check out his posts... Bruce71198 has built a super 335cc engine based on a 250, check out his build... https://www.ninjette.org/forums/show...&highlight=335 you can get ideas by checking out what I have done so far, maybe the difficulties I have encountered might give an idea how hard that kind of project really is... will update soon with progress... https://www.ninjette.org/forums/show...=198145&page=3
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August 18th, 2015, 11:48 AM | #4 |
ninjette.org member
Name: Michael
Location: Tehachapi, CA
Join Date: Oct 2014 Motorcycle(s): 2014 Ninja 300 Posts: 160
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I know how to make it happen.
Its a matter of finding the difference in wrist pin height and making up for it with a spacer plate between the block and upper case. Spacer plates are custom, but not expensive. As for boring and replating Nikasil bores goes, I deal with it daily. Its a long-ish process though where I work but its not hard, nor OVERLY expensive. The other think you need to worry about is engine balance. New pistons dont weigh the same as stock pistons so you will have to get the rotating assembly re-balanced. A gram or two can make a pretty big difference in balance at 13,000 rpm. Gaskets and a spacer plate are really no trouble at all to have made. The trick to more power however is all in the head, and our problem is that the valvetrain materials are junk. They werent made for performance, they are cheap, lawnmower grade, welded valve head-to-stem low quality steel junk. I am currently working on trying to find a way to make some real race quality stainless valves, but it is slow going. The way to go would be to find a real good spring (i know a couple different ones that work), titanium retainers (that nobody makes, yet) stainless valves(working on them), in standard or oversize depending on application, porting from someone who knows what they are doing(my friend/co-worker), some more compression as it is way too low for a modern street motorcycle(JE or Wiseco, pick one for the sticker you like more), and a cam to match the work and what the bike is being used for. Web Cam will be happy to make you a custom grind. |
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August 18th, 2015, 05:14 PM | #5 | |
modaholic junkie
Name: Nick
Location: Athens, Greece
Join Date: Sep 2012 Motorcycle(s): 2001 ZX-12R, 2009 ninja 345cc and plenty of others in the past... Posts: 438
Blog Entries: 2
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Quote:
So that can be easily overcome by a base spacer... Nice idea, I thought so myself, but when I checked thoroughly piston travel, I noticed that a spacer larger than 1-2mm would leave the bottom of the piston skirt go under the block (and I am talking about the 250's short skirted high compression pistons, the 300's stockers are on the limit as they are). The cylinder block (and most importantly its walls) is of the exact same height while now the piston has a longer travelling distance up and down and I bet that is one of the main reasons their 300 piston design has shorter skirts and still reach the bottom edge of the walls... Anyway,measuring the 300's open-decked cylinder block wall, I found it to be about 4.5mm thick... So these observations make me wonder about a couple of things, I hope you can help me understand better... 1. How much overbore do you believe would be reliable for that kind of cylinder wall thickness ? +2mm ? And if only that much, do you believe it is really worth the process ? I mean for the 250's iron sleeves it is probably good value for money (and extra power), but for aluminum nikasil replating on a 300 ? 2. What could be done if the available high-comp, short-skirted 250 short-stroke oriented pistons almost have their bottom tips coming out and under the block walls inside the 300's longer piston travel even without using any base spacer ? Maybe your answers will help me make a breakthrough with my project, so I am really looking forward to your post, thank you in advance !
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If noone has tried it before, I will !!! |
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August 18th, 2015, 06:43 PM | #6 |
ninjette.org member
Name: what
Location: Canada
Join Date: Aug 2015 Motorcycle(s): 2013 Ninja 300 Posts: 37
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Thanks guys for all the detailed response!
Sounds like there's gonna be a lot of work.. and I'm not exactly a gearhead so I don't think I could do all the modifications to make it happen. If I were to look for more power, it would just make more sense for me to get a ZX-6R I guess. |
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August 20th, 2015, 03:13 PM | #7 |
ninjette.org member
Name: Michael
Location: Tehachapi, CA
Join Date: Oct 2014 Motorcycle(s): 2014 Ninja 300 Posts: 160
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You would be surprised at how much skirt can come down before there is an issue. Some of the blocks we have done get the pistons going WAY down in the bore. +11mm stroke Hayabusas come to mind. 9mm of their 27.5mm skirts will be below the bore. Not a small amount, and yet they live and make SERIOUS power. Its all about getting the clearances right.
2.5mm leaves it awfully thin in my opinion for something that is expected to live a good life. A 'hours' engine, sure, go for it. Not a good option for the street. Stock or 1mm over should work well. The 250 block is the way to go for BIG pistons. Just remove the stock sleeves, bore out the block, put larger sleeves in, bore the upper case to match the new sleeves, and bore the sleeves for the new pistons. Thats 45 year old tech. Simple and cheap. Downsides are it will cast just as much to do it for the first time as just having a Nikasil bore done, after that its stupid cheap. It wont last as long between having to re-ring and de-glaze. Heat transfer sucks with iron sleeves compared to aluminum. Nikasil wont be as cheap but the material is MUCH more durable, and heat transfer is substantially better. Not to mention its a lighter block... I really wouldnt bother with extra CCs, as there isint a LOT of power to be found there. Its all about the head and cams, and getting the lower end to last. -Mike |
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August 20th, 2015, 06:54 PM | #8 | |
modaholic junkie
Name: Nick
Location: Athens, Greece
Join Date: Sep 2012 Motorcycle(s): 2001 ZX-12R, 2009 ninja 345cc and plenty of others in the past... Posts: 438
Blog Entries: 2
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Quote:
As for the rest, I just couldn't agree more !! Hope you find some good valve for replacing stock, they are indeed of low quality...
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October 12th, 2015, 07:21 PM | #9 | |
Board Member
Name: ...
Location: WI
Join Date: Dec 2011 Motorcycle(s): 250R (street), 250R (dirt) Posts: A lot.
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