rmz250 - rebuild

[sensfan]

Well, it's been a great summer here in Arnprior -- so that means I'm just now getting back to my attempted rebuild.  

In the video they remove the oil pump and such from the one case, is it necessary to do this? from the video it just doesn't look to me that it goes thru to the other case or that it somehow keeps the cases connected in any way -- just wondering

Also, is it necessary to remove all the transmission parts in order to get the crank out? 

Thanks

[mlatour]

This far deep into a rebuild I'd without a doubt disassemble and closely inspect the oil pump,

especially on an engine that suffered a failure.

 

As for leaving the gearbox components in the case, guess it depends how smoothly it goes when splitting the cases.

On occasion, some parts lift out partially with the case only to drop back inside a moment later.

 

Again, this far into the engine I would want to closely inspect each shift fork, gear dog, shift drum etc.

It would be frustrating to find out your newly rebuilt engine doesn't shift well only once fully re-assembled.

[sensfan]

Hi

I can't argue with what you're saying and totally agree - when I change the winter tires, I check the brake shoes and rotor, no sense doing it all over again.

But just for my own knowledge, from about minute 17 until minute 22 in the video on the first page of this thread, do all those parts need to come off in order to split the cases? The lad doing the video - which is EXTREMELY helpful by the way, needs to get something welded so I get why he removed everything, but i'm curious; if only splitting the cases do those parts need to be removed.

 

thanks again guys, appreciate the help, hopefully this weekend which is looking like rain will give me some time in the garage.

 

 

 

[Torrture]

Any new updates? How goes it?

[sensfan]

sorry for the long delay, long story short I hope to get to this again over the weekend, and should be splitting the cases.  Had a bit of trouble with the reverse threaded nut on the crank shaft (i dont have air tools) and it was pretty tight.  My auto mechanic was able to remove it.

I have found someone relatively close by willing to help too which is great.

once cases are split i'm hoping they can educate me more about how the transmission/gears look, will keep this updated 

[sensfan]

so tried a bit more last night, this is the 3rd-4th screw/bolt that i have found to be almost stripped to start with or over torqued.

i was thinking of drilling it out, or possibly welding a nut to the top? because its flat and flush using my dremel to make it a slot drive might be tricky

 

thoughts? suggestions?

[sensfan]

I guess the bigger question is -- do i need to remove this part in order to split the cases?

 

also, how can i check that the oil pump is working properly?

[MatthewMCRepair]

Use an air chisel:

 

Why it stripped in the first place:

 

 

[sensfan]

thanks for the links - does this piece need to come out before splitting the cases? it would be a lot easier to split the cases and then lay the side flat to do the chisel.

[MatthewMCRepair]

34 minutes ago, sensfan said:

does this piece need to come out before splitting the cases?

Yes.

[sensfan]

Thanks -- I subscribed to your site as well.  Hopefully this weekend I can get some time and get this thing split 

[sensfan]

Well hopefully this doesn't cause too much in the way of issues but we had to drill the screws out, dremel slot drive trick, chisel trick, nothing worked.

The heads came off nice and clean, looks like we still have enough room to tap and redo the threads.

The amount of red loctite was ridiculous.

Got the cases split, insides seem to be good, dirty and cleaning required but no visible damage, which is great -- the learning continues ?

[ar2stroke]

On 9/25/2018 at 9:23 AM, sensfan said:

Well hopefully this doesn't cause too much in the way of issues but we had to drill the screws out, dremel slot drive trick, chisel trick, nothing worked.

The heads came off nice and clean, looks like we still have enough room to tap and redo the threads.

The amount of red loctite was ridiculous.

Got the cases split, insides seem to be good, dirty and cleaning required but no visible damage, which is great -- the learning continues

I would replace those #3 Phillips in the case with the heads stripped out. Also, please note the 'shift paws' the placement (as there is one way they go in). Otherwise that plate that holds it will bind up and not allow it to move.

[ar2stroke]

On 9/21/2018 at 10:15 AM, MatthewMCRepair said:

Use an air chisel:

 

Why it stripped in the first place:

 

 

I would suggest as others get the JIS Screwdrivers - the ones pictured are Vessel and the best ones as they have like the anti-slip on the tips.

[ar2stroke]

Any updates on the engine build or rebuild?

[sensfan]

Hey - he was able to remove the screws with an extractor w/o having to redo the holes.  We've replaced all the seals and gaskets and have started the reassembly.

Tonight we're hoping to get some good headway with this, depending on how it goes we may have this back together soon...hopefully the reassembly goes smoother than the disassembly

[ar2stroke]

8 hours ago, sensfan said:

Hey - he was able to remove the screws with an extractor w/o having to redo the holes.  We've replaced all the seals and gaskets and have started the reassembly.

Tonight we're hoping to get some good headway with this, depending on how it goes we may have this back together soon...hopefully the reassembly goes smoother than the disassembly

Put up some pics!

[sensfan]

ok, so we did some more work last night and got the engine remounted.  one thing we noticed right away is a fuel leak where the line runs into the carb (see pic with red arrow).  I know on most other bikes I've had this copper/brass inlet is always fixed (it doesnt move).  However, on this rmz carb it spins around freely -- is that proper?

we tried to get it started and the thing turns over which is great and feels like it wants to start but it wouldnt.  at one time while we were kicking it over i saw some flame come out the exhaust --- i have never seen that before on any bike.

because i forgot the spark plug i bought he used a cr6e and i'm pretty sure the one you need is cr8e -- not sure if that would cause anything but i definitely plan on swapping them

also - the carb has sat for likely 2 yrs...shit is probably dried out and gummed up (although it was drained)...soim thinking a solid cleaning is in order.

thoughts?

 

thanks again for all the help!!

[sensfan]

ANOTHER QUICK UPDATE: removed gas tank, swapped spark plugs...tried it.....IT STARTED...wow....so long as I can keep it in neutral

however, here is my next issue, as i kick it over it always wants to go into gear - that isnt good, because as you kick it wants to move forward.

any suggestions, is this a clutch setting or more of a gear/tranny issue...heaven help me if its gear/tranny...dont think i could handle tearing it down and splitting it again.

[mlatour]

41 minutes ago, sensfan said:

I know on most other bikes I've had this copper/brass inlet is always fixed (it doesnt move).  However, on this rmz carb it spins around freely -- is that proper?

On both CRF's I maintain the inlet tube swivels, there are 3 small o-ring on it that can wear out and allow leakage.

 

Be careful when cleaning the Keihin FCR carburetor as some harsh solvents can damage internal seals.

Google what is commonly called the 'FCR mid body seal'

I've read a few times that soaking in Pine Sol and warm water gives good results,

and using a single strand of copper wire to ream out the small passages.

 

There are also many wear items that are commonly replaced when overhauling these,

the emulsion tube, the fuel screw's o-ring, the vacuum plate seal, the accelerator pump diaphragm etc.