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Author Topic: LED HPI ignition install with pics  (Read 355 times)

Offline Jerry Hall

Re: LED HPI ignition install with pics
« Reply #15 on: August 06, 2019, 11:13:38 AM »
I do not know if anyone else has noticed a trend with the effects the flywheel weight has upon the life of clutch baskets and broken gears in the transmissions.  I am seeing this trend in customer engines.

Basic engineering and physics supports what I am seeing,

A heavy rotating crankshaft assembly (crankshaft and ignition flywheel) spreads the power impulse delivered to the clutch and transmission over many more degrees of crankshaft rotation than lighter rotating crankshaft assemblies. 

Metals have limits on the amount of stress they can be subject to before they fatigue, crack and then have catastrophic failure.  Lightweight crankshaft assemblies and the increase in the torque of the big bore kits increase the spike in stress that the clutch and transmission must experience.  When a metal is stressed below a certain level the metal behaves like a spring. 

A prefect spring (metal) when stretched, returns back to it.s original shape when a certain stress level is not exceeded with absolutely no long term damage. When a spring (metal) is stressed slightly beyond this certain stress level, the spring will become permanently damaged and begins to fatigue.  Every time this certain stress level is exceeded, another fatigue cycle is added to the count of cycles before the metal fails.  If we dramatically exceed this stress level where permanent deformation of the metal occurs, we dramatically reduce the number of cycles before catastrophic failure occurs.   

In summary: 

As we increase the amount of torque an engine develops and reduce the weight of the ignition flywheel....... the sooner the clutch basket tabs are damaged and transmission gears may break.

Offline coops86250r

Re: LED HPI ignition install with pics
« Reply #16 on: August 07, 2019, 10:26:28 PM »
Sorry for the lengthy time between replies folks, working some hellish hours the last few weeks.

I haven't had a chance to get any ride time, I'm still finishing up the build.  I gotta fab up a small bracket to mount the new coil.  I'm going to tuck it up under the gas tank on the clutch side.  This will give me a nice short run to the plug and also keep the coil away from the CDI box.  Realistically I'm probably a good month away from first start up with it.  Still have a few loose ends to tie up to get it to my liking. 

Jerry, I read your post a few times and was a bit confused by what direction you were going in regard to adding weight.  The bulk of your reply to me read that adding weight is causing failures from what you are seeing but your summary implied by my reading of it that as you increase the power (torque) of your motor a lighter flywheel leads to premature clutch basket wear and possibly transmission gears breaking.  Am I reading that wrong folks???

As far as the weight of the HPI unit including the flywheel weight I'm guessing it is still a tad lighter than oem.  I didn't weigh the HPI flywheel and weight before putting them on.  From the instructions, the flywheel weight is 280 grams.  I still might pull the flywheel back off and get a weight for everything.  Give me a chance to go through the set-up again lol.

Thanks for all the replies folks and I'm happy to help!

Tony
86' 250r, bone stock for now, upgrades coming soon!

Offline All250R

Re: LED HPI ignition install with pics
« Reply #17 on: August 08, 2019, 07:31:13 PM »
Jerry, I read your post a few times and was a bit confused by what direction you were going in regard to adding weight.  The bulk of your reply to me read that adding weight is causing failures from what you are seeing but your summary implied by my reading of it that as you increase the power (torque) of your motor a lighter flywheel leads to premature clutch basket wear and possibly transmission gears breaking.  Am I reading that wrong folks???

He's saying that the more mass that the power pulse of ignition has to move, the less sharp the effect of that pulse has on the connected components, ie, the clutch and trans gears, etc.

Offline mwiley

Re: LED HPI ignition install with pics
« Reply #18 on: August 08, 2019, 10:19:08 PM »
So, does the flywheel still use the key-way on the crank?

Online hickwheeler

Re: LED HPI ignition install with pics
« Reply #19 on: August 08, 2019, 10:23:30 PM »
No it just uses the taper fit
88 hybrid 431 puma
88 (BOF Build) stock motor and oem 89 plastics
More in the works

Offline coops86250r

Re: LED HPI ignition install with pics
« Reply #20 on: August 08, 2019, 10:29:56 PM »
As Gene said, it is a slip fit to the taper of the crank, no key.  Mine was a very nice match flywheel taper to crank taper so all I really needed to do for it to hold position was just pop it with the palm of my hand.

Tony
86' 250r, bone stock for now, upgrades coming soon!

Online The norm

Re: LED HPI ignition install with pics
« Reply #21 on: August 08, 2019, 11:31:40 PM »
It wouldn't be to awful hard to key these aftermarket flywheels, but a taper bore driven up a tapered shaft is an extremely strong connection. What good is the woodruff key in your oem crank shaft alone? It is too weak to hold the flywheel by itself.  It is basically there just to time your flywheel. It would take a whole lot more horse power than a 250r can produce to spin the flywheel out of time if properly seated.

Loren
1986 Trx250r-- Hybrid Engineering 391(Good bye super 310)
1986 Trx250r-- Hybrid Engineering  ported stock 86 cylinder
1986 Trx250r-- craigslist engine with unknown ported 89 cylinder.
1985 Atc250r-- Needs a lot of work (Super 310's new home)