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Main Area => Projects / Builds, Racing and Tech => Topic started by: lucas on August 29, 2014, 10:55:32 PM

Title: My 1991 GS500 project
Post by: lucas on August 29, 2014, 10:55:32 PM
Hi all, I bought a gs500 last year around Christmas time and it was almost completely disassembled.  The engine was taken halfway apart and much of the bike was piled in a laundry basket. 

It is my first motorcycle and over the past couple months I have been slowly building it up.  Thank you to all the helpful and informative members here.  I have learned a great deal and have enjoyed the meditative aspect of picking through each detail on this bike.

I came to these forums constantly to read and get advice.  I had a very interesting time with the build - there were several problems I had to solve.  The head was missing one cam journal cap and I was thinking I would machine a new one at work but I came across a used head for cheap.

I had a bear of a time trying to replace the flywheel.  Two of the magnets were broken.  I bought an m14-1.5 bolt at Napa auto parts and then used a slide hammer to yank on the head of that bolt but that did nothing.  I used an 8" gear puller from Harbor Freight and that popped it right off.  I used an impact wrench to tighten the gear puller, so easy.

The carburetors had several issues, the choke needles were both stuck in place, one carb needed a metal tube re-brazed, and both the black plastic caps were broken.   I bought a set of carbs from a 1999 gs500 but I still would like to know if anyone has advice on un-sticking the choke needles.  I tried tapping on the needle with a punch but that did not move the needle.  I think I might have ruined the carb beyond repair instead of improving the situation.

With the new carbs being shipped to me I think I will have this motor running in a weekend or two.  The last big task I have is to get the brakes working, I am going to replace leaky seals in the rear brake and test out the fronts to see if any replacements are needed there. 

I'm really excited to take a ride on this resurrected gs500.

[attachment deleted by admin]
Title: Re: My 1991 GS500 project
Post by: lucas on August 29, 2014, 11:02:54 PM
This picture shows the carburetor with the missing metal airway.  I put a narrow punch in here to try to tap out the choke needle.  I think I only succeeded in gouging the internal surfaces off the carb.

Does anyone have advice, or perhaps any info on why the needles were frozen.
Title: Re: My 1991 GS500 project
Post by: Krav on August 30, 2014, 12:27:17 AM
A nice technical project! i like :D

For the needles to freeze in place, i guess it has to stay in the same spot for a long time. The rubber doesnt let it stick there, and unless some residue from something in the tank has made it stick for a time, i dont know how those needles would become stuck in the carb body.. Anyways, you could try it with a heater, WD40 stuff like that.
If that doesnt work, disassemble the carbs completely, and put pressure on the main jet. Aim for somewhere it cant hurt someone though :p Because you're basically then making you carb into a pistol :p
Title: Re: My 1991 GS500 project
Post by: pomme123 on August 30, 2014, 12:54:58 AM
Of your gonna do that please set up a cardboard target and film the shot. Haha.


Sent from my iPhone using Tapatalk
Title: Re: My 1991 GS500 project
Post by: lucas on September 04, 2014, 02:56:09 PM
What should I do about the rust in the gas tank?

The interior of the tank has a fair amount of rust left in it after I soaked it in vinegar and agitated it with bolts.  The rust appears to be surface rust and the metal itself is bare and oxidizes immediately.

Is it normal for this bike to have rust in the gas tank?  Will the screen on the petcock catch the rust particles before they get to the carbs?

Is it harmful to the carbs if some rust bits flow into them?

Title: Re: My 1991 GS500 project
Post by: The Buddha on September 04, 2014, 03:28:03 PM
Rust clogs the carbs. The tank rusts often, but we acid treat and coat it if its bad. In the old days you could treat the rust with muriatic acid and keep the tank full @ all times and it wont rust ... oops sorry we put alcohol and oxygen in the gas and that idea is about as quaint as the tooth fairy ...
Cool.
buddha.
Title: Re: My 1991 GS500 project
Post by: lucas on September 05, 2014, 09:36:11 PM
Ok, I think I will leave the tank pretty much as is and see how it performs.

I bought a set of carbs to replace the carbs that came with the bike and I'm going through and cleaning and inspecting them.  I took off the bottom cover (float bowl?) and  I found that the oily residue on the outside of the carbs appears to be inside as well.

This reside is viscous and sticky and black in color.  The float needles were gummed up solid and took a lot of convincing to come out.

What is this nasty stuff?  Any clue?

There was some of this sticky crap on the intake bore and butterfly valve and the fuel inlet line appears to be clean... did someone try to "clean" these carbs with soda-pop? 

The carbs I got with the bike were 8 years older and damaged but were spotless in comparison.  Yuck.
Title: Re: My 1991 GS500 project
Post by: Big Rich on September 05, 2014, 10:23:13 PM
Probably old, OLD gasoline. Given enough time, it turns into a sweet smelling syrup.
Title: Re: My 1991 GS500 project
Post by: lucas on September 09, 2014, 12:29:39 PM
Old carbs.  Both of these old carbs have frozen choke needles.  Both have damaged diaphragm covers.  One of the carbs had a metal air-line broke off - this is the air passage that serves the choke needle. 

Instead of attempt to restore these carbs I bought a newer pair that don't have these problems.
Title: Re: My 1991 GS500 project
Post by: lucas on September 09, 2014, 12:36:50 PM
Newer carbs.  I bought these for cheap on eBay.  They were covered and filed with a smelly thick syrup and took several hours to clean thoroughly.  Gross!

I swapped over the floats and float needles from the old carbs because they were already clean.  They were also missing a spring that goes between the two throttle valves which I pulled off the old pair of carbs.

[attachment deleted by admin]
Title: Re: My 1991 GS500 project
Post by: lucas on September 09, 2014, 12:38:29 PM
This is what the carbs looked like when I received them

[attachment deleted by admin]
Title: Re: My 1991 GS500 project
Post by: lucas on September 09, 2014, 12:43:07 PM
Air filter.  This air filter came with the bike.  Is this the "K&N lunchbox"?

If I try to start the bike with stock needles and this filter will it run?



[attachment deleted by admin]
Title: Re: My 1991 GS500 project
Post by: lucas on September 09, 2014, 12:47:11 PM
I worked through the wiring diagram in the factory service manual and I think I have all the wire connections figured out.  I wasn't able to find connections for a few things though.  I have one ground wire in front of the rectifier and two wires (one ground and one ?green? wire)in the headlight bucket. 

These are all have the female connector on them... what were these for? 
Title: Re: My 1991 GS500 project
Post by: lucas on September 12, 2014, 03:54:56 PM
Making progress.  Here is what it looks like as of last night.

Also a pic of the inside of the gas tank... what should I do about this rust?  I have a small in-line fuel filter should I install it?

[attachment deleted by admin]
Title: Re: My 1991 GS500 project
Post by: Big Rich on September 12, 2014, 04:34:22 PM
I can't help with the wiring, sorry. Check a diagram and see what wires are surrounding your odd wires, hopefully you'll figure it out.

For the rust, check this out:

http://www.mopedarmy.com/wiki/Removing_rust_from_a_gas_tank
Title: Re: My 1991 GS500 project
Post by: lucas on October 05, 2014, 12:08:10 AM
Got the wiring mostly figured out - I have helpful friends!  The bike started right up today.  It's a very good feeling to build a motor and bring it to life.
Title: Re: My 1991 GS500 project
Post by: lucas on November 01, 2015, 04:33:44 PM
Hey all, it has been a while.  Progress on the ol GS has been really slow with moving to a new place, working and going to university full time.  Lately I have been putting more time toward customizing and getting the GS back on the road.

This year I did a bunch of stuff, I made a new battery box for a smaller battery.  I went over the wiring for the whole bike and I ended up cutting out many meters of unnecessary wiring.  I painted my wheels grey and got new tires.  I painted the brake disk hubs (the middle bits).  I installed clip on handlebars and an aftermarket clutch lever.  I've rejetted the carbs with Buddha's recommended sizes.  I chopped the engine cover over the front sprocket for looksies.  Relocated rear brake fluid reservoir Replaced a bunch of stuff, wheel bearings, head bearing, chain, coil, CDI, carbs.  Ditched a bunch of other stuff, center stand, stock headlight, gauges,

Still to do, modify the SV650 rear suspension to fit.  Chop the stock exhaust and install the slip-on I purchased.  Fabricate a mount for the new headlight and turn signals.  Fabricate a permanent mount for the brake light.  Cut off the right side passenger foot peg.

Later I am going to replace the brake lines, replace the engine side covers, machine a beefier front fork brace, install stiffer front springs

(http://i.imgur.com/nrGflbE.jpg)

(http://i.imgur.com/PlaYisr.jpg)

(http://i.imgur.com/fBKa9si.jpg)

(http://i.imgur.com/Z14svpo.jpg)

(http://i.imgur.com/wb27NS2.jpg)











Title: Re: My 1991 GS500 project
Post by: cbrfxr67 on December 22, 2015, 10:56:59 AM
Need update!  Looking good
Title: Re: My 1991 GS500 project
Post by: lucas on January 19, 2016, 01:40:11 PM
OK so there is some news on the project bike.

I got a new helmet!  It is colorful and awesome.  This helmet is much nicer than the first one I bought.  Much much less wind noise and the fit is nice and snug.  I decided to wear it while I watched motorcycle crash videos on youtube.

(http://i.imgur.com/pQdIO8i.jpg)

I rode the motorcycle to work yesterday, it's only a couple minutes away but I started to get really nervous when the sky got cloudy and then started to sprinkle.  I rode home and got my truck instead.

When pulling into the driveway the front suspension bottomed out with a clunk.  I neglected the front dampers and never actually checked the fluid level since putting the bike together.

I ordered .8kg/mm springs from racetech and some 15wt fork oil.  I have a couple sets of seals that came with the bike. 

The front headlight is still not mounted.   I'm working on making my own at work but progress is a little slow.

(http://i.imgur.com/PvQ0BL1.jpg)
(http://i.imgur.com/vjWq9BY.jpg)
Title: Re: My 1991 GS500 project
Post by: The Buddha on January 19, 2016, 02:49:34 PM
Hard mounting the headlight causes it to blow in about a week of riding 20 miles a day.
Original ears and grommets needed to keep it from blowing.
Dunno about the nighthawk headlight though.

Cool.
Buddha.
Title: Re: My 1991 GS500 project
Post by: lucas on January 19, 2016, 02:57:39 PM
Huh, I hadn't thought of that.  Thanks for the tip.

The light is from a WR250X but I suspect this is some kind of standard size light.
Title: Re: My 1991 GS500 project
Post by: lucas on January 19, 2016, 03:19:59 PM
What if I made the clamps .01 or .02 inches lose around the forks and then used some bicycle inner tubes to fill the gap?  I already sold the headlight and brackets, doh!
Title: Re: My 1991 GS500 project
Post by: lucas on January 24, 2016, 06:19:50 PM
Went for a ride today, a buddy of mine showed me this cool abandoned road.
(http://i.imgur.com/86Qex7P.jpg)
Title: Re: My 1991 GS500 project
Post by: ShowBizWolf on January 25, 2016, 10:50:09 AM
mmm I wish I was there!! Wish I could get out and ride. We got 2 ft. of snow on Saturday so... this girl is sad  :icon_sad:
Title: Re: My 1991 GS500 project
Post by: cbrfxr67 on January 27, 2016, 12:14:35 PM
sweet pic  :bstar:
Title: Re: My 1991 GS500 project
Post by: Big Rich on January 27, 2016, 04:50:51 PM
Quote from: cbrfxr67 on January 27, 2016, 12:14:35 PM
sweet pic  :bstar:

Agreed! Very Mad Max looking.....
Title: Re: My 1991 GS500 project
Post by: Suggy on January 28, 2016, 04:34:18 PM
Ah so cool!
Title: Re: My 1991 GS500 project
Post by: lucas on January 28, 2016, 04:46:36 PM
Thanks for the comments, guys!

Last weekend I replaced the fork oil in my GS before going on that long-ish ride.  Before that the front suspension would bottom or unexpectedly on little stuff like driveways and give me a jolt in the wrists.  When I opened up the fork caps I learned that the forks were 100% dry...

So... That's another example of why I should never assume anything when it comes to my basket case.

I measured out precisely 377mL of oil into each and capped it up.  After riding for 30 minutes I noticed some oil leaking and I find that it is leaking from the bottom of the left fork.  The fork oil was getting on the left side of the tire... Not a huge amount, very small amounts of oil actually but I took it extra easy.

Today I installed the racetech springs I bought.  I lifted the front of my bike using a ratcheting tie-down strap looped over a rafter in the garage.  I tightened the damper bolt in the bottom of the left fork and checked the right one.  When I pulled the springs out I noticed that they were much longer than the racetech ones... I thought that was odd, I had noticed that there was no spacer when I had filled up the oil previously but it didn't occur to me that that wasn't normal at that time.

One of the DIY articles I was referencing during the upgrade had a picture comparing the stock spring to a progressive spring and wouldn't you know it, the springs that came with the bike were progressive.

I proceeded with the replacement.  I think I will like having a linear spring response better than a progressive response.

I checked the air gap with the springs out and the forks fully compressed and measured 100mm from the lip of the fork tube.  Dropped the springs in with the spring seat, cut the provided PVC, and screwed everything back together.

I took it out for a short ride and I am not 100% sure but I think I can tell a difference in that the front doesn't dip and much when applying the front brakes.  The other day on a short ride I was pumping the front brake and I got the bike bucking pretty good.  Today the forks seemed to hold up the front end in a more consistent manner.

So now I have an extra set of progressive springs.  Perhaps someday when I have more experience with this bike I'll go back to the progressives to see if there is a noticeable difference.  Especially now that I see how simple it is to swap springs.

Thanks to everyone who contributed to the articles and threads I read that taught me how to tighten the damper bolt, set my preload, and my airgap.

I stopped at a local trail head to snap a picture.

Ooh yeah - almost forgot to mention.  I slapped some unholy crap together to hold up the headlight.  The bracket looks so bad, but now at least I have a light on the front of the bike.

(http://i.imgur.com/OPH11Cg.jpg)
Title: Re: My 1991 GS500 project
Post by: lucas on February 01, 2016, 12:47:39 PM
This morning I started up the motorcycle and was dismayed by a misfire.  I was hoping to ride it today... I unplugged the headlight thinking that it may be overloading the charging system??? Just a wild uneducated guess.  After a minute the misfire went away.  I'll need to do some investigating to figure out the misfire.

(http://imgur.com/IgDuz7B.jpg)

Rode the motorcycle to school today and got a moto parking pass ($47 vs $180, woohoo) and parked in a motorcycle spot for the first time.  Right in front of my building cutting my walk commute from 1 mile to 1 driveway.

I parked next to someone who locked his helmet to his bike.  I had my bike lock in my bag, a habit from the days (yesterday :) ) when I brought my bike in my truck to cut down my walking commute.  I ripped off his idea and locked my helmet up too.

(http://imgur.com/4KwTF1L.jpg)


(http://imgur.com/AMOCMLr.jpg)
Title: Re: My 1991 GS500 project
Post by: cbrfxr67 on February 01, 2016, 02:53:39 PM
(http://tse1.mm.bing.net/th?&id=OIP.M19b7fc7d98859499507a5b8f523f043co0&w=300&h=200&c=0&pid=1.9&rs=0&p=0&r=0)
Title: Re: My 1991 GS500 project
Post by: ShowBizWolf on February 01, 2016, 07:57:16 PM
Well done  :thumb: