Drilling Holes for mounts? - motor mount - pics



Just got the engine from fleebay.

Somewhat of a b**ch to figure where to drill the hole in the frame!

I had to use 6mm washers to shim the back mount - Pain in the you know what.
Fit, Mark, And Drill

I had no problems determining where to drill the hole for the lower mounting. Here's how I did it. [Oh, and NO math involved!]

1. Bribe a friend (in my case - my wife) to help.
2. Cover the down tube and bottom tube with masking tape or a cloth so you won't scratch it.
3. With the front mount attached, but without the center bolt (that will eventually run through the frame), place the engine in position aligning the rear over the down tube and placing the front mount against the lower tube.
4. Move things around until they seem to be sitting flush. You can even put on the rear motor mount bracket to help hold things in place (or just let your friend keep holding it while you act is if you're in no hurry :D )
5. With a sharpie or a pencil mark the edge of the lower mounting plate and the hole if you can reach it.
6. Take everything back off and let your friend's arms rest.
7. Now you can remove the lower bracket and hold it up to the markings you just made in order to ensure that your mark for the center hole is in the right spot.
8. Drill Away! - Be sure to start with a smal bit and get larger.
9. When the hole is just large enough for the bolt, reassemble the mounting brackets with the lower bolt in place.
10. Pull off all the tape on the tubes and with the help of your buddy (whose arms are just starting not to feel like jello anymore) carefully set the engine into place.
11. Tighten down the bolts, touch up any paint scratches, and Ta-Da! Your done!

Hope this helps.



BIG Help !

Straight forward answer.

I greatly appreciate such.

I will search for the pulley (idler) problem next.

It is not parallel with the chain because the lower arms off the crank are not parallel with the chain (perpendicular to the rear axle) - they are slightly angled outward.
lotsa_mpg said:

The bike he brought me had a huge diameter front downtube and I just didn't like the idea of drilling a hole through the frame in order to mount the engine. So, I ended up fabricating a custom aluminum mount that goes over the top of the frame tube with a curved metal plate going around the bottom. It proved to be an awful lot of work to get it right, but it turned out pretty sweet...though it is the main reason I had to mount the engine as high as I did.....Yet, it seems that the higher mounting has worked out for the better and the bike really handles well.
Big Fan of Charlies Fit, Mark & Drill "No Math" technique for wide tube

I actually saw Charlies post after using the same technique myself. It was very reassuring. Since my down tube was too wide, I also drilled using the "No Math" method of taping the area and using a sharpie to mark where I needed to drill and approximate angle - without a friend to help support the motor (my aching back). I needed to replace the long studs from the front engine mount with shorter ones supplied with my kit. I screwed on two nuts to each small stud at a time, got them snug using two wrenches, one right on top of the other, then used the nut closed to the engine block with a wrench to work the studs out counter clockwise. Installed the new shorter studs the same way (righty tighty this time, of course). The original studs were so long they scaped the sides of the wide tube. Then I added the mounting plate with bigger hole in the middle for the bolt. I needed a longer bolt to make it through the tube up to the mounting plate, so I found one at the Hardware store along with a very thick rubber washer, cuz I new I would have some free space between the plate and tube and figured this would be a great way to create a motor mount. The Washer rocks - now I have a rubber isolator on the front, and rubber from an old innertube on the rear tube mount to reduce vibration in both places.:D


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