MC22 Aussie Restoration

114107 Views 228 Replies 53 Participants Last post by kula, Feb 26, 2017

Benny_Jay

Discussion Starter · Jun 30, 2013

Hey guys, new member here. I've actually been browsing for many many hours. Was inspired by many projects to start my own. I found my self a 1998 Honda CBR250rr for sale on Ebay for $1900. Still had over 6 months rego left. Started first time every time.

I didnt really want to get too crazy with it, but I love pulling things apart and understanding how things work. One minute I was pulling things off to see what condition it was in, next minute the bike was in complete bits.

So the overall plan is to break the bike down and rebuild everything to like new condition. As much as I want to play with the engine, it was running fine so Im going to leave it alone. Just give it a fresh look.

I love the look of the bike and will not be going the Tyga kit. The plan was to keep the original look, but once I had everything in pieces I thought I would get everything powdercoated to give it the best chance of looking new again.

So I've been at it for a while, I was going to share it with you guys but for some reason my account wasnt been activated. So now that it is, I'll throw up some random pics ive been taking.

Its pretty much up to rebuilding now. So let the fun begin

Reactions: 3

181 - 200 of 229 Posts

Benny_Jay

Discussion Starter · #181 · Feb 8, 2014

Bluevitz-RS said:
Well if the orders were mixed up and the valves weren't put back into the right guides it's possible the one that failed was bigger than the guide it was put into and got stuck open from lack of lubrication.

Sent from my iPod Touch

Well something went wrong!!! I want to know what it was so it doesn't happen again after spending a ton of money fixing it.

Sent from my iPhone using Tapatalk

clevermetal

· #182 · Feb 9, 2014

I haven't had a look at these valves in a while but a lot of manufacturers friction weld the 'fat' bit of the valve onto the valve stem. Needless to say that they do sometimes fail... which might be what happened in your case. Just bad luck/poor maintenance/25 year old bike.

I doubt that it was an order mixup, for it to assemble perfectly enough to fit together/visually look fine but actually be parts from different bikes would be quite a feat. Especially by accident.

Pro-tip: to ensure your head is flat for when you reassemble it. Buy a really thick pane of glass (or stick two together) that you can stick 2 sheets of wet and dry down onto side by side. Then run the head over it until the entire bottom surface is evenly shiny. 100% flat and only costs around 20 or so bucks.

clevermetal

· #183 · Feb 9, 2014 (Edited)

also if you're getting new bearings (read that as: you need to get new bearings/wrist pins/pistons etc. etc..), it doesn't matter so much about conrod ordering/being in the right order.

When you plastiguage them you might find you have to mix and match to get the best mix of tolerances. But as long as they've got new bearings between them and the crank and are sitting in wrist pin then there's no wear matching that you have to take into account.

EDIT: Do NOT mix and match the main bearing caps. They HAVE to be put back in the same order as they came out as the engine would have been line bored with them in there.

clevermetal

· #184 · Feb 9, 2014

also good luck trying to accurately 'guess' where the centres are on the conrods to measure them. I'd just put them on a flat surface (like the pane of glass you're going to buy to ensure the head is flat)

Benny_Jay

Discussion Starter · #185 · Feb 9, 2014

clevermetal said:
I haven't had a look at these valves in a while but a lot of manufacturers friction weld the 'fat' bit of the valve onto the valve stem. Needless to say that they do sometimes fail... which might be what happened in your case. Just bad luck/poor maintenance/25 year old bike.

I doubt that it was an order mixup, for it to assemble perfectly enough to fit together/visually look fine but actually be parts from different bikes would be quite a feat. Especially by accident.

Pro-tip: to ensure your head is flat for when you reassemble it. Buy a really thick pane of glass (or stick two together) that you can stick 2 sheets of wet and dry down onto side by side. Then run the head over it until the entire bottom surface is evenly shiny. 100% flat and only costs around 20 or so bucks.

Thanks for the help Clevermetal. Ill be giving the head and cylinders to a machinist to skim and make sure its square, hone the cylinders and give everything an acid bath. I'll be checking all the bearings and only replacing as necessary. From the look of CMSNL.com you cant get new wrist pins.

As for the cause of the destruction, Im pretty sure a valve let go. The piston from cylinder 1 also had contact with a valve. What causes this? bad valve clearances? Piston to head clearance?

Bluevitz-RS

· #186 · Feb 9, 2014

Over revving from a missed shift, weak valve springs, timing too far advanced on intake cam, fatigue... all kinds of stuff can cause it. Number one is a missed shift at the rev limiter though.

And I've seen a vid you youtube about decking the head on glass, you can look it up. Works really well and cheap.

Benny_Jay

Discussion Starter · #187 · Feb 13, 2014

So not having much luck. I took my engine case to an Engine machinist in Thorton NSW. I wanted to see if the cylinder will come good with a hone/bore and still be within limits, no luck. I asked him about a re sleeve and he just didn't sound confident about if it could be done or not.

I started to look into a replacement engine and was getting prices around $900.

Can these cylinders be re sleeved? I would only like to take it to a shop that has done MC22 engine sleeves before (NSW). Need some suggestions from people of the forum???

I can't make up the decision whether to:

A) Buy a working engine, break it down and rebuild from scratch with the best parts of the two engines.

B) Try repair the cylinder, find a new head and put it all back together with everything being checked and serviced.

Im leaning towards a new working engine....

See less See more

Reece

· #188 · Feb 14, 2014

Just read the entire thread, amazing job mate!! very inspiring work will have to start my own soon. Loving the black powder coated frames a few people are doing on here.

I had the feeling at the start of the thread that you would end up re-building the motor, and sure enough, it blew up!

I think option A is the better of the 2, but your call!

Good luck bud, I will be watching

Bluevitz-RS

· #189 · Feb 14, 2014

I guess the only way to fix it would be to TIG weld the bad spot and have it bored out to fill the nick.

Sent from my iPod Touch

clevermetal

· #190 · Feb 14, 2014

Depends how bad the scratch is. If you can catch your nail in it then it's significant and you might need oversized rings to fit once the thing has been honed.

Honestly it just comes down to budget:
The best option is definitely to get a new (to you) engine that doesn't have scratched cylinder walls and use that for the rebuild.

If money is tight though you could probably get away with a rebuild with stock rings (depending on how bad the scratches are) but ring are pretty tight and a little bit of blow by isn't going to kill the engine in the 20k kms you'll own the bike.

Benny_Jay

Discussion Starter · #191 · Feb 15, 2014

18

Thanks for all your input guys. So I decide to get a replacement engine from the wreckers. I picked one up on Friday afternoon.

Even though its a running engine I'll be pulling it completely apart, inspecting everything and replacing as necessary.

I started today pulling the engine apart. Just by breaking it down I can already tell this engine is in better condition, and from looking at the part numbers it was built later on the assembly line.

I have pulled everything off the engine so I can take the cases to get professionally cleaned so they look brand new.

Tomorrow I will be checking the bearings for correct clearances so I can start a shopping list of parts. I got some plasti gauge today for the bearing inspections and also some lapping paste and lapping tool so I can service the valves.

I have already found one of the transmission bearings to have some play so will be having a closer look at everything tomorrow.

Here are some happy snaps of todays work

Replacement engine :

Old engine laid out so I can compare to condition of parts:

Pulling the head apart:

Aero Kroil, I swear by this stuff. Its a penetrant that can get into as small as one millionth of an inch. I use it at work. Has saved me so many times. :headbang::headbang:

Checked valve clearances and measured all the shims before pulling apart.

Filter was pretty dirty!!!

See less See more

Benny_Jay

Discussion Starter · #192 · Feb 15, 2014

17

See less See more

Benny_Jay

Discussion Starter · #193 · Feb 15, 2014

4

Some quick checks of the cylinders.

See less See more

Bluevitz-RS

· #194 · Feb 15, 2014

Love all the HQ pictures. You seem to have all the necessary tools for the job.

When you do the plasticgauge make sure everything is oil free and torqued to spec. And do not rotate anything before removal.

Sent from my iPod Touch

MC34

· #195 · Feb 16, 2014

Amazing thread/work, can I ask how you would go about getting the engine block clean? I'm assuming dumping it in some diesel but are there any other specialist tricks?

Reece

· #196 · Feb 16, 2014

Hey mate, awesome pics.. Whats plasticgauge and how does it work? Is that the box you have in the last couple pics?

Benny_Jay

Discussion Starter · #197 · Feb 17, 2014

MC34 said:
Amazing thread/work, can I ask how you would go about getting the engine block clean? I'm assuming dumping it in some diesel but are there any other specialist tricks?

Well since Im spending a fair amount of money rebuilding the engine, I want do it properly and get the block proffessionally honed, skimmed and acid bath to clean the engine like new

Im still looking into what is the best way to get the cases like new but it looks like acid bath from what I have read.

Benny_Jay

Discussion Starter · #198 · Feb 17, 2014

Reece said:
Hey mate, awesome pics.. Whats plasticgauge and how does it work? Is that the box you have in the last couple pics?

Im about to load some photos of the plastiguage. It is a way of measuring the clearances between bearings. The tools I have in the box are bore micrometers. Accurate way of measuring the bore. I found the telescoping gauges and verniers to be just as accurate.

Benny_Jay

Discussion Starter · #199 · Feb 17, 2014

15

So I ordered some plastigauge on the Internet and It still hasnt arrived. I found out you can get it at Repco so I went down to get some. I asked for red plastigauge. So after setting it up I noticed that it was actually a different brand. Flexigauge not Plastigauge. So the measurement range was a little higher than I was after. The oil clearance I was after is 0.022 - 0.040 with a service limit of 0.060 and the range the Flexigauge 0.050 - 0.150

Since I already opened the packet I gave it a shot. It will atlease tell me if the bearings are below the service limit.

Even though all my bearings were fine, except one that had a slight nick that I didnt like. I decided to replace all of them. I have spent so much money and time on this bike, why stop at the heart of the bike........

Torqued down case with 10 bolts securing crank.

And remove case

Pulled all the valves out and attaching hardware.

Valve stem seals

See less See more

Hessian

· #200 · Feb 17, 2014

In focus photos! Good to see a nice write up.

How do you feel about spending some big $$ on a 250? Wouldnt the cash be better spent on a bigger bike?

181 - 200 of 229 Posts

This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.