[0xBC]

Hi, I just recently purchased a new Grom, and currently have done the following modifications (performance wise):

aRacer Mini X ECU
aRacer AF2 module with Bosch 4.9LSU wideband sensor
Toro full exhaust system
Unknown intake (K&N filter, potentially chimera? Last owner did the mod)

The reason I have the aRacer setup and not just an ECU flash is because I planned on modifying the engine further after purchasing it. That time has now come.

I want to install a TB camshaft and a DHM high compression piston for more power in the top end.

My questions are:
1) At what RPM does the TB cam with DHM HC piston stop making power at?
2) Should I also upgrade my injector to a PCX150 if I do the TB cam + DHM HC piston? Keep in mind I also have intake and exhaust without baffle, so will this upgrade max out my injector?
3) If I want to raise my rev limit to have longer time in the powerband (as in above 7k when the cam really starts to kick in), how high can I go safely with stock valves, springs and retainers?
4) If I upgraded to the DHM titanium valve retainers and high rpm valve springs, how high could I safely rev the engine to without having to worry about breaking other components? Would getting a new cam chain tensioner allow me to safely rev slightly higher than without an upgraded cam chain tensioner? If not, what would?
5) In addition to the TB cam and DHM HC piston (and maybe valve springs + retainers), do you think it is worth getting my head ported or getting a larger valve head also?
6) Once I have done the TB cam + DHM HC piston upgrade, is it worth getting a small oil cooler, as I will be making a 2.5 hour journey in a few months and will be sat at 50-60mph for most of it, which is very high in the rev range so will probably get very hot

Sorry for lots of questions, just currently trying to work out the best options for power and reliability at stock bore (I will NOT go big bore so don't even suggest it).

Thanks guys



EDIT: Forgot to add the 6th question

 

[Darmie]

You want to try big bore? Na, just kidding.
Not sure about question 1. From what I gather, the weakest link is crank/rod. Going up on RPM I would do with care.

For 2, I would think the aracer would allow you to track / record your injector usage. Watching some of huntertune video's I remember he was having a problem using the 150 injector with adding to much fuel, so if your current setup is not showing 100% dutycycle, probably can leave the stock in place.
3,4 I'm not knowledgeable but do know the crank/rod is a weak link.
5, there is always benefit on any porting on any engine. It's sort of like free power especially if it's done done by the yourself. With any 4 valve or larger valve head this may cause more stress on the chain and chain tension. As you previously was asking the cam chain tensioner may see more wear. I know that on another huntertune video, he was testing out a new cam chain tensioner and idler gear. Maybe it's worth a look.
6. See if you can figure out a way to check temp now before you go to far with mods and see what mod starts to warm up things. I purchased one that goes where the oil fill cap was and found I'm running about 180 to 200f when i'm all out on the road. As I start doing a few things I'm going to watch and see what happens. I would also think an oil cooler will help no mater what.

Hope others chime in. I'm learning too.

 

[Pyro]

#6 oil cooler is definitely worth it if you are maintaining higher rpm for extended periods. On hotter days I would be sitting at 240°F at 60-65mph now with the cooler I don’t see anything over 212°.


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[Lindy]

Im currently building a potent stock bore, Im using a Takegawa Crank, Kitaco 5 speed, a very ported big valve head, a very agressive cam etc...

 

[Justin V]

Im currently building a potent stock bore, Im using a Takegawa Crank, Kitaco 5 speed, a very ported big valve head, a very agressive cam etc... View attachment 93925 View attachment 93926 View attachment 93927 View attachment 93928 View attachment 93929 View attachment 93930

Any reason for the takegawa crank, it's heavier than the kitaco. And are you using that decha 6.7 cam. I have some others you can try if it's too much of a high rpm pig.

 

[Lindy]

I used the Takegawa crank, because its closer to stock crank weight, the balance factor gets bad with the Kitaco crank in a stock bore, I'm also using a heavier than stock flywheel. Goal is to launch the bike around 10K, and let the flywheel carry it, with a bunch of gear in it, so if it uses the whole 5 speed for a 1/8, so be it. I am using the Deca 6.7 but would be interested in purchasing some other cams to try