2019 kx450 spring fork swap

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7/7/2018 7:54 PM

Looks like Kawasaki went back to a spring fork for their 2019 production kx450. I currently own a 2015 kx450 with the showa air forks (straight garbage IMO). There are a few different ways to get spring forks on my kx. I could send them in to showa and do a conversion, or just get a pair of spring forks from an older kx. I was leaning towards the ladder until today. I did some digging and the 2019 and 2015 forks while one is air and one is spring both happen to be 49mm in diameter. Also the new factory spring forks will come with A-kit internals. This could potentially be the answer I have been looking for in order to get my bike to start handling worth a shit. I just wanted to share this potential idea with you guys in case you were debating on how to get rid of those horrid air forks.

Also what else do you have to take into account when swapping forks? I cant imagine the axle would have changed, maybe you would have to play with the fork height a bit to. Other than that though what is there?

Maybe this is all just wishful thinking, but I sure hope its as simple as buying the oem forks and bolting em on.
A guy can dream right?

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7/7/2018 8:19 PM
Edited Date/Time: 7/7/2018 8:51 PM

2019 has increased front axle size. May take some tinkering and not quite a simple fork swap onto your 15'. Best bet would be to find some 48mm KX450 spring forks (pre-2012) and shim the top clamp? At least that way current wheels/brakes/etc are a direct fit. May be as easy as an axle swap with front wheel bearings, but the 2019 forks will be more costly than older spring setups. Plus, the 48mm KYB spring was actually quite good; some even prefer the feel to 49mm Showa units.

https://www.vitalmx.com/features/First-Look-2019-Kawasaki-KX450F,6001

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7/7/2018 8:49 PM

You won't have to shim anything to put the 2009-2012 KYB Spring AOSS fork on your 2015. They bolt on with no issues. I put a set from a 2010 KX450 on my 2016 KX450 and it was a straight bolt on.

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Take it to the limit, one more time!

7/8/2018 8:35 AM

49mm or 48mm refers to the lower fork legs and does not define the outer dimensions of the upper fork tubes where to the clamping surface is. You will find variances in the diameter of the clamping surfaces, both upper and lower, among the same lower fork legs size.

Like others have mentioned, the 2019 450 has increased the axle diameter. So new hub is used, or perhaps only the bearings were changed but AFAIK no one has confirmed this yet.

2014-2018 KX250F forks are another option for you. They are spring forks, though they use a single fork spring in one leg and the damping is controlled is the other leg. They are a direct swap to your 450. No changes to triple clamps, wheel, or brakes necessary.

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7/8/2018 5:37 PM

pCp 252 wrote:

49mm or 48mm refers to the lower fork legs and does not define the outer dimensions of the upper fork tubes where to the clamping surface is. You will find variances in the diameter of the clamping surfaces, both upper and lower, among the same lower fork legs size.

Like others have mentioned, the 2019 450 has increased the axle diameter. So new hub is used, or perhaps only the bearings were changed but AFAIK no one has confirmed this yet.

2014-2018 KX250F forks are another option for you. They are spring forks, though they use a single fork spring in one leg and the damping is controlled is the other leg. They are a direct swap to your 450. No changes to triple clamps, wheel, or brakes necessary.

"They are spring forks, though they use a single fork spring in one leg and the damping is controlled is the other leg."

Could you elaborate on how this is different from a traditional spring fork?

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7/8/2018 7:14 PM

Just look up Showa SFF spring fork for a thorough explanation. Basically the left fork houses an inner & outer chamber that control compression and rebound damping ONLY, and the right fork houses a longer and stiffer (when compared to a traditional fork springs) spring. You only have one spring in this setup.

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7/9/2018 3:01 PM

I have a 15 KX450, too. The Showa SFF TAC fork is pretty good, so long as you set it up correctly and know what you are doing. Mine have the SKF Glide kit, SKF oil+dust seals, and RaceTech Gold valve and valving. The SKF glide kit solved the initial harshness problem i had with these forks and they work much better as a result. I'm 190lbs and run 180psi inner / 10psi outer / 192psi balance.

I think people get too caught up with playing around with pressures and forget there is a lot of compression and rebound adjustment available. I tend to stick with the same pressure settings regardless of the track, and dial the clickers as needed.

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7/13/2018 8:25 PM

They are not A kit internals. They are A kit specs, but not the coatings and such. Good marketing is what it really is...

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7/13/2018 8:57 PM

I put the older KX450 48 mm KYBs on my 16. I'm really happy with them.

I didn't think the TACs were terrible after I did the glide kit and FC revalve, but there was a lot of harshness and lack of feel on hadpack. The KYB fork swap fixed all that. You can find them pretty cheap on eBay. Look for the 2010+ fork if you can fine one.

One thing to make sure if is the KYB fork is 5 mm longer than the Showa TAC, so make sure you slide the forks up in turn clamps to compensate.

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7/14/2018 6:33 AM

From the Kawasaki site, copied and pasted:

"New 49mm SHOWA Coil Spring Fork with A-KIT Technology"

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7/14/2018 7:22 AM

"New 49mm Showa Coil Spring Fork with Adjustable Pneumatic Air Spring Assist (APASA)"

"New 49mm Showa Coil Spring Fork with Speed Sensitive Damping technology (SSD)"

"New 49mm Showa Coil Spring Fork with External Multi-Adjustable circuitry (EMA)"


Sounds fancy, I should work for the ad department...

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7/14/2018 7:53 AM

Monk wrote:

They are not A kit internals. They are A kit specs, but not the coatings and such. Good marketing is what it really is...

These are a kit internals to the T

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IG @jaredkeller96

7/14/2018 12:50 PM

I did the race tech spring conversion on my 15 and it was night and day Better than the stock air

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7/15/2018 10:57 AM

I have 2011 KYB forks on my 2016. They have Factory Connection valving and .50 springs and the improvement in plushness and front end grip is awesome. I also traded straight up for my SFF Air. The front wheel, brake mount, fork guards, and triples from my 2016 all worked perfectly.

Definitely wouldn’t mind having the new Showa spring forks, but I couldn’t pass on this deal.

Photo

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8/7/2019 12:36 AM

JBecker 72 wrote:

I have 2011 KYB forks on my 2016. They have Factory Connection valving and .50 springs and the improvement in plushness and front end grip is awesome. I also traded straight up for my SFF Air. The front wheel, brake mount, fork guards, and triples from my 2016 all worked perfectly.

Definitely wouldn’t mind having the new Showa spring forks, but I couldn’t pass on this deal.

Photo

I’m looking at my options here and may go your route...everything just bolted right up? No problems?

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8/7/2019 9:51 AM

I installed the Race Tech spring conversion kit into my 2016 air fork. Best thing I ever did to the bike. Cost about $500.00 and is very easy.

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7/15/2020 7:18 PM

Simple question for the Kawi guys on this site. I have a 2017 KX 450 with spring conversion and they seem to work good for me. Now I just bought 2019 KX 450 project bike and was wanting to swap the forks and whole front wheel on the bikes. Can I just swap fork and front wheel including axle and spacers and use the clamps from either bike ?

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7/15/2020 10:49 PM

The A kit copy forks on the new bike are better than the SSF Air shows even with the spring conversion. Don't waste your time and money. Dial in the new forks. I had a 2016 KX450F with all of the procircuit mods. Then I installed a spring conversion. The new Showas are worlds better.

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9/5/2020 1:53 PM

mb60 wrote:

Simple question for the Kawi guys on this site. I have a 2017 KX 450 with spring conversion and they seem to work good for me. Now I just bought 2019 KX 450 project bike and was wanting to swap the forks and whole front wheel on the bikes. Can I just swap fork and front wheel including axle and spacers and use the clamps from either bike ?

I'd really like to know the answer to this question as well.

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November 13th, Forever in our memories !!

9/6/2020 8:38 AM

mb60 wrote:

Simple question for the Kawi guys on this site. I have a 2017 KX 450 with spring conversion and they seem to work good for me. Now I just bought 2019 KX 450 project bike and was wanting to swap the forks and whole front wheel on the bikes. Can I just swap fork and front wheel including axle and spacers and use the clamps from either bike ?

All you need to do is take the 17 forks, front wheel and axle and put it on the 19. The diameter of the fork tubes are the same, either for will work in the clamps....

The triple clamps are different. The difference is the 19 has a 3mm shorter steering stem.

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