Sprocket alignment help!

#1
Hi, everyone. I bought my son a Doodle Bug recently that has a Predator engine. I have two questions.

1. As you can see in the photo, I clamped a ruler to the rear sprocket and it doesn't align with the clutch. Do I have to machine some new holes in the mount for the engine to slide over?

2. The clutch always had a lot of play along the drive shaft, which caused a lot of annoying noise while riding. Is the clutch supposed to be snug against the engine? If so, how do I make up for the space at the end you can see in photo?
20200519_120543.jpg 20200519_120808.jpg
 
#2
Predator 212? Try flipping the clutch (sprocket inboard), common practice when swapping a larger engine onto a small bike. Consensus is that the clutch should "float" on the shaft, allowing a bit of lateral movement, if you think it's excessive you could use a washer (inboard or outboard, whichever provides best chain alignment).
 
#3
Hi, everyone. I bought my son a Doodle Bug recently that has a Predator engine. I have two questions.

1. As you can see in the photo, I clamped a ruler to the rear sprocket and it doesn't align with the clutch. Do I have to machine some new holes in the mount for the engine to slide over?

2. The clutch always had a lot of play along the drive shaft, which caused a lot of annoying noise while riding. Is the clutch supposed to be snug against the engine? If so, how do I make up for the space at the end you can see in photo?
View attachment 262780 View attachment 262781
Flip the Clutch around so sprockets are in-board? Had to so that with a Manco Mini Bike.
 
#4
Hi, everyone. I bought my son a Doodle Bug recently that has a Predator engine. I have two questions.

1. As you can see in the photo, I clamped a ruler to the rear sprocket and it doesn't align with the clutch. Do I have to machine some new holes in the mount for the engine to slide over?

2. The clutch always had a lot of play along the drive shaft, which caused a lot of annoying noise while riding. Is the clutch supposed to be snug against the engine? If so, how do I make up for the space at the end you can see in photo?
View attachment 262780 View attachment 262781
The db30 came with a smaller engine and the bolt pattern is smaller than a 212 bolt pattern, so you have to drill New holes or buy the adjustable motor plate. FYI the plate I bought didn't fit the bolt pattern on my db30. So I drilled New holes,clutch ran inboard
 

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#5
Predator 212? Try flipping the clutch (sprocket inboard), common practice when swapping a larger engine onto a small bike. Consensus is that the clutch should "float" on the shaft, allowing a bit of lateral movement, if you think it's excessive you could use a washer (inboard or outboard, whichever provides best chain alignment).
Thank you. How much lateral movement would you tolerate? If I'm trying to line up clutch with rear sprocket, and if there is movement in clutch ong shaft then it becomes out of alignment, right? And you mentioned a washer. You mean placing the washer on the drive shaft closest to engine?
 
#6
Theoretically, assuming the crankshaft is perfectly parallel to the axle, if allowed to float, the clutch should self-align provided you get it close enough. I'm not an expert on centrifugal clutches but I wouldn't be concerned about 1/8" or so lateral movement. I said you could add a washer inboard (between the clutch and the engine) or outboard (between the clutch and the retaining washer), depending on which location works best for proper chain alignment, if you think it's needed, but I doubt that it would be needed. For expert advice, you could contact Max-Torque.
http://www.maxtorque.com/contact.php

Note: You won't get anything "perfect" unless it's by accident.
 

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