1981 Suzuki GS450L - Cruiser to Scrambler

Northish

If you know what you're doing, you're not learning
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This build thread might start out a little differently, so I hope you can bear with me on it. My hope is that someone will be able take something away from it. Maybe something they like, or maybe an example of what not to do ;)

Firstly, I've never owned a motorcycle. I've also never logged a single mile on public roads on one. This whole "scrambler" build started because I was slated to go to Nepal in Nov. last year as a volunteer to help build houses for a couple weeks. On my one day off I was going to ride a Royal Enfield to the foothills of the Himalayas, which was kind of a dream I guess. Long story short, the trip was cancelled less than two weeks before departure due to political unrest, but I fell in love with the idea of owning a smaller displacement, rugged, simple motorcycle. I was a bit obsessed with the idea.

My brother, who has a huge heart, had an '81 GS450L in rough shape that he didn't pay anything for and decided that it would better off in my hands (I'm a bit more meticulous, I suppose.) So, he surprised the heck out of me and gave me the keys to his GS450 on Christmas. What a guy...

I'm not sure how many previous owners the bike has had, but when my brother someone had put pod filters on it without any carb changes, put a rear tire that was so big it rubbed the swingarm, chopped off the back end behind the rear shock mounts and welded in angle iron for some reason, hacked apart the electronics, etc. It also looked like it was crashed at some point because the handle bars were bent and all the tree bolts on one side were different from the other side.

Here are a few pictures of it as received:
 

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Northish

If you know what you're doing, you're not learning
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Being that it was handed over to me in the dead of a MN winter I had a lot of time to decide that its current state wouldn't do. I've never worked on a bike before, so I wasn't quite ready to dig into engine stuff just yet. I just knew that I wanted to build something I would feel comfortable on, whether it be on city streets or on the gravel roads to my brother's place, and a scrambler or tracker seemed to fit the bill. There are a lot of inspiring projects on this site.

So, I felt that the 16" rear and 19" front wheels were going to have to go. I was able to find an 18" front and a 17" rear wheel so I started there. I did a lot of looking for tires that I thought would do well on gravel without being to loose on pavement, so decided to get some IRC GP-110 Dual Sports. The rear is a 4.60-17 and the front is a 4.10-18. I got the wheels cleaned up and was even able to mount the tires myself, which was a new (and difficult) experience.
 

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Northish

If you know what you're doing, you're not learning
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Here is a good side shot of the bike once I was able to get it to where I could start working on it. I try to use this same shot position for most future pictures so that I could make sure it was heading in the right direction. You can tell it was cold out because if you look closely at the engine you can see it is covered in frost. It was -18°F that first work day. A lot of hot coffee was consumed :)

I also included a picture of the rear frame section where it was cut and welded (I'm no expert at welding but it looked rough.) The PO had welded the rear fender in place to the angle iron and the plastic fender was just sitting in there, held down by the seat. I couldn't quite tell how it was all supposed to go together originally. They had put some Progressive shocks on it, but the bushings were gone. I measured their length at 12" tall. I think stock is supposed to be 13", but If someone knows for certain please correct me if I'm wrong on that.
 

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Northish

If you know what you're doing, you're not learning
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Looking at the side view of the bike I could tell that the back end definitely needed to come up some, so I set about finding some shocks. I did some researching and decided to try TEC's remote reservoir ones. They had a look that I liked, and I could afford them. Ideally, I'd buy Ohlins, but that wasn't an option on my budget. I did know that I wanted to stay away from the remote reservoir RFY versions on Ebay after reading some negative comments about them. I also appreciated this nice write-up by Chris: http://chrislivengood.net/wp/tec-alloy-reservoir-shocks-analysis/

I ended up getting the TEC's with the adjustable dampening option and at 14.6" tall to help level the bike out a bit and increase clearance a bit. They also have a ~1" spacer that one could use to raise them higer, but I think I will leave that out for now. It was in place in the picture below. I was a bit nervous about how they would look in person, but once they arrived I was pleasantly surprised. They seemed on par for the price paid so I think it was a good choice given my budget.

The stock seat wasn't really helping the direction I wanted to go either, so I found a seat on Ebay for a Honda CB350 that I thought I could make work without breaking the bank. If I messed it up then I wouldn't be out too much money. This project is a learning experience, after all. And my first bike so I know that I'll be making plenty of mistakes as I go.

To make the new seat work and to get rid of that questionable angle-iron at the back of the bike I got an upswept hoop section from Dime city. I like the upswept seat look, but the Ebay seat was flat. It had an ABS base to it, so I figured I could do some trimming and heat-gun work to bend it as needed.
 

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Northish

If you know what you're doing, you're not learning
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By this point I've got the old modified rear end cut off and put a slight bend into the new seat to see if I liked where it was heading. I still don't really have an exact picture of what I want it to look like; rather I'm just kind of feeling it out as I go. I can say that I think the new seat is in the right direction. I can also say that the gas tank is definitely going to need some attention. It's got a weird slope to it from it's cruiser roots, so I have decided to cut the mounts and re-position them to make the bottom of the tank run parallel with the new seat and frame.
 

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Northish

If you know what you're doing, you're not learning
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Here's a better shot of the bike's guts with the tank and seat off. I found that the ignition coils were simply zip-tied to the frame under the tank, and were pretty loose. I've got the rear section close to being ready to weld in the new hoop and the gas tank mounts have been removed so that I can start mocking up some tank angles to create some lines that seems to match a scrambler or tracker style. I'm still not really sure which is which at this point, so I hope this tread is in the right section. I should also note my brother found an airbox for it, so that got put on for the time being to make sure it ran OK.

By dropping the front and raising the back of the tank it seems to create a nice flow, so decided I'd go that direction with things.
 

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Northish

If you know what you're doing, you're not learning
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At this point the tank mounts have been modified/created and welded into place. The front was dropped just over an inch and the rear was raised about as much.

I bungee-corded the new seat on to see how things were looking and I was still thinking it was going the right way, more or less.

So, I set about welding in the rear hoop into place. I used frame slugs (also from Dime City) to get a good connection and I was pleased with the results considering my inexperience with welding (I did take a class in high school, once) ;)
 

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adventurco

Nick Ol' Eye
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Sweet! I had a red GS450L as my first bike. I loved that thing. Sold it to a kid who lives down the street and I think he still has it. Looking solid so far.

I like the tread pattern on those tires, may look into them for the XL when the time comes.
 

NoRiders

Member
Looking smart...the rear end raise, coupled with the chunky tyres might make the centre stand redundant.....I'm ditching mine in favour of side stand only....paddock stand in the garage.

Waiting for your next update.... :D
 

Northish

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adventurco said:
Sweet! I had a red GS450L as my first bike. I loved that thing. Sold it to a kid who lives down the street and I think he still has it. Looking solid so far.

I like the tread pattern on those tires, may look into them for the XL when the time comes.
julian.allard66 said:
Thanks adventurco and julian!

After getting the rear hoop welded in and cleaned up I started focusing further ahead on the frame. I wanted to both physically and visually lighten the bike up, so I spent a few days cutting off all the unnecessary frame and panel tabs. You end up with a surprising amount of metal on the ground once they're all off.

The electronics are going to be going into a tray that I'll try my hand at fabricating so they can be tucked under the seat and away from the dirt.

I also started dissecting the wiring, but honestly it has been messed with so many times I am thinking it would be best in the long run to just re-do it with new wire and connections.

This is an exciting point for me because I was able to get the new rear shocks temporarily mounted so that I could get a look at its 'stance.' I must say I don't think it looks half bad compared to where it started. The new rear shock height seems to be right where I was hoping, and the chain doesn't rub on the swing arm so that was exciting. I'm 6'2" so it seems to fit me a little better at this height. It's also really easy to get it on the center stand now. ;D

Next steps are to weld in seat mounting points and then make a tray under the seat for all the electronics that were mounted behind the side covers.
 

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adventurco

Nick Ol' Eye
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If you put taller shocks on, there is a procedure to set your chain slack based on the travel of the swing arm . You cannot go by the manual specs for chain slack as it will be too tight.
 

Northish

If you know what you're doing, you're not learning
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NoRiders said:
Looking smart...the rear end raise, coupled with the chunky tyres might make the centre stand redundant.....I'm ditching mine in favour of side stand only....paddock stand in the garage.

Waiting for your next update.... :D
Thx NoRiders :) You posted right as I was posting an update showing the bike with the raised shocks on the center stand and you can see the back wheel is basically still touching the ground. Good call! I have since shorted the shocks a wee bit so the rear does lift off on the center now. I am thinking I might keep the center for the time being. It is sure has been handy for working on as I don't have a shop stand or anything fancy like that (yet.) I'll try to keep the updates flowing!

adventurco said:
If you put taller shocks on, there is a procedure to set your chain slack based on the travel of the swing arm . You cannot go by the manual specs for chain slack as it will be too tight.
Hey adventurco - I hadn't thought of the height affecting the chain tension... I've got a new chain ready to go on once more of the dirty fab work is done. If you happen to know of a link to the procedure you mentioned I'd be all ears, otherwise I'll do some googling. Thanks for mentioning that, I would have overlooked it!
 

NoRiders

Member
You're welcome :D

I'll be losing the centre stand, using the side stand only (but not cutting anything off). I picked up a new paddock stand for £19 at a local motorcycle jumble (swap meet). It lifts on the swingarm and not the spindle, should be OK for what I want. I love swap meets.

Your bike has changed radically from stock just by minor mods really....nice one.
 

Northish

If you know what you're doing, you're not learning
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This latest update will show some of the progress made on relocating some of the electronics that were previously mounted on the side of the bike under the side covers as well as how I mounted the seat that was originally intended for a CB350.

To make the tray I found some extra sheet metal that my dad didn't need. It was only 5" wide strips, so I had to stitch them together with the wire-feed welder my dad has. Being my first motorcycle and also first build I am trying to save pennies wherever I can so my mistakes aren't too costly. I was able to get it stitched together and bent into shape without too much effort. I'm surprised it turned out as well as it did for a first go. It looks a bit rough, but I will be media blasting it clean along with the frame and other parts later on.

I've also included a shot showing the tray installed along with the new seat mounts. The front mount and mid support are made out of some bar stock. I had to heat the front mount with a torch a few times to get it bent to the right shape, but had a lot of fun doing that. It's hard work! The rear mounts came with the seat, so I cut them down a hair and welded them to the rear hoop. All in all the seat is now very secure and even uses the stock seat rubber pads on the mid support.

The bottom pic shows the seat finally in place and the electronics tray seems to be barely visible beneath it. I don't plan on hiding the battery under the seat, so was able to make the tray fairly slim. You can also see the new header in place. I decided to go with a simple MAC 2-1 in flat black to cut down on the visual mass. I am liking the way it looks, though I wouldn't mind trying my hand at making a true scrambler high-mounted exhaust some day. But alas, I have to draw the line somewhere as I'd love to finish the bike this riding season!

Oh, and I also decided that this would be a solo bike and chopped off the passenger foot pegs and associated tubing. Should help shave a little weight and keep things simpler.
Next area of focus will be fenders. I definitely want to keep this bike functional, so will be re-using the stock fenders and getting a little creative. Thanks for stopping by the build!
 

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adventurco

Nick Ol' Eye
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Looking good. I found a good article on chain adjustment procedure the other day...I was looking for this thread to post it and I couldn't find it but here we are.





We're dealing with the geometric relationship of three points, two of which don't ever move in relation to one another, and one that moves constantly in relation to only one of the other two. The chain rides around a path that encircles all three of these points. You have the counter-shaft sprocket (point A) mounted to the engine, which is mounted to the frame. You have the swingarm pivot (point B) which is also mounted to the frame. Then you have the rear axle (point C), and as a result, the rear sprocket, which is not mounted to the frame.



The two points that are mounted to the frame, points A and B, never move in relation to one another. They are always the exact same distance apart, no matter what anything else on the motorcycles does. Because these two points are static, we can draw a line through their centers and call it the A-B Line that we'll use in minute. Point C rotates around point B. The chain is lashed around points A and C. Starting to sense where things might get funny for the chain?

As C moves in its arc around B, the distance from C to A changes. When C is aligned with the A-B line, such that all three points are perfectly aligned in a straight line, the distance from A to C is at its max. The further out of alignment with A and B that C becomes, the less the distance from A to C.

Now to apply that bit of sorcery to the chain tension adjustment on your motorcycle. You adjust the chain while the suspension is fully, or near fully extended. In other words, when C well out of alignment with the A-B line, in this case, C is below the A-B line. But this is not the point where the chain will be at its tightest as C rotates. It would be a pain in the ass to have to compress the suspension so that C in on the A-B line, and adjust the chain to just the couple millimeters of chain slack that it needs at it's tightest point. Rather, we adjust the chain with an amount of slack that will cause it to have only 2 - 5 mm of play when C passes through the A-B line; at its tightest point. This amount of slack when the suspension is unloaded might be 10 mm, 1/2 inch, two fingers between the chain and swingarm, whatever, that's not what's important in this article.

The critical part here is that there HAS to be enough slack in the chain at the top and bottom of the suspension travel, that when C passes through the A-B line, it does not get too tight and start pulling on things like the transmission shaft that is point A, or overloading the wheel bearings at point C. There are other, more subtle things that happen to the bearings at point B and to the chain when the tension is too high, but we'll skip that today. The other important point I want to make, is that none of this is effected by the load you are carrying on your bike. All this stuff behaves the same no matter what.

SO with that good bit of theory out of the way.
Pull off the bottom bolts of your shocks and tie them up out of the way. Move the swinger to where points A,B,C are in a straight line, you will notice the chain tension change as you get closer and further away from that line. That point where the straight line occurs is the tightest possible point for your chain. Adjust the chain tension so there is adequate slack at that point where A,B,C are in a line. When you put your shocks back on you can write the number down and use it for future reference.
 

Northish

If you know what you're doing, you're not learning
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adventurco said:
Looking good. I found a good article on chain adjustment procedure the other day...I was looking for this thread to post it and I couldn't find it but here we are.
...
Hey adventurco -
I'm glad you dug this up and were able to share it. It makes sense to me now that I read it a few times. I'm thinking I can put the bike on its center stand and remove the rear shocks and test the chain slack at the different swing-arm angles it will likely experience to make sure it doesn't get too tight on the A-B line and too loose in the event the shocks were fully compressed.
I appreciate you taking the time to post that!
 

adventurco

Nick Ol' Eye
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No problem. There has been a lot of talk on the forum about this lately and I found that to help clarify it for myself, as it was something I didn't even think about on my first build.

The most important location to note is what is shown in the diagram. When the points A-B-C are in a straight line, that is the tightest point and therefore the only real location you need to worry about. But If you spin the rear wheel and move the swingarm up and down, you will notice the chain tension change as you get further and closer from that point.
 

Northish

If you know what you're doing, you're not learning
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TJGM said:
I really like how the piping on the seat lines up with the frame !
~T
TJGM - So glad someone else noticed! You can imagine how happy I was when I saw it worked out like that. Every once in a great while you get lucky.
 
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