Naraku 70cc bbk honest opinion?

[proy]

So im looking to start a bbk build on a horizontal Minarelli and am considering a Naraku 70cc kit.

The first build on the motor I wanna keep some what budget minded as far as bbk, pipe and carb.

Whats your honest oppinion on the kit. Any experience and information on this or other kits would be appreciated. Im fairly green as far as 2 sttoke builds go but have a decent amount of knowladge on sport and race 4 stroke builds.

Im currently researching other build threads on here and possible build combinations I might try. Any wisdom from a seasoned 2 stoke builder or links to good completed build threads would be awesome.

[Zino]

Here is a thread that discusses this Kit Just recently and we have a member 2strokd putting one on.
49ccscoot.proboards.com/thread/26643/opinions-on-kit

The Parts for Scooter Guys are very good vendors to work with

You are going the right direction for your first kit .
Cast Iron Sport BBK Kits are very reliable and are a big upgrade over stock.

I have 2 Yamaha Vinos Shortcase Minarelli Engine that have identical Builds .
Malossi Cast iron Sport Kit
Malossi Wild Lion Street exhaust
Malossi Variator
Stock Carb uppjetted

The Kit and Pipe
Are a easy match with overlapping powerbands
Both are Crank Friendly and push to just over 9k rpms .
The Lion is a Half Wave Street Exhaust so it looks like stock but has low down take off power and just a couple miles per hour top end .
The power band for the combo is very similar to stock engine porting so I initially did zero tuning to the Stock CVT and was very happy

Malossi Variator
To pick up a higher gear ratio and better shifting .
It added 2-3 mph over the pipe and Kit combo.

Carb 
Just Upjeted about 5% and raised the needle and reset the mixture and idle speed
The Sport Kits are Ok to Good running on stock carbs since the peak rpm and compression are a notch over stock

Both Vinos are spunky on takeoff and push 50 mph and If I want to wheelie them Easy enough.
Here is my vino thread
49ccscoot.proboards.com/thread/26756/yamaha-vinos-stealthy-build

Plenty of others builds to follow milder like this one to wilder .

[Zino]

2strokd highly reccomends the naraku kit for budget builds in his thread

[proy]

So I finnaly tore down the topend of the motor and here is what I found.

[proy]

Really not all too bad. Topend was definetly overheated at some point. The exhaust port was caked with carbon so I assume it had a major exhaust leak that might have caused a lean condition. The piston is pretty beat up and the cylinder has some minor scoring.

Not really a big deal since I was intending a bbk anyways.

The engine had a 40mm bore and a 10mm wristpin. The bottom end seams ok. I dont see any place where the skirt on the piston or jug broke and no missing lips from the ports so shrappnal in the bottom end is a low chance. The crank bearings seam smooth with no tight spots or any noticable play and no discoloring on the rod or rod bearing.

So far a basic parts list to start off with I have this.

Side cover
Front cvt pully
Starter
New stator/ ignition pickup.
Full rear break set
Tuned pipe (to be determined)
Sport 70cc bbk (still looking at options)
New carb
Drive belt
Motormount bushings
Fan shrowd/cooling shrowd
Reed block
Intake
Possible clutch rebuild.

The only questions I pose are.

Are there options to switch to bearings insted of motormount bushings? I will be building a custom frame and motormounts for the engine anyways.

Second. What are my options for a harness for the electrical. Like I said Its going into a custom frame so I can use anything that will be compatible.

Also what is the broken mount point shown in the last photo for. Just so i have an idea of what needs to be done.

[aeroxbud]

How many miles does the stock crank have on it?

Brent shows how to fit bearings in this video. It's quite a common modification.

[proy]

No idea. All I have is the motor. No idea how meany miles are on it. Judging by carbon build up and general dirt and grime on the motor id say over 3500 outside of that no idea.

[aeroxbud]

As long as there is no grinding of play in the bearings, it should be ok. The Naraku kit is just like a bigger version of the standard cylinder. So shouldn't put too much strain on it.

[proy]

The crank feels smooth and has no tight/rough spots in the full rotation. At first I though it was shot but it turned out to be the starter setup moving since there's no front pully.

I plan on doing a full race/highend sport bbk with a new stoker crank down the line so ill refresh the crank eventually.

[Zino]

May 25, 2020 20:08:59 GMT -5 proy said:

The crank feels smooth and has no tight/rough spots in the full rotation. At first I though it was shot but it turned out to be the starter setup moving since there's no front pully.

I plan on doing a full race/highend sport bbk with a new stoker crank down the line so ill refresh the crank eventually.

I like where your Head is at Budget for now but if it Breaks I am going full on Race mode

[proy]

I have been waiting to come appon a 2 stroke in my area for a while now. I have had 4 strokes that I had built up and sold but I have no real experience in 2 stroke builds so I wanna take it slow and learn what I can along the way.

I had a honda aero 80 about a year ago but with the lack of parts and knowladge I ended up selling it.

Realistically im probubly not going to get near stroker cranks until I can afford or come across another motor. Im more interested in keeping this one alive for as long as possible and getting my feet wet.

[Zino]

These 2 strokes are a blast to build up .
Keep us informed along the way with a build thread so we can keep helping you out .

Posting up a sig line of your mods over stock is ideal

To post your signature line
click on "profile" at the top of the screen it is under the S in 49ccScoot
Then on the next screen in the right corner click on "edit profile"
Next screen click on "personal"
scroll down to "signature "
and post your mods and save

[proy]

May 27, 2020 7:25:16 GMT -5 Zino said:

These 2 strokes are a blast to build up .
Keep us informed along the way with a build thread so we can keep helping you out .

Posting up a sig line of your mods over stock is ideal

To post your signature line
click on "profile" at the top of the screen it is under the S in 49ccScoot
Then on the next screen in the right corner click on "edit profile"
Next screen click on "personal"
scroll down to "signature "
and post your mods and save

Ill deffinetly get too that once i get parts comeing in. Ill probubly start off by adding my current 139qmb setup.

[mrchilled85]

i have been using a naraku 70 kit for 2 days now on my bike just passed 68 miles now so started to open it up more and what can i tell you the standing start pull offs now takes off so good seems to make good power over all the rpm im still using a stock pipe and has reached 9300 rpm still with a bit more to go

as for brakeing it in all i did was let it run for 15mins at idle ( well in my case just over idle as need bigger idle jet )
let it cool off then went for a 30 mile ride only running it upto half throttle but try not to keep the throttle in one place let it get upto speed then back off the throttle a bit then back on

next ride i did was 30 miles again but this time upto 3/4 throttle off and on the throttle a lot and around town riding

since that 60 miles brake in i have been ride it like you stole it

done a compression test this morning and has a nice 191 psi
im using the stock 50cc head on the kit tho

[Zino]

9300 rpms sounds lie good porting for a sport build .
191 psi that is strong do you have a cht to monitor temps for that high compression.
The ride it like you stole it method is what i like also
It is so much easier to explain to my wife .
Just warm it up real good every day vary rpms and get on it from harder and harder over time .

Now that I say it like that It sounds like what I wish for every night since I got married .