Motovox engine swap...no way!

fonz

New Member
#1
Gramma buys the kid down the street a new Motovox Mini the start of summer. The tires go bald, the throttle cable brakes, he bends the front forks and And there is no Dad around. .. Just a kid with no tools. So I order the forks and two new Carlisle Snow Hog tires, I had a doodle throttle cable that fit. Then dumb @ss Fonz remembers I have a gently used HF 6.5 on the shelf. I also had an extra used conversion plate from CJTMINI. I contact him and he sends me new screws.
I start the swap and up pops the devil!! The Motovox bolt pattern is actually larger then the 6.5hp!!! It's a 1/2inch longer and a 1/2 inch wider. CJTMINI's or Hot Rod Mini's convertion kit wont work at all. And new holes cannot be drilled because they are just a 1/4 inch away from the original ones!! I have small round grinding wheels and round files but the whole thing is a "Cluster Flock"
Bottom Line Forget about swapping in a 6.5hp on the Motovox unless you have a welder and fab skills!!!

Fonz
 
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fonz

New Member
#3
I've used magnetic drills before..big ones that could takea 2 inch twist drills. But I did look into your suggestion. A small milwalkee was about 800 bucks. Not the usual thing a guy has in his tool box. And a bit tall. I doubt if it would fit into the frame. If I flipped it over. I would probably have interference from the bottom frame rails. But thank you for your suggestion.
 
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#4
Hello fonz, IMO 1/4" away is probably OK. Just so long it's bolted down properly and doesn't come loose. I have seen holes that overlap with no problems.

Are you referring to the adaptor plate or the mounting plate on the bike or both?

I don't know what a mag-drill is. :shrug:
 

fonz

New Member
#5
Neither of the two adaptor plates from CJTMINI or Hot Rod Mini Bikes are of any use at all. The mounting holes of the Motovox engine is just a 1/2 inch off in both directions of a Honda Clone. I have it bolted on ok, but now I've lost all means of motor adjustment. Unless I want to cut more metal out and end up with a 3/4 x 1.25 slot. Thay's way too sloppy but I may have to resort to that. The Ideal way is to weld up the existing slots in the bike frame and cut new ones. I'm not a welder and don't have one. If you try to swap a Clone for the stock motor, be prepared for a lot of headaches is what I'm saying.:grind:
 
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toomanytoys

Well-Known Member
#6
why not go to lowes or some place, pick up a sheet of 3/16" plate, weld that down to the motor plate, and start over again with a fresh piece of steel. That way it would even be extra thick.
 
#7
Fonz
Do you have a pic of the frame plate on the Motovox, Just curious. The adjustable motor mount plate I designed has allot of flexibility. Usually it can be moved to an area where you can mount the plate to the frame, then adjust the engine on the mount for alignment. I have used it for a number of different Kart and mini bike applications, I also have one on my Dyno system for quick sprocket alignment when testing different engines. Kinda where I came up with the idea because I did not want to swiss cheeze my dyno stand plate with holes.



Mini Bike Performance Parts, Baja Doodlebug, Dirtbug, DB30 and MB165 Performance
 

fonz

New Member
#9
ProMod:
On second thought I owe you an apology. If I drill 4 new holes in the Motovox That matches the bolt pattern on the Doodle engine, your adaptor plate should work. I don't see now why it wouldn't. Please excuse my ignorance.
To the rest on the board. I'd like you to know Promod (Brad?) has helped me a few times over the phone with problems I have had in the past and has always given me good advise and great service. He ships right away.
In fact, I'm going tto order anther plate today because it will be the perfect Fix for an interference problem I have on the Grandson's semi-new go-cart!!
Again my apologies to you and keep up the great innovative work.
My thanks,
Fonz
 
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#10
Thanks Fonz
Always appreciate your business and enjoy talking to you.

In regards to Bigkid's JS question...
Our JS does fit the 99cc Predator. Also the smaller 70cc that was being sold at HF.
I have even sold a few for Motorized Bicycle projects using these engines.
You do however need to use different mount bolts for the plate.
For some reason they decided to change the side cover bolt thread on the new Predator engine line to 5/15 NF . The mount bolts supplied in the kit are 8mm-125
 
#11
You dont need a fancy smancy magnetic drill press.

Just drill a hole in a scrap chuck of steel then use a C-clamp and clamp it in postion on the engine plate and drill the holes using the scrap piece as a drill guide.Thicker steel would work best.

Then mount the cjtmini plate.
 
#12
Does the promod engine mount work with the new predator engines being sold by Harbor Freight? Just curious I have an old blue clone engine from them with the plate, just wondering in case I ever have to get a new engine.
 
#15
OldMiniBikes member MurrayEliminator did a project log on swapping in a predator to the motovox bike, take a look at that, it might help.
 
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