GS 450 tires, brakes, chain, sprockets

[olddaddy]

I am new here and really appreciate this forum, a great group of Suzuki people. I just bought a GS450 that needs a rear tire. One thing leads to another I guess and if the wheel is coming off, might as well do the rear brake shoes. And since it's apart why not do the chain and sprockets? And might as well do the front tire and pads.....all of this is overkill except the rear tire. The bike has under 10K miles and appears to have been well treated. The one thing though is the sprockets. The former owner indicated he has a smaller front sprocket intended to lower top end rpms. Any input on this? What rear sprocket should I put back with this smaller front? Or should I just leave it alone? I've wanted one of these for a long time and finally in about a week it will be here. The shipper is picking it up tomorrow. Thanks for the info and forum!

My bike is like the black one in the pic.

 

[BassCliff]

Greetings and Salutations!!

Greetings and Salutations!!

Hi Mr. olddaddy,

If you don't mind listening to a few thoughts from a guy with a shafty bike, I'll share a bit of what I've learned here.

Going down one tooth on the front can bring your revs down a bit if you spend a lot of time on the freeway. A lot of riders find that more comfortable but you have to downshift a bit more often. I wouldn't change the gearing any more than that due to horsepower issues. Besides, these bikes are built to spin. There are a few websites with calculators to help you obtain a certain rpm at certain speeds, but I don't have any of those bookmarked. Maybe someone will post a link. And it's always a good idea to replace both sprockets and the chain as a set so that they wear together. A worn sprocket will wear out a new chain faster and vice versa.

What year/model is your 450? Different models and years had different combinations of front/rear teeth on the sprockets. They all had 16 teeth on the front but varied between 41 and 45 teeth on the back. Earlier years had 41 or 42 teeth, later years had 43 or 45 teeth.

I think it's a great idea to get both tires replaced on a "new to you" bike. Check the date code (information on my site). You don't want to be riding around on tires more than 5 years old anyway. The same goes for the other consumables you mention, brake pads/shoes, brake fluid, oil, etc, should be replaced, especially if you don't know the complete history of the bike.

OK, I've gone on long enough. I just stopped by to welcome you to the forum in my own, special way.

If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", the Carb Rebuild Series, and the Stator Papers. Now let me roll out the welcome mat for you...

Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

 

[koolaid_kid]

I really hate to do this, BassCliff, but you've got it backwards. Being a shaftie person, it's understandable.
Going smaller on the front gears it down (larger numerical ratio) and will give you more power on takeoff, but raise the revs on the highway.
And vice-versa.
For example:
42/15 = 2.8 final drive ratio.
42/16 = 2.625 final drive ratio.
Think of it this way: for each rev of the countershaft, the front sprocket moves 15 teeth on the rear sprocket. So, if the countershaft is turning 1000 rpm, the rear sprocket is moving 15000 teeth.
If you change to a 16, each revolution will move 16 teeth on the rear sprocket. So, if the countershaft is turning 1000 rpm, the rear sprocket is moving 16000 teeth, which will turn the rear wheel faster, which means you are going faster. So to go the same speed, or 15000 teeth, you would need to reduce the countershaft revs accordingly.
The larger the final drive ratio, the better the takeoff.
The smaller the final drive ratio, the lower revs on the highway.

OP, if you want to know the stock ratio, bikebandit OEM section will list the numbers for you.

 

[olddaddy]

Thanks for the welcome and info. The bike is an 81 GS 450 EX?? It is the black one with red trim and the small nose fairing. The only pics I have are from the seller and they are in a file type that will not load here. I'll get some when it arrives and post. As far as the rpm I would like to slow it down at highway speeds. I commute on a GS850 right now and at 50mph is sounds like it could use another gear. I'm looking forward to learning about this model Suzuki. I've always had bigger 4 cylinder models and always admired the smaller twin. Now that I'm older, slower, and not as strong the bigger bikes are still fun, but a bit more of a chore for me to ride on. In any case the 450 is the queen of the barn soon. My 66 Triumph Trophy is going to have to adjust to some competition for my riding time.

 

[koolaid_kid]

That's a nice little bike. I also appreciate the nimbleness and lighter weight of the smaller bikes. My 1100 is a hog in town and in parking lots.
If you want to lower the revs on the highway, go back to the 16/45 stock combo. You'll lose a bit of takeoff power, but it sounds like you won't mind. Not sure if that small a bike could pull a 17 front sprocket. You'll also need a 104 link 530 chain.
To estimate how many RPM you'll drop, go to a set speed (whatever you travel at on the highway) and note the RPM. Make a couple of runs to minimize tach error.
Since you will basically be running an overdrive if you go back to stock, multiply that RPM by the ratio of overdrive, which is 2.8125/3 = 0.9375.
So if you are turning 7000 rpm at 70 mph, your new rpm at 70 mph would be 7000 x 0.9375, or ~6560 rpm (give or take).

 

[olddaddy]

Here's a pic I found that loads. It is a nice little bike, I'm looking forward to riding it. I enjoy the 850, but it is a wrestling match at low speeds.

 

[BassCliff]

I really hate to do this, BassCliff, but you've got it backwards. Being a shaftie person, it's understandable.
Going smaller on the front gears it down (larger numerical ratio) and will give you more power on takeoff, but raise the revs on the highway.
And vice-versa.

Oops. Thanks Mr. koolaid_kid. I know better but had a little "senior moment". That's not the first time and I'm sure it won't be the last. I appreciate you keeping us straight.

I'll just go polish my final drive unit now.


Thank you for your indulgence,

BassCliff

 

[Charlie G]

olddaddy,

That sorta looks like it might be an "S" model, with fairing and bar end mirrors. Sure wish I had them on my bike. I don't know what my front sprocket is but the rear is marked 45. My 450 is alot easier to move around than my 650. Good luck with the bike.

Charlie G

 

[koolaid_kid]

I really like those bags, and I am not a bag person. They fit the dimensions and shape of the bike well.
If you wish to go on the cheap, you could just replace the front sprocket, as long as the chain and rear sprocket are in good shape.
And you could do just the rear tire, but check the date code on the front. I personally prefer to have a matching set of tires, but others will disagree.
I seriously doubt the rear brake shoes need replacing, I have tons of miles on rear drum bikes and have never worn a set out. But replacing the tire will give you the opportunity to check the shoes and clean everything up.
And the 850G, although a solid, over-built bike, is a tank, even heavier than my 1100E.

 

[bgmart450]

olddaddy,

That sorta looks like it might be an "S" model, with fairing and bar end mirrors. Sure wish I had them on my bike. I don't know what my front sprocket is but the rear is marked 45. My 450 is alot easier to move around than my 650. Good luck with the bike.

Charlie G

I'd say that is an S as well. A pretty darn nice one too. Welcome aboard!

 

[TheSilencer]

Yeah - welcome to the forum oldaddy!

Anyone have the specs for the front brake pads though? Im looking to replace mine also.

Thanks guys! You're all fantastic!