Ajustable timing plates

[2 Stroke Screamer]

I keep reading about how much of a difference the ajustable timing plates make to the performance of the shee's but what I'm not 100% sure of exactly is how much of a difference it makes. Is it a small gain in power or will it yank your arms out of their shoulder sockets kind of performance

[jbooker82]

It is a small gain. It gives you a stronger midrange.

 

Poring and Pipes are much more hp gained.

[madjimmax]

The initial gain is small, but as with any performance mod once you compliment them with other mods thats when they shine.

[muggzy]

I've been considering this mod. for a while too. The common timing change I keep hearing is +4 degrees. I have a Wiseco stock throw crank and cool heads w/22 cc domes. Advancing the timing puts additional stress on the pistons/crank/bearings b/c the plug is firing before the piston reaches top dead center(TDC) - but then most of our mods are stressing something somewhere. Anybody have problems with this or what are you doing to maintain reliability?

Edited July 30, 2010 by muggzy

[2 Stroke Screamer]

I've been considering this mod. for a while too. The common timing change I keep hearing is +4 degrees. I have a Wiseco stock throw crank and cool heads w/22 cc domes. Advancing the timing puts additional stress on the pistons/crank/bearings b/c the plug is firing before the piston reaches top dead center(TDC) - but then most of our mods are stressing something somewhere. Anybody have problems with this or what are you doing to maintain reliability?

 

 

Yeah I'm hearin you Muggzy I suppose allot of people would say welding the crank will maintain reliability but I'm not sure I want to pull down the motor just for that I'd rather wait until it needs a top end rebuild and do it all at once if you know what I mean, I suppose my biggest concern is detonation that will stuff a piston in no time flat which is why were probably hearing a standard bench mark of about +4 degrees. I know in cars we used to run +6 degrees all the time maybe its different for a two stroke.

[2 Stroke Screamer]

most engines do not fire at TBC. the usually fire just after TDC.

 

also putting an adjustable timing plate on will net zero HP. it is the adjsuting of the timing that give or takes HP.

 

and about detenation, you have to use higher octane gas.

 

What octane are you running the best I can get down here is 98 octane

[2 Stroke Screamer]

i will only be running 93 octane, but i am not sure if your 98 is rated the same as our 93.

i think the US uses AKI rating, and where you live they use RON.

AKI = (MON+RON)/2

 

not sure how you work that rating out but I was always under the impression that the fuel you guys have is allot better quality than down here

[2 Stroke Screamer]

all fuel has an octane rating.

there is

RON - Reasearch Octane number

MON - Motor Octane number

AKI - Anti-Knock Index

 

RON is usually the highest and MON the lowest with AKI in the middle.

 

so really 98 RON would be close to 93 AKI

 

Ok thanks for that I'll do a little research on that one . so you recon 93 AKI with timing set at +4 degrees should handle that ok?

[2 Stroke Screamer]

well it depends on what other mods you are running.

 

Uni filter, Jetted carbs 270 mains 27.5 pilots 3rd clip, v-force 3 valves, stock head & bore, fmf sst pipes and silencers. Will be fitting a cool head in a couple of weeks time. thats it so far I think I got it all!!

[2 Stroke Screamer]

run 22-20cc domes and you should be fine with your 98 octane.

 

thanks !

[muggzy]

most engines do not fire at TBC. the usually fire just after TDC.

 

and about detenation, you have to use higher octane gas.

 

Hey guys, just a minor correction;

 

The spark plug in a two stroke engine fires way before TDC.

http://www.southernskies.net/page_info/runningtwostrokeengine.html mid page just under "Compression Stroke"

This gives the fuel time to ignite and reach maximum explosive force just after TDC. The higher octane fuels resist self detonation and higher octane is necessary for higher compression ratios. Igniting the fuel earlier may cause the full force of the ignition to occur before TDC and that is what causes knock. what you're hearing is the up stroke of the piston fighting the fuel detonation wearing out the connecting rod, crankshaft, bearings and burning holes in pistons.

 

Having said that, motor engineers time the ignition system with some "cushion" time for engine reliability and other variables. +4 degrees is probably OK but you might not be able to hear the knock. Are you using the bike for competition or just good times? Do you care if you have to rebuild your engine more often or do you like doing that as much as riding?

[prssantana]

The point of the adjustable timing plate is so you can advance the ignition timing to compensate for the amount of fuel or octane. Like it was already stated higher octane burns slower so the timing needs advanced. If you are bringing in more of the same octane fuel it will take longer to burn. +4 is what most people are using and many of them also say its a starting point. The thing is that you can adjust carbs to compensate or adjust the plate to compensate for the carbs settings. Either way the point is to make you banshee run a little better and hopefully gain a few horse.

[SLORYDER]

Uni filter, Jetted carbs 270 mains 27.5 pilots 3rd clip, v-force 3 valves, stock head & bore, fmf sst pipes and silencers. Will be fitting a cool head in a couple of weeks time. thats it so far I think I got it all!!

 

Dont waste your money on the coolhead.

Don't waste your money on the timing plate.

 

That's 300 ish bucks and you will gain maybe 8-10 horsepower if you stick to pump gas.

 

You can shave your stock head. 35 bucks

You can elongate the holes in the timing plate yourself for free.

You can send your jugs to get ported by RB racing for around 200 bucks. That's 300ish bucks and your gain will be about 20hp.

 

But go ahead and follow the lemmings if you want to

Edited July 30, 2010 by SLORYDER

[muggzy]

Dont waste your money on the coolhead.

Don't waste your money on the timing plate.

 

That's 300 ish bucks and you will gain maybe 8-10 horsepower if you stick to pump gas.

 

You can shave your stock head. 35 bucks

You can elongate the holes in the timing plate yourself for free.

You can send your jugs to get ported by RB racing for around 200 bucks. That's 300ish bucks and your gain will be about 20hp.

 

But go ahead and follow the lemmings if you want to

 

What he said...

The only reason I have some of the stuff I got is b/c the rich kid that owned it b4 me didn't know any better

[prssantana]

If only all of us lemmings were so enlightened or is 35 dollars + shipping worth it for an adjustable plate. I think yes and seems most everyone else does too. You have your opinion we have ours why don't you present it like the rest of us without being a condescending prick.