Hiii ... Iam currently owning a yamaha yd 125 4 stroke bike .... What all mods can i do for it to improve its performance ....kindly advice ....waitin for ur reply

Joel bro, this is an awesome work. I wish I had a R15.

Hi,
yes this is the only ECU for the R15 in the world. The 176cc block is only for my R15 and is in its development stage. Not for sale at the moment.

I meant is the ECU customizable with other aftermarket block??
And can i adjust the fueling using the ECU??
thx.

^Yes my dear friend. I have all the options to change the values as per my choice. Nothing is static. We have full control over the fuelling and ignition.

Awesome,
then when i get a my custom big bore from haen,can you tune the ECU accordingly??

However the tuning options are limited by me and nobody will have access to read or write from the ECU. Sincere suggestion, dont try any oversize and super high compression set-ups. I know what has been around in the Thai/indo market an I have sampled all of them. Which is why I developed my own bigbore block. You could spend a fortune on those kits and still head nowhere. None of those bigbore kit cost below USD 200 excluding shipping. Lets not even talk about reliability.

^^^ I stand and vouch for the quality of Joel's big bore.... money well spent and incredibly refined... no vibrations, no oil seepage, no engine temperature problems... in short runs as reliably as a stock build... one happy bunny here

Hi Joel,
sorry man,don't mean to disturb your thread comparing to other product

I just want to make an informed choice.maybe you can tell me why i shouldn't go with haen big bore kit.because he said it works well with the vixion/fz150,so it should work fine with my r15.178cc seriously sounds tempting.
thx

p/s:i also add u on facebook,name (sham sid jamal),maybe we can discuss there.

I am not trying to poke into your discussion with Joel or anything, but here are some thoughts on your 'little' project that may help bring clarity as I have already gone through the same;

1. Simply poking in parts is not going to help you, every change you make is going to have its pros and cons. Its a totally different matter to have a race prepared engine and one that is meant for streets. It requires a lot of designing, testing, evaluating and redesigning to come up with solutions that are acceptable for street bikes.

2. While size does matter, it needs to be balanced with reliability and longevity. Not only that, going beyond a particular size, issues such as cooling, vibration, fueling, load on drive train, etc, come into serious consideration. Currently, the 165cc big bore by Joel is the best solution. My sincere advice is: don't be lured by what is available abroad. I too have that option, (heck, my RXZ 5 Speed is more English than Indian) but, for the price and the knowledge (believe me when I say this is the most important factor), Joel's solution is unbeatable.

3. Create a road map for your changes. Do not go by what you read in magazines about free flow exhaust, fuel commanders, etc. Such poking creates minuscule changes or no changes at all. All changes need to be thought out as how they affect the complete system.

4. If you want an great individual build go to Joel and get it done under his supervision. If you want to just do it yourself, Joel solution is still pretty straight forward and can be done at your end and since it is tried and tested you have the assurance that it will work. Also remember that Joel will be just a phone call away for any support/ clarifications you require.

Hope this helps....

@abhimanyu31

yes,u are right.i have taken into consideration a 62mm block might vibrate.I have read about Joel kit extensively in your,kathrik_r and kwok thread,and it seem reliable,and extreamly good.

the only thing is,say in the future,after the initial big bore,exhaust,cam upgrade,i'm looking into the ECU and a 22mm/19mm big valve head.

do you think a 178cc big bore would produce a bigger yield in power if added to a larger valve head and an ECU??

also,on the other side of the fence,considering that a yamaha T135,which has a stock bore of 54mm(135cc) and a smaller radiator can fit a 62mm block,the yamaha r15,which has a bigger radiator shouldn't pose any overheating problems.

Of course,all my theory is just based on my still infant bike modding experience and talking to some of my friends in malaysia

all of your suggestions and comments,negative or positive is greatly appreciated

I'll clarify your doubt in open. Makes it clear for the others reading this too.
More CC (cubic capacity) with a large bore is not the only way to make more engine horsepower. You will gain more low end torque, but you significantly loose at top. Because you are still using a cylinder head which was originally designed for a 135cc LC motor. Inlet valve size is 19.5mm and exhaust is 17mm. Not sufficient for a 62mm block to flow at high revs. My 165cc race bike, makes more power (on the dyno too)than a Ninja 250 can even with mild engine works, being 85cc lower. Why?
A stock R15 makes approx 14.2bhp at the rear wheel on the dyno with STP correction factors and ambient conditions. My bigbore 165cc kit gives the engine a good 2.5bhp+ boost without any work. No exhaust, no intake, no cam, no ECU change, no AFR change, no nothing. So please do the math. What are we at now?
Coming to the Dyno part of the story. Most of the dynos used to depict the horsepower values abroad have no reference to SAE correction factors and mostly are defined to simply overstate values to the consumer. Also most are non-branded basic roller dynos and are well under or over real calibration values. Dynojet, Dynapack etc are the reputed and well recognised ones.
Now, coming to the T135 and R15 comparision.
The LC135 and R15 use the cylinder head in stock form. Same valves and same part numbers. The LC135 uses a 54mm piston and the R15 57mm. Technically you are already pushing the flow numbers. As per my flow analysis, 60mm is the limit to what a stock valve can flow. Even cams cant push things too far. Then it has to be taken to next levels of cylinder head development. Now you should realise why I do NOT recommend my custom 176cc block for a stock engine. Thats my test mule for my upgrades and my engine runs nothing stock. Hence makes that much power at top and all rev points.
Now, an engine which is starving from gas flow (read - overbore) will also tend to vibrate a lot. Too many pumping losses and retarded combustion efficiency is what you are then gifted with. Ofcourse you will feel the low-end torque has risen, yes coz you are NOT reaching the max combustion efficiency at low revs.
The LC135 has the same radiator size as the R15. FYI.
Coming to your bigvalve head story.
Thats the black art. Every indo/thai aftermarket company promotes a bigvalve head. What flow and performance you can get out of that head, leaves a lot to be really derived in real world conditions. Its a combination that everybody thinks is making power, but a dyno will prove you wrong. When you are playing with gas-flow, you simply cant agree that bigger and higher is better. Thats where engine development and racing experience comes to play. Making a bigvalve engine bullet proof and super reliable, YET making awesome power is something you always desire. But making it work is a Bittch!
Nobody selling his product will say, he is selling anything inferior. Its always left to the consumer to decide what he needs and what is genuine. Social networking is indeed a common way of selling imports. Every brand vouches for its product, nothing wrong.
There is always a feeling with us humans that the other side of the land is always greener! .
FYI, I have attained the highest specific output ever derived out of the LC yamaha SOHC engine by anybody till date with whatever hardware, or CC in the world! I'm now at 200bhp/ltr and gunning for more!. Which means for every 100cc, I'm making around 20% power of the CC. I sure know something about these engines my friend .

Last bit. I would not guarantee/custom tune any maps to anyone who is using a kit prescribed by themselves from elsewhere. Reliability and performance will depend on the hardware and I do not wish to get blamed that my ECU is at fault and caused the catastrophic engine damage. I will however assure with my tune-up combinations only. ECU tuning is very time consuming and an expensive affair. If something needs to be done as a special case, I will attend it personally but risk is thyselves.

Naaa.... my grass is as green as the AMAZON !!!!

Now, I know what's in store for me and my R15 in the future... bring it on....

Seriously, very happy with the way build has turned out... it runs like a bat out hell !!!

Now waiting for the next level...

Awesome reply Joel,
thank you so much for taking your time to explain everything to a noob like me
finally my search for a big bore kit is over.I will send my bike when i finished my exam.
And one again thank you for explaining everything

Nobody is going to sit down and explain things to such detail. I sure want everybody in this community to know what is real and unreal engine performance. Awareness starts with education. Then again it has its pros and cons. People sideline your advices later and get smarter into doing smarter things.

The ECU development was delayed due to a few unavoidable circumstances. Will be ready shortly.