4 stroke mount ?

GoldenMotor.com

MotoMagz

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Aug 2, 2010
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Not sure, but I just bought one of these exact mounts, and can tell you that neither set of holes are for a harbor freight 79cc engine. I am going to have to redrill, and unfortunately, it seems my new holes will be very close to two of the slots.

Wish I had seen this one before purchasing:
http://www.bicycle-engines.com/Black-V-Frame-Mounting-Plate-Kit.html
could you measure the both sets of mounting holes center to center.Maybe I could get this one from you if it will work and you could get the the one from Bicylceengines.com
 

agk

New Member
Oct 2, 2010
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Santa Barbara CA
You don't want to use this eBay motor mount especially with the 79cc engine. We built some bikes with that same mount using the 49cc 4-stoke. The center plate with the two sets of slotted holes is made from some really thin material. All but one of those mounts we used cracked, bent and failed. The torque from the 79cc engine will tear up that mount in no time.

The motor mount from bicycle-engines.com that atombikes posted looks to be the better mount that uses thicker material for that center plate. We've used several of those with no issues on the 49cc engines.

The 79cc engine is a torque monster compared to the 49cc. Some upgrades from the typical off the shelf parts are needed. The 79cc engine will put your building skills to the test like the 49cc engine never could.
 

atombikes

New Member
Feb 14, 2010
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So the motor mount that AGK offers for the HF79/HF99; what kind of mounts does it bolt up to?

http://www.affordablegokarts.com/mm5/merchant.mvc?Screen=PROD&Store_Code=A&Product_Code=2306&Category_Code=

The description says that the motor mount is not included in the $25 cost. Since the AGK plate is a fixed width, and these 4 stroke mount clamps have a fixed width, how would I know which 4 stroke mount to buy? (unless all these 4 stroke mounts are the same width?).

I figure I can fabricate and save money, or spend money and not fabricate, but definitely don't want to spend money AND fabricate.
 

atombikes

New Member
Feb 14, 2010
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Northern VA
Another geometry related question about these 4 stroke mounts-

Since the angles of the downtube and seat tube vary from frame to frame, as do the tubing diameters, how do these 4 stroke mounts accomodate all the different frame variations?
 

MotoMagz

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Aug 2, 2010
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Another geometry related question about these 4 stroke mounts-

Since the angles of the downtube and seat tube vary from frame to frame, as do the tubing diameters, how do these 4 stroke mounts accomodate all the different frame variations?
You most sand/file it to fit the angle of your tubing.At least that is what I have did in the past.
 

MotoMagz

Well-Known Member
Aug 2, 2010
1,817
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You don't want to use this eBay motor mount especially with the 79cc engine. We built some bikes with that same mount using the 49cc 4-stoke. The center plate with the two sets of slotted holes is made from some really thin material. All but one of those mounts we used cracked, bent and failed. The torque from the 79cc engine will tear up that mount in no time.

The motor mount from bicycle-engines.com that atombikes posted looks to be the better mount that uses thicker material for that center plate. We've used several of those with no issues on the 49cc engines.

The 79cc engine is a torque monster compared to the 49cc. Some upgrades from the typical off the shelf parts are needed. The 79cc engine will put your building skills to the test like the 49cc engine never could.
I am looking for a plate for the doodlebug 97cc not the 79cc but I do see your point.Does your mount fit the doodlebug????
 

atombikes

New Member
Feb 14, 2010
525
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Northern VA
You most sand/file it to fit the angle of your tubing.At least that is what I have did in the past.
Yeah, this mount I have does not look like there is enough material there to allow any material removal. One of the things I like about the one I linked is that it looks like the tube clamp castings are shaped fairly close to a bike frame. My particular frame has a 1.5" downtube (Dyno frame) so I am fearful the bicycle-engines.com engine mount may not fit the downtube properly.

Can someone chime in on this? I think this 4 stroke mount is actually a Grubee mount but I'm not absolutely sure. It's really hard to learn alot about a product based on one or two pics, and these vendors provide very little technical details about the products....

http://www.bicycle-engines.com/Black-V-Frame-Mounting-Plate-Kit.html
 

atombikes

New Member
Feb 14, 2010
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Northern VA
Birddog (bicycle engines) is a national distributor for grubee,
I would think the mount would be Grubee ;)
OK, thanks. So this would mean this mount is drilled for a Huasheng/Honda engine, I suppose. Anyone know the difference between a Harbor Freight and Honda hole mount pattern? I suspect the 4 stroke mount I have is also drilled for the Huasheng/Honda, and the mounting hole pattern is just off by enough that the HF engine won't mount without drilling, but so close that it will make drilling without messing the plate up kind of hard.
 

agk

New Member
Oct 2, 2010
151
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Santa Barbara CA
I am looking for a plate for the doodlebug 97cc not the 79cc but I do see your point.Does your mount fit the doodlebug????
I just checked our engine plate against a 97cc Doodlebug engine and the bolt holes line up. When we get around to building a bike with one of these engines we will use our motor plate and weld two parallel pieces of flat stock in the frame for the plate to sit on. We use 1/4" thick flat stock. Then we drill the holes in the flat stock so the engine plate can be secured to it. This makes a nice solid setup and its adjustable for chain tension.

Some people do not have access to a welder and need a bolt-in option. This is when we combine our engine plate with the frame mounts from a 49cc setup. We use the Black V-Frame Mounting Mounting Plate Kit from www.bicycle-engines.com. Replace the engine plate from the bicycle-engines kit with our engine plate and bolt it in.
 

MotoMagz

Well-Known Member
Aug 2, 2010
1,817
1,154
113
Michigan
I just checked our engine plate against a 97cc Doodlebug engine and the bolt holes line up. When we get around to building a bike with one of these engines we will use our motor plate and weld two parallel pieces of flat stock in the frame for the plate to sit on. We use 1/4" thick flat stock. Then we drill the holes in the flat stock so the engine plate can be secured to it. This makes a nice solid setup and its adjustable for chain tension.

Some people do not have access to a welder and need a bolt-in option. This is when we combine our engine plate with the frame mounts from a 49cc setup. We use the Black V-Frame Mounting Mounting Plate Kit from www.bicycle-engines.com. Replace the engine plate from the bicycle-engines kit with our engine plate and bolt it in.
Thanx Shane I just left your site after ordering the plate!!!Thanx For checking the Doodlebug to see if it lined up.dance1