JA65 Big Bore Kit 145cc

[johnny125]

the ones im running is the 1.6 type from webike, https://japan.webike.net/products/24067601.html

the 1.9 was a tad much. I bought both just fyi. im sure it will work with a 145 and does well on my 164.

I asked Kitaco what size they recommended and if they had the cc rating for the 1.3 & 1.6x the rep did not know cc flow but recommended the 1.6x.. for me. So i got that 1.6 in anticipation of the 145bb and have been running the pcx150 around with ths stock bore, it sure dose go flat on the top end, as you suggested would happen with too much fuel.

 

[johnny125]

Got the Aracer mini x installed, had a local fab shop weld a ss o2 bung i purchased from summit racing onto the Yoshimura, i think it turned out nice. The Aracer is amazing, was able to get it set up and tuned using the autotune, it runs so much better, the exhaust tone has changed/improved and the bike runs fantastic, more power everywhere, now pulls higher speeds on hills. Having the engine temp and tach display on the aracer xtune app is really cool. Ill be tackling the 145 bbk install soon when i get a break from things been pretty busy lately..

 

[m in sc]

so how much was the ar racer setup? like 700 bucks w the auto tune? (less the o2 sensor)?

 

[johnny125]

so how much was the ar racer setup? like 700 bucks w the auto tune? (less the o2 sensor)?

Was about $800 with shipping, I purchased from Hardracing.
the af2 needs the splitter cable thing so i got that as-well.

I'm trying not to keep track of the money spent on the trail lol.

 

[johnny125]

Oh and to add on to the financial insult, the xtune app makes you pay $30 for “back-fire ”and like $10 for spark angle changes.. so stupid.. but i probably will buy those too ha!

 

[m in sc]

i figured thats about where it was. cool, glad you got it sorted and works well.

 

[johnny125]

Kitaco cam installed!

Was very simple to do, got the timing gear back on without releasing the tensioner.

WOW what a power up the cam made, It feels like a completely new machine, much more power than I was expecting, has a cool induction sound as-well. Also finally installed the Michelin city extra tires I had sitting in the shed, did some sbs street ceramic brake pads to boot, happy with those ride is nice + brakes bite a bit harder.

Looking forward to the 145cc install but I think I bought the wrong flywheel puller tool anyone know where the best place to get the socket thing that pops off the flywheel to access the chain tensioner arm?

 

[dmonkey]

Which flywheel puller did you buy?

If the same one fits the JA65 as the JA55, then it would be Honda part number 07KMC-HE00100
I bought one sold by Hard Racing for less than the OEM tool cost, and it is marked as being BikeMaster part number 150620

 

[johnny125]

Which flywheel puller did you buy?

If the same one fits the JA65 as the JA55, then it would be Honda part number 07KMC-HE00100
I bought one sold by Hard Racing for less than the OEM tool cost, and it is marked as being BikeMaster part number 150620

I got that thing off amazon, I'm guessing its the wrong style, was like 7 bucks so no big loss

 

[johnny125]

Which flywheel puller did you buy?

If the same one fits the JA65 as the JA55, then it would be Honda part number 07KMC-HE00100
I bought one sold by Hard Racing for less than the OEM tool cost, and it is marked as being BikeMaster part number 150620

Looks like the JA55 and JA65's are indeed the same, Kitaco's install instructions for their brand of idler arm for the JA65 list a M30X P1.5

https://www.kitaco.co.jp/storage/product/303-1452810.pdf

A link to the BikeMaster 150620 from SR

Pardon Our Interruption

Thank you!

 

[johnny125]

Reading over the BBK install directions, on page 9 there is a reference to liquid gasket being applied to the middle section of the crankcase gasket,

https://www.kitaco.co.jp/storage/product/212-1452050~61en.pdf

For those that have done this install before, did you use liquid gasket on this location? If so, what would be the recommended stuff? Honda Bond?9might not be available locally) Perminex high temp gasket maker?
Thank you!

 

[m in sc]

permatex grey motoseal. any parts stores has it, i use it for case sealant a lot.

 

[johnny125]

Awesome, Thank you for the quick reply!

 

[dmonkey]

Honda list "Three bond 1215 or equivalent" in the USA market service manual, so that's another option if it's available to you.

 

[m in sc]

its equivalent. actually, a bit better to use, its a bit thicker like the old yamabond 4 formula.

 

[johnny125]

Thank you for the recommendations, I picked up a tube of permatex motoseal Today. still waiting on the correct flywheel puller to arrive for the upgraded idler arm install, shipping in another week

Probably will do the 145 cylinder/piston and crankshaft bearing support install tomorrow, also going to change the pcx150 injector to the kitaco 1.6x because i have it.. (either injector would probably be fine with the aracer running afs) theres a fuel setting in the a racer app that allows for targeting fuel rate +- over/under 100%, I've ran miles on it at 80% and 100% with no perceived change.

I certainly am dragging this bbk upgrade out.

 

[johnny125]

And it’s in!!

Install did not go smoothly, my fault.. but now that I know how it all goes together (twice lol) its pretty straight forward stuff.

My big hangup was the upgrade takegawa crank shaft bering w retainer plate.. this plate has a small lip that must face the crank, I put it backwards and it caused the stator to grind and i miss diagnosed it as a piston wrist pin cir-clip failure, as i had trouble with one of the clips (replaced it and seated it correctly the 2nd assembly)🫠 i am not a good mechanic.

Initial tuning and thoughts?

It is torquey, very smooth power, and lots of torque in the mid range, even with light throttle you can feel the difference. still working on tweaking the tune with the aracer but so far its running very nice. The bike now pulls hills well in excess of the posted speed limits even on the crazy grades we have around here (17% in some spots) so with that I am very pleased. I did hope for a bit more top end performance, (65-70mph) still around 62ish mph and somewhat flat initially.. working on dialing in the tune.. may be limited with the stock throttle body/intake pipe anyhow.

Will be changing the oil cooler set up with a set of oil lines that have banjo bolt ends pre installed (chepo amazon) to plumb the cooler into the block (if they fit), saw a max temp of 217f with current configuration of valve cover port/oil lines. The valve cover port is pretty annoying to work with, how the allen head bolts are recessed into the cover and theres not much room with the crash bar in the way if service, valve check is needed.

The mod bug is a slippery slope especially with having the aracer, any part or engine upgrade can be tuned in so easily, makes me want a 4valve head… but as it stands I'm happy with it. The “character” of the bike is certainly not ruined by the extra power, just makes everything better.

Ill put together some video soon

 

[DaleT]

View attachment 10988View attachment 10989
And it’s in!!

Install did not go smoothly, my fault.. but now that I know how it all goes together (twice lol) its pretty straight forward stuff.

My big hangup was the upgrade takegawa crank shaft bering w retainer plate.. this plate has a small lip that must face the crank, I put it backwards and it caused the stator to grind and i miss diagnosed it as a piston wrist pin cir-clip failure, as i had trouble with one of the clips (replaced it and seated it correctly the 2nd assembly)🫠 i am not a good mechanic.

Initial tuning and thoughts?

It is torquey, very smooth power, and lots of torque in the mid range, even with light throttle you can feel the difference. still working on tweaking the tune with the aracer but so far its running very nice. The bike now pulls hills well in excess of the posted speed limits even on the crazy grades we have around here (17% in some spots) so with that I am very pleased. I did hope for a bit more top end performance, (65-70mph) still around 62ish mph and somewhat flat initially.. working on dialing in the tune.. may be limited with the stock throttle body/intake pipe anyhow.

Will be changing the oil cooler set up with a set of oil lines that have banjo bolt ends pre installed (chepo amazon) to plumb the cooler into the block (if they fit), saw a max temp of 217f with current configuration of valve cover port/oil lines. The valve cover port is pretty annoying to work with, how the allen head bolts are recessed into the cover and theres not much room with the crash bar in the way if service, valve check is needed.

The mod bug is a slippery slope especially with having the aracer, any part or engine upgrade can be tuned in so easily, makes me want a 4valve head… but as it stands I'm happy with it. The “character” of the bike is certainly not ruined by the extra power, just makes everything better.

Ill put together some video soon

Awesome job! Would love to hear more about the A-racer and bung install! Was it pretty straight forward? I'm currently running a pretty similar build myself minus the A-racer (chose to go the Efie route set at 250mv). I saw a video of a guy (Ozarks Garage) on YouTube where he removed the sparkplug and used a scope to get a visual on the internal cumbustion chamber and the top of the piston. I did the same and can see quite a bit of carbon build up on top of the piston. Bike runs great but still a little concerning. I'm thinking the Aracer is the next step for me as well.
Congrats again on the build! Keep us updated for sure! These bikes are almost as fun to work and tinker on as they are to ride!

 

[FizzBuzz3000]

I salute you for your efforts. It's good that someone has documented their journey into modding the JA65 trails for others to learn off of. Meanwhile I'm going back to (mostly) stock since I'm prepping my bike to do some wild camping/trail riding this summer.

Godspeed.

 

[johnny125]

Awesome job! Would love to hear more about the A-racer and bung install! Was it pretty straight forward? I'm currently running a pretty similar build myself minus the A-racer (chose to go the Efie route set at 250mv). I saw a video of a guy (Ozarks Garage) on YouTube where he removed the sparkplug and used a scope to get a visual on the internal cumbustion chamber and the top of the piston. I did the same and can see quite a bit of carbon build up on top of the piston. Bike runs great but still a little concerning. I'm thinking the Aracer is the next step for me as well.
Congrats again on the build! Keep us updated for sure! These bikes are almost as fun to work and tinker on as they are to ride!

The Aracer ecm was super easy to install, literally just unplug the factory ecm and plug in the Aracer, it pulls power and ground etc from the factory connection, theres no wiring of anything, With the af2 it pulls power from the Aracer ecm via the splitter cable that is an optional and required accessory to the setup.. from there it runs a bluetooth feed from the O2 sensor back to the Aracer to make all of the fuel adjustments.

With regards to the O2 sensor, you will need a 18mm exhaust bung welded into the exhaust at around 5 to 8 inches away from the exhaust port, I had a fab shop do this for me but it would be a very basic welding job if you have a welder (my welder happens to be in a trailer on the top of a mountain in Idaho) Another option for exhaust is hotlap, https://www.hotlap-japan.com/ they have an option at checkout to add an exhaust bung to their exhaust, I would have gone this route and skipped the Yoshimura, I like the OEM look of the hotlap better and its substantially less expensive than paying for a shop to weld the bung.. labor rate is crazy.

I am really pleased with the Aracer in general, its supper impressive how fast you can make changes to the settings and the autotune basically insures it runs great without having to do anything. I have a quadlock phone mount on my handle bar, and with the Aracer app run the display that shows, tach, afr, engine temp, gps speed, its really nice to have and looks clean.