1991 R9N Track Bike Project

**Fri Apr 17, 2015 12:18 pm » Post: #1 » Download Post**

I have this road registered R9N that gets too little use, and if I keep riding it on the road will likely cost me dearly:

Odometer shows 8,000 km and I'm told it is unmolested. Though it clearly went down on it's right hand side as the radiator is bent.

So I'm converting it to a road racer. It will be my A bike. My current R2K will become my rain bike. Here's my inspiration:

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MC21R9N track
MC18R2J track
CBR954
CR250

**Fri Apr 17, 2015 1:14 pm » Post: #2 » Download Post**

Bike has been stripped down. Suspension sent out to local shop for revalve, respring and service:

Wheels sent out for powdercoat:

New Pirelli Super Corsa Diablo: SC1 in front, SC2 in rear. Took a bit to locate stock 110 and 150 sizes but sourced them form the west coast.

**Fri Apr 17, 2015 1:16 pm » Post: #3 » Download Post**

yeah that's not the correct photo of the suspension!!! where is that photo?
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MC21R9N track
MC18R2J track
CBR954
CR250

**Fri Apr 17, 2015 1:29 pm » Post: #4 » Download Post**

frame cleaned. swingarm was damaged in crash. damage was hidden behind chain slider. crack in weld between casting and tubular aluminum. crack welded. bearings cleaned and lubed. New seals. New steering stem bearings and races. Suspension installed. Real racing clip-ons! Very Happy

wheels installed:

_________________
MC21R9N track
MC18R2J track
CBR954
CR250

**Fri Apr 17, 2015 1:36 pm » Post: #5 » Download Post**

rear caliper rebuilt and resprayed:

rear master cylinder rebuilt, Tyga steps:

still need to sort out the brake line. it doesn't fit onto the master cylinder.
_________________
MC21R9N track
MC18R2J track
CBR954
CR250

**Fri Apr 17, 2015 1:41 pm » Post: #6 » Download Post**

front calipers rebuilt and resprayed:

_________________
MC21R9N track
MC18R2J track
CBR954
CR250

**Sat Apr 18, 2015 11:29 am » Post: #7 » Download Post**

Excellent!

Carlos Cardus is a friend on our Facebook! I'll forward him some photos once it's finished! Wink

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Andy.
NSR-WORLD.COM

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**Sat Apr 18, 2015 8:21 pm » Post: #8 » Download Post**

Nice build, I like the attention to detail.

**Mon Apr 27, 2015 6:30 pm » Post: #9 » Download Post**

Then I'll have to step up my game. Don't want to disappoint Mr. Cardus!
_________________
MC21R9N track
MC18R2J track
CBR954
CR250

**Tue Apr 28, 2015 11:14 am » Post: #10 » Download Post**

Here's a shot of the motor prior to cleaning and disassembly. One exhaust stud is broken, hence the oil and dirt on the top cylinder. Markings at the base of both cylinders indicate that they have been replated and both are from an R model. Heads are SP. So I measured squish and found it to be 1.17 and 1.18 mm. I would have expected a tighter squish with that barrel/head combination and even more so with the possibility of the platers skimming the top of the barrel??? I've run the bike 1500 km on the road and aside from a weak center crank seal it went just fine. Surprised

_________________
MC21R9N track
MC18R2J track
CBR954
CR250

**Tue Apr 28, 2015 11:28 am » Post: #11 » Download Post**

After disassembly I also found the bottom end had been previously stuffed. Damage was evident to the bottom case rear cylinder. The bike was advertised as having never been opened. Clearly that is not the case. But the cylinder bores are in good shape and piston to bore clearance was good. Still don't understand the squish but it measures proper. Decided to go with new OEM crank, pistons, rings, etc. but reuse the barrels. I replaced the front head with a new OEM rear. Deleted the oil pump, boost bottles, kickstart. Reeds are newer Boyeson Power Reeds. And a new clutch will go in as soon as I get the missing thrust washer behind the water pump. Leak down test held 5 PSI but going to 7 PSI and there was leakage across the center seal. I've read others have gone us to 10 PSI. It can't be worse than what was in there as when cold starting it would take up to a full minute for the second cylinder to kick in.
_________________
MC21R9N track
MC18R2J track
CBR954
CR250

**Tue Apr 28, 2015 2:15 pm » Post: #12 » Download Post**

Tyga top triple tree. Koso duel EGT.

CBR radial master cylinder.
_________________
MC21R9N track
MC18R2J track
CBR954
CR250

**Tue Apr 28, 2015 2:54 pm » Post: #13 » Download Post**

Stock shape bodywork fitted. Real racing seal. Very Happy

_________________
MC21R9N track
MC18R2J track
CBR954
CR250

**Tue Apr 28, 2015 5:12 pm » Post: #14 » Download Post**

OEM silhouette... It's the only way to go! Very Happy

_________________
Andy.
NSR-WORLD.COM

Please keep all responses to Forum posts on the Forum so that others may benefit.

Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.

Check us out on Facebook! Please "like" our page!

**Wed Apr 29, 2015 11:43 am » Post: #15 » Download Post**

motor ready to go in except for clutch due to missing water pump thrust washer.
_________________
MC21R9N track
MC18R2J track
CBR954
CR250