Thank you for considering and commenting on this: I had the idea of purchasing a US$32.00 fork brace made of 6065 aluminum designed to fit a Honda CB300R. I though I might have a bit of fun trying to make it fit the EX300. The fork tubes are same distance apart, but the diameter of the lower leg of the Honda fork is 57mm, while the Kawasaki fork's lower leg diameter is 60mm or 2 3/8". I purchased a hole saw for $10 and I'm going to clamp the fork brace up to a drill press and give it a go enlarging the capacity of the brace to accept the Ninja's forks. I'll have to remove a bit of material from the bottom of each inner side as well to clear the fender, but it won't be seen where I loose the black anodization as that area will face downward. I value your thoughts and opinions and appreciate your time. :-)

Oh dear. With nothing to center the hole saw, you'll have a lot of excitement. The only way it could work would be if you'd make plugs of aluminum to fill the holes, and clamp the brace tightly on them. Then the center drill of the hole saw could drill into the plugs. But there would still be a fair amount of chatter, to put it mildly.

A vertical mill and boring head would make it a relatively easy job. If you could find a small local machine shop, you might get a reasomable quote.

No way you’re gonna be able to do clean centered cut with hole-saw!

If your going to try to do this without a proper machine shop I would forgo the hole saw and look for a 60mm Step bit or "uni-bit" it will be much less wild and should self center.

The real question is...

Why?

Aside from the sheer farkle factor, will it offer any benefit?

Sure the Ninjette's forks aren't the stoutest but complaints of undue flexing are not exactly rampant.

If your going to try to do this without a proper machine shop I would forgo the hole saw and look for a 60mm Step bit or "uni-bit" it will be much less wild and should self center.

That might work if Randy puts shims in the adjustment gaps and tightens the bolts. Amazon has an off-brand step bit that goes up to 60mm for under $30.

I agree that the brace isn't going to do much to help, especially since it has large cutouts and won't be terribly stiff in the twisting mode that it needs to be stiff in.

FYI: any misalignment of that hole will result in that brace attempting to misalign your forks.

Think about this. The fork tubes are supposed to be parallel. The lowers ride up and down on the uppers and have bushings and seals for low friction movement. If you get this brace even slightly wrong (we're talking small numbers of thousandths of an inch here, there's very very little allowable slop in fork bushings) you're going to add a ton of friction to the motion of your fork, potentially even binding it up. It all just depends on how far off your hole is. These aren't 40 year old forks that had slop in them in the first place.

As someone who used to run a fork brace... it doesn't really make that much difference for a street rider, it adds friction if it's not 1000% perfect, and you're going to be better to buy one that's purpose built for your bike if you absolutely are intent on ignoring us and still want one.

You're better off spending the $$$ (remember that your hours of labor are worth something, how much is up to you) on emulators to make the suspension better, rather than attempting to hack a fork brace up for negligible benefit or likely even causing more problems than anything.

If you still want to go through with this... find a local machine shop and let them do it. Take the forks in, let them take measurements, and then they can make sure that the hole is enlarged without making an eccentric hole and/or misaligned hole and/or the wrong diameter hole and/or a tapered hole. It has to be right.

Thank you so much for your valued opinions. Fortunately I do have a somewhat proper metal shop (I do architectural fabrication for a living- I make stuff) and a decent drill press that will allow me to precisely clamp the fork brace in positions that will give me exact boring. The pilot drill will be indexed to the center of each 60mm hole if you will, drilling into steel support substrate and nothing shall change as I remove material at slow rpms with good lubrication. I Promise. :-) I think I can achieve the tolerances require to keep the forks parallel. Thank you again for your valued thoughts and opinions. I will certainly keep the thread updated.

The real question is...

Why?

Aside from the sheer farkle factor, will it offer any benefit?

Sure the Ninjette's forks aren't the stoutest but complaints of undue flexing are not exactly rampant.actually it helps out quite a bit.
your forks will finally act a unit. i rode with one on a zrx1200. you will notice a difference.

Keep us posted please. In my experience, a drill press is nowhere near rigid enough for this job, especially if you're really going to try to use the hole saw.

Keep us posted please. In my experience, a drill press is nowhere near rigid enough for this job, especially if you're really going to try to use the hole saw.

Will someone explain the advantages of a fork brace? Is it an attempt to keep the front forks parallel at all times? Do I need one on a street bike? Dunno.

Bill

To find out if you might need a fork brace, stand in front of a motorcycle and clamp the front tire between your knees. Then wiggle the handlebar back and forth with a fair amount of force, watching the fork tubes. If you can wiggle the bar while keeping the tire still, you're twisting the fork tube as a pair. A good brace will stiffen this up a lot. A well made fender bracket will also.

Since it started out as a dirt bike, my little DT100 didn't have a fender mounded on the sliders, and I could twist the tubes a lot. I made a very effective brace that increases the rigidity of the assembly so that it moves maybe 1/4 of the amount it did without the brace. My H2, with its steel fender and fender bracket, is relatively stiff without an additional brace.

Here's the simple one I made for the DT100, that mounts to the previously empty fender bosses: (recognize the caliper?)

Haven’t looked at my 300 yet. But my old 250 had a heavy metal fender mount / fork brace from the factory.
Never felt any twist when I ditched it.

To find out if you might need a fork brace, stand in front of a motorcycle and clamp the front tire between your knees. Then wiggle the handlebar back and forth with a fair amount of force, watching the fork tubes. If you can wiggle the bar while keeping the tire still, you're twisting the fork tube as a pair. A good brace will stiffen this up a lot. A well made fender bracket will also.

Since it started out as a dirt bike, my little DT100 didn't have a fender mounded on the sliders, and I could twist the tubes a lot. I made a very effective brace that increases the rigidity of the assembly so that it moves maybe 1/4 of the amount it did without the brace. My H2, with its steel fender and fender bracket, is relatively stiff without an additional brace.

Here's the simple one I made for the DT100, that mounts to the previously empty fender bosses: (recognize the caliper?)

Thanks. I get it. I don't think I push my Ninja hard enough to be concerned about it. I will say the Ninja has a very stout steel brace holding up the ABS fender. I suppose one could sister two steel front fender support braces together and have a pretty decent fork brace.

No, the caliper doesn't look familiar.

Bill

The caliper is the same one that's stock on a Ninja 250.

The caliper is the same one that's stock on a Ninja 250.

When I first responded I referenced the service manual. Now I just looked at my 2007 and you're right. The service manual shows a different caliper and it's mounted on the left fork leg. Go figure.:wtfsign:

Bill

Not sure what it would offer for you, guys that race don't use anything like that very often, many times they are not even legal to have.

Comparing my race bike vs. street bike yields a lot of clues about a lot of things.One thing I've noticed is that the street-bike tends to be softer and more noodly. But neither has fork-brace other than factory bracket for fender.

The race-bike is solid-feeling at maximum-braking from 100mph. And its turn-in at 100mph is precise and smooth. I'm not sure a fork-brace would do much for it.

The difference? I suspect soft factory fork-springs and damping allows too much movement while cornering with my 85kg mass! First step I'd do is replace the factory oil with 10-15wt and add some preload to spring. That alone should keep the mid-turn wobbles at bay. It's not that fork-blades are moving unevenly, they both just move too much for my weight under spirited riding.

The scales read kg in SF? :)

The scales read kg in SF? :)

He doesn't want you to know he weighs 187.39 lbs.

Bill

The scales read kg in SF? :)

I am more amazed that his 250 does 100 mph!

I am more amazed that his 250 does 100 mph!

As indicated by my speedometer I can pull 100 M.P.H. (just barely) in 6th anytime.

Bill:confused20:

The scales read kg in SF? :)He doesn't want you to know he weighs 187.39 lbs.

Bill

SSshhh..... :bounce:

Target is 68-70kg for next season. Weight-savings on bike is getting extremely costly. ;)

I am more amazed that his 250 does 100 mph!

As indicated by my speedometer I can pull 100 M.P.H. (just barely) in 6th anytime.

Bill:confused20:heh, heh...

+2-3mph = Double-bubble windscreen
+1.5hp = snorkel removal
+4.2hp = Tyga full exhaust
---------------
+5.7hp = +20% more power than stock (http://racingorder.com/wp-content/gallery/tyga-ninja-250r-exhaust-review/ninja-250r-tyga-exhaust-dyno-results-vs-stock.jpg)

At beginning of season, I was barely reaching 90mph at end of straight @ Thunderhill (on calibrated Trailtech Vapour dash). By end of season with mods trickling in, I'm hitting 100mph. Sometimes little more with tow.:p Although I think getting 5mph faster drive out of T15 really helps.

I’ve got gps data of Dangit doing 106 into 10a at Rd Atlanta.

I’ve got gps data of Dangit doing 106 into 10a at Rd Atlanta.

Was the bike modified?

Bill

Was the bike modified?

Bill

WERA FSS legal

WERA FSS legal

Are jetting and exhaust modifications allowed?

Bill

I've got GPS data of 100+ as well. Nothing more than a Yoshi exhaust, Snorkel delete, and Jet shims. I am 230 in full gear.

I've got GPS data of 100+ as well. Nothing more than a Yoshi exhaust, Snorkel delete, and Jet shims. I am 230 in full gear.

Oh, it's a new-gen. Mine's a 2007. Interesting. Thanks.

Bill

Are jetting and exhaust modifications allowed?

Bill

We were on an 09 then. Yes jetted on a dyno, area P exh, air filter panel, keep snorkel, gearing, Good suspension and tires.

We were on an 09 then. Yes jetted on a dyno, area P exh, air filter panel, keep snorkel, gearing, Good suspension and tires.

Thanks.

Bill

Looking at those tracks, I am now curious to see if my bike could break 100 on the track.

Looking at those tracks, I am now curious to see if my bike could break 100 on the track.

You don't need a-lot of strait-a-way to see 100. This Spring I'm going to try it in 5th gear. I pull an indicated 100 in 6th with 15/42 gearing and top out at 10K R.P.M. I really don't care about top speed it's just for giggles and a measure of how well my bike is running.

Bill

I see a lot of spec-sheets on ZZR-250 showing a 110 mph top-speed. Isn't that the same engine?

I see a lot of spec-sheets on ZZR-250 showing a 110 mph top-speed. Isn't that the same engine?

None of the body or chassis parts are interchangeable with a pre-gen. I think the compression ratio is 12:1. The cam cover (cylinder head cover) appear to be the same. Dunno.

Bill

You don't need a-lot of strait-a-way to see 100. This Spring I'm going to try it in 5th gear. I pull an indicated 100 in 6th with 15/42 gearing and top out at 10K R.P.M. I really don't care about top speed it's just for giggles and a measure of how well my bike is running.

Bill

I did this years ago, bike was completely stock back then.

did this 4 years ago:
Elevation in that area is around 1620ft.
now my elevation is between 3200 and 5500

ok folks the study is done and the numbers are in.
using my GPS and glancing down at the speedo:
this is what i did i road each gear up to the rev limiter, except 6th, I didnt feel the need to push it much more then i already had, and it is not worth risking my job.
Gear GPS/Speedo
1st: 36.1/40
2nd: 51.9/56
3rd: 65.5/70
4th: 80.0/86
5th: 93.4/100
6th: 99.1/105

I did this years ago, bike was completely stock back then.

Very interesting. Size of main jet?

Thanks,

Bill

Gear GPS/Speedo
1st: 36.1/40 -> +11%
2nd: 51.9/56 -> +7.9%
3rd: 65.5/70 -> + 6.9%
4th: 80.0/86 -> +7.5%
5th: 93.4/100 -> +7.1%
6th: 99.1/105 -> +6.0%

I've always wondered about this non-linear offset. After all, the speedo is mechanically linked to the front wheel, so shouldn't the offset be the same percentage all the way up? Then I realized that speedo needle is magnetically driven against wound-spring. So it's likely that the offset can be non-linear; the spring gets tighter and tighter as its wound-up, require more and more force for each incremental movement..

Very interesting. Size of main jet?

Thanks,

Bill

What ever stock is.

What ever stock is.

105 probably. Hmmm, I'm running a 110. That's a good performing Ninja,

Bill

What ever stock is.

105 probably. Hmmm, I'm running a 110. That's a good performing Ninja,

Bill
He's got newgen, so 98.

Greetings all. I wanted to provide an update to those interested parties regarding the $32 fork brace from Jhina designed to fit the Honda CB300. I did modify it as I outlined in an initial post and installed it. Works a treat. Took a couple of hours. No issues. I will tidy it up a bit once I remove it again when I begin installing the faring kit fro Jhina in a day or so. I noted that the finish on the ninja's fork lowers is shite. Flat black paint on bare metal... Anyway, the final word on this IMHO is: good, inexpensive mod. Easy to achieve with a drill press, a little experience, etc. It is discreet: you really can't see it on my black bike. Pictures tell the story. :-)

Can you tell if there's any improvement, using the wheel between the legs and twist test method?

Please post some datalogs of laptimes before & after? Broken down into section-splits if possible. Would be nice to know where the biggest gains are. I suspect the slowest transitions would benefit most. Such as Sonoma's 9a/9b chicane or T11 @ Thunderhill.

Thank you so much for your valued opinions. Fortunately I do have a somewhat proper metal shop (I do architectural fabrication for a living- I make stuff) and a decent drill press that will allow me to precisely clamp the fork brace in positions that will give me exact boring. The pilot drill will be indexed to the center of each 60mm hole if you will, drilling into steel support substrate and nothing shall change as I remove material at slow rpms with good lubrication. I Promise. :-) I think I can achieve the tolerances require to keep the forks parallel. Thank you again for your valued thoughts and opinions. I will certainly keep the thread updated.

Choneofakind is right. Using a drill press and a hole saw is pretty much going to guarantee failure. The tolerances for each aren't even close to what you will need to get it right. There are a lot of ways to get this wrong and virtually no benefit. I have done at least ten 3 hour endurance races on my 250 Ninja and I don't use a brace. The front end works great with the right springs, oil, and emulators. (We have seven wins, so we ain't exactly slow.)

My advice is don't waste your time.

Choneofakind is right. Using a drill press and a hole saw is pretty much going to guarantee failure. The tolerances for each aren't even close to what you will need to get it right. There are a lot of ways to get this wrong and virtually no benefit. I have done at least ten 3 hour endurance races on my 250 Ninja and I don't use a brace. The front end works great with the right springs, oil, and emulators. (We have seven wins, so we ain't exactly slow.)

My advice is don't waste your time.

Sorry to disappoint you mate, but it was done weeks ago, took little time for a professional fabricator to machine, and it works a treat. ;-)

Sorry to disappoint you mate, but it was done weeks ago, took little time for a professional fabricator to machine, and it works a treat. ;-)

And what does it actually do for the handling of your bike?

And what does it actually do for the handling of your bike?

You seem to present yourself as very knowledgable and experienced: why would you be asking me what a fork brace does for handling? Please read an earlier post of mine after fitment to get a sense of my experience, observation and opinion. In a few words brother: It feels really good. Stiffer. Corners better on the roads I ride which are sadly a bit bumpy and out of shape. Take it easy. ;-)

Randy,
A defensive posture is not necessary in this group.
On this board there is a large representation of 250/300 racers from across the country. Many with years of experience under their expert plates. None of the racers commenting have seen fit to perform this mod to the 250/300 chassis. Good suspension will go along way farther to improve the handeling of these bikes.

Congrats on a successful DIY mod, just keep in mind it isn’t for everyone.

Randy,
A defensive posture is not necessary in this group.
On this board there is a large representation of 250/300 racers from across the country. Many with years of experience under their expert plates. None of the racers commenting have seen fit to perform this mod to the 250/300 chassis. Good suspension will go along way farther to improve the handeling of these bikes.

Congrats on a successful DIY mod, just keep in mind it isn’t for everyone.

Nor are Mikuni carbs on the Ninja but at my earliest opportunity the Keikins are history.

Bill

Nor are Mikuni carbs on the Ninja but at my earliest opportunity the Keikins are history.

Bill

There’s no production class race rules that allow changing the carbs.

There’s no production class race rules that allow changing the carbs.

There's only one production class I care about - MINE. :clap2:

Bill

You seem to present yourself as very knowledgable and experienced: why would you be asking me what a fork brace does for handling? Please read an earlier post of mine after fitment to get a sense of my experience, observation and opinion. In a few words brother: It feels really good. Stiffer. Corners better on the roads I ride which are sadly a bit bumpy and out of shape. Take it easy. ;-)

Not trying to knock your experience or your ability to machine. I was asking in terms of performance what it did for you as I don't see any of your comments other than "works a treat". Also, when installing the brace were any other suspension mods done at the same time? That is important to know.
Believe it or not, one way that suspension works while leaned over is through flexing to provide bump compliance. This is because the sliders don't move as well when hitting a bump while leaned over and on the edge of the tire.
Some flexibility in the forks also provides good feedback or "feel". A fork can be too rigid and can give you the uncomfortable feeling that you are on the razor's edge but not really able to tell for sure what is going on with the front. So in that respect the "flexiness" of the Ninjette front end is not all bad because it has pretty good feel.
If you want to improve the performance of the front end on the 250/300 Ninja, the best place to start IMHO is correct springs for your weight, cartridge emulators and the correct oil. I did this on my racebike and I haven't had to touch a thing on the front end for two straight seasons.

Not trying to knock your experience or your ability to machine. I was asking in terms of performance what it did for you as I don't see any of your comments other than "works a treat". Also, when installing the brace were any other suspension mods done at the same time? That is important to know.
Believe it or not, one way that suspension works while leaned over is through flexing to provide bump compliance. This is because the sliders don't move as well when hitting a bump while leaned over and on the edge of the tire.
Some flexibility in the forks also provides good feedback or "feel". A fork can be too rigid and can give you the uncomfortable feeling that you are on the razor's edge but not really able to tell for sure what is going on with the front. So in that respect the "flexiness" of the Ninjette front end is not all bad because it has pretty good feel.
If you want to improve the performance of the front end on the 250/300 Ninja, the best place to start IMHO is correct springs for your weight, cartridge emulators and the correct oil. I did this on my racebike and I haven't had to touch a thing on the front end for two straight seasons.
We experienced this when we added a fork brace to our Ninja 500 race bike back-in-the-day.

It made the front feel more vague at the limit and chatter where it didn't before. We took it off.

That's one reason I questioned another member that was installing late-model inverted forks on the Ninja 250. The entire suspension and frame design on these bikes are not that rigid, and all flex together. Making one area more rigid can adversely affect the overall feel of the entire unit.

Thank you all so much for sharing all your accumulated knowledge and for caring so deeply as to take the time to write thoughtful responses with suggestions and ideas. I am swayed most definitely by the community to remove the fork brace and consider other proven mods to the front suspension. Thank you again. Unfortunately the bike was ruined (totaled) by a large SUV in the local market parking lot (driver did not see the black bike).

The fork brace did nothing to limit damage. :-)

I have not seen the bike since I left it with the shop 12/21/17, but I did purchase a white non ABS Ninja 300.

Thank you all so much for sharing all your accumulated knowledge and for caring so deeply as to take the time to write thoughtful responses with suggestions and ideas. I am swayed most definitely by the community to remove the fork brace and consider other proven mods to the front suspension. Thank you again. Unfortunately the bike was ruined (totaled) by a large SUV in the local market parking lot (driver did not see the black bike).

The fork brace did nothing to limit damage. :-)

I have not seen the bike since I left it with the shop 12/21/17, but I did purchase a white non ABS Ninja 300.

Sorry for your loss. That's one reason I avoid parking in the main parking lot with the automobiles. For example, if I go to Walmart I park the bike near the main entrance to the store near a bicycle rack or some outdoor benches and tables. Yes, I park on the sidewalk at the front of most stores. I park out of the way and no one ever gives me a hard time about it.

Just me I guess. Also, if I have to park where the cars do, I park with my tail light in line with the autos tail lights so people don't think there's an empty spot and pull in and bash my bike.

I think you're gonna like the 300. For every door that closes another opens.

Bill

Sorry to hear about your mishap! The iodiocy of SUV drivers never cease to amaze me! I saved these photos from this thread: https://www.s2ki.com/forums/off-topic-talk-3/new-hummer-h2-all-its-glory-146846

https://farm5.staticflickr.com/4596/24712626277_92f72518a4_o.jpg
https://farm5.staticflickr.com/4592/39550835572_25d12b8488_o.jpg
https://farm5.staticflickr.com/4590/39550835252_9c60afcac5_o.jpg
https://farm5.staticflickr.com/4639/24712625897_b2fbc96097_o.jpg

JacRyann

Love the third pic. Looks like a guy is just sitting in the hummer waiting to leave.

That's a bummer about your bike but I hope you enjoy the new one. I always make sure to park so I'm visible, too. Tail lights in line with the cars, owning the whole space, that kind of thing.

JacRyann

Love the third pic. Looks like a guy is just sitting in the hummer waiting to leave.AHahhaha!!! I wished I could've been there to see this! And she had her kids inside too! Amazing how tough concrete is; ultimate strength around 3000psi, even more if steel-reinforced.

Unfortunately the bike was ruined (totaled) by a large SUV in the local market parking lot (driver did not see the black bike).

The fork brace did nothing to limit damage. :-)

I have not seen the bike since I left it with the shop 12/21/17, but I did purchase a white non ABS Ninja 300.

Sorry about your bike. Glad to see that your sense of humor is intact ;)

Yes, sorry Randy, but glad you got a new one.

Thank you so much Sir. I got a great settlement from the insurance company, and I honestly prefer the non-abs and the white color. I love this bike and can't stay off. Cheers!