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  #1  
Old 04-20-2020, 05:14 PM
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Default 1991 CR250R Project Bike Build

Hi all
I signed up here in 2008 or 2009 I don't really know and here are my first messages, it was about time.
I'm French so please excuse me for my language, I translate with Google.

That's it I find an old CR 250 as in my youth, those who have friends on facebook have already seen some pictures.
the time to reduce the size of the photos, I would start posting here with comments.
see you soon for more

It goes from there






For suspensions, original it's really not good, ok at the time we drive with, but we're more at the time and with the evolution that have known the suspensions, I can not see myself go back , this fork is not even adjustable in rebound and rear shock not adjustable in hi-compression.
so for the front, I will adapt the fork (either the original KYB PSF 1 or the spring KYB that I mount on my 450 CRF 2013) triple clapms, the front wheel, the braking assembly and the wheel axle.
for the back I will try to find for cheap, an original damper of 250 cr - crf / 450 crf until 2008 and of course it all go into the magic cauldron of MRP to personalize all that according to what I I appreciate and need.

---------- Post added at 01:13 AM ---------- Previous post was at 01:10 AM ----------

go on attack with some photos








---------- Post added at 01:14 AM ---------- Previous post was at 01:13 AM ----------

we continue with the pictures of this bike and of the dismantling







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  #2  
Old 04-20-2020, 05:21 PM
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very big problem.
the screw is locked in and I can not separate the two parts, I remove the screws from the inside and spraying with oil of sting and I also heat, it does not move a milimeter







and we attack the opening of the engine



surprise by depositing the valve box, the cylinder has been prepared (well we'll see later) and for the moment I'm going to mount only the reeds Boyesen (which I have always done on all my 2 times since the beginning, the change is drastic) and then once the restore is finished and I have a little more side, I would mount a Rad Valve.




not a fart of rust on the stator



the part that made me very scared considering the number of years that the bike did not ride, it's like new.




---------- Post added at 01:21 AM ---------- Previous post was at 01:14 AM ----------



I wondered what it was like to be a rag.



It's okay



this too



not too bad considering the age of the machine



we return to it, preparation but half, no retouched transfers (diagrames) and no cases notigned either, but hey it is neccessary on a 250 ?? although in 88 on the mine I made the total.

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  #3  
Old 04-20-2020, 05:23 PM
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Have you ever seen a crankshaft seal in such condition? that explains the ton of black fat on the engine and the frame.





therefore wear of the ring and therefore replacement



So there sensitive souls abstain, we will proceed to the separation of two casings, the tools of torture are ready



and in the end the bearings are ok, they have been changed in the course of life of the bike, but I will still replace everything as it is open.

the box is ok, no broken teeth or other suspicious marks, me happy




---------- Post added at 01:23 AM ---------- Previous post was at 01:22 AM ----------

here is the rest of the work on the swingarm.
I found myself with the screw of the tension adjustment of the chain of transmission, twisted and blocked by the rust.
Seeing that this part of the swingarm seems to be in 2 separate parts (actually there are three), I decided to get out all to have more ease to deal with the screw in question.






We see that on the 2 photos below, a kind of epoxy glue.




to try to spread, to get out the part where there is the thread.



and after a lot of liters of perspiration, I managed to separate everything, I understand why it was so difficult




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Old 04-20-2020, 05:25 PM
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quick and partial cleaning of the room and as the screw is break flush, drilling and then it will tap.




First sanding and catching impacts, polish later.





---------- Post added at 01:25 AM ---------- Previous post was at 01:24 AM ----------









And in trying to extract the old bearings, huge disaster, I cry.

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Old 04-20-2020, 05:28 PM
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Work on the pipe
So the denting of the pot with compressed air went well, except that at a time -----> air leakage and there I realize that there are cracks where they welded nuts (messed up) to install a protection (carbon, aluminum ... I do not know) so it was necessary to close by welding as I could because I do not know what were soldered nuts, but it m made fireworks, so not simple and the sheet is fine.

I decide anyway to turn these nuts, which took me in the morning, a sanding stroke to see more clearly below the rust and try to remove the solder and solder patches.
Only I can not get rid of these cracks, I weld for the eliminated but once cool I see another that is created next and sanding I see others!
So do you have an idea for me to be, or you know a specialist (can be a cauldron, I do not know) who could redo the two parts of the pot elbow, just cut or it is crack and redo with the sheet intact, if there are welds in + it will be more beautiful, too bad for the original appearance of the Pro Circuit can not be found, if it can save the pot.

I also did a test of blueing on a sanded part to see if I could redo it on the welds as at the origin, it's good it works and it's beautiful











---------- Post added at 01:28 AM ---------- Previous post was at 01:26 AM ----------

[/COLOR]Now we're going to have a good laugh

I started to see the shock and as I've already said, it will not stay on the bike, say that we rolled with it at the time, the rod and the body with the piston are smaller and end that for a 85 YZ, even the KX 85 with its original shock ultra ****ty, is limited bigger (it's an image) in any case as for the fork, out of question that I roll with it, because even if I reach my goal of weight loss for January 2020 I think that for my weight of form I would always be too heavy for the rod cash strength of the receptions of jumps.

So I may be (if I find the parts) recondition and put on sale for anyone looking for an origin of this time.
You will notice that I just cleaned it quickly and especially the color of the oil that must have been the original one 30 years ago.


After cleaning but before dismantling



Yum, a good virgin oil dating back 30 years :







Passage of oil in the stem, closed.
later, the dampers will release this hole to facilitate the exchange of oil flow between the two chambers.

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Old 04-20-2020, 05:35 PM
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Well as the more years go by, the more the parts (even new ones) become rare, I start to take what I need most now to complete the bike and that is or will not be manufactured. Pro Circuit side so it should be the same as the pot is no longer manufactured at PC.

other pieces will arrive, and I will update the photos






---------- Post added at 01:32 AM ---------- Previous post was at 01:32 AM ----------

I get the crankcase and the bolt of the sandblasting, I'm happy but I still expected a better job, already it was necessary for me to blow everything to come home, I told you the sand thickness in the Xmax's trunk, the sand goes everywhere even with the casings closed and filled with bubble plastic + all the plugged holes.
But there are still places where there is still paint and I will be forced to sand, for the price announced at the start which quadruple when I returned the takes! so I'm a little angry, in short, it only takes me once.

All the gearbox bearings are ordered, so the needle cage in the one-handed housing, I'm going to break it down and I'll see to extract the one from the water pump / valve

Fork stop, I test with a large nut to take the measurements, so a stop of 8 mm will be ok, so I think rather than change the frame (before painting) rather as I was blown , drill and tap the tee and install a rubber stop 8 mm thick, it must exist and which is inserted between the two to smoothly damp if I put the handlebars abut on a huge scrub or whip

Spacer for the fork tee made (aluminum) remains to find a dust cover washer of 250/450 crf because that of the CR is in 26 and I need 30 inter diameter, not the most complicated, but I did not not duplicate because the XTrig tee that I mounted on the 450 was not delivered with the dust cover at the price of the thing, finally ... I groan today. lol

it's gone for some photos.








---------- Post added at 01:35 AM ---------- Previous post was at 01:32 AM ----------

So today I am not without fears tied to the linkage triangle, but having soaked all night in the penetrating, I did not have much trouble.






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Old 04-20-2020, 05:37 PM
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Then I decided to attack the two blind bearings, so I test the crumb of bread (because no bread) and it works, and for the other it did not come with the crumb, so I made myself a small makeshift extractor that worked very well after a little heat of the crankcase.








and I received part of the engine bearings yesterday, so before reassembling the bottom engine, I will take care to align the crankcase with the transfers of the cylinder



---------- Post added at 01:37 AM ---------- Previous post was at 01:36 AM ----------

Then disassembly of the parts of the back of frame and extraction of the rusty screws, it cost me the little of the ****-finger of the right hand and 1st blow of cleaning of the box with air










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Old 04-20-2020, 05:38 PM
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A new series of new parts have arrived today, so I add them to the rest of the pieces in the photo.
For info the plastic frame protections are for sale because between the time I place the order and the receipt of the package this morning, I find the Alu protections, so I do not need it.

I post a picture of the set then in detail



DT-One air filter



Boyesen Power Reeds (I have always built this since 1981) waiting to later mount a Rad Valve for the pleasure of the beauty of the parts.



Braking rear brake pads, no need to present the brand, it bites well and the resistance is not bad either



Chain skates



---------- Post added at 01:38 AM ---------- Previous post was at 01:38 AM ----------

The famous front plate typical, to go with the final look that the bike will have



kit DP Clutches (delivered in a complete box, smooth disks, filled disks, springs) no need to oil the disks during the assembly, it is one of the specificities of this kit




Carburetor repair kit




Pipe springs kit



Boyesen ignition and clutch cover




Pro Circuit 304 Silencer




Bel Ray of course



Master cylinder + caliper to go with the fork of 450 2013 that I ride on the bike

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Old 04-20-2020, 05:40 PM
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Operation ..... swingarm bearings.
With a very simple tool that will only cost you a few $, an M10 threaded rod with two nuts, a few washers and some M12 nuts, the rest you have it in the toolbox or in the drawer of the bench, ie sockets, here one of 19 metric to push the bearing cages, and a socket of 28 on the other side.
I also help myself for the 1st mm of shoot, a KYB tool that is used to replace the rings in the rear shock Seal head.







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Old 04-20-2020, 05:41 PM
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Another shipment of new parts including the second-hand rod. I will try not to finguée this one, but in this one we see that there is an aluminum stop inside, so indeed impossible to push the bearing rings.
Thing it was impossible to see the ones I had originally, so it was dusted and she has a small greaser, but where it is placed there is no use, ahah.






The rear wheel spacers are well used



I wanted to do the electrozincing of my hardware this afternoon, so I prepare the zinc chloride (chloridic acid + zinc tips), so the reaction is done, it smoke foam .. in short it's active .. .
But here, the zinc is not dissolved and the "juice" is black, still a few microbubbles, I'll leave it at night, but I think it's not good, no? it is necessary that the zinc bases if I read well the subjects which I saw while traversing google?

In short, if you can tell me if it's normal or not, if I can use the zinc chloride obtained there on the 2nd picture.
Thank you




And until the zinc chloride is done, I continue to work a little on the swingarm.
remember the impatcs of the chain relaxed and other traces of falls .. since the photos there, I also begin to do the side which corresponds, one does not see any more traces also. but then I can not sand anymore


I should also find someone to make me new string tension chocks in square format (and if possible anodized me in blue I think it looks pretty)







Before and during
we no longer see the impacts of the chain, which was probably more than relaxed

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