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Discussion Starter #1
Anybody ever double up the springs in their points to get more RPM out of them? I've been told from racers running them, that the valve springs I just put in my 350 Honda are good to at least 11,500 but they also said the points will float around 10,000. I want that extra 1,500 and can't afford an electronic ignition.

I fully expect them to wear out faster, no biggie. I'm going to try the springs from my current well used points added to a new set and run it, but was wondering if anyone had done it before.
 

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I have never floated points. In my experience, stock valve spring retainers cause valve float at 11,500 RPM. Lightweight aluminum retainers float at 12k and then break.

Ken
 

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i cannot imagine getting retainers to live beyond 12k should be too tough

tried shot peening & cryro of xray confirmed good stockers?

I'd stab them with steel shot to an alemite height of around 15 thou just for chits and grins...

if that did not work I am sure better metals can be had without having to do ti retainers, valves an CuBr seats

you are probably being told right on the points.... what most do not know.... so they cannot tell you is

the same ignition condensors which will result in long point contact life for a street riding... will no balance the LCR circuit for racing speeds...

so you will need to study a bit to decide if I'm blowing smoke... and then decide if you will require more or less capacitance to minimze metal transfer between the points contacts

they are measured in micro farads

mfd's
 

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and of course, double the springs and use some known high quality extreme pressure grease on the points cam so the damnits do not wear rapidly and have you adjusting the points halfway through a race
 

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When I had points on my 175 I always figured if a set of standard points could suffice a V8 revving to 6k, then they'd probably suffice a twin revving to 12k ... if you see what I mean. But then the factory redline on the 175 was 10K anyway.
It's been my experience that most race bikes running points usually have other problems that limit their performance prior to the points becoming an issue.
Ti retainers are cheap enough, long lasting, and I've run them to 13k no problem with lightened rockers, Kibblewhite springs, a reasonable cam profile and good oil.
JohnnyB
 

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Discussion Starter #6
I was told not to lighten my rockers. In fact I was told one of the first things to do when you get a hot cam is to weld them up and have them re-profiled to take the added abuse. I have a stock cam, valves, retainers, and Performance Machining valve springs straight out of the back of Cycle Rider from the 70's.

It's not a race bike, I don't have the money to race, nor the riding skill but I want to do what I can on the street, and maybe if I ever get the itch I can safety wire it and hit the track.
 

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quote:Originally posted by HackAsaw

I'd stab them with steel shot to an alemite height of around 15 thou just for chits and grins...
What does that mean? Do you shot peen them into grease fittings?
 

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it may mean that and could possibly be evidence of dementia

i'll google dementia and get back to you on this one
 

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As far as rocker arms go...depends on the engine and the design of that particular rocker. I can only speak to the rockers on small Hondas 175 and below. I've never personally seen a Honda rocker break, typically they'll eat the cam/lobe side long before they break.
Here's what a typical lightend stock Honda rocker would look like.
http://www.jrbranson.com/HondaRacer/honda/valve_rocker_arms.htm
I performed similar lightening to all the rockers used in my race engines, could spin them to 13K no problem with about twice the spring pressure of stock springs. Important to lighten them in the right areas, areas of low stress and high Moment Arm.

Doesn't seem like much, but a reduction of 7 grams in the right areas can shift the float rpm enough to make it worth while.

Most of the time rocker welding means hardfacing the rocker pad where it contacts the cam, not welding on the structure of the rocker arm itself which would probably just compromise it's strength and warp the rocker shaft bore....which has very small tolerances.

JohnnyB
 

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HackA,
I was just relating my personal experience with the listed components in my race engines. In fact, with the engine configuration I was running, 11.5K worked just fine and was very reliable, for a race motor. 12K didn't seem to offer an advantage in performance but did add noise and accelerated wear to the components I was using. I am sure that I could have easily upgraded the springs, valves, retainers and cam to gain more rpm, but at what expense and cost to reliability? I bet I could have found more HP by getting it on a dyno (or dino since this was in 1981), fine tuning the carburation (30mm Lectrons)and removing the alternator rotor ( I like charging systems).

The package could have been developed further but I didn't feel like it at the time.
Ken
 

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quote:Originally posted by HackAsaw

it may mean that and could possibly be evidence of dementia

i'll google dementia and get back to you on this one
Didja mean Almen height?

It's OK, we still love you.
 

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Points on a 350 run at half engine speed. 12krpm should not be an issue for these, at all. That's only 6k rpm for the points. Meager by any standards.
 

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If you put it on 'scope' or even timing light, you'll see missfire/ points bounce about 11,500rpm.
I don't modify rocker arms to quite the same extent as jbranson but I've never seen one break either, even when modfied.
Seen pads wear and cam bearings seize through lack of oil many times though.
If you have them welded, they need to be slightly longer on front/rear of pad so it doesn't dig in to 'lumpy' cam

PJ
 

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looks like it :D
In my experience, the roller bearing big ends fails mainly because of low oil level, old/dirty oil or heavy pistons and 11,000+ rpm
The way oil is fed into big end works very well, crank doesn't flex enough to break cases or cranks.
I did manage to break big end on my CD175 though, but, I was chasing a GT500 at the time (around 13,500rpm)
The top end is weak spot on CB350 and CB360 (and CB450/500twin)
PJ
 

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I've seen quite a few bits lightened and polished that demonstrated somebody had no clue where to lighten.... why it was to be polished (not to make it shiny in most cases) or why when it was all said and done


the whole shooting match truly needed peening to destroy all that pretty shiny work


I haven't peeked at the link you posted, JB, I'm sure they are fine.

Yes, I meant alum, the stuff found in good douche bags.
 

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Rockers are one of the easier parts to lighten because for the most part...the bits farther from the pivot point are both the most advantagous to lighten, and the area under the least stress. Which is not always the case, some parts are somewhat counter intuitive in spotting the areas stressed the most.
A rule I always try to go by is removing metal from areas in compressive load more than I would an area in tensile load. And remove metal from areas that move more, than from areas that move less.
Some things you just have to try, and if it breaks you don't try it again...at least not the same way. Always keep in mind the cost/benefit analysis.

Only issues I've ever had with Honda twin bottom ends is them starting to stretch the main bearing case bolts when they start touching 13k rpm. I solved that with higher strength bolts from Metric Multistandard and a bit more torque. Again, this was on 175's, can't speak to the different circumstances of a 350.
JohnnyB
 

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I had a stress riser and some parting line flash once.
 

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I looked at the link.....

I can't say the netherlands modified rocker makes complete sense to me or appears finished.

Are there no top & bottom comparison shots?
 

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I've never hopped up one of these engines and probably never will...

from what I see there is only one reason to weld on those rockers when installing a higher lift cam having a smaller base circle approaching or at a maximum area drag race type lobe

I am speaking in very general terms, but, the reason would be along the lines of where PJ has pointed

without having the pieces all in hand... I'd be more inclined to think, in respect to approaching maximum area, the surface which contacts the cam lobe would require it's radius to be modified as opposed to it's span being lengthened

especially so if using larger diameter retainers

I'd gladly stand corrected if wrong



quote:Originally posted by Mercury Kid

In fact I was told one of the first things to do when you get a hot cam is to weld them up and have them re-profiled to take the added abuse. I have a stock cam, valves, retainers, and Performance Machining valve springs straight out of the back of Cycle Rider from the 70's.
 
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