CR500 timing curve comparisons

rsss396 · Post by **rsss396** » February 13th, 2010, 11:33 am

All tests done on my bench tester with a INNOVA EQUUS PRO Digital timing light with timing degrees and rpm display.

All flywheels/stator combos were mocked up on a motor and degreed and marked with true TDC.

A solid stationary timing pointer was mounted on the stator off the pickup coil screw.

The degreed TDC mark is aligned with this tab so you can time the motor while looking down at the flywheel instead of the bottom like the factory did.

JR650 · Post by **JR650** » February 13th, 2010, 6:01 pm

thanks for posting this, nice to see what the 250 curve actually looks like in comparison.

tacogrande · Post by **tacogrande** » February 13th, 2010, 8:57 pm

I read somewhere you have to advance the 2000 cr250 ignition to get it to run, this chart confirms that. What's really interesting is that the 500 falls in between the 250 and 125. It would be cool to superimpose these over a dyno to see which lays down better hp. You can also see the digital 250 picked up way lower in the rpm range for reputedly easier starting.

gregrobo · Post by **gregrobo** » February 14th, 2010, 1:06 am

yeah our 500 starts 1/2 a kick hot cold with or without choke and we are running the 01 250 ignition retarded 10 degrees

Cholo · Post by **Cholo** » February 14th, 2010, 3:25 am

Very useful information

rsss396 · Post by **rsss396** » February 14th, 2010, 7:15 am

I tried to make everything as accurate as possible and repeated my procedures for all of them.

But there are variables with different cdi's, timing lights ect.. so please take this info lightly as it may differ from your own findings.

But I am pretty comfortable with my results as a reference.

I am also in the process of coming up with a accurate rating for power at the spark plug.

preliminary results the puts MSD first then cr250 then cr500
I will post results in the future when I establish a repeatable testing procedure.

eyesky2002 · Post by **eyesky2002** » February 15th, 2010, 2:38 am

gregrobo wrote:yeah our 500 starts 1/2 a kick hot cold with or without choke and we are running the 01 250 ignition advanced 10 degrees

Where exactly is 10 degrees advanced at in the bottom marker??? I am running a 99 ignition and have the bottom case and stator markings lined up, which is where it hits with the bottom mount plate still on. Starts easy, runs good up thru warm up; unfortunately snow, ice and cold temps are keeping me from taking it out to test or tune. Just want it ready come spring time and some warmer weather.

gregrobo · Post by **gregrobo** » February 15th, 2010, 2:47 am

ill try and get some photos this weekend of our backing plate you need to slot some holes to retard the 250 backing plate otherwise it will preignite and run hot also it wont make power it will be flat
we did the same thing just line d up the marks and it starts and runs and sounds good in the shed but as soon as we started riding we new it needed tweeking

tacogrande · Post by **tacogrande** » February 15th, 2010, 6:59 am

gregrobo wrote: otherwise it will preignite and run hot also it wont make power it will be flat

I don't think it will preignite or run hot, because the ignition would occur later if you don't slot the backing plate, no? Usually those are signs of too much timing advance, although the flat power feeling is spot on for retarded timing. Either way it's interesting to see how wide of an ignition curve the motor will run on, and how tame the stock 93 is compared
to the old school bikes. Also timing can really effect power with different fuels, race fuel vs California pump gas is a big difference. The higher the octane the more resistant it is to preignition to a point, I had a chevy huffer motor that would diesel on anything lower than 110 with the msd advanced to peak dyno numbers, but it ran fine on pump gas if I retarded the timin some.

LOVEMYCR500 · Post by **LOVEMYCR500** » February 15th, 2010, 10:38 am

interesting, I assume 2001 cr 250 curve is the same as 2000? A guy would be better off getting a cr 125 box vs trying to advance the 250 curve 10 degrees. I will have to look into a CR 125 box for my TRX 431 cc motor. I have a 01 CR 250 ignition on it and it's a pig down low with the big pipe on it. I know the 125 curve doesn't advance down in the upper rpm's as much but it's really good down low in the RPM's.

gregrobo · Post by **gregrobo** » February 15th, 2010, 3:16 pm

yeah sorry fellas got it round the wrong way ill get some photos of our backing plate and put some measurements on it i fixed my posts to reflect what we did

rsss396 · Post by **rsss396** » February 15th, 2010, 5:53 pm

added 2001 CR250 curve

rsss396 · Post by **rsss396** » February 15th, 2010, 6:07 pm

that might be a little hard to follow here is just the cr250-125 curves

gregrobo · Post by **gregrobo** » February 15th, 2010, 6:20 pm

good info thanks rss396

eyesky2002 · Post by **eyesky2002** » February 21st, 2010, 11:03 am

gregrobo wrote:ill try and get some photos this weekend of our backing plate you need to slot some holes to retard the 250 backing plate otherwise it will preignite and run hot also it wont make power it will be flat
we did the same thing just line d up the marks and it starts and runs and sounds good in the shed but as soon as we started riding we new it needed tweeking

Ever get the pics of the ignition, got mine back apart to slot the holes and line the it up for what will work!

thestuz · Post by **thestuz** » February 21st, 2010, 1:45 pm

awesome work rsss396.

rsss396 · Post by **rsss396** » February 21st, 2010, 9:01 pm

thanks!
will be doing a Vortex cdi on a 90's style cr500 stator that has 10 maps here real soon, will post when I get it mapped out

powermizer · Post by **powermizer** » February 28th, 2010, 7:14 am

Thanks, rss396 good info. I wonder what the curve is on the 94 250 ignition?. I know alot of us run the pre digital ones.

rsss396 · Post by **rsss396** » February 28th, 2010, 9:25 am

Here is a collection of timing curves I have recorded so far.

We can thank CR500MSV "Jason" for sending me his VORTEX ignition box to map for everyone!

rsss396 · Post by **rsss396** » February 28th, 2010, 9:27 am

powermizer wrote:Thanks, rss396 good info. I wonder what the curve is on the 94 250 ignition?. I know alot of us run the pre digital ones.

If someone sends me one I can map it out for everyone.

but would need the stator/flywheel and CDI

asteroid500 · Post by **asteroid500** » March 1st, 2010, 12:19 am

Solid proof a digital CDI is stronger in all aspects....
Nice work you bloody hoon.

http://www.youtube.com/user/500bigbore · Post by **Roostius_Maximus** » March 1st, 2010, 7:24 am

Dude, look at the 86 500 profile it wasnt digital, neither was the 93 500, but they both had bore timing than any of the stock 250 stuff

LOVEMYCR500 · Post by **LOVEMYCR500** » March 1st, 2010, 9:26 am

looking at the curves with everyone that has the 2000-2001 CR250 ignition says it's soft down low but has more overrev. The ignition advance is alot lower right off idle for quite a few RPMs. I will stick with my 93 ignition for my 93 bike.

If you want some big time bark down low, get the CR 125 box, look at it's ignition advance.

eyesky2002 · Post by **eyesky2002** » March 2nd, 2010, 10:27 am

Now that we have the curves, lest see some post showing where people are setting thier timing with the 250 ignitions

Heard a few different opinions, dead center, retarded 10 degrees, 2 strokes need to be advanced and so on.

hoofarted · Post by **hoofarted** » March 2nd, 2010, 1:02 pm

I have a 93 250 setup on mine. When left dead center, it did a little for overall power - wasnt too impressed. Then I advanced it - big difference. Now I see what everyone was talking about.

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CR500 timing curve comparisons

CR500 timing curve comparisons