Front end diving too much when braking

[cuong-nutz]

I'm new to the early gen Ninja's but does the front end suppose to dive a lot when you brake? It's a 2007 and the rear end has been lowered for the previous owner who was a short lady. It had only 1800 miles when I bought it.

I'm use to my new gen 250 and it's a total night and day difference between the two bikes as far as front suspension. When I was braking from 40 mph to a stop, it felt like I was about to go over the handle bars and this was not hard braking. The fork seals are in relatively new condition it seems and I don't see any oil buildup or leaks.

[alex.s]

they say this is "normal" for the pregen. i guess as long as it doesn't bottom out you should be fine? you could try upping the fork oil weight or adding preload spacers

[greg737]

That's a design feature, not a malfunction....

I think the problem here is that you're aware of how a sport-type motorcycle suspension is supposed to feel (and there's no doubt that the pre-gen EX-250 does not feel anything like a sport-bike).

A bit of work and some dollars can completely remedy this designed-in suspension weakness. A few tried-and-true modifications can give you a pre-gen EX-250 that feels well balanced and agile. These mods are well documented in the "how-to" FAQ pages of this website and also the other main EX-250 website.

Or you can save your time and money and just endure the floppy, limp-noodle handling. Whenever you pull the brake lever or transition into or out of a corner you'll just have to imagine all that money you saved by not upgrading. Or you can imagine that you're an extremely skilled rider because you can handle a non-upgraded EX-250 suspension (this method has the advantage of being an ego-enhancing bit of "personal mythology" which is probably good for your overall mental health).

[CmichRider]

I had the same thoughts, so I posted a thread on this not too long ago.

Lots of great info on fork dive and braking here-
http://www.ninjette.org/forums/showthread.php?t=76918

[cuong-nutz]

thanks for the help guys. I had no idea that it was really soft. Is it possible to swap the forks out for those on the new gen to remedy this?

[kkim]

http://faq.ninja250.org/wiki/Front_suspension_upgrades

[coondog]

Originally Posted by cuong-nutz

thanks for the help guys. I had no idea that it was really soft. Is it possible to swap the forks out for those on the new gen to remedy this?

Better to swap out with ex500 ninja springs, $75 delivered (new) and you can change your fork earl at same time.

[alex.s]

have you tried applying the front brakes slower? or "smoother" as some might put it?

[sombo]

Just do what I did. I replaced the springs with progressive springs from racetech. OMG what difference they make. Trust me, you won't regret it.

[choneofakind]

I went with the ex500 springs method. also, when I had the shop do my fork seals over the winter, I had them do heavier fork oil at the same time. what a difference in handling and front end feel. If you upgrade the front though, it really shines light on the really soft shock

[Snake]

Originally Posted by sombo

Just do what I did. I replaced the springs with progressive springs from racetech. OMG what difference they make. Trust me, you won't regret it.

How much did they cost and do you have a link?

[sombo]

This page shows the different products they have for our bikes. Also at the top there's a big link that brings up a spring rate calculator. Use that to find the springs they have and the prices. Overall they range about $110 - $125 for the springs.

[GeorgeRYoung]

If you're really frugal (cheap), you can increase the spring rate by cutting the stock spring shorter and adding a spacer. For example, if you chop 8 of the 32 coils, you end up with a spring rate of 0.440 * 32 / (32 - 8) = 0.587 kg/mm.

[alex.s]

Originally Posted by GeorgeRYoung

If you're really frugal (cheap), you can increase the spring rate by cutting the stock spring shorter and adding a spacer. For example, if you chop 8 of the 32 coils, you end up with a spring rate of 0.440 * 32 / (32 - 8) = 0.587 kg/mm.

are you sure? without progressive springs, i don't think that would increase the spring rate but rather decrease your total travel while keeping the same spring rate... you would bottom out quicker/easier. i think the math you provided is correct if you don't cut the spring but instead add the preload spacers that take up the length of those 8 coils.

[sombo]

Originally Posted by GeorgeRYoung

If you're really frugal (cheap), you can increase the spring rate by cutting the stock spring shorter and adding a spacer. For example, if you chop 8 of the 32 coils, you end up with a spring rate of 0.440 * 32 / (32 - 8) = 0.587 kg/mm.

This is a flawed idea. Many have tried and few have liked it. It does NOT, I repeat does NOT increase the spring rate. What it really does is cause the springs to max out quicker. You are MUCH better off doing it the right way with better springs.

[Snake]

Thanks for the info sombo I appreciate it.

[GeorgeRYoung]

Ah, well, here's a reference:
http://www.calsci.com/motorcycleinfo/Suspension2.html

[alex.s]

Originally Posted by GeorgeRYoung

Ah, well, here's a reference:
http://www.calsci.com/motorcycleinfo/Suspension2.html

Hmm... it presents a valid point i hadn't thought about before that the springs can compress to the point where they don't allow any more compression because each coil is pushed against the next... if this length is less than your travel length, your spring 'bottoms out' before the fork itself does. but regardless its not simply cutting the spring and replacing that chop with a spacer, he's adding spacers to increase preload, decreasing the travel which effectively increases the amount of tension applied over the 'total' travel distance. buying higher tension springs is "better" because it leaves you with more total travel with the same tension rate.

but anyway... why not figure out the proper tension rate you want with spacers before spending $100 or more on springs