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potto

Cota 349 fork seals ?

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Bought new for seals and just wondering about there placement,it would appear they just sit on top of each other with the lips upwards....correct ?

Besides cleaning the sliders and tubes anything else required before reassembly ?.

The spring spacers that In Motion sell are they to compensate for weakened spring or something else?

Thanks.

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The big lips point downwards. Small lips (if any) point upwards. The side with the writing faces up. If you have two seals per leg, yes both seals go the same way up.

What spring spacers are you asking about?

Those forks sometimes suffer from a plastic part at the bottom of the damper rod becoming a tight fit in the hole they go into as the forks bottom. You can test for this by working the sliders. If they stick at the end of the travel, it is a good idea to machine the part back to size or make aluminium replacements while the forks are apart. They are white/translucent plastic tapered cylinder shape and fit between the bottom end of the damper rod and the slider. They are called anti-bottoming cones

Edited by feetupfun
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Point of interest didn't the Montesa Honda 349 variant revert to single seal arrangements

I seem to remember mine quickly leaked the old double seal arrangement being much more reliable

one to remember Honda if it aint broke don't fix it      Viva Montesa :o 

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The spacers I refered to that In Motion sell are made of alloy and fit on the end of the springs as far as I know.

I bought 4 seals as that is correct for my 51M 349 size is 35x47x7 ,hope my info wasn't wrong...parts book shows 2 seals/slider.

Thanks again.

 

 

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Fork spring preload spacers are used to tune the preload to give you the right "sag". You adjust the sag with the bike assembled by taking the caps off. If someone rode it successfully before you got it there is a good chance that the sag will be in the ballpark already.

With fork seals in your 349, you can use two skinny ones or one wide one. You are only limited by the depth of the hole below the retaining clip. Yes, In Motion sell the skinny ones and using two skinny ones was common practice when the bikes were new, and is still commonly done and it usually works well. Some people seeking to reduce the friction fit only one (wider, double-lipped) seal and some people reduce the tension on the tiny springs that hold the lips against the tubes. It's a free world. What you are doing has a good probability of success. SKF have started making fork seals from some modern fancy low friction material and they are available in your size and are expensive. I've yet to try the SKF seals and the Spanish forks I put together last week (Bultaco M85) have the In Motion seals in them. The Spanish forks I did before that I fitted a single 10.5mm wide seal (Bultaco M49) and they worked fine too.

One problem cropping up with our old bikes is that the sliders can develop enough wear to cause the tube to move about too much (radially) in the slider for the seal to work properly. Modern forks have replaceable bushings in the sliders but the old bikes don't have this. If the play is causing problems, they can be machined out to take a sleeve or maybe replaced with less-worn second hand sliders.

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1 hour ago, feetupfun said:

One problem cropping up with our old bikes is that the sliders can develop enough wear to cause the tube to move about too much (radially) in the slider for the seal to work properly. Modern forks have replaceable bushings in the sliders but the old bikes don't have this. If the play is causing problems, they can be machined out to take a sleeve or maybe replaced with less-worn second hand sliders.

The sliders are easy enough to machine if you have access to a reasonable lathe - the outside where the gaiters go is concentric with the bore, so easy to set up - then press in a suitable piece of brass tubing and ream/machine to size. Any competent machine shop should be able to do it.

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On ‎1‎/‎15‎/‎2018 at 4:25 PM, oldaz said:

The sliders are easy enough to machine if you have access to a reasonable lathe - the outside where the gaiters go is concentric with the bore, so easy to set up - then press in a suitable piece of brass tubing and ream/machine to size. Any competent machine shop should be able to do it.

Thanks oldaz,stripped down forks found atf in on leg and gearoil in the other .........jeez what is it with people???,forks generally good condition,talked to the last owner who did little but store it for 15yrs after purchase and he said he had little history on the bike,think the previous owners had been good with exception.

The oil in the forks was mud,lots of ***** in all parts so after a good clean up and new I should be golden.

Happy with progress so far as no hurry till leg heals,mates son give me some riding boots ,a little worn out but still useable for my needs.

Cheers Dean.

 

Edited by potto
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1 hour ago, potto said:

Thanks oldaz,stripped down forks found atf in on leg and gearoil in the other .........jeez what is it with people???,forks generally good condition,talked to the last owner who did little but store it for 15yrs after purchase and he said he had little history on the bike,think the previous owners had been good with exception.

The oil in the forks was mud,lots of ***** in all parts so after a goos clean up and new I should be golden.

Happy with progress so far as no hurry till leg heals,mates son give me some riding boots ,a little worn out but still useable for my needs.

Cheers Dean.

 

Good job potto, yes you certainly wonder about what the previous people were thinking with some of the stuff you find. Mud seems to be one of the things you find in forks that haven't been serviced - as well as just about everywhere else. When you put it back together it might take some experimenting with different weight (viscosity) oil to get it to suit you. I haven't ridden mine yet, so starting with atf, if I find it's too soft, I'll replace with a heavier grade. Good you got some boots :-)

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1 hour ago, oldaz said:

Good job potto, yes you certainly wonder about what the previous people were thinking with some of the stuff you find. Mud seems to be one of the things you find in forks that haven't been serviced - as well as just about everywhere else. When you put it back together it might take some experimenting with different weight (viscosity) oil to get it to suit you. I haven't ridden mine yet, so starting with atf, if I find it's too soft, I'll replace with a heavier grade. Good you got some boots :-)

Thanks ,loaded with 10W oil hope that's ok...won't be riding mine for a while but thinking there has to be an improvement over what I had,lol.

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13 hours ago, potto said:

Thanks ,loaded with 10W oil hope that's ok...won't be riding mine for a while but thinking there has to be an improvement over what I had,lol.

Got the bike off the stand today,checked the forks and the action is great ,found the forks had pre-load spacers already fitted,they looked to be around 25mm so a little larger than the biggest ones InMotion sell,however the forks easily move back to full extension after compression so I feel they are about right.

Overall the forks feel good but a little soft....a ride in the future I will see if they need heavier oil or a little air ???.

Cheers.

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Good progress, you need the ride to be "soft" compared to a trail bike, you just have to figure out how soft actually works for you at your weight - need to allow the wheel to easily follow whatever you're riding over - too hard in the forks and/or with higher tyre pressure and rocks will tend to skid out in front instead of going under the wheel - I'm sure you'll figure it out once you do a few sections on it. 

There are several different valve arrangements in the fork nuts, some of the 247's (like mine) have a spring loaded ball relief built into the nut  - when the oil is aerated and forks suddenly compress, you can end up with a face full of oily mist if you don't have some sort of deflector on there - some have a valve like a tyre valve and these don't squirt like the others. I would be wary of adding positive air pressure through these type valves as the only exit under pressure would be past the fork seals. I've seen bikes where the valves have been shut off and the owner/rider accepts a certain amount of oil leakage past the tube seals. Make sure you do your homework is all I'm saying.

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6 hours ago, oldaz said:

Good progress, you need the ride to be "soft" compared to a trail bike, you just have to figure out how soft actually works for you at your weight - need to allow the wheel to easily follow whatever you're riding over - too hard in the forks and/or with higher tyre pressure and rocks will tend to skid out in front instead of going under the wheel - I'm sure you'll figure it out once you do a few sections on it. 

There are several different valve arrangements in the fork nuts, some of the 247's (like mine) have a spring loaded ball relief built into the nut  - when the oil is aerated and forks suddenly compress, you can end up with a face full of oily mist if you don't have some sort of deflector on there - some have a valve like a tyre valve and these don't squirt like the others. I would be wary of adding positive air pressure through these type valves as the only exit under pressure would be past the fork seals. I've seen bikes where the valves have been shut off and the owner/rider accepts a certain amount of oil leakage past the tube seals. Make sure you do your homework is all I'm saying.

Great info thanks ,nah not going into fork air and have decided that way after checking them again they are right for the bike.

I have 150mm on a had real hard bounce expect more when riding should be fine.

Cheers Dean.

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