2020 KX450 vs 2020 YZ450

dancolvin633
Profile picture for user dancolvin633
Posts
685
Joined
6/28/2016
Location
Plumas Lake, CA, USA
dancolvin633 5/13/2020 5:37am
5/13/2020 5:37am
50 hours with a Pro Circuit and no issues. The issue was with the solid mounted FMF and PC mufflers. All the new ones are good
quadzrulebro 5/13/2020 5:45am
5/13/2020 5:45am
I just swapped out my CRF450R for a KX450. I personally feel like I can go faster safer on the KX. While the hit of the Honda made it feel faster, the KX is far more confidence inspiring for me. I haven’t ridden a YZ for a few years, but last time I did, I was turned off by the ergos. Personal preference, I suppose.
1
Indy mxer
Profile picture for user Indy mxer
Posts
1890
Joined
6/15/2010
Location
The Villages, FL, USA
Indy mxer 5/13/2020 5:58am
5/13/2020 5:58am
dancolvin633 wrote:
50 hours with a Pro Circuit and no issues. The issue was with the solid mounted FMF and PC mufflers. All the new ones are good
I have a 19 KX 450 and love it. I have a solid mounted FMF and it's all good so far, but only 9 hours.

I have a buddy with 19 and the same slip on and his broke off at 16 hours. I called FMF yesterday and of course they said It's Kawi's issue and rubber mounting doesn't help, which I don't believe. I'm trying to be proactive. They said have it beefed up. I'm still going to try and rubber mount it.

That said, I had the same set up on my 16 KX 450 with no issues. So it does seem to be a weakness there on the 19's.
quadzrulebro 5/13/2020 6:30am
5/13/2020 6:30am
Indy mxer wrote:
I have a 19 KX 450 and love it. I have a solid mounted FMF and it's all good so far, but only 9 hours. I...
I have a 19 KX 450 and love it. I have a solid mounted FMF and it's all good so far, but only 9 hours.

I have a buddy with 19 and the same slip on and his broke off at 16 hours. I called FMF yesterday and of course they said It's Kawi's issue and rubber mounting doesn't help, which I don't believe. I'm trying to be proactive. They said have it beefed up. I'm still going to try and rubber mount it.

That said, I had the same set up on my 16 KX 450 with no issues. So it does seem to be a weakness there on the 19's.
Is it a weakness with the bike, or a poorly designed aftermarket muffler? Seems to me that if the stock muffler doesn’t break subframes, then...
1

The Shop

See All »
JohnnyD13
Profile picture for user JohnnyD13
Posts
756
Joined
3/23/2014
Location
Loganville, GA, USA
JohnnyD13 5/13/2020 7:07pm
5/13/2020 7:07pm
I’m pretty sure it’s just the FMF system. Mine is fine. But there’s the biggest fan following page of this bike in vital history. It’s so long now we need to make a shortened version
radmfg2020
Profile picture for user radmfg2020
Posts
10
Joined
12/27/2019
Location
Enoch, UT, USA
radmfg2020 5/13/2020 9:38pm
5/13/2020 9:38pm
ALL OUR HUBS HAVE A LIFE TIME WARRANTY 🇺🇸 excluding bearings. Check out radmfg. Usa made only here. RADMFG2020@GMAIL.COM. Radmfg2020.com we have a new line of hubs with that extra bling. WE ALSO HAVE A A FRONT HUB FOR 250R THREE WHEELERS AND CARRIER BEARINGS FOR ATV. We can also put any logo on the hubs for you. Before we build your wheel set. The phoniex, the falcon, the eagle and the griffin. Radmfg2020@gmail.com for all orders. 435-233-1747 based out of enoch utah.












12
50dippin
Profile picture for user 50dippin
Posts
362
Joined
10/4/2009
Location
Los Angeles, CA, USA
50dippin 5/13/2020 11:24pm
5/13/2020 11:24pm
^^^posting a 3 page ad in the middle of a thread probably isn't the best marketing decision.

Back to the topic tho, I came from a yz450 and currently ride a kx450. I'm 6'4" and the yz and kx are always on my lists since they tend to be the largest feeling bikes. This time the kx won with the adjustability and seat height and it was definitely the best stock bike ive ever ridden.
Yz wins on quality for sure though. I haven't had any mechanical issues with the kx in 50 hours, but I have had a few hardware issues. The bolts are not solid, they are filled with some sort of plastic and break really easily. I have broken 2 oil filter cover bolts, one from leaning the bike on a wall and the other from a rock. Both times the head of the bolt sheared clean off.
The rear skid plate bolts on the kx stick out and are not recessed like on other bikes. This lead to mine shearing off and fusing to the frame. I had to drill out one and gave up on the other, so now I run no skid plate. Kind of pisses me off since I mainly ride sandy SoCal tracks and have never even taken it anywhere near rocky terrain, and I have no idea how this happened.
1
FortyHat
Profile picture for user FortyHat
Posts
345
Joined
5/16/2017
Location
USA
FortyHat 5/14/2020 12:27am
5/14/2020 12:27am
Indy mxer wrote:
I have a 19 KX 450 and love it. I have a solid mounted FMF and it's all good so far, but only 9 hours. I...
I have a 19 KX 450 and love it. I have a solid mounted FMF and it's all good so far, but only 9 hours.

I have a buddy with 19 and the same slip on and his broke off at 16 hours. I called FMF yesterday and of course they said It's Kawi's issue and rubber mounting doesn't help, which I don't believe. I'm trying to be proactive. They said have it beefed up. I'm still going to try and rubber mount it.

That said, I had the same set up on my 16 KX 450 with no issues. So it does seem to be a weakness there on the 19's.
quadzrulebro wrote:
Is it a weakness with the bike, or a poorly designed aftermarket muffler? Seems to me that if the stock muffler doesn’t break subframes, then...
From what I've gathered, it actually happens when the rear tire contacts the muffler and pushes it outward beyond the flex capacity of the bracket on the subframe. There are so many variables involved though. Aftermarket mufflers are typically a tad wider, tire widths vary, it only can happen when the rear suspension is very compressed / near bottom, the tire needs to flex out wide enough (like low tire pressure or soft sidewalls) to make contact, etc etc etc. Some combinations of things will cause it to break for some guys, others not. I have tire marks on my FMF muffler and it's made me worry, but at 52 hours my subframe is still fine.
Indy mxer
Profile picture for user Indy mxer
Posts
1890
Joined
6/15/2010
Location
The Villages, FL, USA
Indy mxer 5/14/2020 4:41am
5/14/2020 4:41am Edited Date/Time 5/14/2020 4:47am
Indy mxer wrote:
I have a 19 KX 450 and love it. I have a solid mounted FMF and it's all good so far, but only 9 hours. I...
I have a 19 KX 450 and love it. I have a solid mounted FMF and it's all good so far, but only 9 hours.

I have a buddy with 19 and the same slip on and his broke off at 16 hours. I called FMF yesterday and of course they said It's Kawi's issue and rubber mounting doesn't help, which I don't believe. I'm trying to be proactive. They said have it beefed up. I'm still going to try and rubber mount it.

That said, I had the same set up on my 16 KX 450 with no issues. So it does seem to be a weakness there on the 19's.
quadzrulebro wrote:
Is it a weakness with the bike, or a poorly designed aftermarket muffler? Seems to me that if the stock muffler doesn’t break subframes, then...
FortyHat wrote:
From what I've gathered, it actually happens when the rear tire contacts the muffler and pushes it outward beyond the flex capacity of the bracket on...
From what I've gathered, it actually happens when the rear tire contacts the muffler and pushes it outward beyond the flex capacity of the bracket on the subframe. There are so many variables involved though. Aftermarket mufflers are typically a tad wider, tire widths vary, it only can happen when the rear suspension is very compressed / near bottom, the tire needs to flex out wide enough (like low tire pressure or soft sidewalls) to make contact, etc etc etc. Some combinations of things will cause it to break for some guys, others not. I have tire marks on my FMF muffler and it's made me worry, but at 52 hours my subframe is still fine.
That isn't the case. He had a FMF Factory 4.1 Titanium on his. There wasn't a trace of the tire rubbing the silencer. The only way that can happen is a wider tire or bent sub frame.

I've had this set up on my 16 KX 450 and now my 19. Never had the tire rub. It has something to do with the solid mount FMF on the 19. This combination is the issue. Maybe a little blame on both sides here.
quadzrulebro 5/14/2020 4:51am
5/14/2020 4:51am
FortyHat wrote:
From what I've gathered, it actually happens when the rear tire contacts the muffler and pushes it outward beyond the flex capacity of the bracket on...
From what I've gathered, it actually happens when the rear tire contacts the muffler and pushes it outward beyond the flex capacity of the bracket on the subframe. There are so many variables involved though. Aftermarket mufflers are typically a tad wider, tire widths vary, it only can happen when the rear suspension is very compressed / near bottom, the tire needs to flex out wide enough (like low tire pressure or soft sidewalls) to make contact, etc etc etc. Some combinations of things will cause it to break for some guys, others not. I have tire marks on my FMF muffler and it's made me worry, but at 52 hours my subframe is still fine.
Sounds like the best bet is to just stick with the stock muffler. That’ll leave me with more money for new tires.
Indy mxer
Profile picture for user Indy mxer
Posts
1890
Joined
6/15/2010
Location
The Villages, FL, USA
Indy mxer 5/14/2020 5:12am
5/14/2020 5:12am
FortyHat wrote:
From what I've gathered, it actually happens when the rear tire contacts the muffler and pushes it outward beyond the flex capacity of the bracket on...
From what I've gathered, it actually happens when the rear tire contacts the muffler and pushes it outward beyond the flex capacity of the bracket on the subframe. There are so many variables involved though. Aftermarket mufflers are typically a tad wider, tire widths vary, it only can happen when the rear suspension is very compressed / near bottom, the tire needs to flex out wide enough (like low tire pressure or soft sidewalls) to make contact, etc etc etc. Some combinations of things will cause it to break for some guys, others not. I have tire marks on my FMF muffler and it's made me worry, but at 52 hours my subframe is still fine.
quadzrulebro wrote:
Sounds like the best bet is to just stick with the stock muffler. That’ll leave me with more money for new tires.
Good thought. Although it doesn't seem to be a problem with Pro Circuit since they're rubber mounted.
SlS257
Profile picture for user SlS257
Posts
85
Joined
6/15/2014
Location
West Palm Beach, FL, USA
SlS257 8/19/2020 6:51pm
8/19/2020 6:51pm
Kinda off topic, but does anyone know where i can snag a 2021 kx 450 service manual?

Kawi is siiiiiick!!!
MX558
Profile picture for user MX558
Posts
1995
Joined
4/1/2008
Location
USA
MX558 8/20/2020 4:15am
8/20/2020 4:15am
FortyHat wrote:
From what I've gathered, it actually happens when the rear tire contacts the muffler and pushes it outward beyond the flex capacity of the bracket on...
From what I've gathered, it actually happens when the rear tire contacts the muffler and pushes it outward beyond the flex capacity of the bracket on the subframe. There are so many variables involved though. Aftermarket mufflers are typically a tad wider, tire widths vary, it only can happen when the rear suspension is very compressed / near bottom, the tire needs to flex out wide enough (like low tire pressure or soft sidewalls) to make contact, etc etc etc. Some combinations of things will cause it to break for some guys, others not. I have tire marks on my FMF muffler and it's made me worry, but at 52 hours my subframe is still fine.
quadzrulebro wrote:
Sounds like the best bet is to just stick with the stock muffler. That’ll leave me with more money for new tires.
It's very easy to rubber mount the FMF muffler . I've had mine on for over 25 hrs and no issues

Pit Row

See All »

Post a reply to: 2020 KX450 vs 2020 YZ450