Doodlebug DB30 Ring Replacement

[Nimdy]

I have a doodlebug DB30 bike I got of a friend for $15. The frame is in really good condition at least mechanically (could use a coat of paint). But the problems start with the engine. Turns out running one of those little 97cc engines ungoverned at full throttle with very low maintenance for 3 years takes a toll on the rings and bore. So now it pukes oil out of the crankcase vent because of the blow by.

Normally this wouldn't be that bad of a fix just buy some rings hone the bore and off you go. The problem comes in with finding the new rings. No matter how much I look I just can't find direct replacement rings for it. The closest I could find was a eBay listing selling a set for $110!

So my question is where should I buy rings? I have found rings that are 52mm like I need but I don't know how thick the rings on the DB30 are so I don't know if they will fit. I would rather not take the piston out to measure the current rings but I will if no one knows the thickness of the rings.

My other option is to pull the piston and hone the cylinder straight then use the old rings. My hope would be that most the damage is in the walls and the rings are less worn.

Any and all opinions on my problem are appreciated!

 

[creia]

You cannot tell anything w/o pulling the head and inspecting the bore for scoring and taking precise bore diameter measurements. If that bore is significantly scored and/or worn oversize (suspected), just honing and putting in new standard size rings will accomplish NOTHING. I would not bother rebuilding that engine. It's time to upgrade to a new (and larger) engine like the HF Predator 6.5 HP. Another option would be to find a good used Briggs 5Hp "flathead".
Michael

 

[sparkwizard]

The 79cc Predator will bolt right on, only costs about $120.
Not a racer or a hill climber. but it is a pretty good, little engine to get you going.