Topic: cyclex lightened alternator cb750 k6 motor

[bucky katt]

i am considering getting the lightened alternator, the version i can still use electric start if i choose to. have anyone here used one, or is using one? this is for my k4 750 with a k6 motor. it has .75mm over pistons, 77 750f cam, 4-1 header and a HondaMan ignition with stock coils and TEC points and last but not least, i'm running a 17/46 sprocket set with a 110/90/18 rear tire. is it worth the money? is there a big difference in how quickly it will rev?

[MRieck]

 It really can't be much lighter than a later model rotor. I'd spend the money on crank work

[bucky katt]

ahhhhhhhhhhh ok. i just had the bottom end apart to check clearances and all. i was just looking to get a little more out of it if possible. if i get the one that is kick only will there much of a difference there? the other reason for not tearing it down now is, i just got it back on the road after more than 2 years and i'm not going to waste the best part of the riding season    thanks for the info Mike!

[754]

I run the stock alternators cut down, and run kickstart.

 You can still chop some weight off the stockers and use electric start.

 I think that alternator kit, cost more than going big bore would have..

[sangyo soichiro]

if i get the one that is kick only will there much of a difference there?

I think the kick-only Cycle X system has an aluminum rotor.  I think this difference in weight would be noticeable.  However, that system costs about $450, and like Mike said, the crank might be more effective (and cost less).  Although I understand why you don't want to take the crank out so close to riding season.

I think the major things to lighten are the crank and the rims.  Expect about a month or more for your crank to get worked on though if you go that route (APE still has mine, and it's been about a month). 

[754]

3 3/4 pounds I think is the kick one.. early rotors are around 8..
 K3 and newer are probably around 5 ish..
 might try to weigh one today..

[Doctor_D]

Sorry for the thread-jack, but does anyone have a picture of a cut-down stock rotor?

I've tried using the search function, but mustn't be using the correct keywords.

[bucky katt]

it's the cut down stock rotor that i was talking about. they had them at 2 levels, cut down but still able to use electric start and kick start only. i'd go with kick only if my back wasnt in such bad shape but there are times when i just cannot kick fuzzycycle over

[ev0lve]

I do love this board.

Went looking for a pic - found a thread on Practical Machinist. I enjoy larning.

http://www.practicalmachinist.com/vb/general/lightening-cb750-alternator-158836/

This guy's machined down rotor. 2.5 lbs lighter


"The only good things I noticed is it seems to be happier at higher RPMs, the motor seems to run smoother when getting on it. It's also easier to shift smoothly. You can let the clutch out with a bigger difference between the road speed and engine speed, and not have as much of a lurch, either way, accel or deccel. Another thing is it seems not to mind cruising in lower gear as much, like when I'm debating on whether to upshift, and stay behind a slow moving car, or crack the throttle and pass, it doesn't seem to mind sitting there in the lower gear until I decide. Overall it just seems to run smoother, but not a big difference either way."

I wonder if folks on here are on there as well. Seems likely  
Hope that's helpful!

[bucky katt]

it is, thank you kind sir

[754]

I weighed a 72 rotor at around 7 lbs yesterday.

 If you are racing off the line and start to bog, you have better control of your  rpm,s with a ligher rotor.

 Really high revvers with the old heavy rotors, have occasionally snapped the end off.. probably did not have a stock clutch and may have not had a cush drive.

 It might just be me but if I want to catchup  or get to speed quicker, I often slip the clutch while grabbing a big handful of R,s.(rather than downshift, and then upshift)

 Usually like if I am doing say 20mph in 2nd type of thing.. but you must have a clutch that can take it..

[Jim F]

Do you know someone that is a machinist ?

I turned mine down my self but I really cant tell much different as I did
this before I built the engine

Jim

[Fabricator]

Jim,

  Are you in Dacula GA?  My shop is in Gainesville.... Keep the parts under 36" and I can turn them! (Up to 26 ft centers    )

Fabricator
 (Christopher on PM forum...)

[754]

Its easier than drilling a disc..

 Most that do them say they rebalance or check them..
 The several I did were checked for balnce and they said they were OK, but I am not positive they used a proper mandrel..

 If you use a lathe with any runout, or dont use a proper mandrel, it will probably need balancing..

[bucky katt]

at one time i did have access to a machine shop but not for the past year or so, and after the treatment i got yesterday and today, i'll not be calling cyclex for any more parts, not if thats how they treat a customer that over the past 5 years has spent a good bit of money with them.

[nokrome]

at one time i did have access to a machine shop but not for the past year or so, and after the treatment i got yesterday and today, i'll not be calling cyclex for any more parts, not if thats how they treat a customer that over the past 5 years has spent a good bit of money with them.

  uh-oh, what happened at cx?

[bucky katt]

not something i want to air out here in this section