newbie build CR500af

trimachinist · Apr 2, 2018

Hello everyone,

Figured i would start a thread on my build and introduce myself. I just picked up a 2004 crf450r with a 1989 CR500. Been wanting to build a snowbike for a couple years. Saw this on CL and figured it was a good enough time to give it a go. Im new to dirtbikes. I have had a couple supermotos and have built a few high end stand up jetskis. This will be a long build and probably wont have a ton of updates untill later in the year as we are selling our house and in the process of moving. Once moved i plan on doing a tear down of the bike and going through it making sure its up to my standard (which it is not at the moment). The guy i bought it from had no information on who build the bike and did the modifications besides he was around the seattle area. Seems to have a few aftermarket parts on it. The guy says the motor was rebuilt and has 49ish hours on it. I dont know if i should do a full tear down on the motor? Would be nice to know what bore its on and if it has any porting work done to it.
I did order a few things
Thermo-Bob 3 for CRF450
1/8TH X 28 BSPP TEMP SENSOR PROBE
Castor 927 anyone running this. I had some left over from my ski.
GN4 4-Stroke Oil to do a oil change and start on a fresh note
BR8EG NGK
Any adcvice on what else i should order would be aprricated
Seems to have hand heaters not sure they work yet
Will be replacing the pipe.
Got a lot still to learn and figure out. Putting a list together of what i want and need.
Been doing a lot of lurking and reading on this over the last week so hopefully i will build it once and build it right.

M5- · Apr 2, 2018

50 snow bike hours is a lot. 50 dirt riding hours probably no big deal. Your problem will be that you will hour out in the middle of the season so if it were me I would tear it right down, check all the bearings measure the crank new seals, piston, rings, deglaze the cylinder then you know you are good to go. Much cheaper to do it over the summer rather than a rush job in February after it grenades.

M5

Sheetmetalfab · Apr 2, 2018

M5- said:
50 snow bike hours is a lot. 50 dirt riding hours probably no big deal. Your problem will be that you will hour out in the middle of the season so if it were me I would tear it right down, check all the bearings measure the crank new seals, piston, rings, deglaze the cylinder then you know you are good to go. Much cheaper to do it over the summer rather than a rush job in February after it grenades.

M5

And check your cases over really good while its apart.

trimachinist · Apr 2, 2018

M5- said:
50 snow bike hours is a lot. 50 dirt riding hours probably no big deal. Your problem will be that you will hour out in the middle of the season so if it were me I would tear it right down, check all the bearings measure the crank new seals, piston, rings, deglaze the cylinder then you know you are good to go. Much cheaper to do it over the summer rather than a rush job in February after it grenades.

M5

Thanks for the reply. Thats what i was thinking. I know it has not seen the snow but has been sitting in the garage for 2+ years.

trimachinist · Apr 2, 2018

Sheetmetalfab said:
And check your cases over really good while its apart.

I am guessing for cracks or abuse to them?

Sheetmetalfab · Apr 2, 2018

trimachinist said:
I am guessing for cracks or abuse to them?

Rumors of a failure between the water jacket and crankcase.
I don’t know exactly where.

trimachinist · Apr 2, 2018

Sheetmetalfab said:
Rumors of a failure between the water jacket and crankcase.
I don’t know exactly where.

Noted... thank you i will definitely be looking in this area.

M5- · Apr 2, 2018

You need to inspect, the water pump area for corrosion, as well as the kick starter area and main crank seal bosses for cracks. If cracked they can be welded, its not ideal but it works. You can still buy a new right side case half but the left side is NLA which blows. Billet case halves are out there as well if you are rich.

M5

trimachinist · Apr 2, 2018

As a machinist not impressed by much. This seems to be well built. Excited to get this on the bike

rhino89523 · Apr 3, 2018

89 doesn't have the corrosion problems in the waterpump area like the 85-88 models do but you might still want to upgrade the outer case and clutch if it hasn't been done already. the 89 runs one less clutch plate. to do it you would need the basket and the outer cover. They make a pretty nice billet basket for not a lot of cash available on ebay but you have to attach the gear off the back of your existing basket. The cases will blow out at the kicker every now and then if you really boot it or just over time but the bottom ends are pretty solid. I'm on three originals that have never been split and I have two that have been rebearing'ed with a few little replacement pieces.

I would definitely pull the top end off and take a look. I personally always have my machinist hone them, he knows what he is doing and always uses a torque plate. The torque plate essentially takes place of the head, it is torqued to spec and then machine work completed. The head studs stress a little under compression and if the machine work is not performed under the torque you end up with the dreaded stop sign cylinder that you can see additional wear corresponding with the 7 head studs. Put some fresh reeds in there too. Mine is sitting at the top of the mountain as we speak waiting for me to get back to it with a new reed block. Had a set of V force 2's in it...didn't even make it one year, I'm back to stockers on the snowbike.

M5- · Apr 3, 2018

I did reeds on mine at the start of this season. The bike came with Vforce 3s which I know some guys don't like but they've been good to me so far. After 3 seasons only 1 petal was showing any sign of wear whatsoever. I just put new petals on and go again. I haven't played with different reed options at all so everybody out there knows more about them than me.

M5

rhino89523 · Apr 3, 2018

On my AF that I ride singletrack and rocks on I basically keep everything stock, it has never left me walking is ultra reliable and takes minimal maintenance. I have never really played with reeds until the last few years. I put a set of the v force 2’s on there with the spacer built in that Adam Millar in Canada makes the mount set up for. Adam is the guy I don’t really know anything. If Adam says they flow....they flow, if Adam says they don’t....you get it. The 2’s are noticeable and the thing comes in strong with them in there. I have them in my sand bikeand they rip so I figured I’d run it in the snow bike. I put them in this year and one completely flakes away. I’m done with that. The stock reeds last days and I just bend the cage out so fat it doesn’t fit into the cylinder and just jam it in there, the difference in power isn’t crazy enough for me to give up reliability. I’m back to a stock cage and reeds with a spare set onboard.

kraut · Apr 15, 2018

Cr 500af

Go on Facebook search cr500 conversions and request to be on the group. Tonnes of help on there.

trimachinist · Apr 17, 2018

Still slowly getting parts together for the rebuild. Spec bolt kit came in.

What gasket kit is worth getting?

What carb are you guys running?

I'd like to try and aquire as much as I can before I start the rebuild. I know I will not have a complete list until it's apart and I know what needs to be repaired or replaced or even what's been done to the motor.

I have got on a couple cr500 forums but they seem pretty dead and it's hard to get accurate information from them. I will look into the Facebook group although I don't like going on there.

M5- · Apr 18, 2018

I normally like Cometic gaskets but the Cometic kit I have here the head gasket did not fit very well, the holes were a bit too close together which caused the gasket to bunch up. I ended up using a complete stock Honda gasket kit. I'm running a PWK 38 mm air striker. It runs flawless which is why I haven't bothered trying a Lectron, but I would like too. You will need carb heat with the PWK or any carb for that matter.

M5

rhino89523 · Apr 18, 2018

I like cometic for top ends, their base gasket is beefy and wont blow out, I didn't have a problem with the head gasket like M5. For all the other gaskets I run factory Honda. Carb PWK is probably the go, but on my trail CR I still run a PJ and love it jetted right out of the book. I run from sea level to over 10,000 and it always runs predictably.

rhino89523 · Apr 18, 2018

I am a moderator on CR500riders.com and I'm pretty good friends with the owner of that site and ride with him every year down in AZ. I'm also friends with the owner and past owner of the bannedcr500riders site. Both sites have people on them that can provide good information but both sites are pretty dead at this point and I have heard most are over on Facebook. I don't do facebook but in all cases look for information from Adam Millar, RoostiusMaximus, Millar Racing Engines, or MRE. that is all Adam and he is pretty much the guy when it comes to 500's. He has taken them apart mic'ed every part and rebuilt or re-manufactured most of the pieces. His information about these monsters is the most reliable and probably the best especially for any of the aftermarket stuff. I am pretty much the guy who for the most part just likes everything stock....except for stock pipes, if you have one in good condition send it to me and I will dispose of it properly

trimachinist · Apr 18, 2018

M5- said:
I normally like Cometic gaskets but the Cometic kit I have here the head gasket did not fit very well, the holes were a bit too close together which caused the gasket to bunch up. I ended up using a complete stock Honda gasket kit. I'm running a PWK 38 mm air striker. It runs flawless which is why I haven't bothered trying a Lectron, but I would like too. You will need carb heat with the PWK or any carb for that matter.

M5

Is that pulse injected?
What carb heater you running?

M5- · Apr 18, 2018

No it is not pulse injected. I was going to do that but Ron had a stroke I believe it was and isn't doing them anymore. I haven't checked lately but that was the last I heard. Honestly I haven't touched the jetting in 4 seasons so I don't worry about it.

As for carb heat I make heaters and sell them, there is a thread on here somewhere. As a machinist you should be able to make your own. The AF is tight and you probably wont be able to run a store bought heater as they are all pretty bulky.

M5

rhino89523 · Apr 18, 2018

Look at M5's heater...I'm on one of his and they are pimp.

newbie build CR500af

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