Getting into racing Part 2: More questions...

[speights_bud]

You can go a long way with the MC21 in terms of making it faster - Steve mentioned the Tyga 300 kit - and if you can find them there are HRC 'TT F3' kit parts available specifically for the MC21. Its all money though. Lots and lots of money...

There's a few fellas running MC21s in the winter series at the moment: Patrick Doohan, Albert Saunders and Jason Daws. Jason's bike definitely runs on slicks and i think Patrick's does too. Jason will most likely race the tri-series again this year so try to find him and check his bike out. It was originally put together by Glenn Mason and is a good example of what modifications to do to your MC21 to make a reliable, quick race bike. I'm pretty sure Dukic did his suspension.

(Paddy Doohan here) Yep we are running Slicks on the NSR, Michelin's mostly because there were some 2nd hand going cheap and we are too poor to buy dunlops... run in the wet on Michelin's too, about to try out an awesome looking Conti front wet next time it rains thanks to Sketchy (way better cond than the nearly poked one we have!). Suspension is stock as far as i know, although looking into stealing the USD's off the VJ22 parked in the shed. if anyone thinks this is a step backwards im all ears...

The NSR's are a great bike to go out and have a spin on, great to see someone else getting 2-stroke fever . First time on the bike at taupo i managed to take out 3rd for F3 at the spectacular for the weekend.
Tyler Firn's giving the NSR a ride over the winter series and managed to get a 3rd, 4th and 5th this weekend just gone in F3 at manfeild.

Before we sorted out the gearing which was miles too short for Manfeild, topping out halfway down the straights, but the bike was good for just inside top 10 in F3. It's taken a lot of hours just to get the bike to where it is now, although its totally worth it in the end.

If i were you, i wouldn't worry about spending $$ shock upgrades just yet, i'd swap over the forks you already have to begin with, (check the geometry matches up & give the oils etc a birthday of course) get it running reliably (test days are great for working on this) and get out there in F3 and get a feel for whats going on. then as you progress as a rider (and your bank account does too) you will find the things that need improving most. I know that good suspension etc makes a huge difference to how quick you can lap, but if you don't have a baseline to start on you won't feel how much of a difference the upgrades will make

The biggest set back for us is the Cranks, unless you buy the new MC21 crank out of Aussie (about Aus$900 i think) the only other re-build option is to bring in the main bearings from Greece at about NZ$300 landed i think. This is the reason why we are running MC-21 barrels on a 2nd hand MC16 bottom end. Because we managed to find a spare crank and are broke. However i am looking into the MC21 crank bearing features to see if i can machine the appropriate features into the bearing casings myself. I modified one main bearing for the MC16 last week and it seems to have held up over the weekends racing no problems.

This guy has done a far bit of importing and stuff for his bike (and spending lots of $$ too) you/someone here probably knows who he is.

http://edetuckracing.blogspot.com/se...max-results=12

I believe the last round of the **edit** winter series is at Taupo which is and awesome track for the 250's. We'll be there and feel free to come and chat

[nsrpaul]

. Suspension is stock as far as i know, although looking into stealing the USD's off the VJ22 parked in the shed. if anyone thinks this is a step backwards im all ears...

:

it is a backward step unless you are running r model (preload adustable only) nsr forks

the biggest issue tho is the offset on the tripple clamps, the nsr has 35mm, cant remember what the rgv is but its heaps less, so will slow the steering up

unless you get clamps made, but then that money would be better spent with dukic

cheers

paul

[speights_bud]

it is a backward step unless you are running r model (preload adustable only) nsr forks

the biggest issue tho is the offset on the tripple clamps, the nsr has 35mm, cant remember what the rgv is but its heaps less, so will slow the steering up

unless you get clamps made, but then that money would be better spent with dukic

cheers

paul

Yea, figured i'd need to do something like that, haven't even put a measuring stick to the idea of changing. I could make the new clamps myself but can't really be bothered going to the effort at the moment. Although if anyone wants clamps billet machined, or anything else custom machined like that let me know, made some at work for a tz125 Ohlins upgrade a while ago, came out pretty choice.

[steveyb]

Yep, just service the standard suspension and then when $ allow get the forks revalved with an emulator and have a good shock put in the back. Don't go for the Suzuki forks, too much trouble for very little gain.
The NSR 250 in pretty much stock trim is capable of running in the 1:16 or better bracket around Manfeild (in good conditions), so until your rider (who is doing really well by the way) can do that consistently, don't go getting hop-up stuff. Just buy decent rubber, oil etc with the money and get out on the track.
The NSR already has capable suspension, but clearly it is not the best, but as Paddy says, find your baseline first by optimising what you have, then get the good stuff.
Having said that, servicing the forks and putting an emulator and revalve in there is not all that dear. (I am assuming they are damper-rod forks, am I right, I can't remember. If cartidge forks it is even easier to do).
Robbity Bob at CKT has all the info for this.

Oh and by the way, those old codgers at EdeTuck racing are washed up drunks and all they are building are their bald spots and beer guts. Well, maybe not Dave, but Wynton most definitely.
Like myself, 250 Production protagonists from days gone by.
Tuck had one of the scariest moments I have seen on old RGV250: Front straight at Pukekohe, full noise, hit bump, tank slapper, people could hear the tyre screeching as it hit the track on each side of the slapper. He made it round turn 1.
I would have wasted Dave at Paeroa except for a buggered 3rd gear!!!
We were all in the 30min warm-up race at World Superbikes at Manfeild back in the day (along with many of our past champion riders).

[steveyb]

It sounds very much, unfortunately, that you have seized a piston, or at the very least, have stuck or broken rings.
As pointed out, there is no 'no-work' way to diagnose and fix it.
First step, pull the exhaust pipes off and have a look up the hole with a torch. Seized piston will be obvious.
Second step, drain coolant and pull cylinder heads off. Damaged piston will be obvious. If no obvious damage, you then need to pull cylinders to inspect rings.
All of this will require some replacement parts (cylinder head gaskets, base gaskets, piston, rings, maybe cylinder repair and replating).

While being a fan of these bikes, there are stumbling blocks, but this is the case for any bike.

The biggest test needed after reassembly is a leak-down test where you pump up the engine with air to check if there are any leaks. Air leaks kill 2-strokes.

[koba]

We were all in the 30min warm-up race at World Superbikes at Manfeild back in the day (along with many of our past champion riders).

I think I may have been in kindy then, and I thought I was old...

Air leaks kill 2-strokes.

Very True.

[sharp2183]

It sounds very much, unfortunately, that you have seized a piston, or at the very least, have stuck or broken rings.
As pointed out, there is no 'no-work' way to diagnose and fix it.
First step, pull the exhaust pipes off and have a look up the hole with a torch. Seized piston will be obvious.
Second step, drain coolant and pull cylinder heads off. Damaged piston will be obvious. If no obvious damage, you then need to pull cylinders to inspect rings.
All of this will require some replacement parts (cylinder head gaskets, base gaskets, piston, rings, maybe cylinder repair and replating).

While being a fan of these bikes, there are stumbling blocks, but this is the case for any bike.

The biggest test needed after reassembly is a leak-down test where you pump up the engine with air to check if there are any leaks. Air leaks kill 2-strokes.

Have just stripped the cylinder off and the piston is indeed munted. Thought it was all managable until I saw a decent sized crack in the exhaust bridge. So the engine is coming out for the time being, until I can find a replacement front cyl.

On that note, if anyone has such a cylinder I would be interested! Unless anyone knows who repairs these things?

In other newa, can anyone confirrm the type of rear shock that came out standard on the MC21? I suspect I may have inherited a different setup on this bike.

[Deano]

Make sure your numbers are legal and very visible !!

[Latte]

Have just stripped the cylinder off and the piston is indeed munted. Thought it was all managable until I saw a decent sized crack in the exhaust bridge. So the engine is coming out for the time being, until I can find a replacement front cyl.

On that note, if anyone has such a cylinder I would be interested! Unless anyone knows who repairs these things?

In other newa, can anyone confirrm the type of rear shock that came out standard on the MC21? I suspect I may have inherited a different setup on this bike.

Depending on R vs SE/SP you'll either have a showa with no remote reservoir, or a showa with a remote reservoir

[Dodgy]

I have some good barrels and pistons if you are interested - please pm me and I will get in touch

[steveyb]

Only pay him half what he is asking!!!

www.nzcylinders.com in Ashburton are the local cylinder repairers.
A good job for a reasonable price and using the leading international technology. You need to send a new piston with the cylinder for repair so they get the clearance correct.

Always handy to have a back up cylinder or two.

Now, the hard part, figuring out what went wrong.

Take some good photos of the piston and cylinder and post/send them. Diagnosis maybe possible therefrom.

[sharp2183]

Only pay him half what he is asking!!!

www.nzcylinders.com in Ashburton are the local cylinder repairers.
A good job for a reasonable price and using the leading international technology. You need to send a new piston with the cylinder for repair so they get the clearance correct.

Always handy to have a back up cylinder or two.

Now, the hard part, figuring out what went wrong.

Take some good photos of the piston and cylinder and post/send them. Diagnosis maybe possible therefrom.

Will do, have got the new gear so just have to get the damn pin out so I can get the piston off (it warped over the pin so it doesn't come out freely). Any ideas there?

Will post pics up as soon as I get it off.

Any ideas how much it will cost to fix?

[eelracing]

Now, the hard part, figuring out what went wrong.

When I first pulled them out both plugs were fairly dry (the front cyl. more than the rear)

That's where i'd be first investigating.

Will do, have got the new gear so just have to get the damn pin out so I can get the piston off (it warped over the pin so it doesn't come out freely). Any ideas there?

Any ideas how much it will cost to fix?

Heat is your friend.

[steveyb]

No heat needed. No hammers either.
You need to build a tool. It consists of a long bolt (or threaded rod is better) that fits through the pin and is about 3 pins long.
A piece of tube that is slightly smaller OD than the pin, but still allows the bolt to pass through, about one pin long.
A piece of tube that has ID larger than the pin to allow it to slide through. about one pin long.
Washer to fit over the larger diameter tube to hold the bolt in place, smaller washer over the end of the smaller diameter tube.
Assemble all this through the pin and then screw the nut onto the bolt pushing the small tube and then the pin out of the piston into the larger tube.
When the pin is out, the whole can be disassembled.
Clear as mud?

Cylinder repairs are $500 + GST as far as I can recall. Welding and reshaping is extra. Remember, you need to send the new piston along with the cylinder and you must remove all of the steel parts: studs, water pipes, RC valve and shaft bearings (which can be a real pain in the ass), dowels.

[cowpoos]

Why don't you get one to do each fork??

because one with work with purpose, with excellent function....and the other one will tell you it will...and then go on to tell you it can drive trains....fly jet aircraft....fight wars in secret armed services...on far away planets...looks good in womans dresses....can grow dope on its pubes....and invented beer!!