Pit Bike Head Stem Bearings

[marksl]

Hi,

My nephew is racing a 125cc pit bike which was purchased from Ebay. The bearings in the front fork head stem are stuffed and we have been unable to find them on ebay. A set was ordered from the supplier and we recieved 1 x 320/22 & 1 x 20/23.5 tapered roller bearings which do not fit on the width or the OD. The orginal bearings are three piece thrust type bearings measuring 22mm & 23.5 mm on the ID. Does anyone have any ideas where these can be purchased from. We tried a bearing company but they aren't a "standard" bearing.

 

[Cactus Jack]

You have to remove the old bearings totally from the steering head tube and steering shaft ... then gently and evenly tap the new tapered outer races into the head tube ... The lower inner race should be a press fit onto the steering stem/pin with a washer under it and the upper inner race is a neat slide on fit ...

Your head tube SHOULD be around 44 mm I/D ...

Sometimes the head tubes can be distorted out of round because the chinese frame manufacturers have machined them up first ... THEN welded them to the frame ... In that case , IF you haven't got a hydraulic or screw press , you need to use a heavier persuader to get 'em in (ie lump hammer ... with a copper or rawhide hammer being preferred) ... but if you do use a steel hammer be careful to use something between the bearing and the hammer head and support the other end of the tube on a block of wood ...

Some frames such as CRF Honda copies take 41 mm O/D bearings ... but the inners are 22.5 mm top and 24 mm bottom ...

 

[marksl]

We have several different brands of pit bikes, the bearing issue is with a YZ02, the tapered bearings we have been send from the seller do fit an Orion, but theres no way they will fit the YZ02

 

[mattbombers]

hey mate it might be easier to buy a new triple.

 

[marksl]

We've already looked at that, even thought of cutting the triple from the Orion but they are too different and we would be to cut out too much meat of the frame to make them fit.

 

[Cactus Jack]

You're going to have to give more info ie

1) What is the I/D of the steering head tube of the frame ?

2) What are the upper and lower measurements of the steering stem/pin ?

Atomic/Orion frames usually take a weird size bearing compared to CRF's (41 x 22.5 top / 41 x 24 bottom) and DHZ/Pitpro/SDG etc (44 x 22 top /44 x 23.5 bottom) ...

I think Atomics take either a 47 OR 45 O/D bearing with something like 25 mm on the bottom of the pin and 23 mm top ... My brother has set of crappo Atomic forks that he wants me to adapt to a 44 O/D twin trellis frame ... The steering pin needs to be machined down to 22 mm top and 23.5 bottom ...

Sometimes people want to fit stock Fast Ace forks to 44 I/D frames ... Their steering pins are 22.5 mm top and 24 mm bottom (CRF 50/XR size) ... so they have to be machined down to suit the CGZ 320/22 and 320/23.5 bearings ...

You can't get any other bearings aside from the Chinese 44 O/D , CRF 41 O/D size and Atomic sizes ... You have to either machine the steering pin OR bush the steering head tube ...

44 mm I/D steering head tubes are 158 mm long and CRF 41mm I/D head tubes are 137 mm long ...

 

[roost666]

just let me know what the ID,OD and width of the bearing is and weather it is a thrust bearing or a tapered roller, i sell bearings for a living im sure i can help you out

 

[foolsp33d]

huh.. funny. you and modee!.. i think still anywho..

Go cactus with the knowledge