Just ordered the 90cc bbbk, what else?

[ritous1]

Hello again fellow scootdawgs. Still new here and to scooters, but I'll be jumping into the deep end of the pool pretty soon. Got a 2012 tao tao atm50a1 that I now love, but it definitely lacks what it takes to deal with all the hills here in Tallahassee. I'm the tinkering type so I'm excited about the project of maxing this thing out. Just want the more experienced of you to look over my list and make sure I've got all my bases covered.

Parts already ordered: all by Naraku

52.4mm (90cc) bbk with race head (nk100.52)
24mm carb (nk200.06)
intake manifold spacer (nk200.04)
24mm intake manifold (generic)
hd crankshaft (nk100.81)
racing camshaft (nk500.02r)
racing fan (nk800.11)

also have an mrp exhaust here already

Parts I'll be ordering next:

rocker arm assembly to convert from 69mm to 64mm valves
new valve cover to delete PAIR system
crankcase ventilation system/oil catch can
free flow air filter

Debating on an upgear kit, but I'll probably wait till I get it built and see how she runs before doing that.
After the wallet heals a bit, Im considering the Naraku racing variator kit (nk900.21), clutch, clutch bell, and vs belt. The racing variator kit is supposedly pretuned for the 51mm bbk (6.3g rollers and 1000rpm spring) so should work pretty well with the 52.4mm. I kind of thought they would've gone with a higher rpm spring, but I'm no expert.

Anyways, any suggestions?

[teddy554]

yeah nice set-up always wanted some one to try the naruku 52.4 kit out, and see how it does, if it does good by you i might buy me a 4t and start a new project like yours. I like the naruku brand and they build some nice stuff for the 4t and some for the 2t i have the naruke 2t trans kit and it did well but the rollers that came with mine were to heavy and the clutch spring needed to be stiffen up it wasnt a ideal set straight out the box but could be different for the 4t but with that much added power and performance i would definitely up gear but smart on waiting to see what your factory gears can do first

[millsc]

Should be quite speedy i have a similiar set up and i couldn't be more pleased, post after you get it all installed i'm sure results will be awesome if all goes well with the install

[ritous1]

millsc, did you install the crank already?

[millsc]

Yes crank is installed

[ritous1]

any tips

[skuttadawg]

You may need an extra base gasket compression can be too high with a BBK . I would get a new belt too since a BBK has more power than the 49cc . With a larger engine you may want to tune the CVT with lighter or heavier weights . Dr Pulley sliders work better than generic rollers .

An exhaust upgrade will help too and will require rejetting

[ritous1]

Yeah, screw them! I got the scooter for free so it makes spending money on toys a lot easier to swallow.

[kyle401]

Yea this build sounds very cool. I might do this with my velocity 50 that is in need of a new crank. Good luck to you!

[millsc]

Use two base gaskets i did works great and take your time

[ritous1]

definitely plan to squish test the valve/piston clearance with clay before deciding on shimming or not. The piston has really large reliefs so it seems Naraku definitely gave it some consideration, just not sure if they took into account the extra lift with the racing cam.

[ritous1]

ordered the rest of the small stuff today! No cvt parts yet.

[millsc]

I could of used one gasket but probably would of had to kickstart it everytime if my battery is slightly low it won't crank with the electric start even with two gaskets

[ritous1]

good to know. So i may need to add a battery with a higher amperage rating and/or a high torque starter. Say the starter for $50 here;
thescooterdoc.ecrater.com/p/14876468/high-torque-starter

[millsc]

Get the starter or keep your battery charged

[teddy554]

Who know naruku might have a thick base gasket then the cheaper kits? Plus the head has a larger combustion area and valves which might help also but either way compression will be higher then stock

[ritous1]

not much info given on Naraku's site or any of the U.S. websites I found, but I did come across a European site where Naraku bragged about the set having perfect compression and squish clearance. So the decision to shim should be gauged both by measured piston/valve clearance as well as the results of a compression test. Gotcha

[skuttadawg]

www.scootershack.co.uk/threads/guide-why-scooters-dont-go-90-100mph.20337/

[kyle401]

Millsc, I only used one base gasket on my velocity when I put the kit on. I have to kick start it because of the high compression. Does two base gaskets help with the high compression?

[millsc]

yes the extra gasket lowered the compression and i can use the electric start and its better for the crank bearings and doesn't affect the power too much

[ritous1]

Update: Pulled an all nighter last night and got everything installed. Went pretty smoothly, only two issues: the Naraku crank had the wrong oil pump drive gear for my 1p39qmb. It comes with a 22 tooth, stock is 16. I pulled the one from my stock crank and swapped it on with my handy harbor freight puller set. The throttle cable was too short for the butterfly to close all the way on the carb. Had to flip the bracket where the cable attaches upside down and bend it a little to get the extra half inch I needed. She was also tough to get started. Tried Larry's trick with using both the push and kick together to no avail. Ran the battery down pretty good after several attempts. After putting in on the charger for a while she finally fired up! Now after a few test drives, the push starts works better than it did stock! The scooter is now giving me exactly what I wanted. I can easily merge with traffic, hills are no problem, and cruising at 40-45 is cake.
I swear I got lucky with the tuning. My naraku carb is still on back order at racingplanetusa so I found a brand new mod cycles mmg carb for $19 shipped on ebay. All i did was change the main jet to 102 instead the 107 that was supplied, left the 35 pilot, and set the idle speed and it runs/idles perfect. Maybe I should cancel the Naraku carb and put that cash into the bone stock cvt.
I was a little concerned about potential valve/piston clearance using the racing cam, but none at all using one base gasket. I did squish test before final assembly. The mrp exhaust is LOUD. Dont really like that, but it ended up being a perfect match to the exhaust port diameter on the naraku head (about 19mm). Exhaust sounds better(deeper) with the silencer removed but of course it's even louder. So much for not drawing attention to myself.

[millsc]

awesome glad it went well, I love the loud exhaust one of my favorite parts.

[ritous1]

thx millsc. Checked the plug a little while ago and it's white. Wouldn't have expected that, guess I wasn't so lucky after all.

[millsc]

I forget to tell you earlier i checked mine today too its white also. i put in the stock 107, may sound big but it needed it. And its even faster.

[ritous1]

Thats good news. Kind of funny, I spent the good part of a day calling and driving to local scooter/moto shops trying to find that 102. No one would just sell me the part I was asking for, they all wanted to know what scooter it was for, what carb it had on it, etc, etc. Of course, once I gave them that info it led to a lecture about how it wouldn't work and both the jet and carb were way too big.

[millsc]

They can think its too big, but when you zoom past them at 50+ mph, they may change their mind.