Topic: Reducing the number of teeth on the front sprocket ....

[Zane]

My '76 400F came stock with 17 teeth on the front sprocket and 38 on the rear.  If I replace the rear with the stock, 38 tooth sprocket but then replace the front sprocket with a 16 tooth version, what will be the effect?

(I ride about half and half between longer, highway trips and tighter, stop and go city riding.  I'm 190 pounds, dressed for riding.)

[nickjtc]

You'll need 6% more engine revs to achieve the same speed as before. So if, for example, you were cruising along at 5,000rpm at 60mph, you will now be having to turn over at 5300rpm to achieve the same speed.

[OldSchool_IsCool]

You will have more acceleration, but you will sacrifice top end speed.  You may also wear your chain quicker as it has a smaller radius to turn through.

This thread is a good read on the topic...

http://www.sohc4.us/forums/index.php?topic=12577.0

[750goes]

Zane,

this is nothing to do with SOHC site but try this link it makes it simple....

 


http://www.dansmc.com/mc_software1.htm

[Zane]

That's three good posts - thanks!  I understand how it works quite a bit better now.

I'm going to stick with the 17 tooth front sprocket for the type of riding I do.  I already rev my bike motor pretty high, and anything that might add stress to the chain sets off alarm bells for me. 

(One of the reasons I wanted info about 16 tooth sprockets was because there's one for sale on ebay (for low bucks), and I thought I might try to win it, just for a back-up.  However, unlike the rear sprocket, I can still get the oem front from Honda.)

(That "danmc" site is fun.  I've seen some good info there before - and his pdf of the 400f parts list is the highest quality - for printing the diagrams - that I've found.  I made 13" x 19" enlargements and they're sharp as a tack.

I also got the idea from him to throw a bit of epsom salt into my battery.  Sounds weird eh?  But it worked for me, and I haven't had a problem with that battery ever since ....)

[nickjtc]

When I recently changed the chain and sprockets on the 650 I went down two teeth on the rear. Most of my riding is highway, so I wanted to reduce the revs at any given cruising speed. The change didn't seem to affect the poke off the line (but then again I'm not particularly fast) certainly made things a tinch more relaxed at highway speed.