Jialing 125 upgrades

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timeeh

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Mornin peepholes, it's time for a new piston and rings in my sisters Vert Expert 125, as it's smoking more than that tree at the back of the college oval. Anyway what i would like to know is;
1)Who stock replacement piston and rings? (besides motovert aus) and/or what are the piston dimensions?
2)Is there an upgraded jug and piston kit available without replacing the head? I have read about a 146 upgrade, but can't seem to find any in Aus or whether or not the head needs replacing if i go that way.
3)What is the difference between the Jialing and the GPX (some sites say there the same?) engine # is JH156FMI

Cheers boys and girls ;)
 

my67xr

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is it a 52.4mm bore, with 57mm stroke and a 13mm gudgeon ?

the 138's were really only 128cc, had a 54mm bore and a 54mm stroke



found this on PM,
DrAtv parts:
Lifan aluminum cylinder part #12112
You can go 56, probably 57.
Piston is IKT56mm part #100058

TBolt US sells them

and a few are recommending a Crower G2 camshaft too,
 
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zwebx

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Timeeh, you could get a cheaper piston from akunar or someone like that..
Could also ask for a bigbore kit.. and he could tell you what will fit (most likley restricted by skirt width and cases)

I think you would benifit from the higher comp piston.. for sure I also think if you are going to order from akunar get a high lift cam *he has alot of cam grinds and some strong valve springs available.


The reason i say akunar is because if you are going to do cam and piston etc the 125 probably isnt worth all the parts from tbolt IMO because theres no class your racing for.

i always thought the all the 125's were 54x54..
Maybe pull the head off and then have a look..

Not sure if they do roller rockers that fit but i think quite alot of gains could come from that for less rolling resistance sucked straight before it even gets to the transmission
 

timeeh

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I just looked at the Tbolt kits but it would be around $500 landed.. Not to keen on that. Thinkin i might just put the TB piston in and see how it runs, after a bit more reading (due to Craigs recomendations) i think he's on the money with the 52.4mm. As far as the 125 not having a class she does fine against the rest of the 160cc + bikes, mine included. That thing sits side by side with my 184 up to the first turn and unless i get a better start than her, she usually stays in front :( Which is not cool, maybe i should look at a downgrade :p
 

zwebx

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Akunar kits are $135 + postage :p incl new piston and rings just saying..
Valve stem seals are like 5 bucks a peice And valves are 15 a set approx.. (assuming you need some not sure how many hours on this motor)
Pretty cheap upgrade in my books (Spent $400 on a head and piston only to cook it twice LOL)

I reckon the 125s are the best thing on this planet lol for the money.. i got one in a psto and it was hauling 2 people around a farm yesterday.. i think it will see more hours than my bike.. many more
 

timeeh

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Akunar kits are $135 + postage :p incl new piston and rings just saying..

Hmm, thats not to bad at all, i'll shoot him a msg tommorow and let you know the results :) Considering the piston alone is gonna set me back $100 by the time i pay for shipping, i might just do that instead.
 

zwebx

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Pretty much, postage is a bit from akunar but his prices make it worth while..
if you are willing to grind at the cases or something like that.. And he makes a sleeve and piston kit that touches the studs is when its probably worth it :p
I could have and should have got a head from akunar, 67mm bore for 400 + 70 postage and thats with the largest valves you can fit in the head :p Needs some clearancing and some care when installing.. i guess thats what your buying from tbolt thats what makes them 'fool proof' and a good product to sell to consumers like aus that dont want to touch a lathe or grinder
 

zwebx

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timeeh

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OORacing - performance monkey bike, pit bike, madass, zoomer, dirt bike components - 57mm ceramic coated cylinder for use with big valve heads 27/23mm (Powered by CubeCart)
Needs a "big valve head" supposedly could probably clearance it for the stock for cheap or get a yx 150 head for cheap and have much larger gains..
Would make it 145cc and i can only assume on the border lines of that slinger clutch (it is the slinger right)
Already got the YX head, but a) I think it has a different stud pattern and b) $300 + is a bit much for a upgrade without a head, be better off going the 146 and race head for that sort of money. Sent an email yesterday to Akunar so I shall wait to hear back.
 

Phil67

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What are you doing giving her more power? Are you mad?
 

Snaptrax

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Its a 52.4mm Timeeh. I had the same bike as her. Awesome little bikes.
I ended up buying a piston from my local pit bike shop for like $56 And it had lasted over 100 hours easy
 

timeeh

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Got an email back from Akunar this morning :) Plenty of options, which is awesome looks like i can go to 54mm without needing a new head or head work (which it already has, just not sure how much) so thats going to be my plan, but once i get the head off i will check that the YX head i have does not fit, if it does i may look at going bigger. For anyone interested this is the email with all the options;

Sure, well we can offer up to a 57mm Bore Kit that can just squeeze in to the stock cases. Its ever so tight with an ever so slim sleeve but a common size. I would typically suggest 56mm but 57mm is typically the preferred. If you have the ability to bore out the cases we can offer 58mm and even 59mm with 60mm doable but we limit it to 59mm unless pleaded with as its just asking for troubles.
Regardless of size the bore kits are $110.00 USD consisting of High Compression Piston Kit, Copper head gakset, base gasket and Cylinder. Unless you running a 27/23v head the limit is around 54mm. If your running a 27/23 head as is common and a cheap upgrade if its not a model with it already which can be bought you can run up to 60mm with it. Technically though you would be better to be running at least a 28/24mm Valve head for anything from 56mm and up. We sell the heads with Race Cam, Porting, Rockers, shafts, seals, collets, titanium retainers and hd race springs for $225.00 USD. If we sell it as a complete kit we can make the combustion chamber mods, to suit, fly cut the piston to suit and so on....

So i'll let you know where i go from here, hopefully check the head by this weekend and then go from there.
 

zwebx

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Its the same price for my 67mm kit for my motor..
I also recommend getting a carby if your one is crap too the oko with powerjet is like 60 bucks..
shipping should be around $50 bucks
 

timeeh

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Its the same price for my 67mm kit for my motor..
I also recommend getting a carby if your one is crap too the oko with powerjet is like 60 bucks..
shipping should be around $50 bucks

got 2 x 26mm Flatslides sitting there doing nothing ;) Better drop the jetting though as they are from my 160 setup. Great minds think alike :p
 

timeeh

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Pulled down/out the motor yesterday, looks like a big valve has already been done :) so I believe the stock motovert run a 27/23 head, which explains why they go so well for a 125, so have decided on a 56mm piston and bore, landed should he round $150 :) the current bore has deffinate wear marks top and bottom on the sleave so it would require a re-bore either way. Will post pics soon :)
 

timeeh

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And it begins
unnamed.jpg
 

my67xr

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looks good, does that cylinder have 1 hole on the l/h side or 2x like the YX/Z engines

i hope you ordered a gasket set too ?
 
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