Rolling Wrench
90cc Monster Big Bore Kit (QMB139)
90cc Monster Big Bore Kit (QMB139)
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This is our more affordable (vs ProBld(now NCY)) monster big bore kit! If you are looking for the largest kit on the market, this is it! It's a true 90cc. Don't let the $30 Ebay and Amazon 100cc kits fool you.
This kit will convert your 49cc Chinese scooter, Kymco Agility or anything with the QMB139 engine to 90cc. The 90cc is as large as you can go with this engine. This kit is great quality . You won't find a nicer big bore kit. Remember you get what you pay for! The stock cylinder head will not fit. The cylinder head supplied in this kit is complete with larger valves and bigger ports, making it a performance head.
ADD 64mm ROCKERS TO YOUR ORDER IF YOU ARE NOT ADDING A CAM: CLICK HERE
Big Valves and Ports:
Intake Valve: 21mm (Stock is 18.5mm)
Intake Port: 20.5mm (Stock is 18.5mm)
Exhaust valve: 22mm (Stock is 16mm)
Exhaust port: 19mm (Stock is 17mm)
This kit includes:
Piston
Piston Rings (not pre installed)
Cylinder
Performance Cylinder Head (Complete with big valves)
Complete rocker box assembly (if you choose)
Performance cam shaft (if you choose)
FREE STEP BY STEP INSTALL VIDEO!
BECAUSE THIS IS A DOMED STYLE PISTON, BE SURE YOU HAVE A HEALTHY BATTERY. THIS IS A HIGH COMPRESSION KIT.
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I haven't installed it yet because I use mine for daily transportation so I have been waiting to get a vehicle to borrow from a family member so I can take my time and not miss work. Happy to say that next week I have a car and I can create my monster! While waiting I have also bought the big bore pwk carburetor from you guys as well the crankcase ventilation dipstick the how to video I also purchased a cold air intake tube from nibbi which I have to say if you guys sold something like that I don't care what it costs I would be buying it from you. So I plan on emailing rolling wrench with all sorts of pictures of what it looks like and how it's doing. I've always loved anything with wheels in a motor I just got my first scooter about 9 months ago but didn't think much about customization or performance until I found rolling wrench online. I'm sure one day I'll have myself a ice bear (can't explain it but I love those) but until then I'm totally customizing a 2018 wolf rx50. I'm grateful for you guys because if all there was was a bored kits on ebay I don't think I ever would have got into creating my own monster with my 139 qmb!
Unfortunately, my valves came opened creating a loss of compression and not being able to start I had to add assembly oil to the valve and free them then it was fine
Wrong items were shipped
Shipped fast, and secure. I would say, it looks like my order was a returned order at somepoint. Partially cut open gasket baggies, G clip baggie was cut open, luckily I found the missing clip. Looks nicely machined, and quality made.