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Jialing(GPX) valve sizes and other measurements

12K views 72 replies 13 participants last post by  perseverance8  
#1 ·
It would be nice if we could have a thread w/ all the info we can get on the Jialing motors. So, whatever good info you have post it here. I am planning on doing a build on mine and I am undecide on exactly what way I want to go w/ it. I am thinking 54mm hc piston, takegawa cam, porting, and 24mm carb. I will of course dyno after I am done and post the results here. Anyone who has done any mods on these engines please post up whatever you have and any downfalls the engine may have. This thread should only be for us who want to get the most out of our Jialing motors so all you hardcore Honda guys don't come in here filling the thread w/ a bunch of nonsense and BS.



What are the valve sizes on the GPX(Jialing) motors?

I know the bore is 52.4mm and the stroke is 57mm.

The wrist pin size is 13mm.

Anyone know the cylinder height?

It can be safely bored to 54mm to give you 131cc and you can get those pistons from Tbolt.

It comes w/ a 22mm carb.

1 down 4 up tranny and now an all up tranny is available.

5 plate primary mounted clutch. Starts in any gear.
 
#27 ·
the dratv lifan cylinder and big valve head go right on, no problems. you can take the cylinder to 56mm and get the ikt 56mm, 13mm pin as well from them

Subject: 124cc engines /big bore



Could you pm me the parts numbers for these parts when you get the time and are you talking about the stock GPX Cylinder to 56mm.....looked to me like the stud holes would interfear....? Im just starting to get into these GPX motors So Any Info is GREATLY appretiated



Thanks Man
 
#33 ·
rkfinch23 said:
you should be able too..... the gpx stock head does have a double dome,, also makes for problems installing oversized valves as well.... here is my new head this one is the lifan big valve with oversized 29/25mm valves. we'll see


Where did you get that head? Did it come w/ those big valves in it or did you install them yourself? I looked on the dratv site and couldn't find it. I couldn't find on w/ valves that big anywhere up there. If you did get it from them what is the part #?
 
#35 ·
melloyello said:
Where did you get that head? Did it come w/ those big valves in it or did you install them yourself? I looked on the dratv site and couldn't find it. I couldn't find on w/ valves that big anywhere up there. If you did get it from them what is the part #?




slow down.... heres a link to the head at dratv, it comes with 27/23 valves, but it's like having 25/22 valves because of how they put them in the seat. we put the 29/25mm valves in it. we also have the big head with 30/25mm valves in it, all Ti. the 29mm valve in the pictured head is Ti as well. http://dratv.com/12mohewi23an.html

http://dratv.com/127852cy.html
 
#39 ·
I have been speaking with sombody that is running a Jailing - Xtreme with 54mm KLX/DRZ 110 Piston, Crower Power G2 Cam (No Headwork, Just Cam), & 26mm Carb. He says that this combo is close to the power produced by a daytona 119 (DOHC) kit!!! He has not dynoed this combo but he is estimating at least slightly over 11hp possibly more, he says it is very torquey. This is the setup im thinkin of using, but im goin to do more research on what piston I should use.
 
#40 ·
Im Not Knocking you but anyone can say this guy says this and that....But rkfinch23 has these motors and has Tried the combinations hes Listed.



By the End of this comming week I will tell you what I think of the 131cc kit Im Putting together:



Parts:

TB 54mm Piston

Ported Stock head

Takegawa Cam

Inner rotor & Machined Flywheel and Oil Sling

22mm, 24mm & 26mm Carbs

17t Sproket



If this Makes Crazy Power I have access to a Motorcycle Dyno but wont waste my time and Money if its not Crazy. I have Honda Stroker Motors Here to Compare it to. the Motor Id Like to Dyno is the Current Motor rkfinch23 has ready to go.......



Later
 
#43 ·
bulkytits said:
Roots type blower should be out in a month or so.


I am so all over that! Nothing in the rules about unnatural aspiration... in fact I was challenged to bring a turbo/supercharged machine to the track...



Any info you've got I'd be interested, particularly if this is something built to operate in draw through mode.
 
#44 ·
yes it will be draw thru, im in the process of drawing up the specs right now. Its going to be machined out of aluminum, with a aluminum/delrin rotors. and its going to run off of the crank with an autotensioner on the belt. full ceramic bearings in the blower. bolt on to head with the carb coming out of the side of it, an intercooler kit will also be available.
 
#45 ·
It would be cheaper and easier just to run the Aisin unit with a large pully in the same configuration and they are inexpensive. It's been done overseas hundreds of times with good results if you keep the boost in check.
 

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#46 ·
I do agree with you about heresay, I will say that I have a hard time believing that (jialing) engine can produce the amount of peak HP (with those mods) as the daytona 119, but I will belive that its performance feels like the daytona 119 because the 119 produces its power at a higher rpm (with narrower power band, but does rev higher, much higher) and the modded jialing comes on earlier and possibly has a wider power band with less top end than the 119, so what I am saying is that i can concieve that the jailing can "feel like" the 119 even actually perform close to that of the 119 without even producing the high dyno HP #'s that the 119 produces, dyno #'s are VERY DECEPTIVE!!! Ill say that again DYNO #'s ARE VERY DECEPTIVE!!! and this is true in any form of motorsports, you can have an engine that peaks out significanly higher than another but still have greater performance out of the lower peak HP engine! most people do not know how to interperet dyno #'s and in my opinion dynos dont really show performance all they do is give HP #'s to make products sell and mainly are a tool for engine tuners.
 
#49 ·
Yeah its not difficult to interpret dyno results, but many if not most people just read the peak HP & Torque numbers and simply compare those two #'s and say that the higher #'s equal better performance and that is simply not true, you can have high HP #'s that are not being produced in the usable power range or are very narrow and peaky but you can have lower HP #'s sometimes significanly lower and have better performance due to where the power is and how long it lasts in the rpm range, that is why I dont use a dyno to tell me how much performance is being produced, I would use it simply as a tool to show me what is happening (because a butt-o-meter isnt that accurate in determining actual #'s, they are very easy to trick while a dyno does not lie as long as you are using it properly) and what I can do to improve my performance. I have seen many engines produce very desirable #'s but not perform as well as an engine with lower #'s, manufacturers like to use #'s all the time and even back them with legit dyno sheets but most of their cusomers do not see those #'s for instance the kitaco 124se kit claimed to produce 17hp (which it can) (in fact ive seen dyno sheets of this kit pumping nearly 18hp!) but most will only see between 13 & 14 HP!!!!! sometimes even as low as around 12 HP on an 'OK' setup. generally most need power in the low and mid range (it is actually pretty easy to get large peak #'s but can be difficult to get good usable power which equals performance) all the approximate #'s are given to reflect @ wheel HP.