MBP Collets - 7MM. Suit early 4 valve. Set of 16. Suit 851, 916, st4, s4R, 749 +

So the OEM standard collets or retainers, or half rings that keep the valve retained in the closing shim and stop them falling in are a piece of wire…. Really.

We are forever finding them broken in motors that were still running- After that, valve drops in the motor and it’s all she wrote.  Apart from Big Cheques for repairs. 

The MBP collets are more like a Japanese collet-spreading the load preventing premature failure.

For Early 4V- 851, 888, 748, 916, 996, 998, 749, 999, ST4, ST4S, Monster S4, S4R, S4RS

Compatible with all 7 mm Closer Shims (OEM and EMS closers).

Requires the use of modified opener shims when used on 4V bikes.

 (We will be uploading those soon. )

How good are they?

The in-house 748SP race bike has done 2 years & a lot of racing at 12000 rpm without failure. 

 Its a Smart Investment.