Dent in fork tube crf450
  • Lewisc450
    Posts: 3
    Joined: Mon Feb 24, 2020 12:47 am

    Dent in fork tube crf450

    by Lewisc450 » Mon Feb 24, 2020 1:54 am

    Hi all I crashed my crf450 r 2017 yesterday have bent the 2 clamps on the top yolk and a little dent in the fork tube, I can no longer push down the forks there fully jammed what's the chances of repairing them or will I have to buy new forks? I will get some pictures up when I'm home I have tried to upload some already but it says the file is to big? TIA
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    JimDirt
    Posts: 4406
    Joined: Sat Nov 25, 2006 6:31 pm

    Re: Dent in fork tube crf450

    by JimDirt » Mon Feb 24, 2020 8:26 pm

    Welcome to the site !! \:D/

    I am assuming your triples are twisted , that is not a issue , just simply loosen the fork pinch bolts (the 4 small bolts on each side of the forks *2 top clamp , 2 bottom clamp*) ........ BUT .... depending on the dent and where it is located , it may be necessary to replace the tube (most likely EBay should net a good used one)

    Without a pic it is hard to discern how bad it is , as it can make the spring bind , or worse the tube could be bent like a banana , (even a slight bend would make it impossible for the fork to work properly and most likely would cause other issues)

    To post a pic , you need a hosting site like IMGUR or similar , that allows posting to forums/message boards (Photobucket used to do this , but now want $500 for you to post your pictures on a site)

    If using IMGUR for example , you would make a account , then upload the pic to their site , when the pic uploads , you click on the pic , it will open a mini box with the pic in it , on the right will be URL links , choose the second from the bottom (for message boards) and copy , then in your post here , paste that link , it will look like this [img]https:/ /i.imgur.com/VGZYX2E.jpg[/img] in your post

    But show up like this
    Image
    2020 CRF450R
    2006 CRF450X
    Image
    Weiser , Idaho
  • Lewisc450
    Posts: 3
    Joined: Mon Feb 24, 2020 12:47 am

    Re: Dent in fork tube crf450

    by Lewisc450 » Tue Mar 03, 2020 1:33 pm

    Thank you for the reply sorry i took a long time to reply myself iv had heaps of stuff going on... any how iv pulled the forks off 1 is dented bad there heading for the scrap bin at this time i cant afford to buy new pair honda want £2000 iv found a 2012 pair on ebay and the diameter of the top tube at both clamp points is pretty much the same the 12s are about 0.2mm thinner will these fit straight on my stock clamps does anyone know? Thanks in advance.
    Welcome to the site !! \:D/

    I am assuming your triples are twisted , that is not a issue , just simply loosen the fork pinch bolts (the 4 small bolts on each side of the forks *2 top clamp , 2 bottom clamp*) ........ BUT .... depending on the dent and where it is located , it may be necessary to replace the tube (most likely EBay should net a good used one)

    Without a pic it is hard to discern how bad it is , as it can make the spring bind , or worse the tube could be bent like a banana , (even a slight bend would make it impossible for the fork to work properly and most likely would cause other issues)

    To post a pic , you need a hosting site like IMGUR or similar , that allows posting to forums/message boards (Photobucket used to do this , but now want $500 for you to post your pictures on a site)

    If using IMGUR for example , you would make a account , then upload the pic to their site , when the pic uploads , you click on the pic , it will open a mini box with the pic in it , on the right will be URL links , choose the second from the bottom (for message boards) and copy , then in your post here , paste that link , it will look like this [img]https:/ /i.imgur.com/VGZYX2E.jpg[/img] in your post

    But show up like this
    Image
  • User avatar
    JimDirt
    Posts: 4406
    Joined: Sat Nov 25, 2006 6:31 pm

    Re: Dent in fork tube crf450

    by JimDirt » Tue Mar 03, 2020 8:27 pm

    They should fit diameter wise , the only things I am not sure of is , the brake caliper mount on the fork lug , as the front rotor on the 12 is 240mm and the 17 has a 260mm rotor , so the size of the mount would be different , and I am not sure if the 17 caliper mount will directly bolt to the 12 fork lug and if the 17 caliper will bolt to the caliper mount , and I am not sure how much offset difference there is in the lug itself (axle offset) , so that needs to be measured as well (the distance from the center of the fork tube , to the center of the axle hole on both your and their fork) .......

    So do some research before purchasing , possibly contacting the seller to send you pics of the mount on the lug itself as well as the caliper mount that bolts to it , including mounting points where the caliper attaches if stuff does not bolt up , then you are going to have to use 12 parts to make it work ........ Then........ If the axle offset is different , it will affect the handling dramatically , I can't say for worse or better ... but the frame geometry of the 17 was designed with specific specs (completely different geometry than the 12) , as to not speed wobble you to death , as well as not knife or push in corners .... the axle lug offset has a major effect on that ...... I am thinking you will end up having to find (on EBay) a used set of 17 or 18 forks ........ as just because the 12's will bolt up to your clamps , does not mean the bike will handle well with the earlier year forks , nor does it mean you can just bolt them on without modifying the brake setup , even a couple mm will make a major difference in axle lug offset , as you are amplifying that measurement over the length of the fork , so it amounts to a great deal of change to the geometry/handling ....... 8-[ :-k


    Like I said , do extensive research before pulling the trigger , it could be a expensive mistake and you would end up having to try to recoup your money and would still need a set of forks .....


    On another note , I have seen sellers sell just 1 fork leg ..... so you might get lucky and only have to purchase 1 instead of a set , that will save you some $$$ .$$

    Also try contacting some of the suspension shops ... they may have a tube that would most likely be much cheaper than OEM
    2020 CRF450R
    2006 CRF450X
    Image
    Weiser , Idaho
  • Lewisc450
    Posts: 3
    Joined: Mon Feb 24, 2020 12:47 am

    Re: Dent in fork tube crf450

    by Lewisc450 » Wed Mar 04, 2020 5:03 am

    I can get my local suspension shop to changem my lug to the other if i was to get the 12 model 1s but after more searching iv found a pair of a crf250 2015 iv had the chap measure The diameter of the 2 clamp positions and there both the same the lug at the bottom is also identical but mine in length are 97.3cm and his are 96cm is this going to be a problem TIA


    They should fit diameter wise , the only things I am not sure of is , the brake caliper mount on the fork lug , as the front rotor on the 12 is 240mm and the 17 has a 260mm rotor , so the size of the mount would be different , and I am not sure if the 17 caliper mount will directly bolt to the 12 fork lug and if the 17 caliper will bolt to the caliper mount , and I am not sure how much offset difference there is in the lug itself (axle offset) , so that needs to be measured as well (the distance from the center of the fork tube , to the center of the axle hole on both your and their fork) .......

    So do some research before purchasing , possibly contacting the seller to send you pics of the mount on the lug itself as well as the caliper mount that bolts to it , including mounting points where the caliper attaches if stuff does not bolt up , then you are going to have to use 12 parts to make it work ........ Then........ If the axle offset is different , it will affect the handling dramatically , I can't say for worse or better ... but the frame geometry of the 17 was designed with specific specs (completely different geometry than the 12) , as to not speed wobble you to death , as well as not knife or push in corners .... the axle lug offset has a major effect on that ...... I am thinking you will end up having to find (on EBay) a used set of 17 or 18 forks ........ as just because the 12's will bolt up to your clamps , does not mean the bike will handle well with the earlier year forks , nor does it mean you can just bolt them on without modifying the brake setup , even a couple mm will make a major difference in axle lug offset , as you are amplifying that measurement over the length of the fork , so it amounts to a great deal of change to the geometry/handling ....... 8-[ :-k


    Like I said , do extensive research before pulling the trigger , it could be a expensive mistake and you would end up having to try to recoup your money and would still need a set of forks .....


    On another note , I have seen sellers sell just 1 fork leg ..... so you might get lucky and only have to purchase 1 instead of a set , that will save you some $$$ .$$

    Also try contacting some of the suspension shops ... they may have a tube that would most likely be much cheaper than OEM
  • User avatar
    JimDirt
    Posts: 4406
    Joined: Sat Nov 25, 2006 6:31 pm

    Re: Dent in fork tube crf450

    by JimDirt » Wed Mar 04, 2020 10:14 am

    The issue would be with the Rebound Rod .... if the other fork tube is shorter than the other , the throw is going to be longer than the tube is made for , it can/would do a few things , first your rebound rod being longer would be in a different part of the stroke compared to the other , this can cause harshness and make it hard or even impossible to dial in the Rebound settings ...... #2 , the Rebound rod would be longer so it could likely bottom out , inside the cartridge doing damage to the rod / seals , cartridge , etc...... #3 , the Rebound rod changes the overall length of the stroke , so you could bottom out the rod itself , damaging the rod without actually bottoming out the tube ... , and the 1 leg would extend farther than the other causing bind and making it so you would have to have one fork for example flush with the top clamp and the other 2mm higher to end up with the same overall distance to the axle , if they were both flus and one being longer , you would have massive fork bind , basically you would try to slide the axle thru and it would hit the lug on the other fork , not go thru the hole because it was higher/lower than the other fork set at the same position in the clamps ...... follow ??

    I would stick with the overall length being the same , basically , it would be like putting CRF150 forks inside a CRF250 .... the parts may fit , as I mentioned before , but that does not mean they are compatible with each other ...... , now if you are using the complete fork assembly , then I do not see any issue , as you can adjust the forks in the clamps and the rear sag to compensate .... but I would not mix different length parts , the bottoming cones , everything is different ... ............ again , stick with what is compatible year wise if at all possible .... you can use 250 forks , the only real difference may be some flex of the tubes (between the R and RX) , and spring rate , which is not a issue................ So 17-18 R/RX forks 250 or 450 would be the way I would go , if at all possible ...... not saying it can't be done , putting on different length fork parts together .... just saying it shouldn't be done ..

    ................................................................................. Getting the complete forks ... no real issue with that difference and you would be fine (swapping both forks complete as a unit)...............
    2020 CRF450R
    2006 CRF450X
    Image
    Weiser , Idaho

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