Rothmans Honda NSR300R SP

[{.bLanK}G_o_D]

Six months ago I purchased this genuine Rothmans Honda MC21 NSR250R SP from Cyclespot in Auckland for $7,995. Pretty reasonably price for this limited edition bike in dam good nick.
The front fairing is fiberglass but the rest of the bike is pretty much stock.
This is the SP model, 1 of 1500 out of the factory in Rothmans colors with the fully adjustable suspension, dry clutch and light weight Magtek wheels.
Gorgeous bike, I use to drool over the brand new Rothmans MC28 in Casbolts years ago.

Three weeks before I got the bike I broke my collar bone and when it arrived I was in no shape at all to ride.
So I sent my trusted mate who has been riding two strokes for years out for a test ride.
We did all the normal things before riding a new (second hand) bike.
Brakes work? Check.
Coolant level ok? Check.
Gearbox oil? Check.
Two stroke oil? Check
Start her up. She's blowing healthy blue smoke.
Warm her up.
Mal takes off down the road.
10 minutes or so pass and Mal comes down the road very sedately, pulls up the drive and shuts her down.
Mal was pretty gutted to report she seized up no more than 3kms down the road. After 20 kicks or so he managed to get it started again, and babied it home.

The bike got picked up by Hampton Honda and was on it's merry way to be diagnosed.
Bad news.
Crank bearing is lunch and it spat bearing bits up into 1 cylinder.

Grant (the big cheese) at Cyclespot was also pretty gutted to hear the motor was toast, but he has been totally awesome about the whole thing. After searching for parts and not being happy replacing them with 2nd hand parts, he ordered 1 new barrel,piston etc and a new crank from Honda Japan.
I asked him "How about I pay for the other barrel, piston etc and I end up with pretty much a brand new motor?"
"And how about this Tyga performance 300cc big bore kit?"
He was cool with that. Worked out cheaper than getting new Honda parts anyway.

As a customer of Cyclespot Honda Auckland who has had to endure an unfortunate event with my purchase, I recommend them to everybody. They have been very helpful and supportive in the repair of my precious motorbike.

So then I realized, you cant big bore a two stroke without letting her breath more.
So the order from Tyga consisted of:
300cc big bore kit
New crank
GP style Stainless steel expansion chambers
Carbon blue mufflers
High flow reed cage and carbon reeds

Other mods are:
Kiss de-restriction loom
Airbox modification

Of course I paid for everything except half the big bore kit and the crank. Which includes a bill at Hamptons for time taken fitting the big bore kit. (It's not a straight bolt on job)

The mechanic drilled an old set of jets out to 170, she is still a little on the slightly too rich side. But it hasn't fouled any plugs yet, and very soon I am going to organize it to be tuned on the dyno.
The average power output of a MC21 with these mods is bordering around the 70bhp mark.
I weighed her today, stock dry weight is 133kgs. Today I forgot to fill the tanks right up before hand so I'll do it again one day, but with about a liter over reserve and the two stroke bottle under half she weighed in at 130kgs wet.

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[racefactory]

Absolutely fucking sick bike man. Great to hear the good news in the end with the story.

[onearmedbandit]

Very nice bike, sounds fricken awesome too. Nothing like the smell of two stroke either.

[del-solider]

Awesome bike there! Hope everything goes well with it!

Nothing beats the enjoyment of riding a 2 stroke

[McWild]

Having seen this bike sitting lonely and depressed in Hampton Honda for far, far too long, I'm stoked to hear it's running and back to spec again. Can't wait to see it.

[quickbuck]

I must admit when i first started to read the thread I went NNNNOOOOOOOOOOOOOOOOOOOO!!!!!!!!
Don't big bore an SP.

After reading that it decided to go CLACK in a big way, then all is forgiven....
At least, by the sounds of it, you have done the full job.

Yes, get it on the dyno, sort out that jetting, and she'll be away ........ an awesome weapon!

[Marmoot]

Grant and Cyclespot boys always know their stuff very well, and are keen roadbikers themselves.
Been their loyal customers since Grant (1999), and then Grant (2008). Even though now I've changed brand, I'm still their customer.
Can't recommend them enough.

If only they can retain their best mechanics for more than 5 years. This is the problem with most Auckland workshops, mechanics go like musical chairs.

[{.bLanK}G_o_D]

Thanks for the nice comments guys.
Bloody Murphy! I fouled a plug plodding around town today.
Pulled over and killed it, decided now is as gooda time as any to stop for a ciggy.
10 minutes later I kicked her over, it started, sounded like it was on 1 cylinder for a second then cleared. So went straight to the closest, safest piece of road to give her a blow out. Running fine again now (touch wood) Those plugs will be stuffed by now anyway.
Done over 500kms already in the 3 days I've had it back, she's pretty much ready for a good thrashing. Before I do that tho I have wheel bearings to do and need to give the sticky brakes a strip down and clean, measure the pistons and order new seals. I'll bleed the brakes and get some nice new fluid in there.

Nothing like the smell of two stroke either.

Filled up the 2t bottle yesterday with TTS once the oil light had come on. I don't think it's fully used all the old unknown (hopefully synthetic) oil yet, I haven't smelt that sweet sweet smell of TTS yet.

I must admit when i first started to read the thread I went NNNNOOOOOOOOOOOOOOOOOOOO!!!!!!!!
Don't big bore an SP.

I don't blame you.
I wouldn't molest this bike like that just for the sake of a big bore.
I did my research into the big bore before deciding on it.
The barrels are genuine Honda barrels plated to their typical high standard. They are modified NSR 150 barrels to accept mating to the 250 crankcase/crank.
People have bored out NSR barrels before, but the power valves get dangerously close to the cylinder wall. Not a problem with the Tyga 300cc kit. I also noticed they did some mild porting too.

Grant and Cyclespot boys always know their stuff very well, and are keen roadbikers themselves.

Good to hear from another happy Cyclespot customer.

It took ages to get it fixed, and I missed the best part of summer, but it hasn't been a simple job, 3 parties involved all trying to keep one another happy, all and all I'm pretty happy with the outcome. I have read of other similar situations that have been complete nightmares.
Thanks Grant for being so cool.

[vifferman]

Good news that things turned out for the best.
It's also good to hear that you have had such good service and dealings with Cyclespot.

I wish I could say the same...

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Replaced the battery in the bike yesterday with an A123 battery.
Old standard lead acid battery weighed just shy of 1.5kgs. New A123 battery weighs 300 grams.
Filled the fuel tank and 2t tank and re-weighed her fully wet. Came in at 137kgs. That's only 4kgs more than it's standard dry weight.

[{.bLanK}G_o_D]

Here is a picture of my lightweight battery.

[hayd3n]

Here is a picture of my lightweight battery.

love the battery did you make it??

[{.bLanK}G_o_D]

did you make it??

In a way yeah.
Sourced the A123 3.3v cells online, bit of solder here, bit of heatshrink there and bob's your uncle.
I'm making another for a KB racer, going to get some more cells in to do a few more batteries too.