CRF Redemption: The 500 Project Part 1

[cnrcpla]

I don't understand, why would high compression wreck the crank cases? Not disputing you here I actually don't know.

If you look where the crack on the case on motoxr's 500 engine, I think having it crack there had to do with to much stress on that area from kicking over the high compression resulting in that. I could be totally wrong, but that's what I'm assuming.

[jar944]

I don't understand, why would high compression wreck the crank cases? Not disputing you here I actually don't know.

If you look where the crack on the case on motoxr's 500 engine, I think having it crack there had to do with to much stress on that area from kicking over the high compression resulting in that. I could be totally wrong, but that's what I'm assuming.

That's correct, the case can't handle the stress. The only surefire solution is a decomp.

[riffraff]

We always called them a compression release and I loved having it, even on a 125 enduro, used it a lot on downhills too.

[evo550]

You have a bit of bad info.

Only the clutch side covers were Mg and those changed to Al in 1990. The cases have always been Al since the 500 was introduced.

The only thing they changed in 93 was the cases were no longer painted black.

Then what caused the waterpump on my '89 CR500 to rot out ?

 
In '93 they change to Al and Honda added another clutch plate, so the clutch basket area is slightly wider.
Check out the pics of the clutch cover in this cr 500 rebuild.
http://forum.2temps.fr/viewtopic.php?f=36&p=105673

That is not the case, that is the clutch case/side cover. The water pump is not in the case its in the case cover.

The case cover was Mag through 1988/89. There was a 89 only Al cover.  They went wider on the clutch in 1990 when they changed it to Al

1993 was a change to no paint, the cases are the same, the clutch case cover is the same...

don't believe me, look here: http://cr500riders.com/cgi/yabb/YaBB.pl?num=1192743820

You've lost me, so that we on the same page, check the pic of the motor that mxer337 posted to start the thread, see the crack in front of the kickstarter, that section of engine casing (whatever it's called) needs replacing, it also houses the waterpump and in 1989 was made of magnesium. Don't buy another magnesium one, buy an Ali one.

[jar944]

You have a bit of bad info.

Only the clutch side covers were Mg and those changed to Al in 1990. The cases have always been Al since the 500 was introduced.

The only thing they changed in 93 was the cases were no longer painted black.

Then what caused the waterpump on my '89 CR500 to rot out ?

 
In '93 they change to Al and Honda added another clutch plate, so the clutch basket area is slightly wider.
Check out the pics of the clutch cover in this cr 500 rebuild.
http://forum.2temps.fr/viewtopic.php?f=36&p=105673

That is not the case, that is the clutch case/side cover. The water pump is not in the case its in the case cover.

The case cover was Mag through 1988/89. There was a 89 only Al cover.  They went wider on the clutch in 1990 when they changed it to Al

1993 was a change to no paint, the cases are the same, the clutch case cover is the same...

don't believe me, look here: http://cr500riders.com/cgi/yabb/YaBB.pl?num=1192743820

You've lost me, so that we on the same page, check the pic of the motor that mxer337 posted to start the thread, see the crack in front of the kickstarter, that section of engine casing (whatever it's called) needs replacing, it also houses the waterpump and in 1989 was made of magnesium. Don't buy another magnesium one, buy an Ali one.

From his post it seems he needs the case side cover what houses the WP, AND the right case.

Needs a new right case, and inner clutch cover.

right case:


side cover/inner clutch cover


identification guide to the side cover

[evo550]

OK, your diagram is wrong.
I owned a 1989 CR500,

It had a magnesium waterpump(whatever case it was attached to) and it corroded/rotted out.
End of story.

[jar944]

I have a 91 motor, its all aluminum.






so i guess we are both wrong..

Actually now that I realize your location I wonder if the US and europe/Aus got different builds. 

[SachsGS]

The last of the Husky 500 2T's were notorious for breaking the cases around the kickstart.

[motoxr377]

Ok guys.

As stated earlier, I will be getting an aluminum inner clutch cover in addition to the right case.
I wanted the closer ratio gearbox.
I'll be using a 99-01 cr250r complete digital ignition which should aid starting.
Tom Morgan will be sorting the top end, and Crankworks will be balancing the rotating assembly.
We're shooting for a mellow hit without the flywheel effect of flywheel weights.

Stay tuned

[jar944]

Ok guys.

As stated earlier, I will be getting an aluminum inner clutch cover in addition to the right case.
I wanted the closer ratio gearbox.
I'll be using a 99-01 cr250r complete digital ignition which should aid starting.
Tom Morgan will be sorting the top end, and Crankworks will be balancing the rotating assembly.
We're shooting for a mellow hit without the flywheel effect of flywheel weights.

Stay tuned

Honestly there isn't much of a hit with a stock setup.

[Stusmoke]

Ok guys.

As stated earlier, I will be getting an aluminum inner clutch cover in addition to the right case.
I wanted the closer ratio gearbox.
I'll be using a 99-01 cr250r complete digital ignition which should aid starting.
Tom Morgan will be sorting the top end, and Crankworks will be balancing the rotating assembly.
We're shooting for a mellow hit without the flywheel effect of flywheel weights.

Stay tuned

Honestly there isn't much of a hit with a stock setup.

Maybe not by 500 standards but by my standards it would probably feel something akin to Mike Tyson

[shanes]

it could be worse you could own a CRF 

my mates bike he was testing last weekend getting ready for the first round of the spanish championships

[motoxr377]

Ouch. That looks pricey

[SwapperMX]

What does "spec'd" mean exactly?

I will be checking the tolerances of critical wear parts in relation to their factory specifications, and replacing those which don't meet the standard. This is a fairly common practice during a major rebuild. Do forgive my lack of clarity.
[/quote]
You are preaching to the choir with that post dude. 2T was prob hoping it was gonna be a crazy build chasing real strong hp numbers with plenty of rideability. Just building it to oem spec, while good, isn't very exciting.

[eprovenzano]

it could be worse you could own a CRF 

my mates bike he was testing last weekend getting ready for the first round of the spanish championships

While this can happen to a smoker too, it just seems to happen to the thumpers at an alarming rate.