Vintage Dirt Bike Q & A

i know this part is NLA so i was wondering what some of you have done besides find a reproduction or a NOS part. My swing arm has chain wear on the very front of the swing arm somehow. Has anyone bought something like acrylic sheet and then formed it with a heat gun or used something like rubber conveyor belt or somethign rubber and made your own? I'm trying to get the swing arm bolt out and man is it stuck in there. So as i've seen in other threads i'm gonna soak the heck out of it with a penitrant and hopefully be able to pound it out. is there something special about this bolt or could it be replaced with a high grade bolt?

Also where is a good place to get the front sprocket? i've looked on sprocket specialist couldn't find anything and looked on a couple other websites but were unsure if the website was any good.?


ahh i'm just full of questions but i'm eager to learn. thanks to everyone who has some input to give.


-brad

Brad, you're in luck. The chain slider can be purchased from: http://www.red-devil-racing.com//0/hond ... lider.html
A good reliable vendor I can recommend from past purchases.

The Swingarm bolt is a problem. My guess is the needle bearings in each swingarm leg were neglected and have rusted
and seized the bolt. You should be able to get some penetrant to them by removing the dust caps (all four) and spraying
directly on them. Mount the swingarm in a vice with padded jaws and thread the nut on to the bolt to protect the threads
(because hopefully you can salvage it), and try to break it loose with a mallet. Another possibility is heat from a torch,
just be sure to clean all the penetrant off with something non flammable first. You are obviously going to need new
bearings and seals for the swingarm which are also still available from Honda.

The OEM front sprocket is available from: http://www.bikebandit.com/
also a good reliable company. In fact I just purchased the same sprocket from them for my restoration
last week. You can also get front sprockets from Service Honda, Chaparral and Dennis Kirk.

Now if I could only find a replacement for the 20 X 33 X 15 caged needle bearing I ruined while removing it from the case
of my '79, life would be good.

Good luck with it.

dogger

_________________
1973 CR250M
1979 CR250R
1993 CR250R
2008 CR500R
2009 CR250R

You see new bearings for sale on eBay from time to time. Vintage Elsinore does (did?) a complete bearing/spacer/end cap kit. If for any reason the bolt gets damaged, I think I know two places that will machine a replacement...

http://cgi.ebay.com/ebaymotors/SWINGARM-BEARINGS-HONDA-CR250-CR250R-ELSINORE-1978-80_W0QQitemZ250236037765QQcmdZViewItem

_________________
Michael Stiles
1979 Honda CR250R Elsinore | 2006 Husqvarna SM510R | 2007 Service Honda CR500R-AF

DOGGER : Which bearing is that in the engine, I found a guy that has a couple bikes that he is wrecking i believe and he might have other vintage stuff also. I was able to pick up the kickstart knuckle from him cause mine was starting to split. If you want i can find his phone number again. He is just out of Kelowna, BC, Canada, about 5 hour drive away from Spokane, Washington.

REDROCKET: Yeah i figured i can always get something machined just that machine shops around here are 80 bucks an hour, but then again, i guess thats better than a bike with a defunct swingarm, Damn i wish this was back in the year 2000 when i was able to get my hands on a lathe in shop class. ahh well

Brad,

The bearing is for the mainshaft in the right side case. Honda part #91020430004 superceded by 008. If you look
at a exploded parts diagram for the crankcase on any Honda dealer website, it is part #14 also known as "unavailable".

I'm sure I can find it or a suitable replacement eventually. I'm just griping because I pulled all the bearings out of the cases
and already had replacement bearings to go back in for all but this mainshaft bearing, and wouldn't you know
that's the one I screw up.

I knew things were going too smoothly to this point.

dogger

_________________
1973 CR250M
1979 CR250R
1993 CR250R
2008 CR500R
2009 CR250R

Hey Dogger,

Try Speedsupplies.com for that 91020-430-008 BEARING (20X33X15).

Enjoy,
Jon

Thanks Jon. I tried to call them today but the part availability number they list is a closed loop automated
message that disconnects. I emailed them my request too, so hopefully I will hear from someone. I'll let
you know how it ends.

dogger

_________________
1973 CR250M
1979 CR250R
1993 CR250R
2008 CR500R
2009 CR250R

Did you try Vintage Iron for that bearing? I know they have a good selection..

No I haven't, but I will. Thanks for the tip. I may have a bite from my ad and I also found a used set of cases with bearings for cheap so I think I may be out of the woods on this one.

Brad, I didn't mean to hijack your thread, sorry. How's it going with the pivot bolt removal?

dogger

_________________
1973 CR250M
1979 CR250R
1993 CR250R
2008 CR500R
2009 CR250R

just a warning....This is a long reply


meh, it's going okay i guess. but ofcourse found snags because i havn't done any of this before and so it gets frustrating.

Swingarm bolt, left it installed everything pivots well and doesn't seem to have any sideplay, but i have bought new bearings for it and will maybe get into it next winter.

Original problem of smoking like crazy, well it doesn't smoke as bad but still smokes. i had installed a seal i bought and through in a new o-ring i had (not the one from honda) took it for a rip up and down the street today.... still smoking. How much oil do you think could be in the crankcase from the previous leak? it's probably run for maybe 3 or 4 mins and still smokes. I am hoping that if i install the new honda seal and the honda o-ring that will be the end of that. could there be so much oil in the crankcase that i have to dump the bike upside down?? but there is more stuff now

clutch -- went to go for a test run before the one i just did, holding the clutch, put it down into first, unit dies try to move the bike around with clutch lever pulled in and it's a no go. so took apart the clutch and the discs and plates were pretty stuck together, so i hit them all with a scotch brite pad thing re install. while i was doing this i grabbed the rear part of the basket and it seems like i can get some twisting movement out of it. but if i move it straight laterally is stll has a little play but not much, maybe .020 or less. continue putting the clutch together, dipping plates and discs in oil before putting them in the basket. all together, pull the clutch, it kinda works, i had side cover off and with some rocking, i could finally get it to spin with the clutch lever pulled in. Now when i was scotch briting the discs, i noticed that on the tabs only on one face of them all the way around it looked like they have contactact with something. now have i maybe put these plates and discs in wrong, are thoose faces that have shine on them suppose to face each other so that when you pull the clutch those tabs push everything apart a bit?? i know when i first got it i could pull the clutch and it would roll just fine but now it's a real struggle. I'm guessing the bike will have more pep too when it stops burning this oil cause it feels like it isn't winding out like it should.

good things - got new sprockets and chain on there, got a new kickstart knuckle thing so now it's not cracking apart, ummm and yeah i guess thats where i am, So if anyone can help out with some ideas/info feel more then free to give it. thanks

alright maybe forget that thing with it unable to roll in first, i could of sworn i was able to do that before i touched the clutches. but after my friend showd me on his new 2008 dirtbike that it does the same thing, i'm cool with that now.

Brad,

Let's take each problem in turn. The smoking will continue until all the oil is out of the crankwell. The problem is you don't know if more oil is leaking in via the seal, right?

If you have a set of top end gaskets (cylinder and head), I would remove the cylinder and take a look in the crankwell to see how much oil is there. The problem with trying to burn it out is 10W-30 doesn't mix well with pre-mix and will coak up the combustion chamber, expansion chamber, spark plug (your lucky you don't have a power valve) and cause the bike to run like crap for long after the oil is gone.

Since you don't know if you still have a leaky seal, I would get all the oil out of the crank well, clean the piston dome, cylinder head and plug and put it back together. Do a test ride and see if the smoke continues after a few minutes of riding. If not, you are good to go. If it keeps smoking, new seals are in your future.

The clutch. Lateral play is not good. The clutch outer rides on a pair of needle bearings, my guess is either the bearings or the clutch basket or both are worn. Also check the inner and outer baskets for chatter marks - looks like scalloping on the tines - this will cause the clutch plates to hang up and cause erratic performance. Unless your clutch has been rebuilt, my guess is you have all the above along with worn friction plates and sacked springs.

The only thing that get's more abuse than the clutch on a 250 race bike is the clutch on a 125 race bike. Even though I used steel clutch plates and Hinson components in my modern 250 race bikes, I changed the oil after every moto and it was still full of contamination. I replaced the clutch pack and springs every race and the pressure plate, inner and outer clutch basket each season. So if your 30+ year old bike has an original clutch, you can imagine the shape it's in

If you decide to rebuild it, let me know if you need the service limits for all the high wear components, I'll send them along.

dogger

_________________
1973 CR250M
1979 CR250R
1993 CR250R
2008 CR500R
2009 CR250R

Just as a bit of a side not I will more then likely never use this bike for racing, I'll be using it for riding a few hours on a couple weekends a month maybe, use it when i go camping, most likely doing logging roads, deactivations, throwing some mud and probably never doing anything more then 10 feet in jumping distance ( i took my first jump today on a buddy's bike i borrowed. it was a kicker about 18 inches high and maybe went 2 or 3 feet haha, but ofcourse that developed into some other jumps like 3 feet in the air and 8 feet long. hey this is big air for a guy that has never caught it before)

I am not 100% sure if the new seal is leaking, But i do have the honda seal comming in and also have the honda o-ring to fit behind the collar so i will be replacing those in the future. I was trying to get the bike together for a ride this weekend but didn't work out that way. I am thinking about throwing in a seal on the RH side also. not that the idle is all over the place when sitting there or when i tip the bike from side to side, but just fig it would be good to have two new seals. Do you have the proceedure for removing the ignition stuff and then setting it afterwards?

Since i believe i've had a new top end done, couldn't i just get away with just a new cyl gasket. hmm is this all possible with leaving the engine mounted on the frame?

Yeah i think i might order up a pair of needle bearing, someone has forsure been inside the clutch before because the washer that gets folded over was folded over two additional times. The friction discs and plates don't look in bad condition at all, no discoloration, blocks of friction material on still on discs. There is a bit of chattering on the outter basket, for the amount that i will be using this bike and for the type of use, I am not to worried about it. do you think i should be? I also have to do a good tuning on it all once everything is tickity boo! It was running not to bad when i first got the bike but now doesn't have a constant rise in RPM's and winding out like it should.

I guess if i wanted a nice bike that i wouldn't have a bunch of things to do to it i should of spent a few grand, you think this bike was worth the $960 i bought it for? I am kind of glad i did get it though. it's always nice learning about something older then yourself (i was born in 82) and taking in all the knowledge from people passionate about all this. In the end of this all i want a reliable bike, that i don't have to worry about if i ride 20 miles from my camp site.

Hi Dogger, I can help you with the bearing problem. All bearings are available from your local bearing supplier except for the right mainshaft bearing, the cupped needle roller. It is NLA from Honda but luckily it is also a Yamaha part and at last check was still available. If you can bring yourself to having something Yamaha on your bike the part # is 93311-42045.

P.S. Thanks for the chain slider reference, much appreciated.

Brad,

A lot of corners can be cut if you are building a trail vs race bike. Since you aren't trying to squeeze every ounce of performance and reliability (mutually exclusive) out of your ride, you can opt for much less scrutiny and less time on the rebuild.

You're shooting for reliability so you still need to address the seals and the clutch. A lot of the work can be done with the motor in the frame. Let me know which problem you want to tackle first and I will send you what I know to help.

By the way, once you get this bike sorted out, you are going to love it. These old CRs have big, fun power and really are "Red Rockets". You will be out busting doubles in no time.

dogger

_________________
1973 CR250M
1979 CR250R
1993 CR250R
2008 CR500R
2009 CR250R