New guy needing some info.

[4stroker]

Hey guys, my name is Mark.  I am from Australia and I am helping a buddy seriously modify his 2001 KX500.

I have done a search but need help finding the following:

1) Standard Piston dimensions. (eg skirt length, pin height/diameter, basically everything...)

2) Standard port map showing all dimensions.

Surely this info must exist and surely you guys know where it is!

Thanks, Mark.

[ID KX500]

You need to talk to stewart on this website.

[stewart]

hello mark ,there  are  lot of great threads here that have many mods you should look at ...would start by reading the k5 section,,enjoy the info

[4stroker]

Hi Stewart.

We are actually looking to design our own porting specs for the engine based on a +5mm stroker crank and 91mm CR500 piston or possibly custom 91mm KX500 piston.

My buddy already has the stroker crank on the way, second hand, the guy he is getting it from says he got it from the UK somewhere and he has been running it in his MX sidecar outfit!

So anyways, now you can see why I want the dimensions mentioned above?

Any ideas where to get them from?  I have already emailed Wiseco for the piston dimensions and i await their reply however im not holding my breath on that one!

thanks, mark

[4stroker]

Stewart, I have just finished reading the "need help with kx560" thread.

In regards to that engine, what if you made your own sleeve with reset exhaust and transfer heights to achieve optimum blow-down pressure, do you think that then it could make more power than your current 86*86 combo?

surely a properly thought out 91*91 combo (for example) would have to make more power than a 86*86, provided that everything else was optimised to match, such as exhaust pipe, cylinder head, ignition curve etc..

i have been doing a bit of searching on here and found alot of people talking about "short circuiting", when the piston uncovers the exhaust port at TDC.  does a stock KX500 do this?  if not, how much room is there to play?  is a +5 stroker with no spacer, stock rod and piston going to uncover the ex port at TDC?

of course we are going to find all this out when my buddies stroker crank arrives and he tears the motor down, but like i said to you in my email, im trying to stay one step ahead and get some calcs done asap!

thanks, mark

[stewart]

4 stroker  ..im glad to see you putting the thought your putting in to the k5 moter ,,i cant speak for any one else  but i have found in the last 25 years of engine work that i should first get a handle on and wring all i can out of a setup then make changes 1 at a time to see whats helping and hurting  the combo,,and to get a  better understanding  of what each move does ...that  bieng said  alot of effort was made on sizing the k5 at 86 by 86,,the stuff ive work on that was stroke or big bore on the k5  did not make the power of my current 86 86 combos,,and is was not for lack  of trying...but i hope you can find something to help us improve if its there , thanks stewart

[4stroker]

i should first get a handle on and wring all i can out of a setup then make changes 1 at a time

i hear ya there! 

my buddies bike in its current 88*86 configuration is making similar numbers to yours, but on a dyno dynamics dyno, which we know to read lower than inertia dynos such as dynojet.

I am confident that he has more actual rwhp than your setup, however the power delivery (no KIPS anymore) and the hand made down pipe would not suit your riding requirements!  (you do alot of hill climbing and the like yeah?)

it has made dozens of dyno runs, tried several hand made pipes, countless combustion chamber designs and custom ignition curves, not to mention variations in porting and carb/reed choice.  the engine runs on methanol.  it is also very reliable, being built for ultra long track speedway events.

so now we have come across a stroker crank and looking to make more power with it.  the class the bike competes in has a 600cc limit, so we are looking to take full advantage of that.  i think a 91*91 combo fits the bill nicely!

oh yeah, wiseco sent me the dimensions i was looking for, dont spose anyone has a port map for me eh?

thanks, mark

[stewart]

i found more power and same tq  with oxgenated fuel from vp  than  alky  and i spent alot of time  on that comparsion ,,dont know why the numbers would be off from 1 dyno to next or not  but we have been very honest with our settings to get accurate comparsion  ,,if you could please show us a dyno sheet so we can see what   is up   with the rpm and tq numbers  as well,,i m always  ready to learn,,,my experience  with kips removal has been only a loss of bottom end power ,,..what carb do you use on that combo,,thanks for the info  stewart

[4stroker]

yeah mate i am not disputing your honesty or the accuracy of your dyno, just stating some findings we have made. one direct comparison example i can think of off the top of my head is a Hayuabusa street bike that a guy went drag racing with.  it was modified to some extent and made 190+rwhp on a dyno jet.  then it came into the local shop here with the dyno dynamics dyno, and after a tune up only made 160+rwhp, but it turned in consistently faster ET's on the strip than it had before.

the difference in power is not linear of course, the difference when at around 70-80hp is probably more like 7-10 hp between dyno's.  this is due to the fact that the dyno jet is an inertia dyno, and the dyno dynamics is a retarder dyno.

when all is said and done everyone knows that all dynos are different and should only be used as tuning tools.

i believe the carb is a highly modified keihin 41 pwk. (taper bored power jet etc etc...)

not sure on the main jet and power jet sizes but i know it runs a 1.0mm pilot jet and a custom needle/needle jet.

i do not believe he has tried a lectron, or oxygenated fuel, maybe there is more power to be found in this 88*86 combo yet!

i will see what i can do about a dyno sheet.

[stewart]

what is the average altitude there.. were at 1000 feet roughly..i like the 41 pwk carb  they work great on gas and very ridable..but a 44 lectron will make more  power  is what i have seen thats why they use them on the pro stock nhra bikes

[4stroker]

we are at sea level.

i will tell him about the 44 lectron.

[k5abuser]

stewart knows more about alky  than a wine-o . but i know that stewarts motor hold up to all we can dish out and that the dyno numbers are right on . i have a quadzilla that at one time made 100 hp at the chank (7 flat in the 1/8 97 mph taking off in 5th) when i rode stewarts bike i told him it felt like my quad on  120 otane and nitro mix. it dyno'd right at 100 hp at chrank . he has seen close to 105 . everyone that rides it comes back and says thats enough. resleving the motor with a steel sleve is the wrong move the k5 motors were not designed to run a steel sleve . the 560 was steel sleved and the piston sezed.i hope the 91x91 works would love to see it . others have tried to bore bigger 60 over (with out stroke to match ) makes the most hp but you lose the reliabilty. wolbrinkrace  took a stock motor we built  to bonnelville salt flats and set the modified record at 132.4 mph with a stock motor on 110 octane. 2miles up to speed  with the third mile a flying timed mile wide open .run after run on the same motor and piston . they are riding it on the dirt now and playing . that motor pulled 110 mph with my 290 lb butt on it in full mx trim before we sent it to wol brink.

[4stroker]

resleving the motor with a steel sleve is the wrong move the k5 motors were not designed to run a steel sleve . the 560 was steel sleved and the piston sezed.

doesnt have to be a steel sleeve!

others have tried to bore bigger 60 over (with out stroke to match ) makes the most hp but you lose the reliabilty

the motor im talking about is at 80thou over reliably...

[kaw rider]

if you what to make more power then you will have to make a oversquare motor or fix the many things that this motor has wrong.

[4stroker]

that whose motor has wrong??