Mike SVOR

My Feedback: (1)

...could also drill 'lightening' holes in the clutch shoes themselves to increase stall and decrease rotating weight.
Shown in red circles in the pic...

lt250dave

I would be more inclined to "lightening" the shoes than to try the fuel tubing trick, since adding preload to a spring doesnt change the "rate" or stiffness of the spring.

highspeeddirt

My Feedback: (1)

Why not just buy an adjustable clutch? Or a 4 shoe racing clutch for a FG? I wouldn't drill holes in the shoes it could throw the clutch out of balance.

Mike SVOR

My Feedback: (1)

Did you say 'buy'??? [sm=tired.gif] lol j/k

It isn't hard to drill the holes in the same spot if you mark it out right.
Start with a small hole and move to larger drill bits till the stall is cool.



you gota link for that adjustable one?

Mike SVOR

My Feedback: (1)

I've heard this saying go around the internet for a few years now. I'm wondering where it came from.

If that saying were true, then adding shims to the top of my valve springs wouldn't increase the seat pressure.

A spring DOES get harder when compressed and tension Does increase the farther it's stretched.
Take that clutch spring and pull it appart just slightly. Then try to pull it all the way out.

lt250dave

there are different types of springs. Progressive rate and linear or fixed rate


Spring rate: refers to the amount of weight needed to compress a spring an inch (Example: 500 lb. per inch) To understand and properly check a spring for rate you need to know the factors that determine the rate of the spring. Fortunately, there are only three things that affect spring
1. Wire diameter - This affects rate since greater diameter wire is stronger than lesser diameter wire. So, when wire diameter is increased, spring rate increases.
2. Mean diameter of spring - Mean diameter is the overall outside diameter of the spring less one wire diameter. When mean diameter increases, the spring rate decreases.
3. Active coils - Determination of the number of active coils varies according to spring design. Count the total coils minus two for springs with both ends closed. Count
the total coils minus one for springs with one end closed and one end open. As the number of active coils increases, the spring
rate decreases.

If a spring's rate is linear (most racing springs have linear rates) its rate is not affected by the load put onto the spring. For example, a linear rate spring rated at
500 lb. per inch will compress 1" when a 500 lb. weight is placed onto the spring. If another 500
lb. weight is put onto the spring the spring will compress another inch. At this point the load on the spring has increased to 1000 pounds. The rate of the spring, however, remains constant at 500 lb. per inch.

If the load put onto a spring increases the rate of the spring, the spring is said to have a progressive rate. Progressive rate springs are sometimes used on torque arms to absorb engine torque. Keep in mind that the load (or preload) put onto a progressive rate spring can greatly increase the rate of the spring.

Progressive rate springs are made by varying the spacing between the springs' active coils. During compression the close coils bottom out and deaden. This reduces the amount of active coils and spring rate increases as a result.

Springs that are designed to include coils of different diameter or are wound using a tapered wire will also produce a progressive rate.

After i found this, it sounds to me like a clutch spring has a fixed or linear rate

Mike SVOR

My Feedback: (1)

yep, I agree

TurtleRacing

The clutch springs are fixed rate & will not provide more tension as extended. Tubing will not help. Lightening the shoes will do the most for higher stall & it's not a problem, use the same drill on both shoes & get close to the same location.

Mike SVOR

My Feedback: (1)

So you're saying if I can stretch that spring .005 thousandths it will take say 5 lbs of force. And if I want to stretch that spring 6 inches, it only takes 5 lbs of force?





it's a spring. the further you stretch it, the harder it gets.

TurtleRacing

A 5lb. spring is a 5lb. spring unless it's dual rate. Do a search on the subject, I have an engineers book here that says the same thing.

Mike SVOR

My Feedback: (1)

Now take that 5lb spring and stretch it 1". It's now exerting 5 lbs of force. Stretch it another inch. It's now exerting 10 lbs of force.

Please explain how you can stretch a linear rate spring and not see increased tension.

TurtleRacing

If a spring's rate is linear (most racing springs have linear rates) its rate is not affected by the load put onto the spring. For example, a linear rate spring rated at
500 lb. per inch will compress 1" when a 500 lb. weight is placed onto the spring. If another 500
lb. weight is put onto the spring the spring will compress another inch. At this point the load on the spring has increased to 1000 pounds. The rate of the spring, however, remains constant at 500 lb. per inch.


What you're saying is there is no need for dual rate or progressive rate springs, linear springs already do what the progressives are designed for?

Mike SVOR

My Feedback: (1)

Huh what? No.

Look. How about this.
I'll bet you 1 dollar, that if you put tubing over the ends of the stock clutch spring to increase the pre-load, you'll see an increased stall rpm.

Plain and simple.
No engineering books needed.

radio_controlled_mad

or u could just add a ,3,4 shoe fg adjutable clutch

TurtleRacing

Do you take PayPal?? I'll take your word for it, but I'm not sure there's enough room for tubing on these springs is there??

Mike SVOR

My Feedback: (1)

Yea, I think that's gona be the best way. I looked at the spring holes again and it doesn't look like there's room enough for anything other than the spring.

ammdrew

you may increase stall, very slightly, but you will not change the spring rate.

The best option is to lighten the shoe or go aftermarket on the clutch.

look into the 1/4 world they have some pretty trick two shoe clutches that have been extensivly lightened, only real issue is the shoe blowing up, you will not have any balance issue, the tolerance levels are not very close on the stock shoes.

note depending on were you remove weight will vary how hard the shoe hits and when.


you can gain and loose a lot of power in a clutch.

Mike SVOR

My Feedback: (1)

any and all clutch links would be appreciated.

lt250dave

My Jetpro pipe came today for my Baja and i have to say what a difference [sm=thumbup.gif]. where it use to be a turd for twenty feet and then run good, now its blows the tires off from just above idle and revs to the moon. (I still need to twist on the screws a bit, i think i can get it tuned a little better on the bottom end.) Not to mention its a nice piece of eye candy. I was kinda worried about it hanging out the back but it looks to be tucked back under the wing far enough that it should be fairly safe. Next i think i am gonna look into a reed kit for it. I am gonna try to keep the CY23 for as long as i can cause i love how high a small displacement motor will rev............

I would have to give the Jetpro pipe a 9/10.

*Great finish
*Great fit / for the lack room they had to work with
*Great price from DDM and super fast shipping
*Nice vinly stickers
*Included fasteners & gasket

the only negative i have is the instruction sheet i got with the pipe was unreadable, it looks like their color copier ran out of ink. But really, how hard is it to put on a pipe? it might have taken 15 minutes total to put it on and that included getting out the Dremel and cutting off the stock tail pipe mount. Piece of cake.

in closing i am a very happy customer both with Jetpro and DDM. I am sure i will be buying from them in the future.

Timmahh

theres a guy who just posted in another forum for exactly that, an aftermarket reed kit for CY and Z engines. 150.00 i think was the going rate. he cliams it adds alot to the overall engine in hp. says he developed for goped racing, and is now focusing on RC! i ll post the link to it when i find it again.
Timmahh

ryan@ddm

A reed intake plus proper reed porting (intake matching & increasing the intake timing to essentially always open - as the reed is now doing the job the piston skirt used to do)increases power on the Zenoah and CY motors substantially. Reduces low end bog and allows significantly higher RPMs as well.

lt250dave

well it didnt take long, i was running my Baja today and came off a jump very nose high and landed on the right rear, and my new Jetpro pipe augered into terra firma. It looks like it bent it about 5 degrees towards the tire because the wing was actually sitting on the silencer, not next to it as it was when i installed it. Oh well, i guess i couldnt expect it to last forever.

If your not breakin stuff,your not runnin it hard enough

Timmahh

dought, how much that set you back LtD. 160?
Timmahh

lt250dave

$179 from DDM. I got out a 3/8 extension though and slipped it down into the pipe and tweaked back into position just a bit ago. looks good as new [sm=thumbup.gif]

rcrcman1

Hi all I'm back after some time...but I bring goodies! a new vid from our dunes last weekend.

On the clutch mod your all talking about, lightening the shoes is the best way for two reasons: 1) Its easy and free! 2) A lighter shoe is easier on the spring so it will retain its tension longer....dont worry about the balance issue, its far to the center of all rotating parts so its balance overall is minimal if changed. We've done it for years on .21's and no issues...they turn about 2x the RPM's as these motors.

Also on the reed porting just like Ryan@DDM previously stated the reason to run a reed kit is to add intake port timing essentially letting the intake charge fill the crankcase for 360' of crank rotation, thus increasing the volumetric efficiency. Always keeping a charge in the crankcase ready to rush into the cylinder to make power. If you just simply bolt on the reeed kit without any other mods its useless. My 5b has gone through a ton of changes and a few motor R&R's to get it right but its close, I have a few exhaust timing mods to do and it will just about be done until HPI comes out with gearing options...thats what I need more than anything.

Paddles: I used the 40 series paddles just for the lower profile I used 16 per side, I remember having some of the prolines on another truck I had and they threw sand all over the car, forward, on the top.....everywhere. The 40's were shortened to minimize that, but you can cut them shorter and do the same thing insead of buying new ones....if you go to hpibajaforum dot com and look in my gallery there's a bunch of pics on the buildup of my paddles...I recently filled the paddles up with CA ta make them more rigid and stop them from folding over....it worked awesome! the CA stays put and they get a ton of grip.

Anyway onto the vid...

http://media.putfile.com/HPI-Baja-in-utah-sand-dunes

Its tough to see and the buggy is so big but I stepped off the average in distance at 40' some were longer after I leaned out the motor a bit....I need higher gearing if I'm gonna get to my 60'+ goal. But it will happen.