cracked swingarm... whats next?


36 replies to this topic
  • tool

Posted September 26, 2004 - 12:18 PM

#1

i just got back from the track where i was attempting a big step down, and slamming very hard. i got back to the truck and saw a small crack on the left, top side of my swingarm, right under the chain slider where the swingarm is carved out for the slider... on the top! :cry: its the weakest part of the swingarm since there is less material there.
its small, but there is No Way i will go try that jump again. no matter if its welded, replaced or whatever. i do NOT trust my bike on big jumps anymore.
what should i do? is it time for a 450?
obviously i am pushing this bike too hard and the entire (heavy :cry: ) rolling chassis is suspect now. whats next? cracked frame, linkage... it feels like the bike is gonna come apart. and it scares the hell out of me.
:cry:

  • Yamaha600Racer

Posted September 26, 2004 - 04:53 PM

#2

I feel your pain....I just cracked my linkage and bent the shock shaft 2 months ago....just got it back together recently $400 leter but still missing one bolt...time for me to get a 05' CRF250R...the bike is just too old and heavy to mx anymore...Pete :cry: It hurts to say goodbye.... :cry: I would say throw it in the local paper, and put the money twards the new bike of your choice!

  • Satch0922

Posted September 26, 2004 - 05:35 PM

#3

The swingarm is not "carved out for the slider". That is where the slider has worn the the swingarm. This is a common problem with YZ's and can be avoided. I know it's a little late but check this out (from Motoman393's site)

Fixing Yz's swingarm/chain slider

Regardless of what brand of bike you ride you should do this. I laid a bead of clear silicone under my slider 2 years ago (and everytime I change the slider) and no cracks yet.

  • tool

Posted September 27, 2004 - 01:11 AM

#4

the bike is just too old and heavy to mx anymore...Pete :cry: It hurts to say goodbye.... :cry: I would say throw it in the local paper, and put the money twards the new bike of your choice!


exactly, the 2000 is THE heaviest racing 4 stroke out there, and it shows. the bike is beating itself up.
but it really does hurt, i love this bike. :cry:
but i have a feeling i will love my new '04 450. :cry:

  • tool

Posted September 27, 2004 - 01:18 AM

#5

The swingarm is not "carved out for the slider". That is where the slider has worn the the swingarm. This is a common problem with YZ's and can be avoided.


satch, i just compared the pics on motoman's website with my swingarm... :cry: the two look nothing alike. my swingarm looks like its "carved out" to perfectly fit the slider, but its actually been bashed in so much its cracking.
my swingarm have been beat to death by my chain!? i had no idea this was possible. i know its a little late now, but thanks for telling me about this.

  • Matt96xr6

Posted September 27, 2004 - 06:21 AM

#6

Sounds like the chain was out of adjustment.

Check ebay for a replacement swingarm. They will be the same from 98-01, then a different one for 02-04 - not interchangeable from those years.

  • YAMAKAZE

Posted September 27, 2004 - 06:54 AM

#7

This is really not that big of a deal really. I have seen it several times before. Remove the swingarm and take it to a good welder and have it repaired. Everyone who has done so has never had a repeat crack. I had one done for a friend last year and it cost $45.00. The other thing I would recommend is that you replace the chain slider with a Ty-Davis indestructable one. I used to have to change the slider twice a race season, I have one of these sliders and 2 seasons it's still looking goo.

Bonzai :cry:

  • R_Little

Posted September 27, 2004 - 07:01 AM

#8

This has nothing to do with jumping the bike.
Riding with a loose/ worn slider will actually wear the swing arm out. As suggested see motoman393 site for a fix.

Also the 200 has phillips scews holding the slider in place. Replace those with the 2001 and later hex screws and buy brand new hat washers while you are at it. They are cheap so don't bother rebending the stockers. I keep 2 swingarms so I can replace and relube the other at regular intervals.

I have an extra 01 swingarm which is interchangeable with back to 98 at least. If you want you can send me $20 for shipping and I'll send it to you. It is a bare swingarm, no bearings, no chain guide just the swingarm. Very little wear under the slider. A little flat spot on the pivot shaft seal lip from shipping but nothing that would affect it's use. I bought it with some other stuff and I used it for the bearings. I was gonna heave it, but if you want it....

  • Satch0922

Posted September 27, 2004 - 07:17 AM

#9

Way to go R. Little!! That is what I like to see.

BTW...the 2000 is not that much heavier than an 02...if at all. I still see alot of 426's racing and riding MX every weekend....including mine. BUT if you need help to justify buying a new bike then I say....YEAH THAT THING IS OLD , HEAVY, OUTDATED and FALLING APART!! :cry:

  • tool

Posted September 27, 2004 - 09:05 PM

#10

R little, your the man. :cry: ... ladies and gentlemen, R little :cry: .

i didnt realize that fixing the chain slap was this important. i will keep an eye on this from now on. it just scares me to see cracks on the bike i just launched 60 ft.
my bike was flyin around the track up until i saw this crack. i really want this bike back. my engine is near perfect.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • Satch0922

Posted September 28, 2004 - 05:33 AM

#11

Tool,

Get the swingarm on the bike, read Motoman393's tech articles and you will be fine. THe 426 is still competetive. IF you can't ride it chances are you can't ride a 450 either.
Posted Image

  • R_Little

Posted September 28, 2004 - 09:17 AM

#12

Tool,

Check your Pm's. Send me your address.
You are going to have to put new bearings in it.
I'd get a pivot works kit. Any used swingarm you buy will need new bearings anyway. The outer bearings rust up right away.

When you get it you will notice the left side lip that covers the outer seal is dented in a bit. The metal is very thin there and any bang at all on the corner will mangle that area.

It's not a structural issue, so don't worry just throw a little expoy weld or even silicone over the area after you push the new seals in to keep water from getting behind the seal and you'll be good to go.

Now get back to Roostin'

  • tool

Posted September 28, 2004 - 03:43 PM

#13

i think i see what your talking about. sounds minimal. im sure it will work better than my swingarm.
this is so much easier than a getting a new bike right now
thanks man :cry:

my bike will fly again.

  • R_Little

Posted September 29, 2004 - 08:35 AM

#14

Use some bolts and a few sockets and washers to pull the bearings and seals in. Put a little grease on them first.
Just make sure they don't go in sideways and get deformed. The manual shows the correct configuration for the bearings seals and thrust washers. You do have a manual, no?

If you have your swingarm off already, you will see the lip I'm talking about. If when you bend it back a piece breaks off, just fill it with something to keep water from getting behind the seal. Cast aluminum does not like to be bent more than once, kinda like cast levers that snap when you try to bend them back. In any case it's not a load bearing area so don't worry about it.

Anyway, did the hi-compression piston make any difference on your bike? I need to do an overhual of my top end after 4 seasons of moderate riding. Boy these Yamaha 4 strokes take a licking for sure!!

  • Ga426owner

Posted September 29, 2004 - 12:42 PM

#15

i just got back from the track where i was attempting a big step down, and slamming very hard. i got back to the truck and saw a small crack on the left, top side of my swingarm, right under the chain slider where the swingarm is carved out for the slider... on the top! :cry: its the weakest part of the swingarm since there is less material there.
its small, but there is No Way i will go try that jump again. no matter if its welded, replaced or whatever. i do NOT trust my bike on big jumps anymore.
what should i do? is it time for a 450?
obviously i am pushing this bike too hard and the entire (heavy :cry: ) rolling chassis is suspect now. whats next? cracked frame, linkage... it feels like the bike is gonna come apart. and it scares the hell out of me.
:cry:


I found that my 426's (I had 4 of them)did wear out over time - frame and welds were cracking. My 03 450 has about 1 more year of my type of riding before it will fall victim to this...I have seen some other 450's already breaking in the same places. They all wear out over time if you are a halfway to very aggressive rider - if you are a putter/jump roller they won't wear as fast, plain and simple - If I were you - I would sell it and buy a new or newer bike. It will only get worse over time - I learned that the hard way with Yamaha's. :cry:

  • tool

Posted September 29, 2004 - 02:41 PM

#16

Anyway, did the hi-compression piston make any difference on your bike? I need to do an overhual of my top end...


man, you wouldnt believe it. the higher compression gave it more torque. but i have to say that the hotcam (exhaust only) gave me as much of a power gain as the piston, only it gave it more top end.
both mods add up to a very wide power band, and it pulls 15/47 like its 14/49. seriously, i need taller gearing now. :cry:

  • tool

Posted September 29, 2004 - 03:04 PM

#17

I found that my 426's (I had 4 of them)did wear out over time - frame and welds were cracking. My 03 450 has about 1 more year of my type of riding before it will fall victim to this...I have seen some other 450's already breaking in the same places. They all wear out over time if you are a halfway to very aggressive rider - if you are a putter/jump roller they won't wear as fast, plain and simple - If I were you - I would sell it and buy a new or newer bike. It will only get worse over time - I learned that the hard way with Yamaha's. :cry:


thats what im talking about. when i was a beginner, my bike was way more than i needed. now my bike wont even allow me to do what i want to do. i was coming up short on this step down because i didnt have enough power from a dead stop. i clutched it with full throttle, bounced the hell out of the bike, and i just could not fully clear it.
slam, after slam, after slam.
and to think, if i just had the power to clear it. :cry:

  • Ga426owner

Posted September 29, 2004 - 03:48 PM

#18

Tool the 450 will give you that power! :cry:

  • Satch0922

Posted September 29, 2004 - 04:34 PM

#19

part of the problem Tool is that your running 15/47 gearing. That is insane for a 5 speed 426 on a motocross track. Let that thing rev!!! I have found that 14/50 is ideal for the tracks I ride. 15/47 will lug that bike too much. You need it bouncing off the rev limiter! LOL

  • R_Little

Posted September 29, 2004 - 06:43 PM

#20

<<and to think, if i just had the power to clear it>>

Or if you had carried enough speed from the last turn and didn't have to hit it from a dead stop.
Not raggin on anyone but I'm sure you've seen real fast guys clear it on 125s. no? I've found the real factor is the rider not the bike. I'd keep practicing maybe more in the turns and less jumping maybe?





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