[2big4me]

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I was wondering if anyone has heard of a particular way to determine if the forks on a GL1500 need to be overhauled. Another post mentioned on an older wing that the fork oil should be changed. The factory service manual doesn't mention a scheduled fork oil change.

My 95 GL1500A has about 42k miles and I don't think the forks have ever been "great" (owned since new). They have always felt kind of mushy and on a recent 2800 mile tour across the USA, I noticed what others might term pretty consistent "pumping" of the front end from 20-45 mph...sort of feels like the road is washboardedor the tire has gone egg-shaped. It's not horrible and most of the time I don't notice it. The bike rides well at speed with no balance concerns. I really don't think the tire is out of round and I run the pressures at 33 front and 41 rear.

I was wondering if there might be a stuck valve in a fork leg or something like the anti-dive mechanism. Anyone heard of this?

I am a little intimidated with the exploded view of the forks in the manual and my ability to disassemble and rebuild.

Thanks for any feedback.

Greg :waving:

 

[AZWinger]

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Welcome to the forum 2big4me! :waving:

I just looked inthe shop manualfor my 83 GL1100. It doesn't list any specific time or mileage interval for changing the fork fluid either. If your suspension is mushy the manual says to change it with a heavier oil. I don't know what wt. oil is stock on the 1500 but I put 10wt. fork oil in my 1100 when I had to replace the seal. Works OK for me. You can also use ATF.

You could also try Progressive Springs. I have heard great things about them and may get some myself.

Bob :11grey:

 

[exavid]

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Yep, I sure like the progressive springs on my bike. 2big4me as a first step you might want to drain and refill your forks, it's possible there isn't much oil in them. I use ATF in mine and have been satisfied, but if you do a search on fork oil you will find many different recommendations.

 

[Budegan]

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Hi Greg and welcome to the forum. You have a classic case of tired fork oil. Change the oil first before anything else. If you are happy with the improvement then you won't need Progressives, if you still think the ride could be firmer then you have the option of buying them. Progressives give a very firm ride, but they aren't the answer for everyone.

 

[jj]

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hi, and yes you should change the fork oil. Mine was the original oil in a 91 se and my oil was tired for a couple of years and similiar conditions you speak of. Like you I was intimidated by the job. With help from the guru`s on this site I did it last month and a big improvement. I opted to stay with my original springs. No instructions in manual? I removed fork cap cover to gain access to fork allen bolt 17mm size. Removed some plastic parts around handle bar area, placed towels around general area to prevent scratching from me and/or fork cap when tension is released and cap goes some where not intended. Then drain bolt removed at bottom end of forks and a system to guide old oil to a container and walk away and let oil drain at least over night. I had used 20 w fork oil but some used 15 w oil. Measure exactly and add to your fork from top. I had a little trouble getting my fork allen cap on at first. Not much room for tool and my hands in this area. I ended up using a 2x4 cut to fit the small area. Notching an indent the size of the allen bolt into the 2x4 centre to hold the allen bolt into the wood and prevent side sliding. Then on each side I drill a smallhole to allow me to insert two 6 or 7 inch 3/8 bolts through. This would allow me to get another piece of wood (1x6). This 1x6 would be attached to the 2x4 using the long bolts and nuts,but higher up. This gave me more room to have my hands holding the 1x6 and applying pressure downward to install allen bolt. I then drilled a hole in the centre of both pieces of wood to allow the extention to go through and meet the 17mm allen tool andallen capfor forks. With just me and my wife I had difficulty applying a steady force to get the fork bolt cap to thread(no cross threading) so after sitting there sipping my beer I decided to try to improve my downward pressure application by tieing a 3 inch wide web sling (used in the crane business) to theside crash bars on bike. Fiddling to get the right distance and then placing my back inside the web sling and now when I pushed down I was able to control my downward pressure much more easily and I then did not require as muchof my energy either. (for every action there is an opposite and equal reaction). By using the slingfor my back it made it alot easier and then press the fork allen cap down compressing the spring and then the wife screwed the cap in place a few threads at leasted andthen I was ready to move to the other side. It was easy, but the way I started with just my hands applying pressure would of been difficult with no room and with nothing on my back to push against. Any question on my system just ask. It was worth it though.

 

[Jason]

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Hi Greg. That's all good advice. The cheap and easy job to do first is change the fork oil. This alone will make a big difference and you can then decide if you really need Orogressives.

 

[BenMC]

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Hi Greg. If the forks will compress really easy all the way down then it's fork oil. Fork oil goespasty after a couple of years and there is no way that it will last 10 years without needing replacement.

 

[englishted]

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Hi Greg and welcome. If you reckon the oil hasn't been done in years then I'd say that's all you need to do.

 

[2big4me]

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Greg here...

azwinger, exavid, budegan, jj, jason, BenMC and englishted...

You guys are GREAT!:clapper:

I changed the fork oil on my 95 GL1500A this morning by draining the small plugs at the base of the anti-dive units and removing the air fittings in the top fork nuts. I improvised a cheap, small hand inflater pump (came with one of those exercise balls) to allow me to push the new fork oil through the air fitting holes (worked great).

I found the old fluid very dirty and dark. It shot out of the hole when the plugs were removed (a small mess). My garage this morning was almost 100 degrees (in the shade) here in Tucson so, perhaps the leaving it overnight stuff wasn't really necessary here.

I measured the new 15w oil with a Ratio-Ritecup and put in 12.6 oz in the left leg and 12.7 oz. in the right. I'm not surewhy all the worry about a tenth of an oz. of oil...seems strange to me. There certainly was less that that amount that came out...even with the spillage, only about 8-10 oz each side with the right side being a bit less. There are no leaks on either leg. I wonder where the oil goes?

Anyway, my co-pilot and I just returned from a half hour ride (pretty hot here...going up to 109 today, I think) and I must say, this bike hasn't felt this good for a LONG time. I immediately noticed that the bike was smoother...WAY smoother. Fantastic.

I wonder why they don't mention replacement of the oil in the maintenance section of the factory manual. Hmmm. I would have done this several times by now.

THANK YOU...all of you, for your responses and expertise.

:action:Greg

 

[AZWinger]

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I'm glad you got it fixed! Thats what this forum is all about. Helping each other out.

How did you get off so cool yesterday? It was 93 at 0455 AM yesterday morning when I went to work and still 111 at 730 PM last night when I left work! The high was forecast at 121 but I don't know if it got there or not. I almost wished I had taken my car!

Bob :11grey:

 

[Gayle]

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On this same subject, can anyone tell me if the fork oil quantities are any different on a '96A than on 2big4me's '95?....I'm getting ready to change seals and oil, and can't find any specific info on a '96.....My shop manual goes from '93 to 00 but the table within covers only to '95, so I'm wondering if they changed anything in '96 and beyond?...Thanks in advance...

 

[2big4me]

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Gayle,

I'm sorry that I only have the 95 manual...I can't imagine they would be different. I think the two bikes are almost identical, aren't they?

Greg

 

[Gayle]

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Thanks for the answer, Greg......I made that assumption Friday night as I torn both forks down and replaced seals and bushings....Used the '95 data and they seem OK after @ 500 miles Sat.....

 

[kirk flesher]

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2big4me, i used your method of filling the oil through the air fitting holes. it worked good.

kirk.

 

[DBohrer]

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Greg, You need to pump that front tire up..........

33 psi is way too low. 38 front will work much better.

 

[2big4me]

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Kirk,

I'm glad it worked for you. Mine still works well. I guess it's about time for me to change the fork oil again.

 

[2big4me]

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You know...there's a lot of debate about tire pressures, handling, mileage, etc. I've always stuck with the original equipment Dunlop K177s on this bike. I'm not really sure why, I just like the O.E. tires and I've always stuck with the published pressures. I'm getting 15k miles out of each tire so I guess that's pretty good, right?



Greg

 

[DBohrer]

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2big4me wrote:

You know...there's a lot of debate about tire pressures, handling, mileage, etc. I've always stuck with the original equipment Dunlop K177s on this bike. I'm not really sure why, I just like the O.E. tires and I've always stuck with the published pressures. I'm getting 15k miles out of each tire so I guess that's pretty good, right?



Greg

I have ran several sets of Elite II's and III's and got 27 - 30k miles from them using 38 front and 41 rear. And I don't let the tread depth get lower than 2/32 inch. Yep, I carry and use a tread depth gauge and tire pressure gauge all the time.

I ride a lot of mountain roads, not overly aggressive but don't poke around either if you get what I mean.

Works for me...............

Personally, I think that 15k is really low tire mileage on a GL1500.........!

 

[2big4me]

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Wow! That's quite a bit. Thanks...I'll pump them up!

 

[AZgl1800]

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Those recommended tire pressures are cold at rest pressures.

Don't let any air out if you look at the pressures in the heat of the day on a long ride.