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netley

349 forks.

18 posts in this topic

Putting the bike back together after having fork leg welded. All installed and forks are free to be pushed up and return well. When I put the wheel in, not simple as the wheel, brake plate and spacer are a tight fit, the forks are really hard to compress and when compressed do not return without pulling back on bars.

What can I have done wrong?

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Posted (edited)

Loosen the yolks and compress a few times. re-tighten without twisting.Infact loosen everything,wheel,mudguard etc.

Edited by stan wellback
missed a point or two.
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Possibly that but also do not tighten the pinch bolt on the bottom of the fork leg until you have tightened the wheel spindle nut and then bounced forks up and down.  It is possible to draw the bottom of the legs together otherwise, taking the forks slightly out of parallel, which can have disastrous consequences when hitting a bump.  Check now - take my word for it.

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Again I tried to reassemble but with the stanchions in the clamps but not tightened to get the wheel in I have to prise the sliders apart a little and they will not compress and return.

Stanchions then pulled through the top clamp.

I have loosened everything off and loosely fitted the wheel and axle. As you can see in the pic the top of the triple clamp doesn't line up with the stanchion. There is a spacer on the pinch bolt side and as this bike does seem to have had a few things replaced ie the sliders I wondered if this wasn't the correct one.Anyone knew the correct size of the spacer. It's all I can think of.

There also seems to be a washer on the brake side, between slider and brake plate, and this is missing on mine but surely this would make it worse!

20170609_174553.jpg

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I can't remember if this bike was new to you or you've had it for a while before you broke the axle clamp. Welding up the axle clamp shouldn't do anything like you are seeing there unless the shoulder of the axle clamp now sticks out inwards compared to what it was before.

If you are not familiar with the bike, it is possible that one or both of the fork tubes was already bent and you are reassembling the forks with the tube bend in a position that causes the problem you are seeing

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1 hour ago, feetupfun said:

I can't remember if this bike was new to you or you've had it for a while before you broke the axle clamp. Welding up the axle clamp shouldn't do anything like you are seeing there unless the shoulder of the axle clamp now sticks out inwards compared to what it was before.

If you are not familiar with the bike, it is possible that one or both of the fork tubes was already bent and you are reassembling the forks with the tube bend in a position that causes the problem you are seeing

Hi, Yes I only bought this bike at the beginning of April.

I took the forks apart to clean up the internals and then discovered the broken axle clamp. I've only ridden it once, over rough ground, and this was after re-assembling them and this is when I noticed the stanchion sticking in the slider.

I will pull them apart again later and see if I can see if they are bent which, as you say, is most probably the case.

Thanks for the advice. Nice one.

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Yup, bent as a 9 bob note.

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On Tuesday, June 13, 2017 at 6:58 AM, netley said:

Yup, bent as a 9 bob note.

Having had them looked at by a bike dealer he says they aren't too bad and he's used forks as good as them before. Yolks seem ok as well.

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If you line the bends up in both tubes so they are both point the same way (either forwards or backwards) you will have the best chance of the sliders moving freely

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It's a fairly common procedure for people who rechrome fork tubes to straighten them before they rechrome them so if you want you can probably get yours straightened quite economically

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Having spent an hour with a friend trying to figure out the fork stanchion issue, I make a phone call to Bultaco UK who says I have the wrong front wheel and this is why it doesn't fit. I will get a smaller spacer made and see if this helps.

pic1.jpg

pic2.jpg

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email from inmotion.

Hello Neil ,

OK the wheel is not a Montesa wheel , we do not recognise the hub , the brake plate is a grimeca one
possibly off of a fantic.....

thanks

Pete

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the hub is definately not from a cota 349. to be sure about the straightness of fork tubes , remove the wheel and put the axle on, be sure that it can be installed easyly. Remove the axle turn one of the fork tube from the triple clamp 180 degrees and apply the same procedure . The axle shouldbe easyly anstalled on each attempt. 

I have a similar problem by the way. the forks arent moving freely. it requires a lot of pressure to compress the fork. I tried to refurb the forks but I found that the parts under the seals are both missing. The part number I can on the spare parts is C000.993547 ( if this is the right part??) . make sure they are in place

Anyone have any picture of this part? any dimensiones related? I will probably have to make one since I could not find it any where.

 

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Hi dr. I think I've traced why my forks didn't work properly when the wheel was in. They work perfectly without a wheel regardless of the rotation of the stansions. As you said neither the hub or brake plate belong to my bike and when I sent some pictures to InMotion trials they said the brake plate was off a Fantic and had no idea what the hub was from. I had to prise the fork legs apart to get the wheel in.

I had a friend machine the brake plate either side and take a little off the spacer so it was 1mm narrower than the forks and this seems to have worked.

I looked at a diagram of the 349 forks and the part you say is actually a second fork seal. When I rebuilt mine my local trials place who just happens to have an extensive knowledge of Montesa and Bultaco twin shock looked it up on his microfiche. I've attached the 349 manual I saw it on and hope it helps.

Neil

manualcota349-4.pdf

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On 28.07.2017 at 3:06 PM, netley said:

Hi dr. I think I've traced why my forks didn't work properly when the wheel was in. They work perfectly without a wheel regardless of the rotation of the stansions. As you said neither the hub or brake plate belong to my bike and when I sent some pictures to InMotion trials they said the brake plate was off a Fantic and had no idea what the hub was from. I had to prise the fork legs apart to get the wheel in.

I had a friend machine the brake plate either side and take a little off the spacer so it was 1mm narrower than the forks and this seems to have worked.

I looked at a diagram of the 349 forks and the part you say is actually a second fork seal. When I rebuilt mine my local trials place who just happens to have an extensive knowledge of Montesa and Bultaco twin shock looked it up on his microfiche. I've attached the 349 manual I saw it on and hope it helps.

Neil

manualcota349-4.pdf

Hi Netley;

 

Thanks for your information. well ı havent seen the part in person, ı havent seen any pictures but it is a little odd to me to use a second seal at that place. one reason is there shoul be some pressure build up inside the seal to seal properly. if there is a second seal under the actual seal , it would prevent pressure buid up and the actual seal becomes useless. 

cota 349 is using 35 mm fork tubes, but the inside diameter of the fork legs is around 36 mm. so imo there should be some kind of friction bearing material under the seal. my bikes forks had to be used without those parts for long time and I can see the signs of wear on the lower part of the fork tubes. Besides every other fork that I have taken apart up to now had some kind of friction bearings in that place. so I have drawn a piece to be manufactured out of engineering polimers that you can find below. if anybody needs to make one of these, this drawing belogs to a piece to be used with 6mm height seal. the seal dimentioned should be 47*35*6 mm.   

I will some oil chanels and install them in shortest time. I can share the result.

But I still wonder what the actual part is under the seal. Even if it is second seal, a picture would help me a lot. I live in turkey and I think this is the only example around.

Dr770 

DSC_1371[1].JPG

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