Wow! Great Mod. 90cc Naraku Big Bore Kit on a Maddog 50cc 139QMB GY6. Way Faster

[@JasonWilson-b9s]

That is the best setup the downfall is they don't sell a good CVT you have to make it

[@xaviero3679]

I appreciate all of your content so much.

[@edwinmendija8087]

Just finished assembling a gy6 50cc engine with the 52.4mm Naraku BBK, A9 cam, and 44mm HOCA stroker crankshaft. Haven't started it yet but itching to do it soon when I finish building my test bench and fabricating another exhaust system. I have a 24mm and 26mm NIBBI carbs that I'll be testing as well. I have messed around with variators and clutch springs but ended utilizing all the stock stuff. Gearing change is where I think I could really improve performance but I'm a wait on that also. Great video!

[@GhettoWrench]

I just ordered the gear kit. I got the "least" amount of gear upness I could find. I don't think it work... but gotta try it. When I get it I will make a video with the results. So wait for that before you buy a kit.

[@edwinmendija8087]

@@GhettoWrench following!

[@thephranc]

Now you have the power to install taller drive gears

[@djilu9916]

i slapped a bbk, and left it there just to get up hills better lol

[@GhettoWrench]

@@djilu9916 that makes a lot of sense

[@GhettoWrench]

For sure

[@mrpartridge8765]

I had an issue with the valves on the naraku head. The stems are soft and mushroom over. It would never hold its valve lash. Thankfully I had a glixal head that had the same size valves and I'm running those valves in the naraku head. To prevent the stem from mushrooming agains I got 2 5mm valve lash caps from EC carburetors. Hopefully you don't have that problem just keep an eye on the valve lash.

[@GhettoWrench]

Great to know. Thanks. Did you grind the Valves smooth to not trash the guides before pulling them out? I had no idea glixel made valves that size. Did it require anything more than a simple lapping to make them work?

[@mrpartridge8765]

@@GhettoWrench I used a Dremel to grind them down as to not ruin the guides. The glixal 52.4mm head has the same size valves all I did was lap them and they have been going for about 1000 km without issues.

[@evidentloss]

I have the same exact kit and have been chasing down what's causing my valve lash to grow every few miles. I get about 5-10 miles before it's so bad it loses compression and dies. Everything has been replaced except the BBK and it's components. I bet I'm having the exact same issue. I'll be ordering the Glixal 52mm head later today and the swapping the valves out to see. Was the damage (mushrooming) on your valve stems obvious?

[@jeffkrauss5582]

I got that same bbk to 57 mph on a taotao racer with 21mm carb,final drive setup,port and polished head and a nyc 150cc exhaust

[@Jacrazzz]

WOW

[@GhettoWrench]

Nice!

[@blackdownchannel2227]

How you got it to 57 mph

[@hesperidesbell4643]

For the 72cc bbk that I got recently, i plan to use a 16/42 tooth final drive gear. I’m sure there’s a good set for a 90

[@GhettoWrench]

Let me know how it works. I may be wanting to try one though. That would prob work fine for a 90 also.

[@kooboos89]

I've got Airsal 81.3cc on my Romet 777 and custom CVT on Polini Variator, clutch spring 4.1mm and bell and also Naraku cnc alley, spring beared sleeve + Malossi yellow slide and I've got 90km/h and 128 downhill. Jasil crank shaft and 19mm cvk carburator. Now chanching to 24mm pwk, will let you know.

[@GhettoWrench]

@kooboos89 that thing sounds sweet. For sure. Will be curious to see that big PWK on there. I think you will gain some more speed.

[@skynetdds]

I bought a completely new WM 139QMB 80cc engine and also a Naraku v.2 90cc head plus cylinder kit. At first I was able to install only the cylinder, but I couldn't install the head because the rocker arm didn't fit, about 1 cm to the valves, it was impossible to adjust. When I installed the 90cc cylinder and 72mm head, everything was great. Then I installed the Naraku 90cc head and everything disappeared!!! The scooter barely starts (like a train), accelerates weakly and almost doesn't accelerate and wants to stop. I left the same carburetor, but even when I installed a larger 24mm carburetor, nothing much changed! What should I do???

[@GhettoWrench]

@skynetdds that Naraku head has 64mm valves and needs the 64mm rocker arms. Did you get those?

[@Br0ken]

What are you using for a gauge cluster/monitor? I got my icebear maddog pmz50-19 and at 188 miles on the odometer the speedometer cable snapped into 3 pieces. I want to know the rpm and all the normal gauges but am unsure what to buy.

[@GhettoWrench]

@Br0ken I have zero gauges... like a dirtbike. LOL. I put one of those cheap square RPM gauges you see on ebay etc that has the wire that wraps around the spark plug wire. I just put it on when testing and velcro it to the tank

[@markdavis29]

Have you ever run the Naraku 72cc kit? Getting my Maddog 50 delivered this week and trying to decide between the 72 & 90 kits. What other up grades would you advise? Thanks in advanced. ✌🏻

[@kooboos89]

There's no replacement for displacement.

[@Slane583]

The engine in my Vitacci Clash is a Lifan version of the standard GY6 150. So the engine model serial number is different than normal. It's also being sold as a 200cc model scooter (which it isn't actually 200cc.) so the engine is technically a big bore stock since it's a 170. The actual engine displacement on the dealers site who sold it says it's a 168. Sometime down the line I can always get a 190 kit or something for it to bring it closer to its' sticker size. That would be fun. :)

[@GhettoWrench]

The only issue would be if the cylinder sleeve fits in the case. On the regular chinese GY6 I think anything 180cc and over is too big and you have to "bore" the case. I have heard guys just do it with a drimmel as it does not have to be precision round.

[@Slane583]

@@GhettoWrench I'm sure it's probably going to be the same for mine. I think 170cc is within the limits of what stock engine cases can hold before they need to be opened up more. GY6 Racing has a 204cc big bore kit that includes everything needed including the case boring tool. But it's $830 and since my scoot runs and drives just fine for now it's not needed. Besides, I have two vintage big bore 2-stroke dirt bikes that need to be worked on first instead of tearing apart something that already runs and drives. :)

[@samupk]

Did you put your oem rocker assembly on that Naraku head? The rockers on those 69mm oem valves vs Naraku 64mm valves don't match.

[@GhettoWrench]

@samupk No I used 64mm rockers. You can either use the 64mm rocker box assembly they sell or just buy the 2 64mm rockers and install them on your OEM rocker box. I tried both and for the price I would just buy the whole assembly because the individual rockers did not fit on the OEM shafts perfectly. They felt too tight.

[@samupk]

@@GhettoWrench Yeah, it's a pity that 69mm valve head has much more tuning and porting potential than the 64mm, but the available valve diameters on the 69mm are crap.

[@hammah_3928]

Now that's power 🙌🤘👍

[@jacken9343]

The naraku 52.4mm kit has a lil bit more then most 23/20 heads. Slightly bigger ports vs Ssp-g and Ncy. As well as a niksil coated oiston and cast iron liner. Years ago naraku had a race cam for the 139qmb but its long gone. Just the Ssp-g, ncy and bullock cam. I would be interested on the weight of the naraku piston vs a Ssp-g or Ncy 52mm. And what the compression comes out to on the naraku kit

[@GhettoWrench]

Thats interesting. Thanks. I could do a compression check. Can't believe I forgot to do a before and after test as I usually do.

[@Cpl_Spoons]

Would you recommend a Icebear from all of your experience? Just looking for something to cruise around town on

[@GhettoWrench]

Tough call. I just like the looks. For cruising around town, prob something more like a traditional moped or vespa would work better. They are all the same engine and cheap chinese throttles and carbs etc.. so unless you go japanese or real vespa then it is going to be crap quality. If you want cool looks then the maddog is good. They just don't have luggage compartments and helmet locks and other amenities the typical mopeds have.

[@Cpl_Spoons]

@@GhettoWrench Thank you! I’m really torn between a ruckus and the maddog, but I know if I get a ruckus I’m just gonna end up making it look like the maddog anyways. Just trying to decide on which route, but negative reviews on the maddogs have me a bit torn.

[@GhettoWrench]

@issachutchison8239 people that are used to working on and modifying stuff like maddogs. People that are not hate them. And for a good reason because they are just not put together good. Now the frame and engine are super solid reliable components. The GY6 is one of the most reliable engines in the world. If you make your ruckus like a maddig you will end up with a Honda frame and GY6 engine and everything else aftermarket that is made in china. So the maddog would be best option for customizing. Way less to do. Already stretched. Already has fat tires. Already GY6. All you have to do is take off all the crap that is gonna rattle off anyway. My videos from buying my 150 and 50 new show all that. Pretty simple.

[@SpACeCruizeR2o3]

Will this work on the minimax 50 was thinking bout getting one just had my 125cc motor frame mount crack on me which do u think has stronger tubing the maddog or the minimax

[@GhettoWrench]

I have never even seen the minimax in real life. The maddog frame is pretty beefy tho. Look on the side of you engine under the CVT... there will be numbers. If it says 139QMB or 1P39QMB then it should fit. These motors are all the same.

[@lithiumbattery5577]

i saw that you have some cool rims, can you link to where i can buy some affordable rims?

[@GhettoWrench]

On the all white scoot? The rear is a stock gen 1 maddog rim that comes on the bike. The front is a stock gen 4 maddog rim off another bike I have. I had them both powder coated white. I'm gonna reply again with a video about rims. Rims get tough on these.

[@GhettoWrench]

2nd reply.... this video will also link you to how I did the front rim. And now you know why I had a spare gen 4 front rim. LOL kzbin.info/www/bejne/fJWndGeDoc2ll7csi=n6Ux5AEXVno_Bbbi

[@lithiumbattery5577]

Would be a really good help because finding rims are hell rn, and its even worse if ur not in the us

[@GhettoWrench]

@@lithiumbattery5577 I did the entire front on AliExpress. I think the rear can all be done there as well. Just have to know what hub spacing you need and want and the bolt pattern and size. That stretched back tire video will put you to sleep, but it covers all the numbers your need to start your search. Think Golf Cart wheels. LOL

[@lithiumbattery5577]

@@GhettoWrench i found some atv wheels with the same bolt pattern, but still thanks for commenting back i really appreciate it man

[@JasonWilson-b9s]

My 52 naraku and a 51naraku head they do not sell it no more it was $250 4 year ago but it turned 12: 5 on the tech with no base gasket no head gasket so I put Tower gears in it 17-41 he would do 57 at 9000 with a 21 flat slide

[@GhettoWrench]

@@JasonWilson-b9s damn. Wish they made that still

[@samuelclopper7998]

I have tech my big board at twelve thousand and held it there for 2 minutes

[@GhettoWrench]

@samuelclopper7998 good to know. Thanks. Didn't know how high they could go.

[@djilu9916]

whats the max rpm these things are rated at?

[@GhettoWrench]

I never really figured it out. I can feel valve float before 10k on the stock ones, but I ran 11k with stiffer springs. Motor seemed smooth. Not real sure where they come apart. LOL

[@GhettoWrench]

I have seen power curves and they seem to peak around 8500 to 9000. But that all depends on when the guy on the dyno backs off or when the Valves float

[@SuperPooh1961]

I think the Space Ghost is going to beat the MadMax top speed. Could be the fastest... Ghetto Wrench strikes again...

[@GhettoWrench]

Idk. I have to find another 5mph somewhere.... not looking hopeful. I may be building my own variator again. That homade one I did was 🔥

[@bnorby213]

Shoulda got the 150 in the first place lol

[@GhettoWrench]

LOL. I have two 150s. I wanted a 50.

[@bnorby213]

@@GhettoWrench it looks awesome!! Nice work

[@GhettoWrench]

@bnorby213 thanks. The 50s are fun. You can try and go as fast as you want and never get a speeding ticket. LOL. I got it for the wife as you don't need a motorcycle endorsement for a 50 in florida. So figured I would at least make it rideable around town. We just use them to cruise the beach roads and get around in city traffic if we go to Miami or something.

[@frednetherlands887]

Thank you again. Wish I could legally upgrade to a bigger cilinder :)

[@GhettoWrench]

Sometimes you gotta go outlaw.

[@frednetherlands887]

@@GhettoWrench in my country they will take you drivers license for something like this!. My legal max is 50cc and max 45km/h...they will sort of allow 50km/h as a margin but no faster for a scooter!

[@ThePitProductions]

​@@frednetherlands887 do a big bore and then just gear it to max out at your 50 limit. It will just get there a lot faster.

[@frednetherlands887]

@@ThePitProductions even that is against the law as it would exceed 50 cc! Life is not easy here ')

[@ThePitProductions]

@@frednetherlands887 I did understand that sir, My thought is, If your never speeding, it looks factory stock, and is not super loud. What would make them even look at the cc? Grind numbers on the jug and it would have to be "measured" I AM NOT ADVOCATING BREAKING ANY LAWS. Well not my laws. FINE good sir. WE will look into go fast without cc increase.

[@samuelclopper7998]

Mine topped out at 85mph 100cc 50cc Bottom end

[@GhettoWrench]

@samuelclopper7998 need a video of that one. It would go viral. That's the fastest 50 in the world.

[@samuelclopper7998]

@@GhettoWrench Put 2000 RPM Springs on it. Amazon 100. C c c board kit And spray a little on a true stuff And mine runs on cam 2. Fifteen dollars a gallon

[@samuelclopper7998]

Twenty gram weights in the clutch

[@evidentloss]

AHAHAHAHAHAHAHA!!

[@evidentloss]

@@samuelclopper7998That doesn't even make sense. Heavier weights don't mean more speed if you are already at the edge of the variator. It just kills acceleration, and delays shifting at that point. Why are all your comments lies? Like for real, why lie? What do you gain from that?