Greggo's MC21 Rebirth

[greggo]

So far I have bought a bike (R model), a spare rolling chassis (SE model), and a tonne of Tyga bits to make it pretty and pretty fast.

The bike is coming from Japan, bought off the auctions there. It is still 6 weeks away but i'm already champing at the bit to get things underway.

Here's the bike:
http://i261.photobucket.com/albums/i...g/Pa030749.jpg
http://i261.photobucket.com/albums/i...g/Pa030747.jpg

And here's the spare chassis (with bonus electrics):
http://i261.photobucket.com/albums/i...rctxa90784.jpg
http://i261.photobucket.com/albums/i...kth9c90784.jpg

Here is the list of stuff that showed up from TYGA today:
1 x Screen Clear, NSR250 MC28, Kit. (SCRE-0021) = $31.85AUS
1 x 2T Blank Plug (TYLY-0012) = $4.13AUS
1 x Front Fender (GRP), RSW style (BPFF-9001) = $34.25AUS
1 x .Set, Exhaust Chamber, Side By Side Type, Stainless Steel, MC21/28 (EXCS-0005) = $601.66AUS
1 x TYGA Flywheel Puller/RC Valve Remover Combo Tool, NSR250 (TYTO-0014) = $41.36AUS
1 x Upper Cowling (Race GRP), NSR250 Suzuka Style, Race (BPFU-9108) = $109.60AUS
1 x Lower Cowling (GRP), NSR250 Tyga, Stock Shape, Assy. (BPFL-0001) = $141.80AUS
1 x Kit, Seat Set, budget (Race) MC21 GP Race (BPFS-0059) = $330.47AUS
1 x HRC Radiator Overflow Bottle Kit, Assy. (BPAC-0002) = $25.86AUS
2 x Silencer, Aluminium, Two Stroke, (Special Promotion), Assy. (EXSL-0005) = $68.25AUS
2 x Blank Plug holder (TYLY-0015) = $8.13AUS
1 x Hi Flo reeds, MC21/MC28, Assy. (TPER-0001) = $87.84AUS
1 x Ignition Rotor (Total Loss), MC28 (TPER-0040) = $75.19AUS
1 x Woodruff Key, Offset, 2 Degrees, NSR250 (TPER-2044) = $6.63AUS
1 x GPS Blank Plug (TYLY-0014) = $10.21AUS
2 x Spark Plug BR10ECM, MC21/28 (98079-60875) = $25.67AUS
2 x Top End Rebuild Kit MC21/28, Cyl B Assy. (NHPS-0001 = $199.61AUS
1 x Holder, Fork, 41mm (TYTO-0018) = $23.78AUS
1 x Engine Stand, NSR250 (TYTO-0006) = $34.19AUS
1 x Clutch Lever CNC Black, NSR250, CBR250RR (LEVC-9011) = $19.81AUS
1 x MC21 rear stand bobbins, Assy. (TYLY-0009) = $9.44AUS
1 x Brake Lever CNC Black, NSR250/MC22/NC30/NC35 (LEVB-9011) = $35.15AUS
2 x Main Jet, #170 (99101-393-1700) = $9.60AUS
2 x Main Jet, #175 (99101-MCK-1750) = $9.60AUS
2 x Main Jet, #180 (99101-GHB-1800) = $9.60AUS
2 x Main Jet, #185 (99101-MAA-1850) = $9.60AUS
2 x Collar, Manifold, NSR250 (Special) (EXMN-9003) = $87.00AUS

Now, I've also started accumulating some other bits and pieces that will be needed;
Clutch springs
Bearings
Complete Gasket set
Fork bushes and seals

As well as spare cylinders (in excellent condition I might add)
spare rear cylinder head with HRC hose
Spare tank
Steering damper (needs rebuild)

My plan is to do a ground up rebuild of the chassis (new bearings everywhere) and a top end rebuild on the engine. Having said that the engine will be coming apart to remove those nasty casting burr's and the like. Hopefully the crank is in good order as I'm not keen on replacing that yet!

My plans so far (other than bolting on all the tasty bits listed above) are;
Powder coat wheels (black)
Powder coat swing arm (to fit my planned replica paint scheme)
Powder coat Fork bottoms
Powder coat other misc. parts as I deem worthy (top triple clamp comes to mind)
Rebuild front calipers (and possibly master cylinder)
Bead blast engine cases/cylinders etc to give it that 'new' look
Run total loss
Pod Air filters (no airbox but I can't bring myself to run just open carbs)
Remove oil pump
Investigating running a GPT GPS timer/dash
Hand make a new wiring loom
Refresh all bolts with tasty stainless and alloy where ever possible
Rebuild front and rear suspension (rear unit I will have to send off)
If I can find enough information I may have a go at some mild porting. We shall see.

As the bike still hasn't shipped yet I will kick things off with building myself a timber workbench (I've no garage and have to do most of the work on the back deck) and paint the bodywork at my friends place. This of course means a second round of painting when the bike arrives and I have a petrol tank!

I added up the money spent so far and got a bit of a fright. I will probably try and sell off the stock bodywork and some of the road gear to help resuscitate my credit card. Once I'm done riding this little beastie it will get a tidy up and preparation, and be sealed into a perspex box to become the feature 'bar' in my man shed (when I stop spending money on bikes and buy a house).

[Benno #03]

Should be a pretty special bike when your done. Keep us posted as to the progress, it's always cool to follow build threads especially two strokes. What color scheme are you going with, if I may have a guess. I'd be doing a Doohan Replica in either Rothman's or maybe even Repsol in a Doohan/Stoner Tribute. That'd be cool...

[greggo]

Something more now. It was almost stoner ktm colours or aoyama colours. But its not....

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[greggo]

So my first job was to build a bench. Job jobbed. Only took 3/4's of the day. I was surprised, it went together easily.

I turned this:
http://i261.photobucket.com/albums/i...0-29122824.jpg

Into this:
http://i261.photobucket.com/albums/i...0-29132054.jpg

into this:
http://i261.photobucket.com/albums/i...0-29155232.jpg

and finally, into this:
http://i261.photobucket.com/albums/i...0-29190903.jpg
http://i261.photobucket.com/albums/i...0-29190916.jpg

Designed to fit in my garden shed when not in use, hence the castors to get it there. A friend of mine is going to bend me some stainless steel to put on part of the top. Handy for working on some bits and pieces as it is easier to keep clean (like working on suspension etc).

Next job is to start surfance prep on the fibreglass (and seal in the belly pan for racing). Knowing the quality of tyga output, prep won't take long. Chances are I will have the body work well and truly done before the bike is half way here.

[darkfibre]

Very nice job.
The only suggestion I have is to make some way of removing the weight on those little wheels when doing any heavy work.

[greggo]

You make a good point. I have some offcuts of the 100x100 timber used for the legs so might make up some chocks with those.

[Loud]

Sweet project. Look forward to seeing it come together.

[greggo]

So i've got confirmation that my bike is in a container, on a boat, on it's way from Japan. Can't wait.

I rebuilt my steering damper today, I wasn't able to get new seals, so reused the old ones and used fresh 2.5W oil. It's cured the inconsistent movement, but will have to wait and see how it goes with the reused seals. It may only be temporary (which means i'll be forced to invest in a hyper pro - how terrible).

And to keep myself busy I removed the studs and power valves from the cylinders, fairly easy job, I expected them to be much more stubborn. I measure the ring gaps on the piston/rings that came out of the cylinders and got .045-0.5mm on the top ring and 0.40-0.45 on the bottom ring (both cylinders). Cylinders themselves look to be in pretty good nick, and i will prep these to go back in (but i'll wait until i've compared them to the cylinders on the bike when it arrives before assembling the power valves).



Cyl 1:




Cyl 2:



Next job is to prep the fibreglass for paint (including seal in the belly pan), and prep the gasket surfaces of the cylinders.

[greggo]

So part way through painting and all work must cease while i recover from a pulped pinky.

Its called a nail bed injury. Fancy name for a smashed finger.



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[greggo]

Bugger me. Soda blasting is awesome.



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[greggo]

So the bike finally arrived. Just in time for Christmas, just as well, i've 10 days off so plenty of time to build an engine assuming I don't discover I need to buy a crank or something.

So all this will eventually become a bike:



After unpacking I have stripped the engine of ancillary naff so I can clean it before complete dissassembly.



Learnt some things about the bike. It is an ex racer - various bolts are drilled for lock wire. The spare chassis I got is quite rough, the fork tubes will not be useable, but I got those for the internals anyway.

The importers also snapped a couple of the carb joints so they will need replacing at some stage.

Crank web has a stain on it from what appears to be rust that has been removed.

So first job is the engine. Clean, dismantle, inspect, tidy the cases inside with the die grinder, reassemble and put away for when the chassis is ready to meet it....

Can't wait...

I now have a shed load of crappola up for grabs if anyone needs any road going stuff. Everything from fairings, chambers, straight subframes, to a full lock set with key.

[greggo]

Preparing for complete disassembly...



It all came apart quite easily....



Here's a pic of the water damage on the crank webbing. I'm guessing this engine was left idle for a period of time.



The thin rubber o-ring in on the centre has been quite badly stretched, will this be a problem? (I can see it at least being a PITA to reassemble)

Checked the crank condition against the specs listed elsewhere and the crank/conrod gaps are .6 and .55 so well within tolerance.

My only real concern at this stage is the water damage to the webbing, and the bearing condition. They feel okay....but....

Clutch looks near brand new, basket included. Everything else looks to be in great knick.

Next step is to clean the engine and cases with the soda blaster...I reckon that will be enough for today. While I research the centre o ring on the crank...

It's hard to see but this is the o-ring...

[greggo]

Left outer bearing I think is knackered, as I can 'feel'/'hear' it rotate (not surprising if the seal was goosed).

Centre bearing is quite stiff, it turns okay and I can't feel the rollers working just concerned over it's relative stiffness.

The right hand bearing rolls smoothly and without sensation or sound - so presumably is okay.

Well I made my decision, I've ordered a new crank. I figure so much of the rest of the bike is effectively going to be brand new that it may as well have a new crank.

I will send the old one off at my leisure to be rebuilt and hang on to that as a spare. Same as I plan to send off the spare cylinders at my leisure to be replated.

The extra expense means some bits and pieces won't get the attention I wanted, like a complete caliper rebuild (although they look in excellent condition), at least not right away.

Todays activities inlcuded tidying up the gasket surfaces with some lapping paste and a sheet of glass.



Then I stripped down the two frames ready for a good clean down. The SE shock is in a very sorry state. The R shock is not bad at all. Not too sure what i'll do. I may just get the R shock rebuilt. The SE shock looks like trash.

I also dismantled the forks. Of two sets of forks all the chrome needs to be redone. Bugger.



I've crossed the financial line into scary territory. And with a set of stands, warmers and tyres needed before it rolls onto track this bike will come close to 5 figures.

[g0zer]

yeah track prepping old 2t bikes is not cheap

its an interesting exhaust port profile and heat stain honda have got going on there.

[Benno #03]

Keep going mate, it's only money after all.
That 1st ride will erode any feelings of cost, you can't buy those moments.

[greggo]

So I'm about to have a wee go at the crank cases with the die grinder.

BUt before I do I just want to confirm i'm not about to turn the bike into a pile of expensive slag.

First up I plan to match the exhaust port and Tyga manifold, to remove any steps as they aren;t quite a perfoect match:



Second I'm wondering if it is worth matching the base of the cylinder to the crank casting to make a smoother entry at A? and I'll remove the casting edge at B.



Is it worth matching the port entry here to the case at A? Thats a massive step? And B already has a nice flush finish, i'm assuming that is good and what I would be looking for at A in the above pic?



Finally the edges here are really rough, is it worth smoothing these over a little?



I know there are people here who make a living off this and I don't want to be stealing any info. But I really would appreciate a little advice to stop me doing some damage.

Also, living in Melbourne, does anyone know a good place to send my spare cylinders to be ported and replated? Having read a fair bit on the web about porting the cylinders to match the RS250, i'm interested in getting that done (then swapping out the set on the bike for the ported set).

[EEKNOWS]

Do you want to sell your old crank? What ever you do leave the step at the flange in the exhaust duct. Grinding the cases will do SFA except make lots of swarf.
I can help you with the cylinders BUT the NSR is good for 65HP without touching the cylinders. I actually spend more time these days adding material to cylinders than taking it away. Sorting those crap NSR cylinder heads (back to TYGA) and setting the compression and squish is what really helps.

[greggo]

PM Sent EEKNOWS

Did a few little jobs today;

Regreased the swing arm bearings and put the swing arm back into the cleaned frame.

Put the new head bearings on (and promptly fuggered the lower rollers). So that will be a repeat job.

Removed the tyres and bearings from the rims to go to the powder coaters. I then went to the bearing shop to get some newies for when the rims come back ($176 for 2 complete sets for bearings and seals! ).

I'll keep tackling the little jobs until I get the cases done, the new crank, and a host of other bits and pieces I'm still waiting for!

Powder coaters, and suspension (fork chrome and rear rebuild) people are off line till the 8th/9th of Jan. So a few major pieces can't be done yet.

[greggo]

More small jobs today:

Stripped and rebuilt the rear caliper, internals look good but full of gunge. Works well now. What a dogs breakfast. The footpegs make the original hose too short unless mounted how you see it now.

Mounted the subframe, polished and remounted the footpegs. Including replacing rose joints as one was seized. These will do until later when i've recovered from ordering the crank and can get a nicer set of rearsets.

In the bits I bought I got MC21 clocks and MC18 clocks. I like the MC18 clocks as the speedo is seperate, but they appear to mount on the same front bracket. Tomorrows job is to confirm they do both mount on one bracket, then put the MC21 internals into the MC18 bits. Maybe. Or maybe I just use the MC18 as is.

Might even remount the wiring loom and clocks using the 'spare' front mount, while the other one waits to go to the powder coaters.

I've already done the base coats on my fairing and they have been at the signwriters for 3-4 weeks, to do a one week (quoted as one week) job to put the decals on before I clear coat. Wish they would hurry up and come back!

[greggo]

So, not much progress in the last two days. Rebuilt the power valves, cleaned the actuator arms and put them back in. Measured the ring gaps for the new rings in the cylinders.

Decided not to do any porting, I think I will get my spare cylinders done professionally when I get them replated.

I'll make sure I get the squish right (prob need some adivce on this...like umm how do I adjust it? Different thickness base gaskets?)

Currently waiting for my fairings to be finished by the sign writer so I can clear coat, crank to arrive in the mail, the powder coaters and suspension people to reopen after the christmas break.......sigh.