CR 500 engine Performance Mods ?

[Hbmtr]

So i bought a cr 500 engine off of ebay yesterday with the intention of putting it in my 07 crf frame after i build up engine a little.this bike will only be used as a snowbike with a 14 ST kit on it.
I have looked RPM mfg big bore kits but i would like to keep a reasonable price on the project.With some reliability ,ease of starting ,good torque and hp.

So guys and gals what would you do for a build? looking for opinions and real world experience.

 

[egesledder]

Big bores can be fun, but just some solid porting for top end, higher compression, and top-end pipe can make a huge difference. Then put money into carb heater, intake, hand warmers, fork springs/valving, bigger tank, etc.

 

[Hbmtr]

so i figured on the carb heat and the small acc.like heaters etc.thx for your opinon

 

[SEOINAGE]

I know my motor had been ported, but not exactly sure so I didn't mess with it. But it always had an fmf fatty on it, so I bought a new one that would fit with the aluminum frame. Then mostly necessities, bored, rebuilt crank. Hinson clutch basket. Just try to get some more revs and upper power if you can, might consider a cr250 ignition conversion, or one of the other options. Then the basics for a snow bike.

Heard a few good things about some carb mods etc, so you might consider something like pulse injection.

 

[eskimojoe77]

bannedcr500riders.com

Go to bannedcr500riders.com for a ton of info. You'll see my bike it there, titled something like Alaska snowbike conversion. It's in a 2007 CRF250R chassis and has a homemade kit on it. I recommend the Rekluse auto clutch, a compression release, carb heater, and a FMF fatty or Pro Circuit pipe, steer clear of the Gnarly for snow not enough RPMs. My buddy did a cr500 in a 2003 ktm and it was a whole lot simpler swap and it vibrates less, something to think about.

 

[wwillf01]

So i bought a cr 500 engine off of ebay yesterday with the intention of putting it in my 07 crf frame after i build up engine a little.this bike will only be used as a snowbike with a 14 ST kit on it.
I have looked RPM mfg big bore kits but i would like to keep a reasonable price on the project.With some reliability ,ease of starting ,good torque and hp.

So guys and gals what would you do for a build? looking for opinions and real world experience.

I can tell you this in my research of porting...


You have rtek (Same comapny doing big bores ect for sleds)- He seems to know what he's talking about but no personal experience
Then there is the guy in Canada which I have heard great things about but his name is slipping

I went the GSS in California route and its a powerhouse and I have been very happy running 100 octane and a deleted exhaust bridge.. Ran this last year.. 70 hours doing rings in a week or two... Only used as a snowbike. But when I sent him my engine he was 8 weeks out...


Either way they all are from 800 to 1200 and always remember not all port jobs are the same. I think you should reach high 70's maybe 80ish with racefuel if the job is done right.... Along with a few more 1000 rpms... Plus reliable

It is crazy easy to start.. no compression release needed.. Almost like my 300

 

[eskimojoe77]

canadian cr500 guru

The Canadian you were trying to think of is adam millar. He's got a bunch of bikes and info in www.bannnedcr500riders.com Summitboy on here has his twirp porting on his snowbike cr500, a good source for info as well.

 

[wwillf01]

Yep thats him heard great things.... It was close for me when I was deciding but GSS was a lot closer and I was able to reach him to talk....

 

[Hbmtr]

The Canadian you were trying to think of is adam millar. He's got a bunch of bikes and info in www.bannnedcr500riders.com Summitboy on here has his twirp porting on his snowbike cr500, a good source for info as well.

I have been on Banned riders and cr 500 riders as well and have read good things on Adam Millar engines.Seems his technical articles and his posts on differences in the cr 500 engines are outstanding.
My original plan was to go with a big bore 600 at a big cost but the thought of simplicity and a port /head work would be the way to go.
thankyou for your opinions.
Maybe summit boy will chime in soon?

 

[wwillf01]

I have been on Banned riders and cr 500 riders as well and have read good things on Adam Millar engines.Seems his technical articles and his posts on differences in the cr 500 engines are outstanding.
My original plan was to go with a big bore 600 at a big cost but the thought of simplicity and a port /head work would be the way to go.
thankyou for your opinions.
Maybe summit boy will chime in soon?

You can search he has many great things to say about the port job in the forum along with the pulse carb... It seems he is pretty sold... The smartcarb did not work for him... For me it has worked very well with the q5 rod with a primer... That being said they have 4 richer rods now so I will be installing an egr this week with a big arse cpi pipe.... Let me repeat its huge so I will hopefully have that dialed in for the winter. One thing about the GSS port it loves fuel

 

[kanedog]

Decompression switch

 

[portgrinder]

you need alot of work to get to 70 or 80. big time porting, a good pipe, bigger carb, more timing ect

i personally don't understand getting rid of the exhaust bridge. i would leave it there to support the piston and make it wider on the sides. but maybe it works.

 

[wwillf01]

you need alot of work to get to 70 or 80. big time porting, a good pipe, bigger carb, more timing ect

i personally don't understand getting rid of the exhaust bridge. i would leave it there to support the piston and make it wider on the sides. but maybe it works.

For me it has worked very well.. Gives it a snowmobile type power band which I like ..


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[Hbmtr]

You can search he has many great things to say about the port job in the forum along with the pulse carb... It seems he is pretty sold... The smartcarb did not work for him... For me it has worked very well with the q5 rod with a primer... That being said they have 4 richer rods now so I will be installing an egr this week with a big arse cpi pipe.... Let me repeat its huge so I will hopefully have that dialed in for the winter. One thing about the GSS port it loves fuel

Is the cpi pipe custom to your build or off the shelf unit? Tell me more about a egr as i only know that acronym from my early car days.I manage a service dept. for a marina at lake Tahoe ,boats these days are running cats and o2 sensors but no egr"s

 

[wwillf01]

So cpi is a pipe builder in utah.. Coi racing it should mate well with the porting. Then the egr is for exhaust temps and tuning... I want to get the jetting dialed in better with the smart carb... For me all rods have worked with my bike but everything gets better the richer I go.. I am going to power it with a lighting coil.. I think I have not hit its potential... Smartcarb now has four richer rods than a q5. Attached a picture of what mine looks like


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[wwillf01]

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[Hbmtr]

So cpi is a pipe builder in utah.. Coi racing it should mate well with the porting. Then the egr is for exhaust temps and tuning... I want to get the jetting dialed in better with the smart carb... For me all rods have worked with my bike but everything gets better the richer I go.. I am going to power it with a lighting coil.. I think I have not hit its potential... Smartcarb now has four richer rods than a q5. Attached a picture of what mine looks like

So you are tuning with exhaust temps and o2 sensor,so you need to weld bung at header of the pipe.More accurate that way i'm sure than doing throttle chops and plug readings.Some of the pipes from cpi look Scalvini like.Is your bike snow only then or do you ride as a bike also?

 

[wwillf01]

Correct.. I want to really want to watch it throughout the season.. Instead of pulling the plug... It is snow only .. I have a 300 for the summer ... I don't think it would be a good pipe for summer unless you were just using it at the dunes... I would be too afraid of denting it because it is pricey plus the expansion chamber almost hits the tire


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[Hbmtr]

were you riding in one of jethros videos from last year when he got his cr 500 af?

 

[wwillf01]

Yep but had a cracked head pipe .. I had serious vibe issues and finally at the end of the season figured out the engine mounting bolts stretched to where I ran out of threads ... The vibes broke my radiator and pipe even lost a Spingarm bolt! So that being said I hope everything is down to fine tuning


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