I've been riding the Yamaha FZ150i in SG for quite some time now, and I have come to a conclusion that I will not be upgrading to a bigger bike in the future as it is more economically viable for me to mod the current one.

It's a 2009 Yamaha FZ150i, first generation with 0 mods done to it, coming towards the need of doing an overhaul; I thought might as well I use this opportunity to upgrade its drivability especially during lower RPMs while ensuring that it is reliable and it looks and sound as close to stock as possible (SG's LTA is not very modification friendly)

I have been doing some research on what it could be done, which most of them came from the 135LC forums all over the internet and our own Lowyat forums; I have shortlisted a few:

Cylinder Block: UMA BLOCK 65MM FOR SUPERHEAD
Piston: UMA SUPER HEAD PRO IN25/EX22 (included: Piston Rings, Upper Gasket, Lower Gasket, Wrist Pin)
ECU: FSR TuneBoss
Injector: 160cc

What else do I need to take note of apart from other things like stronger clutch springs, new clutch plates, 6 speed transmission, smaller sprockets as they shall come in later

Add: Just thinking out loud... Perhaps I should be looking at increasing the stroke length? Since i'm looking at increasing the torque, an under squared engine might be what i'm looking for? However I might be making things more complicated as I read that it requires the timing gears to be changed.


This post has been edited by ((Xa))0102: Nov 14 2017, 02:40 PM

Hi, just want share my view.
65mm block is consider extreme modification for fz150i because it need to tune with dyno to get an optimum performance and need bigger cost then 63/62mm spec. 65mm need to change to bigger throttle body and injector.
65mm = 196cc
63mm = 183cc
62mm = 178cc
63/62mm will be easier to tune and not need to change throttle body.
Injection type need to tune using dyno and only certain shop available with dyno machine while carburetor can be tune by yourself and almost all shop can tune it. You need to change your exhaust to good air flow exhaust because standard exhaust will be to restrictive for 65mm. You need to find workshop that can tune using dyno.
You can change to UMA 62mm and UMA SuperHead 23/20. FSR TuneBoss is good ecu. Camshaft and valve spring already included in UMA SuperHead if I'm not mistaken. You can change to bigger exhaust manifold if 62mm spec. Change your stiffer clutch spring and clutch plate avoid using racing clutch plate. 6 speed transmission will be headache when you want to tune your sprocket. Better avoid it.

This post has been edited by man_sate: Nov 12 2017, 12:06 PM

Looks like ur not out for speed n just want better drivability as u mentioned....

I assume u want more pickup at lower rpms like u mentioned? Most likely for traffic jam etc?

Then i suggest forget everything...overhaul n use stock parts for durability n just increase rear sprocket size

Thanks for sharing, I wonder will those superbike tuners will layan such small bikes tho as I was only able to find one in JB, but they mainly tune superbikes

Will the 62mm improve the power tho? If improvements are rather minimal, I rather stick to what I have

6 speed gearbox, not that hard actually, I can just use solutions from the R15 which are common and aplenty here in SG. Just wondering if i'm able to re-use my existing gearbox and make internal modifications instead of buying an entire gearbox instead.

Exhaust wise, I can only get Yoshimura slip-ons that are LTA certified, I wonder if that helps. I really wish I was back in bolehland where yearly inspections weren't necessary.

Correct. However, i'm actually looking ways to make my rear sprockets smaller as my bike is always asking for a 6th gear when I go up to speeds like 70-80km/h (currently on stock 42, decreasing to 38 or 40 makes my bike even worse at low speeds) then I guess more power will be the way.

Already have? If already have then proceed.
65mm more pickup then 62mm but not plug n play like 62mm.
62mm is enough if you dont want headache. It's already make a huge difference rather than standard block which is 57mm.
Existing gearbox cannot modified to 6 gear. Standard gearbox can replace their ratio with the change of gearbox teeth.
Don't know if superbike dyno can accept fz150 maybe if you modified your bike to 'serupabike' they can accept it. Hahahaha.
I and my friend already try 6 speed gearbox if you modified from 5speed to 6 speed then the spocket tune will be harder. It's not simply follow other's bike spocket ratio because your bike need different spocket ratio in order to feel the performance gain.

I'll consider 62mm if that's the case hahaha. But how much more of a headache if I were to go for the 65mm solution tho?

Let's say if I go for the 62mm, do I need to change the conrod to a more durable one? Does the TuneBoss ECU require custom mapping?

Perhaps I'll stick the the stock box and play around with the sprocket until I source for the R15 when existing owners are starting to scrap theirs when it reaches 10 years.

Good question, no point giving bigger volume of combustion chamber (bore up kit) with standard conrod and crankshaft.. else it will bend or cracked soon...

Also you need to strenghten the Clutch as it will tend to slip when carrying bigger load before passing upon to your transmission..

personally, stay stock with minor mods such as sprocket.

in Singapore, realistically you will be at speed limit within 3-5 seconds.
unless you're looking for higher speeds then i rest my case.

And one more thing, all the money u spend.. will be the same as buying the 2nd hand 250cc bike..

65mm spec need to upgrade bigger throttle body and injector. It need more fuel to burn and if you didn't provide the required amount or tune then it will effect your head, block, piston and rod. Tuning 65mm spec required dyno to ensure your tune is accurate.
FZ150 rod can withstand 65mm. I have been use it around 4- 5 years and frequently check the rod condition after 2 years of usage. No need to change no problem with 62mm. TuneBoss ECU required custom mapping if you feel sluggish or drop in performance. You can search at website in bolehland or other's for 62mm mapping. I have read somewhere their are sharing dyno custom mapping for base tune. You can DIY from there or just go to ask if any dyno shop can tune for you.

My 135LC spec is 67mm with adding extra 10mm jackrod. It's around 243cc = 245cc. Use it daily and convoy never had problem in 2-3 years. Before this spec, I have use 65mm as daily and convoy for 5 years during my study never had problem. You need to change your engine oil and oil filter when the milage come. Take care of your bike carefully. You dont need full throttle if you only going to shop

This post has been edited by man_sate: Nov 14 2017, 02:15 PM

Will plan accordingly after I get a clear idea on what to do, thanks.

Tried those when I just got the bike a few years ago, it does improve in one way or another comes at the expense of another. The stock one is a good compromise for 1st-2nd gear pickup with pillion and cruising at 110-120km/h. I'm not exactly someone that follows the speed limit here

Stock is 42T, I've tried 40T which is good when i'm riding alone, 38T is the best as I don't feel that the bike is asking for a 6th gear when I reach 70km/h when cruising. However, I have to rembat the hell when moving off in 1st. Since 38T is a good sprocket setup, but lacks push at the lower ends; I guess I will have to increase low-end torque hence this thread.

Other minor mods that I could look at would be aftermarket ECUs and intake, or maybe modifying the stock pipe by removing the zig-zag interior that houses the various pollutant removers since I don't really have much choices apart from:
a) Street legal slip-on Yoshi - LTA certified that requires cutting
b) Modify stock pipe
c) Stock pipe

By going for option b, I will have to swap over a stock exhaust for the yearly emission tests.



No R25 here, R3 used costs around RM30-39k

ah well 300sgd is a bit too much for me in that "Fine" city
but of course if you can take that risk/observant on cameras etc, by all means right XD

there's always compromise, and i personally prefer acceleration over top speed as on average you'd be able to maintain much higher speeds.
and of course, torque is way more fun

now on your choice:
a: expensive and doesnt improve much, if even any.
also assuming you dont even lose power (i'm talking about power band, not your peak hp which you wont really be at often especially in city riding)
b: similar as a, just cheaper, but obviously even more uncertainties on gain. and if you need to do swapping, then the cost will add up, not to mention taking up space for a stock exhaust lying around.

consider watching videos such as these when it comes to tuning/exhaust.

and these are talking about 200hp bikes on the crank that could yield power in the 10-40 hp.

a 150cc would only yield single digit gains, and mainly on the high rpm power band, that typically HURT low rpm power gains and the end result is money being wasted into the ocean.
overall the gains you're yielding is very VERY minimal for just exhaust and full tune/engine mods etc will cost you a huge fortune that as ajaibman posted, you're better off with an actual higher cc bike. even a 30-40k R3

and hey that's a very nice girl after all. (i mean the bike! ... honest!)

Wow, that's some serious modification. Yes, have those mods in mind already. I feel that the most difficult part now is to find a solution for the exhaust, as it has to be legal or at least sound or looks legal.

Good to hear that you had positive experience with the ori parts supporting the various modifications.




I guess the guys that I'm gonna look for knows that they are doing... I was only able to find one shop that has a dyno for bikes in JB area, but I doubt they will even take such small bikes seriously as the mainly tune likes of the Hayabusa, R1 or even the H2.

$130 saja hahaha. Traffic police here don't really play ambush hide and seek nonsense, either they are AES style cameras or they will strategically park at the road shoulder along a blind curve with their strobe lights on and it is very rare during the day time. So speed je hahahaha

As much as I would love to go top speed, roads here aren't really suitable for it. So acceleration would still be my priority, its just that cruising as slow as 70km/h, my dear bike is already asking for 6th gear

a) confirm will improve geh, there are many dyno charts of 62/65mm tunes with low end power being marginally higher than stock
b) I have 2 identical bikes, can just swap between each other

Thanks for the video, will do more research towards that direction

True that whatever mods that are readily available are catered to speed demons where the power band is shifted towards the right hand side of the graph. But as a single cylinder, i'm pretty sure that the low-end torque would still remain there more or less. I'm ready to spend RM2-3k for this and another RM1k to swap the entire cover set, new rims etc. The reason why i'm sticking to this bike rather than upgrading is due to the costs of getting a new bike, it is really not worth it since my license is only allows me to ride bikes under the 200cc category.

No point getting a midweight in SG. The MT03 and MT07 costs almost the same, CB400X and NC750 is only $1k away

Try ask them.
Is it aracer ecu is yours?
Already have custom map. Don't need dyno lah.
Don't know if FSR Ecu also have this custom map.

Not mine, it's from their FB

Thats why I said they macam know their shit

Aracer more expensive than FSR Tuneboss.
Aracer have many series and most expensive is aracer m1.
Just modified your standard exhaust. Install big manifold 32mm and remove CAT near the connection of manifold and exhaust chamber.

Will remove the catalyser cause big changes in emission readings?

Don't remove all. Remove a bit of it around 20cm long. Removing all CAT same like open exhaust.

Means no back pressure right?

Back pressure still have with open exhaust. Chamber design is difference from standard exhaust but don't have CAT.
Standard exhaust after CAT there is stopper.

I never try to remove all of CAT because dont want the sound change. You can try if you want.

This post has been edited by man_sate: Nov 15 2017, 05:20 PM