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Post by richclare on Nov 1, 2017 17:15:07 GMT 1
Good evenin',
I have nearly covered the first 100 miles of running-in my 350 4l0. I'm having a lot of fun and lots of ☺☺☺☺.
Having not ridden for nearly 20 years I'm not sure if the front suspension was this bad!? Going over a bumpy surface feels a little like holding on to a pneumatic hammer😨. Are there any simple tests to ascertain if the problem lies with the springs, oil or stanchions?
With the front brake on they move freely up and down.
Any ideas or advice would be gratefully received.
Cheers Rich
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Post by bare on Nov 1, 2017 18:46:43 GMT 1
Front forks Ain't great.. but they should work passably at least. Reads like yours are not working.
Possible reason being little to No oil in there, as a first guess.
Brakes being on or off shouldn't have effect on fork damping action.. at least when bouncing the bike when stationary.
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Post by richclare on Nov 1, 2017 18:54:28 GMT 1
Front forks Ain't great.. but they should work passably at least. Reads like yours are not working. Possible reason being little to No oil in there, as a first guess. Brakes being on or off shouldn't have effect on fork damping action.. at least when bouncing the bike when stationary. Thanks Bare, I will check and replace the oil as it may not have been replaced - ever! Cheers Rich |
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Post by Tobyjugs on Nov 1, 2017 20:20:31 GMT 1
Hi richclare i find you description difficult to understand. Is it a soft springy feeling or a harsh knocking feeling?
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Post by richclare on Nov 1, 2017 20:35:04 GMT 1
Hi richclare i find you description difficult to understand. Is it a soft springy feeling or a harsh knocking feeling? It is more of a hard feeling, although when I pump the forks they seem easy (very little sprung resistance). When I'm riding and look at the fork it doesn't seem to be absorbing the bumps, more following the surface . To me it doesn't make a lot of sense. I would expect the springs to be too hard. Rich |
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Post by Tobyjugs on Nov 1, 2017 21:02:14 GMT 1
I think the oil might be a bit too thick or you might have too much in the legs. What oil are you using? have you got any preloading on the fork springs? If it's too much oil i would start by putting a tie wrap around the chrome part of the fork leg and do some braking tests. The fork dust cover should push the tie wrap up the leg. Do the braking a couple of times so you get used to making the same braking procedure. Measure the distance of the tie wrap to the bottom of the lower yoke. write the distance down. Then care fully open up your forks and remove a small amount of oil using a piece of pipe connected to a syringe. Remove equal amounts from both forks and note the amount. Do your braking procedure and measure the new distance of the tie wrap. Continue this process until your happy with the feeling. If it is still too harsh and the tie wrap is very close to the lower yoke i think you should use a lower viscosity (thinner) oil. Start with the manufactures reccommended amount and gradually build the amount up until happy, always noting all the changes. I would like to point out i am not a suspension expert and someone else might have a better suggestion  |
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Post by richclare on Nov 1, 2017 21:53:57 GMT 1
I think the oil might be a bit too thick or you might have too much in the legs. What oil are you using? have you got any preloading on the fork springs? If it's too much oil i would start by putting a tie wrap around the chrome part of the fork leg and do some braking tests. The fork dust cover should push the tie wrap up the leg. Do the braking a couple of times so you get used to making the same braking procedure. Measure the distance of the tie wrap to the bottom of the lower yoke. write the distance down. Then care fully open up your forks and remove a small amount of oil using a piece of pipe connected to a syringe. Remove equal amounts from both forks and note the amount. Do your braking procedure and measure the new distance of the tie wrap. Continue this process until your happy with the feeling. If it is still too harsh and the tie wrap is very close to the lower yoke i think you should use a lower viscosity (thinner) oil. Start with the manufactures reccommended amount and gradually build the amount up until happy, always noting all the changes. I would like to point out i am not a suspension expert and someone else might have a better suggestion Hi tobyjugs, Thank you for your detailed reponse. You may not be a suspension expert, but that seems pretty logical advice. To be honest, I haven't done anything with the forks, up until now. They seemed in good working order, so I left them alone (that'll teach me!). So I'm not sure what oil or liquid is inside! I will try and do the tests this weekend and will let you know the results. Thanks again. Rich |
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Post by Tobyjugs on Nov 1, 2017 21:58:51 GMT 1
I think the oil might be a bit too thick or you might have too much in the legs. What oil are you using? have you got any preloading on the fork springs? If it's too much oil i would start by putting a tie wrap around the chrome part of the fork leg and do some braking tests. The fork dust cover should push the tie wrap up the leg. Do the braking a couple of times so you get used to making the same braking procedure. Measure the distance of the tie wrap to the bottom of the lower yoke. write the distance down. Then care fully open up your forks and remove a small amount of oil using a piece of pipe connected to a syringe. Remove equal amounts from both forks and note the amount. Do your braking procedure and measure the new distance of the tie wrap. Continue this process until your happy with the feeling. If it is still too harsh and the tie wrap is very close to the lower yoke i think you should use a lower viscosity (thinner) oil. Start with the manufactures reccommended amount and gradually build the amount up until happy, always noting all the changes. I would like to point out i am not a suspension expert and someone else might have a better suggestion Hi tobyjugs, Thank you for your detailed reponse. You may not be a suspension expert, but that seems pretty logical advice. To be honest, I haven't done anything with the forks, up until now. They seemed in good working order, so I left them alone (that'll teach me!). So I'm not sure what oil or liquid is inside! I will let you know the results. Thanks again. Rich I will try and do the tests this weekend. In that case drain them, take the springs out and start from fresh. |
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Post by richclare on Nov 5, 2017 15:33:30 GMT 1
Hi chaps, I decided to dismantle the fork legs completely. All the components seem in good condition, but I have 3 questions:  1. The springs were upside down, with the tightly wound section at the bottom - would this adversely affect the action? 2. The spring length is 295 and 296mm - is it worth replacing them? Just for info - I am a skinny rake at 70kg, so I'm not sure if I need 'harder' springs, if I replace them. Recommendations would be welcome. 3. I found a copper washer on the Allen bolt which holds the stanchion to the leg. It makes sense there is one, but the manual doesn't show it! Can someone confirm this is correct?  Many thanks Rich |
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Post by Tobyjugs on Nov 5, 2017 19:28:42 GMT 1
I think you might have measured the wrong length fork springs, they certainly look bigger than 300mm Click this LINK
I do not have any 4LO forks but there are some references made to them in this link |
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Post by stusco on Nov 5, 2017 19:43:10 GMT 1
The copper washer is correct
the springs look like progressive maybe Hagon I can’t remember which way up they go
they are longer than 296mm
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Post by richclare on Nov 5, 2017 20:15:03 GMT 1
I think you might have measured the wrong length fork springs, they certainly look bigger than 300mm Click this LINK
I do not have any 4LO forks but there are some references made to them in this link Hi tobyjugs, You would never believe I use a tape measure everyday  The measurements should be 495 and 496mm! Thanks for the link as well. Rich |
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Post by richclare on Nov 5, 2017 20:20:37 GMT 1
The copper washer is correct the springs look like progressive maybe Hagon I can’t remember which way up they go they are longer than 296mm Hi Stusco, Thanks for that. My measuring skills are rubbish and should read 495/496mm. I thought the springs were standard (they look the same as the photo in Haynes manual). Rich |
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Post by Tobyjugs on Nov 5, 2017 20:38:03 GMT 1
The tighter coils should go to the top. it's all to do with unsprung weight
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Post by richclare on Nov 5, 2017 20:52:07 GMT 1
The tighter coils should go to the top. it's all to do with unsprung weight Do you think the forks would work differently if inverted? |
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Post by Tobyjugs on Nov 5, 2017 20:55:33 GMT 1
Yes but i think you really have to be in tune with your bike to notice it
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Post by LC_BOTT on Nov 6, 2017 14:31:03 GMT 1
The tighter coils should go to the top. it's all to do with unsprung weight Do you think the forks would work differently if inverted? I'd like to hear some expert opinion on this, as I cannot see how it makes any difference which way they go. I had to strip 3 sets down this weekend, as the ones fitted didn't have a nice smooth action, found both legs bent, and surprisingly, the cast bottoms were also what I believe to be bent, as the stanchions would not bottom out when put in loose, so might be worth checking these too. (Always thought it was 'impossible' to bend this part, suppose it depends how hard the impact was.) I did put standard oil, 10w and a 20mm spacer to try. |
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