Re:BM DB 30 engine problem

[robo5050]

hello oldminibikes.com forum members,

I have a problem with a Bjaj Motorsports DB30 97 cc 4 cycle engine tha recently won't turn over when rope starting; have been running the motor staionary while doing a little PTO machining( with a double-cut Bastard file on the crank end machined to 625 inch for better clutch assortment!),but when
after letting the engine sit overnight then trying to pull-start the Lil' engine it froze-up!!??!!

I took out the top-mounted gas tank,spark plug was caked with carbon deposits(as well as, what I could see in the top cylinder!!);I can rock the crank a little more than 90 degrees either direction but then the crank freezes up!?!

I was wondering if I should get rid of this engine(and replace with HF clone
mentioned in this forum),or find a rebuild kit-if this is possble-to repair it???

Seems like the bottom-end may have let go(only have run it stationary,and only at idle while grinding the PTO!!),and therefore this engine is toast???:doah:

Thanks in advance for any replies!

 

[Strigoi]

i'd just take it apart and see how everything looks inside.

how long did you have it running at idle for? did it start making any weird noises?

 

[robo5050]

Hello Strigoi,
I think I ran it a total of under 2 hours itime streched out uver periods of time to give the engine a break to cool down between bastard filing attempts!!), strictly at idle speeds to do the "Ghetto" crank grind procedure;the PTO was machined to 5/8 inch without anything to indicate that the crank bearing(or whatever!!) would break- the engine DID Get a little to hot to touch at grinding sessions!!

I subsequently removed the carb filter(foam-type),gas tank(w/ the heat-shield underneath,then shook the engine like a spray bomb can, and heard a rattling sound the seems to be coming from the bottom of from the Lifan!?!

I am expecting/usuming the rod cap bearing fastener "Sheared,or broke while near the end of fine grinding the PTO smooth??:grind:

I am hoping that all that is wrong is one rod cap bolt broke,and that the rest of rod cap is in "undamamged"condition!!

Anyways,I will probably upload some digital camera pix of the Lifans bottom-end in hope that someone may know where I could get replacement parts for thid engine "out-of-warranty"!!