Mikkh's WPB 125 CRF 70 framed build

[my67xr]

With the R6/R1 having linkage suspension the spring might be a bit soft, you will have to try it out.

Honda CBF110 2004 have a 295mm rear shock, not sure on the spring rating though
2004 ERA Honda CBF 1100 Showa MFA 921 GAS Filled Shock 295mm Length Silvr Spring | eBay


If you cant find anything that'd work off a Jap bike, then i'd go for something adjustable like this DNM or the Volt
DNM fully adjustable 295mm rear shock :: suspension :: Mini Bike Parts - Mini MX
295mm Volt V2 Pit Bike Adjustable Shock Absorber Suspension 140cc 160cc Pitbike | eBay
PIT BIKE VOLT RACING V2 295MM REAR SHOCK 1000LBS SPRING ADJUSTABLE COMPRESSION REBOUND

Or an Elka
Shock Elka 36PBCR Pit Bike Piranha SSR Pitster Pro | eBay

 

[my67xr]

The standard WPB rear shock uses a 400 lb spring
Pit Bike Gas Shock Absorber Suspension 295mm 400lb In White For Pit Bikes & Quads ? PetrolScooter UK

I just read that the R1 rear spring's are around 450 lb's-500 lb's
So you might get away with an R1 rear shock

 

[mikkh]

WPB 125 CRF70 - Welsh Pit Bikes

Well according to that it is a 1000lbs spring (maybe not in lbs/inch but in total length?)
Those R1 rear shocks which are newer than 98-03 have stiffer springs (should be excellent for pitbike use). Those 98-03 R1 rear shocks feel much better (stiffer, dampening etc) than those cheap no name china shocks.

 

[mikkh]

Does anybody know if CRF70F swingarm bolt fits those china CRF70F pitbikes (mx swingarmed ones like mine)?

 

[mikkh]

Got myself an used set of GPX black labels for 65.- . They are good, don´t leak etc but have 3-4 total tiny rust spots on the chrome tubes. Thinking of sanding down to rust and using superglue to patch it (forks don´t leak by the way). Otherwise they are in usable condition.

Don´t know yet if I am going to use them for this bike. Or buy a CRF70 Pitsterpro rival pitbike for 400 (Swedish PitPro, but somebody has swapped the forks and swingarm with pitsterpro X4R . I f those fork tubes are excellent, I might swap those tubes and put those adjusters on the better bike. The Swedish Pitpro has DNM rear shock and 172cc 4 valve YX engine.)

Here is an example of the bike (not the one I am considering).

 

[gottagetacheaperhobby]

That pitpro would be a good buy, although I have heard the 4 valve 172cc yx engine is held back by its porting and combustion chamber size, pretty sure they are copied from a head designed for 125cc. I do know a stock bre tb head and piston will make a 160ho eat a yx 4 valve despite giving away 17ccs to the yx and 2 less valves.. with some good port work they would no doubt be a good engine, but stock they are soooo restricted..

 

[mikkh]

Maybe I can check that pitpro tomorrow, but according to the pictures in the listing the front forks and rear shock are leaking. If the tubes (chrome part) are OK then it shouldn´t be a problem. The bike looks rough too.

Thinking of fixing those adjustable forks using superglue

 

[gottagetacheaperhobby]

I have sanded back a couple of high spots on the stanchions before, I gave it a coat of clear spray paint to seal it but superglue could work to, no harm in trying. May even be able swap the stanchions over between the two, if it has x4r forks on it they are the same as black labels anyway, and you would have to fix the leaky seals anyway...

 

[mikkh]

The my set doesn´t leak at all, the seals are new. Well superglue has worked good on even rougher forks , but surface prep is the key, going to try out superglue.
Actually my forks are off 2009 Motovert PRO.

 

[gottagetacheaperhobby]

I meant if you got the pit pro you would have to pull em apart to fix seals so swap stanchions over then....

 

[mikkh]

The chrome issue got me thinking of using hydraulic cylinder chromed tubes. I have had only problems with that china pitbike chrome. I have NO scratches, wear, rust whatsoever on my 2001 KX250 front fork chrome tubes.

Is it possible to make those fork lower tubes myself? Does anybody have pictures of those (Marzocchi as my forks look like marzocchi replicas, will check them with caliper to be sure if they are indeed 35mm or 33mm)?

 

[my67xr]

Get your fork tube's Hard Chromed, it cost's about $150-$200 ea for the stanchion's for most bike's

There is also a company (forgotten where) that can make new stanchion tube's for you, have them hard chromed of anodised etc, they make longer/shorter tube's etc etc too.
They cost around $400 per pair and will last for year's

KLX110 Marzocchi Worx stanchion's

http://moto.marzocchi.com/System/11230/9001281_SHIVER_35_2007_WEB.pdf

 

[mikkh]

One fork leg is about 3.5 dm2 and prices for hard chroming in my area are about 10-20 euros per dm2. And other price was less than 100 euros per m2. Will check the chrome layer thickness, but for the price of it seems kinda pointless to me, hoping to find pre chromed 37mm tube.

 

[mikkh]

The front end is still problematic. Made new mounts etc for the number plate and front fender. I need to make new brake caliper mount, because the stock china one was 8mm and the angle is different too, the GPX style fork has 6mm mounting bolts.
Thinking of making my own fork guards from 5mm thick plastic pipe and call it a day , could get an R6 2004 rear shock for 40 and I will hopefully get the crank for christmas (or wait until I get piston rings for my 128cc 59mm stroke engine and shove it in there ).

 

[mikkh]

What other pitbike forks have 6mm caliper mounts? Friend of mine offered me his YCF double piston front caliper, the mounts line up, but they are 8mm.

 

[my67xr]

My Braaap has M6 caliper mounting bolt's.

Could you Helicoil them down to 6mm ?
Or drill it out and use a thread insert with some Hi strength Loctite ? Timesert, Champion make them

 

[mikkh]

Got those forks fixed with superglue. Still need to sort out the bar risers (regular china ones shoud fit). And the front brake caliper mount. Still want to keep it 6mm bolts though. Have to decide whether to use honda style brake hose routing or outside (honda style routing brake hose runs next to wheel). Made fork protectors myself too out of 5mm thick plastic tube.

Planning to use R1 rear shock on my bike. There is one for sale for ok price, but it is like 60km away from me and I want to check it first.
Hopefully I will get those parts (daytona crank, yx cranks, klx style engine parts etc) for christmas .

The 120 lifan engine I am building is going slowly - got 54mm rings with the piston not 52.4 and don´t want to file back those 54mm rings to make em fit.

And a bit of offtopic about my other build (still in the planning stage). There is a set of Fastace AS-02 660mm ones for sale for 30, but they are off Orion AGB 29 and I´m uite sure they are fake (the clamps are fake for sure) and they are 200kms away from me and I would like to check em first if the clickers work etc.

And near those forks there is one guy selling roached up bike like this for cheap

BUT it has fastace AS-02 forks and CNC hubs (might be off X MOTOS XM-33A or similar, not sure if those are cnc or cast)
XMOTOS XM-33A for reference

 

[mikkh]

Well I tried the forks today and I need to weld a new steering stop to fit those triple clamps

 

[mikkh]

Welded the new steering stop and it fits excellent, but my about 6mm thick o-ring is too thick for the bottom triple clamp seal, thinking of trimming it to fit.

 

[mikkh]

Just the assembly left basically. I am going to use the lifan monster 120cc engine, converted to secondary clutch at first then the lifan 150

But the only problem is the rear shock. Still haven´t got it.