View Single Post
Old 10-06-2012, 09:12 PM
Nashville Kat's Avatar
Nashville Kat Nashville Kat is offline
Motorized Bicycle Elite Member
Join Date: Apr 2009
Location: Jacksonville, Florida
Posts: 1,403
Default Re: Looking Low Weight Engine Kit

My two builds so far have been about pedal-ability and light weightness.

The four largest gains I think one can make with the China Girl kits- if you chose that- are:

1. Eliminate the chain tensioner- I use a cruiser frame with pretty wide rear seat stay clearance- unfortunately i think a mountain bike may be a bit harder to get rid of the tensioner- but I've never tried

2. Use a 415 Trike/ Industrial chain- only about HALF the weight of a standard kit chain- and ROLLS BETTER too with smaller plates- helps BOTH the motor and for peddlin.

3. Use a smaller alloy motor sprocket
The smaller the motor sprocket- the less weight it is and the less links the chain is- when you use a 36 or 34 sprock with NO tensioner, you can take out iNCHES of motor chain links. Depending on your riding style and the bike- so light narrow rolling wheels and tires are what I like.

Outside of the motor the heaviest pieces are the tensioner (gone), the motor chained (halved), and the motor sprock and rag joint- (less than halved while still ragged and way less than halved directly bolted to the hub with titanium)

4. Use a smaller tank- the smaller of the two sizes is only a slight dif empty, but the weight of gas really adds up fast- depending on how far you ride and how easily you can get gas. Mc Donalds is tried and true for that!

Another thing- slightly more cost- but don't discount it- TITANIUM BOLTS-

You'd be surprised how many bolts you can replace in a motor- but you may spend another 40 or 50 dollars to do it all- still they are really clean looking allen bolts that reduce the need for a lot of screwdrivers Also titanium on rag joint/ motor sproket bolts- I have a build with a 34 alloy sprock bolted directly to a high flange flip flop hub with small 5 mm TITANIUM bolts- The RAG JOINT is TOTALLY eliminated.
It's a 700c wheel that feels like a featherweight road bike wheel but still 36 spokes and about a 1 1/4 inch profile worth of rubber.

I'm not sure what the weight of my kits are under the stock weight- but it's a considerable chunk- and I've generally yet only replaced the clutch and cover bolts with titanium- two motors I think cost about 20 dollars so far

good luck
Attached Images
File Type: jpg b.jpg (308.4 KB, 24 views)
File Type: jpg b2.jpg (305.9 KB, 27 views)

Last edited by Nashville Kat; 10-06-2012 at 09:23 PM.
Reply With Quote