Best engine mounts for oversized tubes

[Movie Mike]

Hi everyone. I'm new to MBs and to this forum.

My Grubee SkyHawk 48cc arrived today. I bought a Giant SedonaST casual mountain bike rather than a cruiser. I'm a big guy: 6' 8" and 270 lbs. I think that two caliper brakes will stop me better than a coaster brake. I knew ahead of time that the Giant's seat tube and the down tube (the one that goes from the handlebars to the crank) are oversized. The stock mounts won't fit.

I'm using the steel "adapter" plate to connect the rear engine mount to the seat tube. What do you guys use to connect the front mount to the front tube? Another adapter? Something else?

Mike


Mods: I posted in the wrong spot. Move it to the "Mounting Techniques" if you think it's a better fit.

 

[leftywoody]

I have used this type of mount on my last build and was so glad I did If you can get some strap, steel from a farm supply store . And some muffler clamps . A drill and good drillbits , a hand metal file . And some hardened nuts and bolts from an auto parts store or a farm supply store , a Tap and die set . And if you want to rubber mount it you can use a rubber union sleeve from a hardware or farm supply store( in the PVC pipe section .)The yellow dots indicate the rubber mounting material .Red dot is for the nut and bolt that holds your new steel strap to the kits 3 holed short steel strap . Blue dots for your steel
strap . Green dots for the muffler clamp . Last picture is The front mount at the point that your strap steel is mounted to the kits small, 3 holed strap steel. That small 3 holed strap should have been included in your kit ,and the hardened 6mm bolts that bolt your new( T shaped mount) to the motor . Pic 2 is the steel strap clamped to the frame . I used 1 clamp and its doing ok. 2 clamps would be better . Let your strap be long enough to allow 2 clamps if needed .

 

[leftywoody]

One More of the T section in front .The center bolt is larger and hardened and the center hole has been drilled out and threaded through both steel straps to join them together . Or they could be welded at that joint . The strap running down to the muffler clamp was bent in an arc to fit the curve of the frame . The thickness and width of that strap should be close to the thickness of the 3 holed strap you got with your kit .

 

[Movie Mike]

Thanks, Woody. That makes perfect sense. I'm off to the store.

 

[leftywoody]

P.S. the muffler clamp may have a nice crossbar with it from the store . Or with that same piece of strap steel you buy , just cut a length off at the desired measurment and drill 2 holes for your U-clamp to go through . All drilling and cutting should be done using plenty of squirts of oil . to reduce friction and heat . a real must . I used hardened 6mm bolts to mount my motor to the T strap not from the kit but from a farm store such as Rural king . I did not use the mounting studs .
Or get them at a auto parts store . I think I cut them to fit . I did not have much faith in the bolts or studs that came with the kit however if you have to use them just use locktight and don't overtighten them . If you cut a bolt or a stud , spin a nut on it past the point of the cut . using oil and a good hacksaw blade , make your cut and then spin the nut back off the bolt or stud right over your fresh cut . This will re-establish a starter thread .

 

[reg454]

Sick bike parts has a good large tube mount they are a good place to get things that they have for your bike. Here is a link to the page with the mount.
Sick Bike Parts

 

[Crazy Horse]

!HOW! Crazy Horse has another suggestion for you movie mike!

The motor mounts I used were designed by RedB66 you can put the A24's in a vise bend them so your motor will fit in the frame drill your holes thru the A 24's for studs from your motor to go thru then drill holes for the bolts & muffler brackets and bolt them up!

Careful don't the U-bolts they will crush your frame tubes!!! use only the brackets that come with the muffler clamps ok.

Depending on your frame tube diameter you may have to get the next larger size muffler clamps take bike with you to auto zone if possible.

Here's a few instructions,

I used simpson A24 strong ties available at your local home improvement store for about $2.00 a piece, use two (2) for the front mount & one (1) for rear mount they are 12 gauge steel.

Then I also used four (4) 1-1/2" muffler clamps available autozone auto parts store, except I threw away the u bolts and used the brackets only 1 on each motor mount, bottom of frame tube and 1 each on top for a total of four, also need four 3-inch bolts & nuts washer, & lock washer.

Movie mike see my post on (new stretch cruiser motor mounts), I'll try and post it here if I can.

See if these will help you here's the thread some of it below.

From thread on 07-13-2009, 04:12 PM

Default Notice: Stretch Cruiser Mounts
!HOW! Just wanted to say easiest way to mount on stretch cruiser was first brought to my attention,

By: RedB66 who suggested the (Simpson A24 Strong Ties) available for about $2.00 a piece at your local home improvement stores.

Will post more information soon.

Pic's attached show stretch cruiser I'm building for a customer using the RedB66 designed motor mounts!

Three (3) of the pic's are from RedB66 a black stretch cruiser he built !

RedB66 used heavy duty wheels on his build, however my customer requested that he wants to use the 68 spoke wheel.

Crazy Horse makem big mistake on this build take my advice don't try it mounting a sprocket on a 68 spoke wheel took me about 6 hours to finally get it right.

Poor Crazy Horse now suffers from 68 spoke-finger-itis won't be able to shoot bow & arrows for a while after mounting sprocket to this 68 spoke wheel!!!

Peace Crazy Horse.
Attached Thumbnails
notice-stretch-cruiser-mounts-dscn0752.jpg notice-stretch-cruiser-mounts-dscn0753.jpg notice-stretch-cruiser-mounts-dscn0750.jpg notice-stretch-cruiser-mounts-barronsblackstretchpic2.jpg notice-stretch-cruiser-mounts-barronsblackstretch.jpg
MOVIE MIKE YOU HAVE TO GO TO THIS TREAD TO SEE THESE PIC'S.

 

[Movie Mike]

Thanks for all the ideas.

I was too impatient to order a mount from SBP so I modified Leftywoody's design. I ended up drilling through the frame. It's steel and enough riders have reported no problems, so I will hope that it will hold. I bought a couple of rubber grommets to isolate the engine from the frame. This is only day two for me, but I do not feel any vibrations.

 

[leftywoody]

I sure would like to see some pics of your bike and your idea for the motor mount I am always looking for new designs . Thanks John

 

[Movie Mike]

I will take a few photos when I get my garage cleaned. I've been having so much fun riding that I left my tools all over the place.

My birth certificate says that I'm 37, but I am sure I'm really 14.

 

[leftywoody]

We like to snoop in other members garages so leave the good stuff out where we can see it .

 

[Crazy Horse]

Leftwoody, I (ROT-TEEPEE-F), rolling on the teepee floor that was funny, leave the good stuff out where we can see IT!!!!!

Peace Crazy Horse.