PitPro 140XR Upgrades

[av8]

G'day,

So I bought one of these puppies:
PitPro Dirt Bikes - Mini Mid Sized Pit Bikes - Pitpro 140XR

with the 1P56FMJ 140cc Lifan Big Bore Factory Race Engine

I would love to do some mods, but am not sure where to source them for cheap. Local shops charge too much, and I would have more fun doing it myself anyway.

What do you recommend/and where from. I can pick up the 150cc big bore upgrade for 99 bucks, but am unsure if it'll fit.

Cheers.

 

[thump*140]

Mate i wouldnt suggest going straight for a big bore kit. There are a lot of mods you can do relatively cheaply, particularly if you source them from ebay.
DHZ on ebay is a great place to start, as are some of the shops from both Hong Kong and China. Whilst this isnt exactly doing your bit for local business, it can be cheaper by a fair amount if you are on a strict budget. Many parts on my bikes have been sourced from overseas via ebay, and i am yet to have any postal problems etc..
I built up a thread to answer exactly your question, so if you have a look through it, it's basically a guideline for modifying your engine and bike from basic to wild... you should be able to answer every question from that thread...
http://www.miniriders.com.au/tech-talk/24009-performance-upgrades-guidelines-stage-i-iii.html

 

[av8]

One thing that I fucked up, is in the side of the block where the oil cooler lines go and bolt in, I seem to have stripped the plate where the bolt goes into on the side of the block.

I've gotten a high tensile bolt, drilled holes in it, (3 hours work with shitty drillbits that kept snapping) and its just holding on.

Where would I get that side part for the engine where the oil cooler lines go?

 

[thump*140]

pics mate... put a pic up of what's been damaged, will make it easier to determine which part it is that you've busted..

 

[av8]

 

[DvDRip]

my one of them came stripped from factory, Motorbike city sold me one for like $10

where you from?

 

[thump*140]

hmm... i'd be ringing the place you bought the bike from, and seeing if they can supply a new one...
Failing that, an engine dress up kit from ebay may be worth a try, but it could be a bit tricky finding one that has the ports for screwing the oil cooler lines into the side cover...
Me personally, if i couldnt source a replacement side cover from the dealer, i'd see if it was possible to have the thing tapped and rethreaded. Most mechanics workshops should be able to sort that, and fit a larger banjo bolt. (banjo bolt is the one with the holes in it, that you spent time drilling as a replacement)
The heads on these arent overly hard steel-wise, and threads are stripped easily so go gently when you put the replacement in.
Still reckon your first port of call would be the place you got the bike from... they should be able to supply a new head side cover.

 

[av8]

Just ordered the new part yeah i know what a banjo bolt is but it was a sunday and the only thing open was supercheap.. haha. Was worth it, had a sweet ride all afternoon.

Probably going to try and get a bigger intake manifold, the one in it when I took it off is tiny opening.

 

[DvDRip]

A better carby would be better than port matching, otherwise you could port out the stock manifold to fit carby because it already matches the intake on the head

these are the basic mods for a pitpro:

Unifilter
RK or D.I.D chain
Tires (not needed for the xr models)
Fastace or DNM Rear Shock (not needed for the xr models)
Protaper Bars (xr50 bend) and some decent grips
Rim Lock
Copper exhaust Gaskets and double nuts on the exhaust mainifold
Hi-Tensil Bolts EVERYWHERE
Billet 1/4 Turn throttle
Lube the cables, grease all other moving parts
Replace fuel line and install an inline fuel filter
Sprockets for better speed and turn it into a 4 speed
Dot 4 Brake Fluid and new Fork oil, and of course engine oil
Decent Carby

that's all I can think of for now but all these mods are worth it but some more necessary than others
__________________

 

[av8]

yeah but ordering and installing a new carby sounds insanely hard to do. Do you recommend any decent ones that are fairly easy to do?

I just took mine out soaked it in fuel, cleaned it out, my bike doesn't seem to start well, or idle until its really warmed up.

It's doing my head in!

 

[DvDRip]

look at the guides in my signature, they should help you get your bike running better, the main reason I hate those cheap mikuni's is the mixture screw is underneath in a really hard to get spot, so good luck with that lol

do the valve clearances before trying to tune the carby

 

[av8]

You think that could be it?

Basically when it starts (after 20 fucken kicks) it'll be awesome if I keep some throttle on. Turn the idle screw up, and she idles..

but its low.. then it'll rev high for a bit, then low again then poof stalls.

If you think it would be the valves, I'll give it a go .. after that video, surely i cant fuck that up. I told a mate im going to try it and he laughs and says "haha you idiot, thats a major job"

But in the video it looks pretty straight forward!

 

[DvDRip]

You think that could be it?

Basically when it starts (after 20 fucken kicks) it'll be awesome if I keep some throttle on. Turn the idle screw up, and she idles..

but its low.. then it'll rev high for a bit, then low again then poof stalls.

If you think it would be the valves, I'll give it a go .. after that video, surely i cant fuck that up. I told a mate im going to try it and he laughs and says "haha you idiot, thats a major job"

But in the video it looks pretty straight forward!

He's the idiot lol, it's easy as piss on these china engines and if you know what you're doing only takes 15mins.

Is your compression low (easy as hell to kick the bike over)?? If it takes 20 kick to start the bike that's a good indication you need to set your valve clearances, either that or your carby's completely out of tune

another thing you need to keep an eye on is the exhaust gasket, mojo are tightasses and only use corrugated aluminum gaskets so after a couple rides they flog out and spiral up the header pipe, I've seen this happen on 2 pitpro's and then replace gasket with another mojo one and the same thing happens again. The gaskets are just shithouse. send an email to Ken at DHZ and he'll hook you up with some proper copper gaskets.
If your gasket flogs out you bog down at low revs and the bike runs like crap until it's fully warmed up, then it runs a bit better becuz the metal expands with the heat

 

[av8]

It's got compression, but compared to when I first got the bike, its easy as piss to kick over now. It does get the odd kick back and rapes my foot haha. But I can move the kick starter with my arm, with a decent force of course, but yeah. Gonna give this valve clearance a go. Just got to find all the tools!

 

[av8]

Do you recommend .003?

 

[DvDRip]

yep .003 or .004

 

[y0 ash-tray!]

hey mate, have the same bike, same kickback and cold idle problems,
i have installed a uni filter and pro taper bars,
chain and a few things mentioned in this thread are next on the list

oh and by the way its a YX 140cc motor not a lifan like it says on the rear fender haha
________
The cigar boss

 

[av8]

Turns out I don't have the measuring guages.. 2 sheets of A4 paper will work?

 

[DvDRip]

Turns out I don't have the measuring guages.. 2 sheets of A4 paper will work?

yep should work, as long as you have a gap it's fine.

 

[av8]

I ended up going down to Mitre 10 buying some feeler guages. Took off the inlet valve cover, and there was no clearance, fucker was tight as!

After heaps of bending of the feeler guage I got it in there but because of such a tight squeeze I dont think I got the exact .003 however when its all tightened up there is a slight movement when I move the valve and wriggle it up and down...

Didn't do the exhaust valve... but she started first kick!!!!! with the choke on, but when i took it off she conked out. Started it up again (first kick btw it feels like there's more compression now? im probably just tripping though)

Adjusted the idle screw and it seems to be running sweet.

Is it bad if I don't have it at exactly .003 and it is most likely a bit more more like .005 and I can see / feel it move when I play with it?


EDIT:
I just read bout the exhaust gasket.. I guess the only way to check would be to take the exhaust off?