Dyno Von Franco cruiser- HF79 engine

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atombikes

New Member
Feb 14, 2010
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Northern VA
Hi All-

Been sitting on a new in box HF79 engine for several years, also been lurking off and on in this forum. Had several thoughts about what to do with the HF79, but always thought I wanted to stuff it in a cruiser frame.

Fate was smiling on me this morning, I did my usual craigslist search and found a Dyno Von Franco bike that someone was giving away- for FREE! I knew nothing of this particular version of the bike, which appears to be a decal package and fake tank. An hour later, I was hauling the bike home in my truck.

Pictures below. The fork dropouts are bent, so I am going to have to replace the fork. Also, the rear fender is bent. Other than that, it's all there.

I'm interesting in standing the engine vertically as several members are doing with the larger 6.5HP engines; will this be a problem with the HF79?

Thanks everyone for the inspiration. Maybe now I can actually start moving on this project.







 
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atombikes

New Member
Feb 14, 2010
525
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Northern VA
Yup, it was free. But like I said, I been waiting a loonnngg time for this deal to come along. Other projects to be done so no big deal to wait. But now that I have this frame, it's time to move along.

CCC, I have definitely checked out your builds, quite amazing. I can only hope to build something similar.

What kind of budgets do you guys plan for a build? I already have the frame, engine, jackshaft (but no pillow blocks), gearing for jackshaft, and #41 chain. Oh and a Maxpower clutch.

How do you guys think I should build this thing? Use the CB antenna bracket approach to mounting the engine? Or weld (braze) in a mount? I have a mapp torch that might be hot enough to braze in a mount (maybe). Bolt on might be better.

What do you think?

Thanks for your responses.
Ed
 
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atombikes

New Member
Feb 14, 2010
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Northern VA
Just finished stripping the bike of all components. The paint is excellent, HOWEVER the paint under those plastic tanks on the top tube is destroyed. Seems the plastic must have been cutting into the paint, causing rust. It's so bad that on the one side, there is a hole in the top tube...

This is bad news, but it's not gonna stop me from using this frame. I'll just braze repair that area. Stupid fake tanks.
 
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atombikes

New Member
Feb 14, 2010
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Northern VA
MotoMagz said:
Nice find!! Sounds like your moving right along.Will you be making a custom tank???
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Not sure about the tank yet. Does anyone here do fiberglass tanks? Like make a foam form and fiberglass over the foam? (then melt the foam out with acetone, obviously). Not sure if that is a stupid idea or not?
 
MotoMagz

MotoMagz

Well-Known Member
Aug 2, 2010
1,817
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Michigan
Good luck getting a fiberglass tank made..Do you have room to put a small weedwacker tank inside of the tank that is on the bike now??That would be the fast and cheap.Steel Tanks have cost me $200-250 to have built and thats cheap.
 
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young grease monkey

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Sep 20, 2011
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Chicago
you could pick up a cheap welder from harbor freight for $100 that will do sheet metal just fine, and make your own gas tank. then use it a lot for other projects till it fries and get your money back! as for the mount, pm me i can make custom cast aluminum for very cheap. i am working on my own for a 99cc hf, should be done by the end of the week. look at my thread "custom ht parts and 4 stroke mount". the mounts that are available to buy aren't that great, the agk mount is supposed to be a weld on but can be bolted on with less effectiveness. other than that your only option is custom made.
 
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atombikes

New Member
Feb 14, 2010
525
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Northern VA
some pics of the bare frame

So I am done pulling the bike apart (except for the bottom bracket retainers and the headset/front fork). Trying to assess the condition of the frame. It really is like new, except for that one problem area that was hidden under the fake tank. Based on how new looking the rest of the paint is, and how rusted the hole is, I am wondering if the hole in the top tube was a factory defect?

Anyway, even though I was digging the paint color, looks like I will be stripping this frame down to bare steel and starting over after the repair to the top tube.



frame abrasion on right side (no hole in frame)


agghh- hole in frame. The metal almost looks split:


rear quarter view- a lovely frame:
 
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atombikes

New Member
Feb 14, 2010
525
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Northern VA
welds

culvercityclassic said:
You scored bro... Stand that engine up. Check out some of my past builds and you will see what I have do e with Dyno's

They are one of the best bikes made....
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CCC, do you ever reinforce any of the factory welds on your Dyno frames? I noticed while looking over the frame that, for instance, the rear dropouts are welded all around on the outside (maybe for appearance?) but on the inside edges, there is nothing but a tiny tack weld? Any issues with dropout flex or strength? I suppose the weld on the outside is kinda long, so that may be enough.
 
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culvercityclassic

Well-Known Member
Sep 27, 2009
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Culver City, Ca
Never had a problem and have a 200cc motor in one of them. Best frame made...I would just have the problem area welded up and ground down. It would be the chit if you could find a bladder type gas tank to put under the fake tank...and run it like that.

If you are going to paint it find the post I made how strip and paint it...it will save you some time for sure. http://motorbicycling.com/showthread.php?t=40563&page=2
 
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atombikes

New Member
Feb 14, 2010
525
2
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Northern VA
culvercityclassic said:
Never had a problem and have a 200cc motor in one of them. Best frame made...I would just have the problem area welded up and ground down. It would be the chit if you could find a bladder type gas tank to put under the fake tank...and run it like that.

If you are going to paint it find the post I made how strip and paint it...it will save you some time for sure. http://motorbicycling.com/showthread.php?t=40563&page=2
Click to expand...
Good to know about the strength of the frame. I was a little bit worried about it at first. Regarding the tank, that's a good idea about using the plastic faux tank halves with either a small hard tank or a bladder inside. However, these plastic halves are what caused the current problem with the frame...they butt up against the frame, so any vibration will cause them to abrade the paint. There was a black vinyl edging between the frame and tank halves, apparently that didn't work.

Tank seems eons away at this point.

Tanks for the help and comments.
 
locell

locell

Member
Jan 16, 2010
215
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mesa
the rear horizontal dropouts on the frame are excellent, those make all the difference in the world - also it looks like that frame is a bit "laid back", that's cool, maes it a bit more comfortable to ride but you have to run a longer drive chain(s) than some setups.
 
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dmb

Active Member
Dec 4, 2010
1,354
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lakewood ca
the dyno frames are so nice looking. remind me of the 1939 lincoln zephyr automobiles with their flowing lines. too bad their not made anymore. snag em when you can
 
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atombikes

New Member
Feb 14, 2010
525
2
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Northern VA
fork and engine

Good lord that was alot of work getting that fork off! After taking off the top cap I had to repeatedly strike the top of the fork with a 2lb mallet and plenty of PB Blaster. But the deed is done. The fork is twisted, apparently from a prior wreck, so I will have to find a new fork. I'm thinking triple tree or diy springer of some sort. Any ideas? Kinda have a limited budget.

I removed the gas tank and other items off the engine to check fit. Of course we know the HF 79 fits the Dyno glide frame, since many have done it and fit larger engines. I'm more interested in trying to figure out whether I mount it horizontally or stand it up.

What would I have to modify internally if I decided to stand the engine vertically? What's the best 4 stroke mounting kit to buy? Or do you make your own?







 
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young grease monkey

New Member
Sep 20, 2011
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Chicago
You will want the cylinder to be at least a few degrees back from vertical for oil to get into the head. The only thing you will need to do to the engine to mount vertical will be to put a hose barb on the drain hole with the proper oil level and have a clear hose attached to it so you can see the oil level in relation to the crankshaft. Then turn it vertical and see what happens to the oil level. Add/remove oil so it is at the same level it was. You will need to fab a mount if going vertical.
 
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atombikes

New Member
Feb 14, 2010
525
2
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Northern VA
Per motorbicycleracing's request, a couple more pics of mounting options, this time with wheels on to give some sense of level.

First is the engine with mounting oriented to the seat tube:



Next is the mounting at about 70 deg angle- I think this is similar to others I have seen:



Finally the flat mounting option.



This frame has enough room to do it any way (at least with these small 79cc engines).

I'm thinking I will want to do a bolt-in mounting to leave my options open for a larger 196 or 212cc engine later.
 
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