500 Ninja turtle has big suprise inside!

[Frame Maker]

If you recall my earlier thread about a 500 Ninja project, I was kinda all over with different projects and Ninja purchases. I've decided to sell off a few of the 500s and focus on just one... hence the new thread.

Here's the original thread...
https://bayarearidersforum.com/forums/showthread.php?t=553883

When we left off back in December of last year I had purchased 3 Ninjas in a package deal. One had some suspension upgrades and was said to have a 600cc big-bore engine! The seller mentioned that "a shop in Petaluma" did the big bore. He didn't have any other details and said it had been done many years ago. This was a bit hard to believe as there were no other engine mods and it even had the stock exhaust. Kinda odd, but I got a good deal, so I didn't question it.

20230101_123056 by andbike, on Flickr

A few weeks after the purchase, I decided to call Engine Dynamics (only shop in Petaluma likely to do this type of work) to see if they had any record of installing a big bore kit. Turns out they had! Records indicated a 598cc kit and custom copper head gasket had been purchased and installed. This is awesome to know as these big bore kits are no longer available.

20230730_195739 by andbike, on Flickr

So of course I've decided to keep this Ninja. Now to get it back together with the nice green bodywork and have a nice little sleeper bike. One thing was buggy me though. An early R6 front end and wheel had been installed and didn't match the CBR600F2 rear wheel. The easy solution would have been to install a CBR600F2 or F3 front end. I had already made an extra custom stem shaft so it would have been an easy swap. But no!

I found a nice set of forks and calipers on Marketplace off a 2003 CBR600RR. I liked that these are modern fully adjustable forks while being last generation of right side up configuration. Now just need to figure out what rotors to use as the 2003 CBR had larger diameter rotors than the older F2/F3 CBRs. Of course axle were different as well as rotor bolt patterns. This was going to be fun!

First up was to make spacers to allow the CBR-F3 wheel and axle to fit the CBR-RR forks.

20230729_180513 by andbike, on Flickr

20230729_175932 by andbike, on Flickr

That worked well. After a little research (okay, a lot of research) I discovered that late 90s era CBR900 rotors have the same diameter as the CBR600RR rotors. But the inner diameter and bolt pattern is slightly different than the CBR600F3 wheel that I want to use. So more spacers will be require as well as some re-drilling of the bolt holes. For the spacers I had the profiles laser cut, then a bit of machining to create the step fit.

20230820_181227 by andbike, on Flickr

20230820_181448 by andbike, on Flickr

20231028_145802 by andbike, on Flickr

20231028_150900 by andbike, on Flickr

20231029_110408 by andbike, on Flickr


I was hoping I could use the extra custom (+15mm longer) stem shaft that I had made for doing CBR600 F2/F3 fork conversions. But no, the CBR600RR stem was just slightly larger where it presses into the bottom triple clamp. The difference is only 0.5mm, but that's a big enough gap to require a new stem shaft to be made. So I made a new CAD model and sent it off to my friends in China. A few weeks later a new shaft arrives on my front porch.

20231028_203743 by andbike, on Flickr

20231030_114343 by andbike, on Flickr

20231030_114505 by andbike, on Flickr

Now I just need to order the correct bearings and ready to install the new front end. But that won't go as planned. Crap!

To be continued...

 

[Frame Maker]

As I was getting ready to install the updated CBR600RR front-end, I discover something VERY odd. It appears that a previous owner had drilled holes through the lower bearing cup of the frame...WTF!!! I assume that the purpose was to make it easier when needing to extract the lower bearing race. But these holes were so large that it made it very easy for dirt to get into the bearings. Not good!

I would need to sand off the surrounding paint, then weld up the holes. I decided to weld from the outside, then again from the inside to make sure I had good penetration completely filling the holes. Then very careful grinding the inside of the cup to be sure the landing surface is nice and flat. Followed by some rattle can paint on the outside. I think it came out nice and the bearing race seems to still fit well.

20231115_123101 by andbike, on Flickr

20231115_124913 by andbike, on Flickr

20231115_124918 by andbike, on Flickr

20231115_133110 by andbike, on Flickr

The steering stop has been cut up pretty badly, so that will be need to be repaired and matched to the CBR triple clamp. But that will get fixed later.

I also discovered that the rear of the frame had been previously chopped and then replaced with the worst possible repair I have ever seen on a frame. The rear of the frame was spliced back together with oversize square tubing, and NOT welded! Again...WTF!!! The frame was literally held together with bondo in the joints! The first time I tried to pick up the bike by the rear of the frame all four joints broke loose. This is a disaster. It would almost be less work to just buy a replacement frame off eBay, but I'm cash poor at the moment, so going to take on the challenge of repairing it properly.

20231114_160602 by andbike, on Flickr

20231114_160609 by andbike, on Flickr

Anyway, I continue with the front-end swap. I like how it looks and very happy to finally have matching wheels


20231116_120056 by andbike, on Flickr


Stay tuned for more frame repair craziness coming soon...

 

[auntiebling]

so THAAAAAATS what you wanted the brake rotor info for. excellent. I likethe 900rr forks myself they're so... METAL but those F4 units are a solid option

please keep updating even if you don't get a lot of feedback. i'm not the only one that loves to see what's going on and has basically noting to add

 

[bobl]

so THAAAAAATS what you wanted the brake rotor info for. excellent. I likethe 900rr forks myself they're so... METAL but those F4 units are a solid option

please keep updating even if you don't get a lot of feedback. i'm not the only one that loves to see what's going on and has basically noting to add

Yes, I'm watching too. As Always.

 

[budman]

Yes, I'm watching too. As Always.

Me too. I often wonder when Julian finds time to eat.

 

[Jung]

Ah - this is what we've been missing. Excellent.

What size rear tyre are you running? 170? The wheels look great and it should STOP with those brakes out front. Nice weld on the headstock, very impressive it didn't melt the vin sticker! What a bizarre thing to find, still with the subframe bondo'd together, I guess nothing should surprise.

Steerer tube looks really well machined, they do a good job.

Look forward to more progress!

 

[kpke]

Lots of "interesting" mods by the PO. The holes in the head stock were probably there so it could be greased on a regular basis. Smart. And I didn't know bondo could be used for gluing those darn broken frames back together. I thought you had to use 2 part epoxy for that. Oh well, you learn something new every day.

Great stuff here. Thanks for posting Julian.

 

[Frame Maker]

so THAAAAAATS what you wanted the brake rotor info for. excellent. I likethe 900rr forks myself they're so... METAL but those F4 units are a solid option

please keep updating even if you don't get a lot of feedback. i'm not the only one that loves to see what's going on and has basically noting to add

Yes, I'm watching too. As Always.

Me too. I often wonder when Julian finds time to eat.

Yep, eating isn't a big priority when I'm in the shop, although a quick trip for a Jack Snack has been known to happen.

Ah - this is what we've been missing. Excellent.

What size rear tyre are you running? 170? The wheels look great and it should STOP with those brakes out front. Nice weld on the headstock, very impressive it didn't melt the vin sticker! What a bizarre thing to find, still with the subframe bondo'd together, I guess nothing should surprise.

Steerer tube looks really well machined, they do a good job.

Look forward to more progress!

Rear tire is a pretty common 160/60.

The VIN sticker did get a little melted. But I had a wet rag handy to cool down the area after welding which helped minimized damage to the sticker.

Lots of "interesting" mods by the PO. The holes in the head stock were probably there so it could be greased on a regular basis. Smart. And I didn't know bondo could be used for gluing those darn broken frames back together. I thought you had to use 2 part epoxy for that. Oh well, you learn something new every day.

Great stuff here. Thanks for posting Julian.

While I've seen 2-part epoxy used to "fix" some DBC bikes, this one is going to be properly welded... with real metal

 

[Frame Maker]

With the holes in the lower steering cup welded up, next I'd like to repair the steering stop.

I'll start by making paper patterns, then transfer the shape to steel. Then weld in the steel bits...

20231124_130343 by andbike, on Flickr

20231124_133550 by andbike, on Flickr

20231124_143026 by andbike, on Flickr



Finally a little sanding, then some black paint and looking goodarty

20231124_144443 by andbike, on Flickr

20231125_103054 by andbike, on Flickr

After the bike is re-assembled with the tank in place and hand controls mounted, then I'll trim the steering stop a bit more to optimize steering rotation to each side. But for now I'm happy with the repair.

Then yesterday this arrived from my good friends at eBay...

20231128_164730 by andbike, on Flickr


Stay tuned for some serious frame repair!

 

[Frame Maker]

Last week the big frame repair happened...

To prep for the frame graft, I machined up some inserts to reinforce each of the four graft locations.

20240117_150526 by andbike, on Flickr

20240117_154115 by andbike, on Flickr

Then it was a simple matter to cut and weld, along with a bunch of measuring to make sure the frame graft is in the correct position.

20240202_135335 by andbike, on Flickr

20240202_141203 by andbike, on Flickr

20240202_160759 by andbike, on Flickr

20240202_163531 by andbike, on Flickr

20240202_163716 by andbike, on Flickr



And this is what was left over after surgery.

20240202_170529 by andbike, on Flickr



Also noticed some unusual tumors growing within the old limb. Yes, very odd to find inside a motorcycle frame!

20240202_133028 by andbike, on Flickr



Next up is to do a little grinding, filing, and hand sanding, followed by some black rattle can... and the frame looks good as new!

20240209_132525 by andbike, on Flickr

20240209_132529 by andbike, on Flickr

20240209_132543 by andbike, on Flickr

20240209_153256 by andbike, on Flickr

20240209_153325 by andbike, on Flickr



Next up, I want to make some changes to the swingarm and rear brake arrangement. Stay tuned...

 

[SFMCjohn]

^^

I loved the Kawasaki EX500 so much … really fun watching this one getting some expert love and attention toward a second life.