97cc DB-30 head

mr.modified

mr.modified

New Member
#81
#81
I was going to try to use briggs 3 1/2hp lifters in this thing, but haven't yet. Maybe if I have a problem with the lifters on this block, i'll try it on the next motor. I've got a 90 degree angle air drill and was thinking about trying to carefully "free hand" it. I don't know if the drill would even fit in the block though, or if I could get the holes strait enough. Like you said, it would be nice to have proper tools to do these jobs... Anyway, their still holding up. The 2.8 block is pretty rugged. Steel sleeve cylinder, dual ball bearing crank. They just skimp on material, like the lifters, valves, crank. The rod looks beefy enough, except the tiny end cap bolts look kind of weak. The piston is ok. Rings look kind of rounded on the wear surface (I noticed a stripe in the center where it's been hitting). Still working on my bullet proof scattershield flywheel shroud. I'm using some scavenged seat belt from a junk car.
 
redclayhd

redclayhd

Member
#82
#82
Well, necessity is the mother of invention. We have to try stuff to learn anything. If Chuck Yeager hadn't pushed the envelope, where would we be? And that's just one of many, many examples. Tim.
 
mr.modified

mr.modified

New Member
#83
#83
Rain off and on here over the past few days. I did get several high speed runs up and down my street though. Still running good. About half way done on the scatter shield fan shroud...
 
G

gokart95

Banned
#84
#84
Strigoi said:
i think i've seen it all now. :laugh:

you ruined that head. just throw it in the garbage or use it as a paper weight now.
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you dont know anything , just a retard with a keyboard ... the best you can do is STFU because if you don't have a machine shop , somethings you have to do on your own ....
 
robby12

robby12

New Member
#88
#88
Hey while your testing stuff out try throwing some shims or washers on the top of the valve springs for more seat pressure, there for you would have less valve float and it would spin more rpms
 
B

Bill Ellerby

New Member
#89
#89
Very impressive, nothing like taking a turd and making it come up smelling like a rose? Now you need to get one of those new 99cc Predator motors from HF and see what you can do with that!
 
mr.modified

mr.modified

New Member
#90
#90
When I run out of 97cc parts, I might try putting a 250cc polaris 2 stroke on it. The latest update is that the super stock and the 5hp flathead DB30 are going to be in a parade on monday for memorial day. I'm gonna drain the 5-20 out of the super stock and put in some straight 40 ive got on the shelf. We'll see how it holds up for 20 minutes of slow traffic on hot pavement. Should be a good reliability test. Also I have to plug a hole in the back tire of the super stock, It picked up a screw somewhere.
 
mr.modified

mr.modified

New Member
#93
#93
Both machines made it through the parade today with no problems. After the parade, I burned back through town with the flathead 5hp to where the truck was parked. I had my sister run the "super stock". It couldn't keep up with the 5hp too good, even with a 40 or so pound wieght advantage...
 
mr.modified

mr.modified

New Member
#94
#94
Here's some pictures of the bikes at the parade. Also some pics of my last minute attempt to add some fuel capacity. I just electrical taped a tecumseh vertical shaft mower tank to the frame.
 
mr.modified

mr.modified

New Member
#96
#96
Thanks. One of these days i've got to make a good gas tank setup for my 5hp db. I was originally going to try welding one out of 16 gauge steel and soldering on the cap and neck from a factory 5hp flathead tank. Then I was going to coat the inside with POR 15. Haven't gotten back to it yet though. In fact I used some of the steel I planed on making the tank out of for the number plate.
 
Clayon

Clayon

#97
#97
mr.modified said:
Thanks. One of these days i've got to make a good gas tank setup for my 5hp db. I was originally going to try welding one out of 16 gauge steel and soldering on the cap and neck from a factory 5hp flathead tank. Then I was going to coat the inside with POR 15. Haven't gotten back to it yet though. In fact I used some of the steel I planed on making the tank out of for the number plate.
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I have thought of that same idea about using the Briggs gas tank neck and cap, but I haven't welded my own tank because all I got is an arc welder. If I could get access to a tig I would weld one up in a heart beat.
 
mr.modified

mr.modified

New Member
#98
#98
Started up the super stock last night after it had been sitting the past couple of weeks. I guess it isn't going to blow up too easily in it's current state, so it's almost time for some more upgrades. I was thinking of running it on methanol. I'd have to use a different carb since I don't want to ruin the vintage tillotson thats on it now. Maybe I'll also advance the timing a little and add a few inches to the exhaust pipe. I'd probably eliminate the muffler altogether. I can take the fan off the flywheel and eliminate some of the tinwork around the engine. I never did finish the scatter shield flywheel shoud I was working on, I've got it about 3/4 done.
 
mr.modified

mr.modified

New Member
#100
#100
Clayon said:
Mr. Modified, how do you advance the timing? Do you just line the dimples on the cam and crank up differently?
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I actually meant ignition timing, but yes you can set the cam a tooth one way or the other. Advanced is better for low end while retarded is better for top end. You probably won't be able to notice the difference. Generally you don't want to change it more than about 8 degrees either way. Count the teeth on the cam gear and divide by 360. The answer is how many degrees each tooth is. I welded the cam lobes in the super stock and I have it advanced two teeth. To advance the ignition timing a little, I would probably file the key down some and set the flywheel ahead. Either that or file the bolt holes in the coil a little and move it to the left some.
 
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