B1 rep engine pictures and diagnostic of a broken bike

**Leyton** · 23rd December 2008, 11:19

Hello

I thought I would share in a different post what I have discovered and the events that lead up to no spark.. and bent crank..

http://minibikediy.blogspot.com/

I have blogged it, I am new to blogging but it was easyer then finding webhosting space

**DELLORTO** · 23rd December 2008, 11:26

your piston looks stuffed

**BigAl** · 23rd December 2008, 11:28

Cool Leyton, but a bit of a bugger that it happened on your first outing.

I wonder who fitted the small end bearing?

**Leyton** · 23rd December 2008, 11:54

Hehe well it was not the bikes first outing thats for sure :P And yeah the bearing was a shocker. I would say some chinese guy fitting the bearing :P hehe

I was very impressed at the little bikes performance up until the stopping point

I am ordering a whole complete engine to save a bit of mucking around before Tamruanui, it comes with many spare parts that I am likely to need for the season like a coil

Clutch, Radiator everything.. carb you name it. It will save me spending near the same amount rebuilding my current engine. I will rebuild it eventually in the next month or too when my irratic minibike spending slows down

**racefactory** · 1st January 2009, 21:48

Nice work dude!

Btw, that is the INFAMOUS problem with the B1 engine- shitty quality wrist pin bearings letting go. People have these bikes do it all the time. It is the one major weakness with the B1.

Don't rebuild the motor with another shit chinese wrist pin bearing... instead buy the real bearing the chinese copied which is a 10x 14mmOD 12mmID 'Blata' european bearing. It is miles better quality and is the bearing that the real 'Blata B1' bike takes.

I got mine from some aussi pocketbike site a long time ago for about 25 bucks total including shipping. Cheap insurance to save you a whole new engine.....

There is also one other thing people do to stop the wrist pin bearing letting go- a very simple trick called the
'oil hole mod'. What you do is drill a 1.5mm hole either side of the current 'oil hole' in the piston on the exhaust port side. What it does is let more oil go to the wrist pin bearing.