View Full Version : How Many Ignition Advance Should I Try

Dutch Royal T
03-19-2003, 08:30 PM
How Many Ignition Advance Should I Try without risking my Evo cilinder. 3 degrees aprox.?

I do not have an advanced ignition key. I am about to remove it all along and advance the flywheel myself. But ofcourse the wheel could move a bit when I tighten the bold.

So I might also file out the two holes that hold the igition groundplate, so I can rotate it and thus moving the pick-up couter clockwise and advance the ignition that way. That way I can keep the stock ignition key and don't have to worry about moving the flywheel while tightening.

But back to my initial question. How many advance should I try. I do not want the maximum possible, because it might screw the cilinder. Any tips 'n hints?

03-19-2003, 10:38 PM
So dutch what maintanance you have to do on your EVO cylinder and what? its probably not good for longer trips such as 50 Miles

Dutch Royal T
03-20-2003, 08:30 AM

I do not drive on it for more than 30 minutes or so. Right now I haven't been riding for 3 months.
No real maintanance. I'm gonna buy a new pistonring next week and that's it for now. Cilinder is still brand new and stuff. Has a total of 1500 km's on it. (aprox 900 miles)

tiba karotsu
03-20-2003, 08:52 AM
with .6mm squish clearance 24 degrees initial advance should be enough if you're using 98 octane pump gas. stock ignition advance is about 16 degrees so i think you should elongate the bolt holes of the stator plate by 5mm to get to that setting.

you'll notice the power kicks in sooner than with stock ignition advance which is set for 50cc cilinders. if you hear any sounds of detonation just back off the timing by 1 to 2 degrees and it's done.

03-21-2003, 06:16 AM

I will modify my original advance too! But if I want to tune it I have to decrease the ignition timing or not? U suggest increase the ignition advance from 16 to 24 degrees! (24 degrees counterclockwise is to mutch from the top dead center)

tiba karotsu
03-21-2003, 09:35 AM
for 70cc cilinders 22 to 24 degrees is good 'coz with bigger piston the flame must traverse a bigger area for complete combustion so that's why you need to compensate by making it fire earlier.

16 degrees is good for 50cc but for fine tuning it needs to be retarded by 1 to 2 degrees to get best power.

03-21-2003, 10:20 AM
This is at the EVO Cylinder's description: (this text is italian)
- a 7000 g/i a 13° dal Punto Morto Superiore

What does it mean?
a little help: Punto Morto Superiore = Top dead center

I hope u have a wrinkle!

micah apriliaforum com
03-21-2003, 10:27 AM
It means at 13 degrees before TDC at 7,000 rpm I think.

03-21-2003, 10:46 AM
13 degrees before TDC is okey! But it has got fix advance. But then 7000 rpm is unecessary detail.

tiba karotsu
03-21-2003, 11:36 AM
13 degrees is good for the EVO 70............ if you keep it at 13,000+ rpm that is.

that ignition timing will work on an EVO50 but for EVO 70cc even with 15:1 compression ratio it will be a slug below 10,000 rpm.

03-21-2003, 12:04 PM
Too much possibility!!
13, 16, 22 or 24 which is the BEST for EVO70??

Dutch Royal T
03-23-2003, 07:50 AM
13 degrees? 22 :eek:

I thought it was just a small bit, or perhaps I'm mistaken degrees for milimeters.

Ok here's the deal: we tested it on my friends Evo setup (btw is the EVO crank itself advanced?)

Ok we didn't do the ignition plate trick. We just took out the ignition key and rotated the flywheel a couple of mm clockwise.
And indeed he noticed a big difference. But he experienced that on "top" rpm. the scooter wanted to even rev more.

I just got my new pistonring. I have dome other stuff to do, but I hope i'll be riding soon again.

PS my mate bought a Yasuni 16 for his evo setup and he has my gearing (RF 14) so very short gearing. With the C16 and stuff damn, it accelerates like crazy!

tiba karotsu
03-23-2003, 08:13 AM

put the key back or the flywheel could rotate then timing goes out of whack & you end up with the scooter not starting.

no i don't think the evo crank is advanced.

what no C20?!:D


i ran 22 to 24 degrees on my stock but lightened flywheel when i didn't have the MHR inner rotor ignition & it worked great. Polini recommended 13 degrees 'coz they tested it under race conditions where rpm is always at peak.

03-23-2003, 09:30 AM
I'll try 22-24 degrees. Is it good for medium rpm use?
I think I have to change the standard CDI.

Hmm! How did u lighten the flywheel?

Dutch Royal T
03-23-2003, 12:54 PM

It seems the key isn't the thing that holds the flywheel in place. I mean like that it makes it stuck. Or at least that's how it seems to be. And when the nut is bolted on tight enough, I think it'll stay in place. Ok maybe the high RPM's could make it go loose or turn a little bit.

I'll keep it in mind and I'll probably do it the save way and customize my ground plate. Let's hope I can dremel the holes in the good diameter (the bend it has to have.)

03-23-2003, 01:26 PM
the key doesn't hold the flywheel in place, it is only there to make sure the flywheel is in the "right" place. cuz' with conical{ think that's what it is called} shape of the crankshaft the flywheel lock's itself once the nut is tightend! thats why you need a flywheel puller to get it of! if the nut is tightend like i should, it should stay there!:)

Dutch Royal T
03-23-2003, 08:08 PM
That was exactly how I thought it was.

03-24-2003, 08:58 AM
13 degrees before TDC at 7,000 rpm using a timing gun with engine doing 7000 on the tach ,

look at mallossi manual for iner rotor ,it has 2sets of recomandations depending useing a timing gun or using degree wheel

03-24-2003, 11:29 AM
Thanks iiph!!

Dutch Royal T
03-24-2003, 02:38 PM
Just to be clear enough. I'm using stock ignition and flywheel. Is it save enought to have a little bit of advance or will it run way hotter and stuff (detonation etc.)

03-24-2003, 05:52 PM
I have drilled 9 mm holes on my ignition plate and it is exstreamly rew-y. But now you are all talking about degrees. How many mm from TDC are we talking about with f.eks. 22 vs. 24ş advance?

Dutch Royal T
03-25-2003, 09:17 AM
How come yáll talk about 22-24 degrees :eek:

Here's it's 10 MAX on low RPM and about 3 on top RPM 12.000+

tiba karotsu
03-25-2003, 09:37 AM
on latest Malossi manual set ignition advance at 25 degrees BTDC (2.25mm BTDC) and with timing gun check if ignition advance is at 32 degrees BTDC @ 4,000 rpm. (using MHR inner rotor digitronic ignition).

03-25-2003, 01:00 PM
Tiba u have 3 answers for my question

"for 70cc cilinders 22 to 24 degrees is good 'coz with bigger piston.."

"13 degrees is good for the EVO 70...."

and again
" ran 22 to 24 degrees on my stock but lightened flywheel "

16, 22 or 24???

p.s. How did u lighten the flywheel?

Dutch Royal T
03-25-2003, 05:50 PM
I guess I have mistaken degrees for mm <img src=http://www.ezboard.com/intl/aenglish/images/emoticons/embarassed.gif ALT=":o">

I have now an advance of 4mm I guess. I filed out the groundplate so I could turn it, but some well known scooterguy here told me I'd better not advance at all, it could run hot or seize too easily. I don't know what you're experience is (ok my 4mm is too much, I did not test anything yet, but I'll set it to about 2mm before I will).

You did run a long time with advanced ignition with stock coils & flywheel (Tiba) ?

tiba karotsu
03-25-2003, 07:44 PM

yes and i've done so on my previous MHR 70cc AC cilinder set-up with no cooling fan (drag racing). i used 95 octane premium unleaded pump gas mixed with octane booster (now 96.5 octane).

about the 13 degrees BTDC like i said before it's OK if you want the engine pegged at 13,000+ rpm all the time but for road use you don't need peak rpm right? if you're in doubt try 20 degrees BTDC.

i had my flywheel lightened at the local machine shop, stock weight is 750g now it's 480g. for a yamaha flywheel equipped scooter we have brought it down from 108mm OD to 105.5mm, 106mm should be OK for road, do not shave off material from the face of the flywheel like we do and leave the short strip of metal intact on the flywheel's surface 'coz that triggers the ignition thru the magnetic pick-up coil.

03-26-2003, 05:59 AM
Can U change over 22 degrees to mm?
108 mm? My flywheel is 100 mm size!!

Dutch Royal T
03-26-2003, 07:45 AM
I've been using 98 octane fuel since I have my evo cilinder

98 fuel mixed with Motul 800 @ 35:1

Ok I'll try a little but of advancing.

Tiba, people on the Dutch forum (experienced people) claim that the ignition should be retarded onces on top RPM (above 12.000) and that with the set ignition, you would get too much advanving on top RPM. And too less on low RPM.

And that on low rpm's you should have more advancing than on top RPM.

I'm getting confused now. What do I do on my road setup. I do run it on the road. Of course in theory you always operate at full throttle and thus on top rpm. But not always. So I should set the advancing just a small bit so it runs good on top RPM.

Or should I just forget it at all. After all I never had any troubles so far (1500 evo km's)

03-26-2003, 08:32 AM

Tiba mentioned that the original advance is not good for EVO70 because the engine is powerless at medium RPM. 22-24° is good for road, because the engine is powerfull at medium RPM and maybe at high RPM.

(I have 4000 evo km's I won;) )

tiba karotsu
03-26-2003, 09:05 AM

dutch tuners are always extreme they all want full power from road set-up.:lol: my suggestion is to try a bit of timing advance from stock. you can get away with 22* timing advance 'coz you seldom go over 12,000 rpm anyway when you're cruising.

i have to mention that i now use MHR digitronic ignition which requires 25* BTDC timing advance then EPROM takes over and advances it up to 32 degrees @ 10,000 rpm (i think) then retards it down to 15 or 13* @ peak rpm (13 to 15,000 rpm).

you'll sacrifice a bit of overrey though but it'll make it up on throttle response & mid range where you do most of your riding.

03-26-2003, 11:21 AM
Thanks Tiba!

And what do u think about this: www.polini.com/news/uk/motori_news7.html (http://www.polini.com/news/uk/motori_news7.html)

Dutch Royal T
03-26-2003, 06:34 PM
Thx Tiba,

Much clearer now. PS Polini now also has an inner rotor (also selettra, just like Malossi, only different color and I bet also another ignition curve)

PS: I race on the road, so I do not cruise. I ride my bike on the streets like I should ride on a circuit. So I'll set the advancement to a couple degrees so it'll run good in my 12.000~12.600 powerband. about 2-3 degrees I think.


Those 4000 Evo km's, was that (partly) with ignition advancing?

tiba karotsu
03-26-2003, 08:40 PM

that's EVO ignition box, it will work the same as digitronic EPROM of MHR ignition only it has that switch to to choose from 2 different timing curves, saw that 2 moths ago on Polini's full product catalog.


i'm also surprised to see Polini also has an inner rotor (SELETTRA), yes it has the same inner rotor/stator as MHR but it has different coil & CDI (also different timing curve). have you seen one in person? can you tell me if it has reprogrammable EPROM chip like that of MHR? i saw it too on the catalog but the CDI doesn't seem to have a removeable/reprogrammable EPROM.

also i have to add about my timing advance, EVO cilinder head squish band of combustion chamber is narrower compared to that of MHR combustion chambers. narrow squish band = low MSV & wide squish band = high MSV (MSV = maximum squish velocity), even though they both have 15.0:1 compression ratio (uncorrected) normally rule of thumb follows that combustion chamber with low MSV can run more timing than the one with high MSV.

for advancing stator plates my rule of thumb is for every .5mm of movement (clockwise or counter clockwise) you retard or advance timing 1*. take note that this depends upon the diameter of the stator plate but i think we have same diameter plate 'coz we all run minarelli engines.

03-27-2003, 02:25 AM
Dutch Royal T

No, with original advancing:mad:

03-27-2003, 03:01 AM
Sorry<img src=http://www.ezboard.com/intl/aenglish/images/emoticons/embarassed.gif ALT=":o"> , but this is for minarelli engine: www.polini.com/news/uk/motori_news8.html (http://www.polini.com/news/uk/motori_news8.html) this is'nt the same CDI.

Dutch Royal T
03-27-2003, 07:27 PM
<blockquote><strong><em>Quote:</em></strong><hr>Dutch Royal T No, with original advancing[/quote]

Well that's ain't a bad thing, right?


I'll get a degree wheel and will try different setting. I will get an inner rotor someday, but they are so expansive! Haven't seen the polini one in real life, so I can't tell.

LSV/HSV, never heard of that before. Learned something again. What is better? or do both have pros & cons? My Squish is set to the Polini recommanded 0.7mm for AC Evo's

Also in the past people always said that the crankcase had to be enlarged to fit the Polini Evo crank. Well my little information pamphlet does have a graphic of the inside crank, but text is all italian. I know now that crank fits without any tuning to the cases. Or does crankcase pressure get's to high? I also heard something the enlarging had not to do with crank fitment itself, but the space is used to have mixture "waiting" underneath the transferports in the case.....(?)

03-28-2003, 03:14 AM
Do U use the original crankshaft for the EVO cylinder?

I have polini EVO crankshaft with 12 mm gudgeon pin size. And U have to enlarge the crankcase to reach the correct primary compression.

Dutch Royal T
03-28-2003, 05:13 AM
I do have the evo crankshaft with 12mm gudeon pin. The stock crank wouldn't hold.

Nor would the bearings, I also have Polini race bearings. The crankcase is tuned; the ports have enlarged to the Evo's cilinder size.

I do not know about the internal diamter though.

tiba karotsu
03-28-2003, 11:08 AM
MHR Team crankshaft has more volume than EVO unit but the difference in the price isn't very encouraging.

EVO crank will fit crankcase with no mods done.

i also have tuned carter, crankcase compression ratio is a whopping 1.43 : 1!:eek:

03-28-2003, 12:09 PM
Hey there. Read what you wrote about EVO vs Malossi Cranks.
I haven't seen a "Real" MHR crank but the EVO has more Primary compression than the Normal (and ř 12mm) RHQ Malossi crank.

An other thing. Conserning the EVO ignition box.

It is an intruder that you connect with your original CDI where it will improve Spark timing. And it does not look like it can be changes. (But you can drill bigger holes in you Igniton plate and turn this counter clockvise)

Problem about this one is that it need DC voltage...

Dutch Royal T
03-28-2003, 01:21 PM

When I got to my friends house he totally surprised me. As one of the first in Holland, he got the Polini Inner Rotor. So I can now confirm that the Polini DOES HAVE an Eprom. I saw the card in it and it's replaceable. For the rest it's the same as Malossi. Stator is black.

tiba karotsu
03-29-2003, 09:30 AM

believe me i've seen the EVO crank and compared them side by side plus i took measurements, MHR Team crank has same diameter as MHR RHQ crank but when you measure the thickness of the counterweights the Team crank is up by 1.5mm. here is comparison below of the 3 cranks.

MHR RHQ pin 12 (53 8009) 71.5mm OD x 15mm Th
Polini EVO pin 12 71.8mm OD x 16mm Th
MHR Team pin 12(53 9864) 71.5mm OD x 16.5mm Th


how much did he get Polini inner rotor? is it the same price as MHR?

03-29-2003, 11:01 AM
So I think the Polini EVO has more primary compression, than Malossi MHR.

03-31-2003, 04:20 PM
I have just bought a HPI ignition, but i don't really understand the "manual"

De afstelling os ongeveer 3mm voor het bovenste dode punt zoals op de afbeelding geschetst is.

So have i understod it right when this is what i thinks that they meen:

I set the piston at absolut BTDC, then i adjust the HPI ignition, soo the to marks are infront of eatch other, and then the ignition advance will be 3mm? (~27 degrees)

do they meen that:

I set the pisten at 3mm BTDC (~27 degrees), and then adjust the ignition, soo the to marks are infront of eatch other, and then the ignition advance will be 3mm (~27 degrees)?

I my head´, it sounds like my first idea is the right, but what does you say? Some of you are Dutch, and you cuold maybe understand the dutch i have written of from the "manual"

Regards Mads

Slider Rider
03-31-2003, 04:27 PM
I have just bought a HPI ignition, but i don't really understand the "manual"

De afstelling os ongeveer 3mm voor het bovenste dode punt zoals op de afbeelding geschetst is.

So have i understod it right when this is what i thinks that they meen:

I set the piston at absolut BTDC, then i adjust the HPI ignition, soo the to marks are infront of eatch other, and then the ignition advance will be 3mm? (~27 degrees)

do they meen that:

I set the pisten at 3mm BTDC (~27 degrees), and then adjust the ignition, soo the to marks are infront of eatch other, and then the ignition advance will be 3mm (~27 degrees)?

I my head´, it sounds like my first idea is the right, but what does you say? Some of you are Dutch, and you cuold maybe understand the dutch i have written of from the "manual"

Regards Mads

Slider Rider
03-31-2003, 04:29 PM
Woops, seams like ezboard had i little problem with me, sorry for double posting.

Dutch Royal T
03-31-2003, 05:04 PM
Just a note, it's well known that the marks on a HPI DON'T always are what that say. So when you think the ignition is set the right way, it might not.

tiba karotsu
03-31-2003, 09:00 PM
i think 3mm BTDC is too much for initial timing, try 2.25mm BTDC and align the timing marks on the inner rotor & stator.

tiba karotsu
03-31-2003, 09:02 PM

yes EVO crank has more primary compression than MHR RHQ crank but MHR Team crank has higher primary compression than EVO crank.

Slider Rider
04-01-2003, 09:16 AM
No no, my question was not about how many degrees i should advance my ignition, but more about how i mounted it, and the 3mm's is just what the ignition is advanced when it is with the to marks infront of each other, but there my question is: When i mount the ignition, must i then set the piston at TDC and then point the to marks at each other, or:

Must i set the piston 3mm BTDC, and then point the to marks at each other?

Because i don't understand the dutch in the "manual"

PS: It's a HPI ignition.

tiba karotsu
04-01-2003, 09:23 AM
set the piston 3mm BTDC then align timing marks on rotor & stator

Slider Rider
04-01-2003, 09:52 AM
Okey, that way, thanks Tiba.

04-08-2003, 03:27 PM
I tryed the 22 or 24 degrees but I can't feel any changes??!!

My other problem is I use the original retarded ignition 4 the EVO setup so it can't raise 11000 RPM. How can I derestrict the CDI (I dont want to change it ).

tiba karotsu
04-08-2003, 08:23 PM
what's the use of EVO cilinder etc. race parts if you still have the stock restricted CDI.

get rid of stock CDI & get a racing unit, you're wasting good power from your combo so if i were you i'll do it NOW.;)

04-09-2003, 12:16 AM
Hehe EVO wiht restricted RPM :lol: :lol: :lol: :lol:

Thanks tiba!

What do u recommend (I need the light)?

04-09-2003, 03:09 AM
The Newest Malossi TC-unit or a MVT HQ ignition set.

Tiba. Sorry for asking you here. But the malossi Crankshaft you are driving with. What part number is that?

04-09-2003, 03:58 AM
But the Malossi TC Unit has fix advance timing.
So that ignition map is not so good! But it's very cheap!!

04-09-2003, 05:51 AM
Say what you want. If you want to drive fast WITH LIGHT. You can not have everything.

If you want to change timing.
Drill holes in the ignition plate and rotate as much as you like.

04-09-2003, 08:52 AM

Look at my post above:

"I tryed the 22 or 24 degrees but I can't feel any changes??!!"

04-09-2003, 09:12 AM
Not even slightly?
Trottle response or anything? NOTHING?
Have you tryed to change setup of the thing?
Can't help you then.

04-09-2003, 11:43 AM
Why not just get the Malossi inner rotor ignition and run your lights from a battery. Sure it is a pain to manually recharge the battery every few days, but you'd have a screaming street/track setup.

04-10-2003, 10:36 PM
Malossi inner rotor is very expensive, so I would like to by only a CDI Unit:

What do U think about these:
-Malossi CDI unit
-TOP performaces CDI unit (yellow or red?)
-Daytona Racing Progress tc unit

Which is the best 4 the EVO!

04-11-2003, 08:13 AM
use dytona or mallosi

tiba karotsu
04-15-2003, 03:54 AM

it's MHR Team 2000 crankshaft part # 53 9864, the expensive one.:cool:

04-22-2003, 01:00 PM
Good. That was what i thought as well.
Do you know the differance in "rod 80" and "Rod 85"?

BTW. I got a Malossi Selletra unit today. Nice little cooling fans on the back side!

Dutch Royal T
04-22-2003, 06:01 PM
The Rod 80 crank has a 80mm conrod, while the 85 one (yes you guessed it) has an 85mm conrod.

The 85mm gives a longer stroke and this has some kind of positive effects on the forces the piston undergoes on its sidewalls. (I might be a little bit of here, but it does have something to do with forces)

Probably also with the port timing.

Tiba you want to do the honors......:D

04-22-2003, 07:32 PM
long rod increase power at very high rpm because fritction reduced and better leverage but it also increase crank volume which might offset some of gains

tiba karotsu
04-23-2003, 02:48 AM
long con rods have less sidewall thrust so that equals less piston & ring wear, better leverage so more force is exerted per degree of rotation, gives shorter port durations for a set port height.

a longer con rod does not increase crankshaft stroke as most people believe, if used with a standard piston for 80mm con rods then it will surely make the primary compression lower 'coz of increased crankcase volume. luckily Malossi has made a special piston for the 85mm con rod Malossi cranks.

basically MHR Speed & Cross barrels are one & the same, by altering the length of the con rods they have varied the port durations by as much as 3 degrees on exhaust & transfer ports. if you want both speed & reliability from a set-up then get the 85mm con rod crankshaft & port the cilinder to get the same duration as the Speed barrel so that means you may have to raise the ports by .45 to .50mm.

if you don't want the hassle of porting your cilinder too much then stick with the 80mm con rod crank.

and congrats Velo for getting the malossi/selettra ignition, have fun with your new toy.


i just won the 70cc class scooter drags last Sunday.

Dutch Royal T
04-23-2003, 06:18 PM
Congrats Tiba,

But please explain to me how a longer stroke gives <span style="text-decoration:underline">shorter</span> port duration? Seems the "wrong" way around to me. <img src=http://www.ezboard.com/intl/aenglish/images/emoticons/ohwell.gif ALT=":\"> Since the stroke is longer, the ports are opened longer, because the piston has a longer distance to travel.

Or is this only the case with a normal piston and not with the special 85rod piston. Or is my whole thinking wrong?

tiba karotsu
04-23-2003, 09:00 PM

i didn't say the longer stroke gives shorter port durations, what i said was a LONGER CON ROD gives shorter port durations and it makes the piston "dwell" at TDC longer hence the reason for shortened port durations. a shorter con rod does the opposite.

of course a longer STROKE will increase both exhaust & transfer port duration, when you change from a standard 39.2mm stroke crank to a long stroke 40.2mm crank you'll gain more port duration.

no matter what piston compression height you use it will still give the same port duration.

04-23-2003, 11:04 PM
another benefit is crank angle reduce with long rod = less friction in both upper and lower bearings

friction depends on rpm - the higher the rpm the more the friction reduction will manifest itself so a extremely high rpm pipe and porting must be used to take advantage of long rod set up