Hey, I need help getting my motor to stay on my frame. My down tube is too big, and whatever else I try will scratch my bike really bad.....I even put tape and it when throgh the tape. I need an alternative to drilling holes in my bike.((something less complicated))).
I noticed on both my builds that thru bolt mounts for those willing to drill a hole in the frame suffer a little from the loss of the original saddle config which made a more stable and centered fit ... chain tension and torque,especially with the 55 tooth sprocket tend to make the motor lean left a bit ... there is a slight advantage to that because it creates an added 1/8 inch of chain clearance past the tire sidewall .... if you mount up and look straight down its easy to check for that lean because you'll see 2 indications ... the spark plug sits left of the mens center bar, and you see only 2 of the engine top bolts to the left .. the other 2 are hidden under the centwer post ... to correct that lean, use a hose clamp or nicely finished chrome or brushed strap around the muffler right at the exhaust bend where it crosses over the frame .... as you tighten the strap, the engine straightens itself back to dead center no matter how tight you have made the front thru bolt because the hole has created a little metal fatigue. The lean can't re-occur because the entire top of the muffler and strap is acting in the same way as the coaser brake .... that is its now a stabilizing lever for the whole engine. I checked my first build closely over 1300 miles to see if the muffler bend was suffering any stress or fatigue when hot from this strap and nothing bad occurred, its as tight as the original install and the motor is dead on straight up. just remember that the straighter up the engine is, the closer the chain moves to the tire sidewall.