BannedCR500Riders.com

OK all,
i pulled the barrel off one of my spare motors yesterday,
i was going to get some port work done but it looks to have had a wand waved over it already.
What level do you the members recon this is
Mild or wild.

It's junk, please send it to me for further evaluation........


Never seen one with extra holes in the intake, Looks kinda radical from with that

I gotta chime in ............No I better not
Aliso use to just roast these guys

theres way too much intake for the ammount of exhasut work done,
a little wicked for a bush bike

You say this is "one" of your motors, and you had thought about porting it.

I would ask...how do you think the one pictured above runs, comparitively, if you felt it needed ported in the first place?

Granted your other motors aren't heavily worked over, I'd say whatever work has been done to this one didn't amount to shit.

Mick,
i wouldnt kniow a good port job from a shit 1, unless the final finish was deplorable.

I swaped 3 CR500 motors for a well credentialed dirt kart last year.
1 fully reconditioned.
1 a season old (the jug in question)
1 requiring a full rebuild with a stuffed up case were the chain wanted to be inside the motor more then out.

i'm sitting at home on the weekend wating for my e-bay bits to finish my Gen-1 and desided to pull the rebuilder down, i also used this motor to make my measurments and dummy fitting.

I knew nothing of there heritige or specs all i knew was the owner was very competitive and threw alot of mony on his speedway car (formula5000-a half size sprint car)

Thats how i came to asking what stage do the members feel this jug is at, for all i knew it could of been a vergin or crap port job.
Fuck ive reconditioned, replaced, serviced, polished, cleaned, lubricated every bloody part on this bike so the motor will get the same.

Different builders have different ideas on what does and does'nt work,
these people are the people i'd like to give me some feedback or allrounders that have had shit loads of jugs done over the years, maybe like your self.
Check on a map of Australia......Look at the Northern Territory, check it's square mile coverage....well only 2 thats right two people do portwork, & there both in Alice Springs.

3 motors = 3bike to me.

For what it's worth, the exhast bridge wasnt relieved or if it was not nearly enough.



the holes drilled on the intake side have done well to protect the piston in that erea but as you can see it could do with a few more either side.



"ASK AND YE SHALL FIND"

I wonder if holes drilled all the way around like that will prolong the life of the piston? it sure seemed to help on that side.

The intake side has a contunious blast of oil cooling and lubing it. Of course its going to look better.

Ok I'll give my thoughts on that cylinder. The extra holes remind me of GSS, he does that too, and the intake looks properly done. The exhaust looks good from the outside looking in, but the exhaust ports don't look ported right to me. They don't look equally hogged out, and it looks like they are close to stock height and no relief on the bridge. It also looks like the knife edging was done allitle sloppy as they dug into the cylinder more than needed, but I've seen way worse jobs. My guess is that cylinder will produce more power than stock, but not much, I'd open up those exhaust ports properly and see what she gives.

Ported&Polished wrote:... The exhaust looks good from the outside ...

thats the worst part of the porting, theres nothing there, they've overlooked the biggest problem on the entire bike

asteroid500 wrote:I swaped 3 CR500 motors for a well credentialed dirt kart last year.
1 fully reconditioned.
1 a season old (the jug in question)
1 requiring a full rebuild with a stuffed up case were the chain wanted to be inside the motor more then out...I knew nothing of there heritige or specs all i knew was the owner was very competitive and threw alot of mony on his speedway car (formula5000-a half size sprint car)

Oh ok, so you don't have a good warm and fuzzy on any of these I thought maybe this was one of any three bikes you were running at any given time. Welp...I don't know what to tell ya...

...other than I'm planning on visiting Australia this summer and we should go ride

...also want to hit up the island of Komodo and New Guinea!

feel free to visit,
i can organise a good ride or if theres a 3hr enduro on we could enter that, 30-35km a lap. i do the full 3hr's but you can also enter 2 man teams. In the Northern Territory you dont need licences or registration to ride in the bush or govornment land, Roostmaster has a excelent loop threw the scrub around his property

The enduros are good fun because you can ride like a maniac and know theres an ambulance not to far away

Those engines came from Car speedway use, or am I getting you mixed up with another NT bloke?

If so, and the engines were set up for Alc/Methanol, whatever they use, in the speedway cars that have started to move over to 600 multis, that porting seems pretty indicative of that.

Most of those fuels don't have the same calorific value / BTUs of petrol, they get the power from the shear volume of fuel and its inherent cooling properties, being pumped into the motor. I know I haven't put that well or particularly accurately, but I hope you get my intended meaning. So a porting job like that, with much more done to it on the intake circuit, would be accommodating the fuels traits. I'd think, that by Alc/Meth tuning standards, that would be a fairly mild (?) level of porting, but necessary to make use of the benefits of the fuel being used.

I could be wrong, as I'm not much of an engine tinkerer, all I've ever done to my CRs is clean up the ports, as it delivers more than enough for my riding use. I've always concentrated on the suspension & chassis set up.

NightBiker07 wrote:I wonder if holes drilled all the way around like that will prolong the life of the piston? it sure seemed to help on that side.

AlisoBoob prolonged the life of this piston another riding season by drilling this hole:

It a old airplane mechanics trick.... works every time!

This is the vehicle my motors came from this time last year, owned by Glen out at Gove (nhulunbuy) population 4500, nearest town,900km as the crow flies, they love there speedway there.



They had a rule change so he now runs a R6 motor, and believe it or not the 500 singles are still up the front both the CR and KX are well represented.

They run Methanol and castor oils.mmmsmells so good, thats why the inlet is of a high porting level then the outlet.

So I remembered correctly about the cars, and got it right with the fuels. I'm not getting as old and stupid as I thought.

And the 500 singles still do OK, huh? Do any of the CR engined blokes use stroker kits?, that would be a great thing for car applications.

Perhaps the lighter Big Bang affect of the single, revving to perhaps at the most 8/9 grand gets better traction than an R6 screaming its guts out @ 16/17K?

I think the other fellow who has scored a couple (or three) of speedway car motors is Stan, from the other site. I'll have to go looking for engines from that source soon myself, but they will probably be gone by the time I've got the bucks to spare - too many other things eating up my wallet contents, till at least mid year. Oh well, it's 2.34 am and I'll get back to machining some alloy tank cap spigots.

Have fun with your bike.

You can pick up a CR motor with little effort,
Anyone here picked up a inline sports bike motor latley....
the power to wieght in motor sport is paramount as we all know.

Ok, i kept the jug and piston,
i had the piston Bead blasted on the scuffed up areas, my engine builder swears by it.... i guess i'll know sooner then later.

we measured it all up and found it only reqired a hone & for good measure i added some new piston rings.

Bead blasted inlet side-notice the 2 new oil holes ive added.


Bead blasted exhaust side of the piston


Barrel (jug) lightly honed.

l hope you didnt use glass silicon bead

Yeah that seems kind of counterintuitive to scuff up the piston like that. What is the reasoning he gave? I'm curious how long it will run until it seizes.

tacogrande wrote:Yeah that seems kind of counterintuitive to scuff up the piston like that. What is the reasoning he gave? I'm curious how long it will run until it seizes.

X2 Why did he blast the piston? seems you'd be asking for a major failure?

X3. I can't wait for Bob to put in his

surely you asked your builder the reasoning behind this? there must be a good reason and i would hope he had some good credentials to back his methods

tacogrande wrote:Yeah that seems kind of counterintuitive to scuff up the piston like that. What is the reasoning he gave? I'm curious how long it will run until it seizes.

I think the theory of the a scuffing is to have oil in the low spots of the scuffing for lubrication.

As for it seizing, why would it be anymore proned to seizing, the piston would not be any bigger in diameter, if anything it would have more clearance ( less chance of seizing? )

Just my 2c

BTW it won't make it right if it is completely wrong.