Two Stroke Motocross
Two Stroke Motocross Forum => General Two Stroke Talk => Topic started by: motoxr377 on February 27, 2013, 11:14:43 PM
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2004 CRF250R - Cheap, and still runs well. That only matters for the part-out.
1989 CR500R Engine - Needs a new right case, and inner clutch cover. The very new Wiseco looks badly scored over the exhaust bridge area, which leads me to believe the relief is incorrect. Either way, the engine will be completely disassembled, spec'd, and rebuilt to a high standard.
I'll be attending a military school shortly so I'll be breaking ground on this around May. The meantime will be spent gathering parts.
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Will be watching this with keen interest!
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me want!!!!!
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Bit of advise, go with a '93 or later case, the earlier models where made of evil magnesium, '93 onwards where alloy. They have a different part number but fit right up.
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What does "spec'd" mean exactly?
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this will be good
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Bit of advise, go with a '93 or later case, the earlier models where made of evil magnesium, '93 onwards where alloy. They have a different part number but fit right up.
Thanks for that. I definitely wish to remain risk averse. This seems hypocritical considering what I'm building. I'll be on the lookout for a nice used set, or a good deal on new ones.
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.
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That is too funny right there!
I definitely wish to remain risk averse. This seems hypocritical considering what I'm building.
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I had a 2005 CRF250R. The suspenders on that thing were the best I've ever ridden on. Although I haven't ridden on much newer since. Anyways good luck, I'll be watching closely.
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Bit of advise, go with a '93 or later case, the earlier models where made of evil magnesium, '93 onwards where alloy. They have a different part number but fit right up.
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.
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the gear ratios also changed after 92. 4th and 5th anyway
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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
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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
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That picture of the broken cases of your 500 - the best advertisement for a decompression system you can find!
The type that Jar944 and others use, is a simple, cheap, no weld / bugger-all effort solution. My solution, is more expensive / involved.
Of course, you could be a 'hard man' and say "I don't need no frigging Decomp" - but your wallet will argue with you (especially if the breakage extends into the main case - if so, hopefully it can be welded / repaired - just pay a lot of attention to the correct alignment of the various shaft / bearing holes ), and you'll also be ID'ing yourself as a bit of a Drongo. What's not to love about an easier to fire up bike?
Oh, a better KS lever stop on the foot peg, can help, as well.
As for the WP area rot, Magnesium protected only by a bit of paint (if that) and water, especially under turbulence / cavitation - not a good idea. Yuck!
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That picture of the broken cases of your 500 - the best advertisement for a decompression system you can find!
The type that Jar944 and others use, is a simple, cheap, no weld / bugger-all effort solution. My solution, is more expensive / involved.
Of course, you could be a 'hard man' and say "I don't need no frigging Decomp" - but your wallet will argue with you (especially if the breakage extends into the main case - if so, hopefully it can be welded / repaired - just pay a lot of attention to the correct alignment of the various shaft / bearing holes ), and you'll also be ID'ing yourself as a bit of a Drongo. What's not to love about an easier to fire up bike?
Oh, a better KS lever stop on the foot peg, can help, as well.
As for the WP area rot, Magnesium protected only by a bit of paint (if that) and water, especially under turbulence / cavitation - not a good idea. Yuck!
I don't understand, why would high compression wreck the crank cases? Not disputing you here I actually don't know.
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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.
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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.
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We always called them a compression release and I loved having it, even on a 125 enduro, used it a lot on downhills too.
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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.
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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
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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.
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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.
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The last of the Husky 500 2T's were notorious for breaking the cases around the kickstart.
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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
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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.
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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
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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
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Ouch. That looks pricey
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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.
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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.
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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.
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Welcome to the land of 14000 rpm motors. Only way you can make a 250F make power.
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.
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Welcome to the land of 14000 rpm motors. Only way you can make a 250F make power.
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.
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Thats usually about where a 250Fs rev limiter is and its not its working range. Although the 250SXF does get wrung the **** out. 450s are lower at around 11 grand but again thats not their working range.
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Looks like a worthy project.
Some suggestions if I may:
I recently started re-sleeving CR500 cylinders with Aluminum sleeves on the engines I've been building. The re -sleeve is
done by Advanced and I send the finished cylinder to Millennium Technologies for their version of NIKASIL plating. This gets
you a piston and cylinder that expand at a similar rate (reducing the possibility of cold seizures), saves a couple of pounds,
and benefits from a much more durable cylinder wall. I recommend a Wiseco or Wossner forged piston and make sure you
drill the two oiling holes for the exhaust bridge.
As others have alluded to, I also recommend a compression release. Larry Wiechman does a real nice mod that looks
factory. There is real merit to the claims of cracks in the case cover caused by kickstarter stress. The kickstart assembly
is a robust design, but the housing is a weak point over time.
Another item to look at is the clutch. You will find there is very little in the way of aftermarket support in this area. One of
the mods I like is converting the stock CR500 clutch assembly over to the CR250 version. This allows you to run all the hard
anodized Hinson components which will extend clutch life and performance.
I noticed you want to use TMR for the port work. It will be interesting to hear if his idea of a toned down powerband is the
same as yours. Also, very good idea having the crankshaft balanced. If you go with Crankworks, I recommend you send it
in now and if you're lucky, it might be finished in May when you're ready to start.
Finally, there is a real benefit in using the older 89 cases over the new ones. Over time, the tooling used is increasingly worn
and the newer cases have poor tolerances. Most noticeably, the amount of lash between the primary gear and clutch ring gear.
Your cases were manufactured the first year that tooling was used and as a result, should be very precise.
Enjoy the build.
dogger
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^ this guy speaks the truth.
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I was wondering when you'd tune in dogger! I've been hanging out for you to do another build that puts jeremys factory CR to shame, so far I've been disappointed.
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so far I've been disappointed.
Sorry Stu, my bike projects have taken a back seat to my racecar project lately.
I'm still working on the 09 CR250. I have the engine, wheels, brakes, airbox
and plastic done. Of course the big ticket items like the frame and suspension
are still to go.
I'll get back to work on it soon. In the mean time, I'm looking forward to seeing
motoxr377's CR500 come to life.
dogger
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Thanks dogger!
I'll look into everything you said! I'll be done with my course in late April, and get going from there.
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so far I've been disappointed.
Sorry Stu, my bike projects have taken a back seat to my racecar project lately.
I'm still working on the 09 CR250. I have the engine, wheels, brakes, airbox
and plastic done. Of course the big ticket items like the frame and suspension
are still to go.
I'll get back to work on it soon. In the mean time, I'm looking forward to seeing
motoxr377's CR500 come to life.
dogger
Awesome. And I'm definitely looking forward to this build too
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i look forward to growlers as you post this s!@T.
ok growlers no match for racer x. look forward to more than a growler while you post this s!@T!
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UPDATE. I'm back from learning how to shoot people from far away.
Sold the CRF250R engine to some Fooper lover. Anyone want to buy a 40mm Keihin FCR?
Excuse the mess, things get crazy when I'm taking out an engine.
The project is starting to pick up, and although it won't ever finish as quick as I'd like, I am determined to do it right. An aluminum sleeve is on its way from Advanced Sleeve, and I have contacted Larry Wiechman about getting my head modified for his compression release. Compression Release Modification
I'll post a new "update" thread, once I roll my other project off of my workbench and onto completion.
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Just remember how much potential the CR500 has. Over the years honda deliberately detuned it so that people didn't you know... Empty their bowels whilst riding.