Hacksaw head job

Just putting some picture on here from a chinese minibike engine that I was messing with a while back on another website. Thought it might be interesting to look at. They are supposed to be clones of honda g100s or something.









Here a link to the thread too, if anyone cares to do some reading for the heck of it. Good for a laugh.
http://www.oldminibikes.com/forum/engines-modifications/46300-97cc-db-30-head.html

Ah, HA!!! THAT'S where I've seen you before...

Are you a member of oldminibikes? I haven't been on there in a while.

I signed up and made a couple posts after I bought a pair of DB30's for my kids. Mostly, I just sandbag some. But I definitely remember seeing your "hacksaw headjob" and my jaw hit the floor... LOL

Its awesome to read it and see the turn of events in a few pages
page 1: "You might as well throw that head out now!"

page 4: "holy crap it runs?!"

LOL

Now I remember why I don't spend much time at OMB. I think their flywheel policy is crapola. They are perfectly within their rights to have and enforce such a policy, and that policy just ain't right for me..

Doc Sprocket wrote:

Now I remember why I don't spend much time at OMB. I think their flywheel policy is crapola. They are perfectly within their rights to have and enforce such a policy, and that policy just ain't right for me..

Is it like the lawn mower racing assoosiation where if its un gov'd, you have to run billet?

Yup. If you so much as HINT about using a stock 'wheel above governed speed, adios. There's a thread there somewhere that tells you this, along with some carnage pictures. Naturally, they don't tell you anything like "5 minutes before this horrible destruction, they guy had beaten his flywheel off the engine with a sledgehammer for the third time"...

I dunno- as many folks are aware, I run stock 'wheels well beyond 3600RPM, and so do many kart racers in certain classes. I guess we're all so incredibly fortunate not to have killed every living thing in a 100-square-mile radius.

Yeah, they're nuts about flywheels over there. I'm not saying it can't happen, but it sure doesn't happen very often. The people who blew up the engines in the pictures were probably running them over 8000 rpm, they use fancy cams and all kinds of stuff racing them out in los angles. Like you said, you don't know what happened to the flywheels before. They use stock flywheels for quarter midgets around where I am. If they thought it was dangerous for the kids, they would probably have a rule about it. You guys are much more realistic about the whole situation here. Takes the fun out of talking about your build if you aren't allowed to talk about your throttle setup.

yea, I run direct to the carb..... no govoner except my foot.................

this is very interesting

yes it is.

that must have taken a while

mr.modified wrote:

Here a link to the thread too, if anyone cares to do some reading for the heck of it. Good for a laugh.
http://www.oldminibikes.com/forum/engines-modifications/46300-97cc-db-30-head.html

Reading, is right. You have to be a member of the forum, to see the pictures posted there.

It really irritates me when forums do that.

I have been administrating forums since a lot of the members here were still in diapers. (14 years.) And it has always struck me that making people become a member before allowing them to see the pictures that are posted, is a recipe for pissing people off. Not enticing them to join.

I am really impressed with the job you did on that motor!

even with a band saw this would be a feat that would seem impossible, let alone a hacksaw. do you remember how long you took cutting that sliver off? i think it's amazing that you were able to do this with out any specialized equipment

Good job. It seems like most people under the age of 60 don't have any skill or patience for hand tool work. Everyone wants to jump to the easy way out. And like the other guy mentioned, I don't go to sites that require membership to see pics, so i take it it ran and did good?

jamcco wrote:

even with a band saw this would be a feat that would seem impossible, let alone a hacksaw. do you remember how long you took cutting that sliver off? i think it's amazing that you were able to do this with out any specialized equipment

Thanks. Maybe took me a couple of hours to make the cut, then quite a bit of cutting and checking to mill out spaces for the valves. I tried to go slowly and carefully to keep the cut going straight, also started with a brand new blade. I was most worried that I was going to cut through the head where the valves go, must be thin in the corner where the cut is deepest.

Jamus wrote:

Good job. It seems like most people under the age of 60 don't have any skill or patience for hand tool work. Everyone wants to jump to the easy way out. And like the other guy mentioned, I don't go to sites that require membership to see pics, so i take it it ran and did good?

Also thanks. As it turned out, it actually did run pretty good. First I had a carb on it that didn't work out, but once I tried a different one it was ok. Didn't like to idle down real low, but I think my carb and intake was too big for the low end. I also welded up the lobes on the cam for a little extra duration. I really expected it to blow up, but it survived many ungoverned high speed runs and now lives a quiet life on a shelf where I work, next to some vintage oil cans. Drained the gas out of it and everything, so maybe I'll get it going for the heck of it some time. Turned out kind of neat for a junk chinese clone.