Whilst I am working on an MC18 track bike I have an MC21 engine to rebuild. I'll keep this as a seperate thread. Here are photos after cleaning in "soup":
Yes, it has one MC18 cylinder. And the MC21 barrel is SE/SP with R head, nikasil damage and cracked bridge.
The good news: I sorted out how to download full size images. Thanks yakama. _________________ MC21R9N track
MC18R2J track
CBR954
CR250
Water pump cover is cracked at hose connection. Wasn't visible until after cleaning. A new one is on the way from david Silver Spares.
Burned up my Dad's compressor in the process. It's not worth fixing so looking to replace it.
Done a good bit of clean up with a dremel inside and out. I was surprised to find so much casting flaw. Some even looked like cracks but were raised. Carefully nipped them off with dremel and polished with 800 grit wet paper. Still have more to do.
Seals, o-rings, clutch, crank, waterpump gear, studs, dowel pins, 2T blank, GPS blank, threebond 1207b all received or on their way. Almost up to current status. _________________ MC21R9N track
MC18R2J track
CBR954
CR250
Mating surfaces cleaned up and flattened on glass with 800 grit wet/dry paper, all threads cleaned out with taps, final cleaning and deburring:
Transmission cleaned, inspected, installed:
Waterpump rebuild kit from Tyga. And a used waterpump drive gear (also from Tyga, thanks Matt). Just waiting on a new water pump cover from David Silver Spares to replace the cracked one, and some free time:
Even a magnetic oil pan drain plug! I'm a big fan of magentic drain plugs and put them in all my bikes.
_________________ MC21R9N track
MC18R2J track
CBR954
CR250
MC21 cylinder disassembled and ready for cleaning. Nikasil damaged and needs a replate. Bridge is cracked but extent can't fully be determined until it is clean:
MC18 cylinder disassembly underway. Waiting for penetrating oil to do its job before trying to remove studs:
Power valves all coked up. Not a good shot but there is almost 1/4" build up on one:
Does the color of this head look about right?
I am now up to current. Time is short what with work and family and progress comes in short bursts but super slow at work so ordering parts and research can be fit in the day quite easily. _________________ MC21R9N track
MC18R2J track
CBR954
CR250
Waterpump rebuild underway:
The helical splines on the water pump shaft drive the oil pump. I'm not using the water pump. I guess i didn't need that new water pump shaft afer all. Doh!
All parts in hand and got reassembly straight in my head. That's more than half the battle anyways. _________________ MC21R9N track
MC18R2J track
CBR954
CR250
This is how I resurfaced the cylinder base:
That's a piece of glass siliconed to a piece of plywood with a 3" diameter hole drilled through the glass and plywood. How do others address this surface? _________________ MC21R9N track
MC18R2J track
CBR954
CR250
Made much progress this weekend:
Clutch basket has a good amount of wear. Need to sort out what to do.
And kickstarter spring does not seem to get much pretension. Does it get wound one full rotation before installation? _________________ MC21R9N track
MC18R2J track
CBR954
CR250
Stymied on clutch so moved on to reeds/insulators and stator:
Flywheel rusted up good so it is getting a paint job. _________________ MC21R9N track
MC18R2J track
CBR954
CR250
Flywheel, pick ups and new front sprocket installed:
Waterpump rebuilt and installed. Clutch cover installed temporarily. Awaiting new clutch basket:
The start of a leak down test:
Kickstand was a rusty mess: Cleaned it up on the wire wheel and coated with clearcoat. Wasn't quite what to do to prevent it from rusting again. And not sure how it is treated at the factory to prevent rust?:
Cans blasted, powder-coated, and repacked:
Never been a fan of pop-rivets but am very much liking this rivnut tool. It secures well and draws the two pieces of sheet metal together:
Pipes blasted and coated with barbecue paint. Should have decoked them first. Next time i guess:
_________________ MC21R9N track
MC18R2J track
CBR954
CR250
An inexpensive enough tool and a good solution. Slow going if you have many to do.
I also have stock cans on my MC21 that need disassembly and then of course reassembly. I'm sure the packing is a nasty mess inside. They are not well suited for disassembly. Have you to sort that one out. Though i'm pretty sure this tool will be used in reassembly.
Good work on the engine restoration & rebuild. _________________ Rich
MC21 Track Bike / RS250 NF5 'Spencer', NX5 'Cadalora' & NXA 'Aoyama' / RS500 / Two Brothers Racing RC30
cangus wrote:An inexpensive enough tool and a good solution. Slow going if you have many to do.
I also have stock cans on my MC21 that need disassembly and then of course reassembly. I'm sure the packing is a nasty mess inside. They are not well suited for disassembly. Have you to sort that one out. Though i'm pretty sure this tool will be used in reassembly.
Sorry to be a know-all, it looks to me like you've used those riv-nuts as normal rivets?
I apologise if I'm teaching my Grandmother to suck eggs but you do know they're meant to be a re-useable fitting? Meaning they're installed on one part of the two pieces, then a bolt can be screwed in to hold the two pieces together.
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