Gpx125 bore kit 146cc

[Motovert17]

Has any1 put a 146 bore kit on the Logan/gpx125? Is or would be worth it? And would it be competitive with 150, 160cc engines

 

[The_GDFP]

Not since yesterday Without a big-valve head, you'll get thumped, but the lighter weight, along with high squeeze piston and a worked head, is competitive. This one's a BV 146, e-start, for a CT70. Getting boxed and sent out today.

 

[Motovert17]

 

 
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China Pit Bikes/China Performance/TB 160 Bore Kit - 124-140-146cc Engines China Pit Bikes/China Pe

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160cc (60mm) Bore Kit for Chinese 124/140cc Engines:

All aluminum ceramic plated 60mm skirtless cylinder
High compression 60mm piston with rings, pin, & clips
Head gasket kit
This will make a huge difference in performance over your stock setup or a nice upgrade to our previous 146 bore kit. Additionally, it is a very quick and easy upgrade as it does not require case boring. The kit includes an all aluminum ceramic plated 60mm skirtless cylinder which will increase your engine displacement to 160cc. This cylinder is lighter than a steel sleeved aluminum cylinder, reduces friction (increasing power), improves sealing, and provides better heat transfer (runs and cools down quicker). Also included is a very light weight high revving piston and a head gasket kit.

Important Note: This kit will only work on Chinese 124/140/146cc engines with a 57mm stroke and a 13mm piston wrist pin. Common models are Pitster/GPX and Thumpstar but there are so many Chinese brands/models that you absolutely need to know your stroke and piston wrist pin size. Many vendors also call 120cc engines "124" so its important you get the actual specifications from your engine vendor or measure yourself. Unfortunately, we are unable to tell you what you have based on a brand name as there are so many unknown Chinese brands. This kit is also recommended for use only with big valve heads such as the common Lifan head with 27/23mm valves. We also will have a new Race Head for this kit sometime in October 08.

Installation Notes: Its very important that you use Hondabond (or similar quality) sealer on the head gasket. Also, don't use the original o-rings between the head and cylinder (not needed) but do use the large o-ring at the bottom of the cylinder between the cylinder and the engine case at the oil return.

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product code: TBW9037

Price: $260



 

 



Does this have a big valve head?

 

[sean01]

your talking about this engine yeah? New 2010 GPX 125CC RACE ENGINE, HIGH COMP PISTON, RACE CAM. One of the quickest 125cc Engine on the Market | Mini Bikes | Pitbikes | Dirt Bike Parts & Accessories | DHZ Mini Moto

if so then the bore kit above may not be compatible.. the kit is to suit a 57mm stroke setup but you only have 54.5mm stroke.
you would have to check piston pin size and barrel height. then you would need to check how far up the bore the piston will go.. but to do all this it would require you to purchase the kit first..

it would be easier to buy a kit from akunar, just give him the specs of your engine.. barrel height and pin size and away you go.. the kit would cost you approx $125usd..

and as terry has mentioned, be sure to check the valve sizes as small valves dont work to good with big bores..

 

[Motovert17]

Yes that engine, would the crower gpx g2 cam fit in this engine?

 

[The_GDFP]

Ah, crap in a cruller. I forgot aboot the "New" parts-bin 125cc engine. You should already have a 27/23 head, from the old Zonger 125, disguised by the screw-in valve caps compared to Lifan/YX versions. Early ones had a big dip in the intake floor that needs filled. Not sure if the fault still exists. Easy to do while porting, though. If contacting Ranuka, get a set of his 28/24 valves and use just the intake. Back-cut the valves, do a decent 3-angle seat job. I dunno the pin size on yours, but the TB 57mm kits are now available with a 13 or 14mm pin for the big-valve head. 14mm unit is new, lighter than most choices and slick as. Kit with jug, slug, gaskets is pretty reasonable in the States ($139), not much worse in AU, prolly. The YX150 DT crank one of the forum lads was parting (very slight mod needed) and the 57mm kit will go from 139cc to 153cc. G2 grind is a little soft for the bigger engines(except the 236 degree CRF70 grind). Look at a Z40 or some thing from Akunar, or best, a Tak R15 or 20.
http://www.x386.net/TTR/tech/cam2.html
Check ignition timing. 28 degrees or so is all you need/want, as long as you get the quench tight. Degree what ever cam you choose, as the Chinese Q-C is all over the map on locating the crank sprocket.
That's every thing I know. In the whole world.