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Old 06-24-2013, 04:38 PM   #1
cptmoney OP
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project 1989 CR250 - where to begin with this thing?

So....I took in an '89 CR250 from a buddy. Long story short: he picked it up from a buddy of his. Hasn't run in forever, and is apart right now. Here she is:







Rumor has it that the carb went bad. Carb is off of the bike now, but as far as I can tell (and I've NEVER owned a two-stroke before), that's all that is off the bike. Supposedly, the carb began giving the guy problems, so he yanked it, ran out of gumption, and passed it on to my buddy.

My buddy needed a buck, so he's passed it on to me....and here we are.

Being a complete rookie on this two-stroke business, where should I begin? Same as any other bike? Check for compression and spark? Should I reinstall the carb and throw some fuel at her, just to see if there's something obvious going on?

There is one thing that I've noticed - and I'm hoping one of you gents will have some input on as well. There's a small plate with the initials HPP on it. Looks to cover the valves. It's loose, like somebody's been doing some investigating in there. That mean anything to anyone? Maybe a bad valve or two, potentially? Here's the cover:



All I know about it is that the engine turns over. That's it. Bike is relatively complete. Tires look decent. And.....that's it. That's all I know.

So where should I jump in? Just check for all the regular stuff? Compression, spark, and fuel?

What would you do first? Again, I'm a noob on these old two strokes - so I appreciate your input.
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Old 06-24-2013, 05:10 PM   #2
ssregal39
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I would, at a minimum, tear down the motor and go through everything. It will need crank seals, rings, maybe piston/bore, reseal the case halves, look at the clutch basket, all the bearings then go from there.
Fork seals and oil change, rusty linkage and swing arm bolt yadda yadda...sounds like a fun project. I love two strokes!!
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Old 06-24-2013, 05:16 PM   #3
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Quote:
Originally Posted by ssregal39 View Post
I would, at a minimum, tear down the motor and go through everything. It will need crank seals, rings, maybe piston/bore, reseal the case halves, look at the clutch basket, all the bearings then go from there.
Fork seals and oil change, rusty linkage and swing arm bolt yadda yadda...sounds like a fun project. I love two strokes!!
Wait - you serious?

That sounds like $1500 worth of work! Is the bike worth it? What's it going to bring when I'm finished with it? $800?

I'm not all about the dollar - but it's got to make SOME sense, right?

I halfway assumed it might need a top end to accompany the carb rebuild - but I wasn't expecting much more. Now you've got me officially scared.

Splitting the cases is the red zone! I've seen WAY too many bikes never return from such an ordeal. Like open heart surgery, in my eyes...

I better carefully evaluate this whole thing! Going to need some serious consideration before I roll up my sleeves and jump in.
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Old 06-24-2013, 05:30 PM   #4
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I didn't mean replace all the bearings just inspect them. The only way to know what you have is to split it. Granted, this is what I would do. Not to scare you but, you could just do a top end and get it running. But if the crank seals are dry cracked the motor will run lean and you risk seizing the piston.
Anyone can split cases. Just have to buy/borrow a fly wheel puller. You can do it!!!

Quote:
Originally Posted by cptmoney View Post
Wait - you serious?

That sounds like $1500 worth of work! Is the bike worth it? What's it going to bring when I'm finished with it? $800?

I'm not all about the dollar - but it's got to make SOME sense, right?

I halfway assumed it might need a top end to accompany the carb rebuild - but I wasn't expecting much more. Now you've got me officially scared.

Splitting the cases is the red zone! I've seen WAY too many bikes never return from such an ordeal. Like open heart surgery, in my eyes...

I better carefully evaluate this whole thing! Going to need some serious consideration before I roll up my sleeves and jump in.
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Old 06-24-2013, 09:57 PM   #5
Jimmy the Heater
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Here is a total detailed breakdown of assembling an HPP CR250 engine.

http://twostrokemotocross.com/2010/0...-cr250-part-1/ Part 7 goes into the HPP portion of the build and as far as a powervalve goes, it's pretty simple.

ssregal39 does have a point. If the crank seals are toast, it will run lean and do bad things. However I will make a counterpoint. When first starting the engine, it's gonna be under choke, therefore much richer and less of a chance of a lean condition. Once it starts to warm up if it is still running well (not starting to burble, like an engine normally does when too rich) then that is an indication of a lean condition and you should start taking plug readings.

I really don't think that a complete teardown is necessary right off the bat. I would certainly pull the top end because it's so dang simple on a 2 stroke and give things a good looking over but splitting the cases, I just don't see it.

I would do the following.

Clean the heck out of that carb and then clean it again and again.

Verify which jets it has in there and if necessary new jets for your altitude.

Pull the top end and have a good look. Check ring gaps, cylinder condition, replace antifreeze, take a look in the bottom end for anything amiss.

New reeds, I wouldn't trust the ones that are in it to not break and do a lot of damage.

Make sure the HPP valve is clean and working as designed.

Check spark/New plug

Change tranny oil

Fresh gas with the correct oil ratio

Try to start it up.

It is a big list but realistically you could easily do that in a day and have well under $100 in parts if the bore and piston/rings look good.

Once it's running, watch for a lean condition, take plug readings often as the engine warms up and the choke comes off. Don't go out and hammer on it til you verified it's not running too lean.

After that, give it a good cleaning, service the suspension and ride the hell out of it! They are damn fun bikes!
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Old 06-24-2013, 10:28 PM   #6
yzedf
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Clean carb. Gas it up and fire it up. If it doesn't start with minimal work its not worth sense money wise unless you have a ton of spare parts. Doing the work is fairly simple.
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Old 06-24-2013, 10:56 PM   #7
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ALRIGHT! Now we're talking more along the lines of what I was thinking.

Let me gather up some resources, a manual, and that killer link that Jimmy the Heater tossed up - and get to work.

Honestly - this won't be one of those "labor of love" projects for me. It sort of landed in my lap (after I bought it!), but I don't have any real sentimental attachment to the bike. I'd love to have a killer dirt bike, and if this one comes around relatively smoothly, it just might be this one. If it looks like it's going to take more than The Heater's list, I'll probably pass. Clean it up and sell it off as a project bike to someone with more passion for this model. Kind of frank, but I'm being honest about it. I can't really make into much more than that - just too many other irons in the fire right now.

I like the way ysedf put it - do a few things, and I'll know in a hurry whether it's worth taking to the next level or not. Based on the condition of the bike, I'm guessing that not much of the bike is going to be in stellar condition. However - I've been pleasantly surprised by many a bike before!

I appreciate your help/input so much! Once again - I love this place. Couldn't make it without you.
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Old 06-25-2013, 07:00 AM   #8
Foot dragger
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Quote:
Originally Posted by cptmoney View Post
Wait - you serious?

That sounds like $1500 worth of work! Is the bike worth it? What's it going to bring when I'm finished with it? $800?

I'm not all about the dollar - but it's got to make SOME sense, right?

I halfway assumed it might need a top end to accompany the carb rebuild - but I wasn't expecting much more. Now you've got me officially scared.

Splitting the cases is the red zone! I've seen WAY too many bikes never return from such an ordeal. Like open heart surgery, in my eyes...

I better carefully evaluate this whole thing! Going to need some serious consideration before I roll up my sleeves and jump in.
A friend has done just this to the exact same bike,complete engine redo,suspension,big tank,newer seat,ready to change forks out now,etc,etc.
He wont give us a figure,says he loves the bike.
2000.00 is a fair guess if labor was free.
And he still has a bike with a 24 year old ignition and trans and rusted solid spokes and numerous other old parts.

If he put it up for sale............maybe 600.00 if you can find a buyer.
Hes kind of a new rider and is convinced the 89 CR250 was a high point of engineering.

It would seem simpler to just buy a newer bike from the get go,1989 was a long time ago in dirtbike terms.
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Old 06-25-2013, 07:04 AM   #9
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Quote:
Originally Posted by Foot dragger View Post
A friend has done just this to the exact same bike,complete engine redo,suspension,big tank,newer seat,ready to change forks out now,etc,etc.
He wont give us a figure,says he loves the bike.
2000.00 is a fair guess if labor was free.
And he still has a bike with a 24 year old ignition and trans and rusted solid spokes and numerous other old parts.

If he put it up for sale............maybe 600.00 if you can find a buyer.
Hes kind of a new rider and is convinced the 89 CR250 was a high point of engineering.

It would seem simpler to just buy a newer bike from the get go,1989 was a long time ago in dirtbike terms.
My point exactly, Dragger. If I were looking for my dream 250, I'd spend much more up front, get a much newer/cleaner bike, and enjoy the decade or more worth of mechanical advances. I'm going to tinker with this thing a bit to see if she'll respond, but if things look grim, I'm passing on this one.

I don't have the time/space to dedicate to a full resto - although I LOVE that kind of stuff. Timing isn't right for me at this point, however.
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Old 06-25-2013, 07:04 AM   #10
Foot dragger
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Quote:
Originally Posted by Jimmy the Heater View Post
Here is a total detailed breakdown of assembling an HPP CR250 engine.

http://twostrokemotocross.com/2010/0...-cr250-part-1/ Part 7 goes into the HPP portion of the build and as far as a powervalve goes, it's pretty simple.

ssregal39 does have a point. If the crank seals are toast, it will run lean and do bad things. However I will make a counterpoint. When first starting the engine, it's gonna be under choke, therefore much richer and less of a chance of a lean condition. Once it starts to warm up if it is still running well (not starting to burble, like an engine normally does when too rich) then that is an indication of a lean condition and you should start taking plug readings.

I really don't think that a complete teardown is necessary right off the bat. I would certainly pull the top end because it's so dang simple on a 2 stroke and give things a good looking over but splitting the cases, I just don't see it.

I would do the following.

Clean the heck out of that carb and then clean it again and again.

Verify which jets it has in there and if necessary new jets for your altitude.

Pull the top end and have a good look. Check ring gaps, cylinder condition, replace antifreeze, take a look in the bottom end for anything amiss.

New reeds, I wouldn't trust the ones that are in it to not break and do a lot of damage.

Make sure the HPP valve is clean and working as designed.

Check spark/New plug

Change tranny oil

Fresh gas with the correct oil ratio

Try to start it up.

It is a big list but realistically you could easily do that in a day and have well under $100 in parts if the bore and piston/rings look good.

Once it's running, watch for a lean condition, take plug readings often as the engine warms up and the choke comes off. Don't go out and hammer on it til you verified it's not running too lean.

After that, give it a good cleaning, service the suspension and ride the hell out of it! They are damn fun bikes!
If it was me,Id try to start it with the top end as is,unless its already at 0 compression and been seized like most old 2 strokes. There's a 10% chance it could work as is. (Yours DOES look about 80% better then his did when he got it for 100.00)
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Old 06-25-2013, 07:08 AM   #11
TNC
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I wouldn't sink any money or time in that thing. Two-strokes are dead. Manufacturers don't even make them anymore because they are so old fashioned.




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Old 06-25-2013, 07:11 AM   #12
Navin
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Actually, your friend might be right about the 1989!

http://www.youtube.com/watch?v=2GE5dQwAgyI

Rear disc and a few other changes.

I'd check the carb, clean it well, fire it up and leak down test it. Keep it cheap unless you really like it, then a full rebuild should be under $1000. Everything else can work well enough or be built to win local races under the right rider. I raced the 1987 and 88 versions. I'd be just as fast on one today (not fast!) as any other 250 2t.

Make sure everything under the power valve cover is attached and secure!
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Old 06-25-2013, 07:12 AM   #13
cptmoney OP
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Quote:
Originally Posted by TNC View Post
I wouldn't sink any money or time in that thing. Two-strokes are dead. Manufacturers don't even make them anymore because they are so old fashioned.




Hahaha! Yeah - I hear ya! Haha - may as well just drag it to the dump, right?

NO WAY! If this baby roars to life, we're going to get out and start eating some dust!
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Old 06-25-2013, 07:17 AM   #14
gravityisnotmyfriend
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If that bike landed in my lap, I would do a complete tear down and rebuild it from the bottom up.

Way back when I raced motocross, it was on a 1989 CR250. I blew the top end a few weeks before I was finishing up my 4 year enlistment in the USAF. I chose to sell the bike for parts instead of moving it 1300 miles in pieces. I still regret that.

I haven't been on a modern 250 2 stroke, but that bike was a monster for its day.

You've gotten alot of good advice, but be real careful about those crank seals. And keep an eye on the plugs. I'm pretty certain that the seals are exactly what killed my engine - and that's when they were less than 10 years old. If they're original, you're looking at 25 year old rubber and springs. And, if they haven't seen pre-mix fuel for a few years, they are most likely dried out and junk.
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Old 06-25-2013, 07:26 AM   #15
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Thanks, all -

I won't be doing any racing; I'm getting to be too old for any of that! The falls hurt worse and worse each time.

I would enjoy doing more trail/dirt riding, but nothing like what that young buck in Navin's viddy was doing. Shazaam! That kid gets after it. Just want a knock-around bike to drag through the trees/mud/hills....but I don't need a rocket to do that.

I'm going to try and jazz up the carb to see what happens. From what I've been reading, the lean fuel condition and the shot crank seals are the real deal breakers. I guess the water pump covers are notorious for rotting to pieces as well. I'm going to peel off the water pump cover today just to see what I find. Maybe if it's all shot to crap, things will become very clear to me in a hurry!

I'll see what's going on in there and keep you posted....
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