1980 GS450 "Sport" - Resto / Mod

[Big Rich]

Cornelius, Tyler Durden, Pete,...... just saying, it happens. Ha!

I had this all typed out, and my phone erased it. But here's the rack installed:



Pete, you have a pm incoming sometime tonight when I get a chance.

[pete]

Cool, cheers Rich! That helps a bit... have replied to your PM...

[Big Rich]

Not much to show, but an update nonetheless :



These are the stock 450 cams - I replaced them with some GS500 cams for the added lift (and I'd assume more duration). I was checking my valve clearances and had them laying around so I figured "why not?". My valves were on the tight side, and now the intake valves are at .08mm and the exhaust are at .10mm.

[pete]

Be very keen to know if there's any performance improvements Rich... very interested!

Any difference to timing or anything like that? Just a straight swap?

I have a feeling I need to replace the dodgy Athena head gasket at the next service or the service after, so my cam's will have to come out anyway...

[Big Rich]

According to my butt dyno...... just kidding. My valves were at the tight side of the clearance when I started this, so any gains that I feel could be chalked up to the new / proper clearances. I do have to admit, the bike has more pep in the upper rpm range though.

The good news: they are a straight swap. No timing changes or anything, just toss in the new cams. They even have the same pin count between the numbered arrows (#1 arrow pointing at the gasket surface, 18 pins between the #2 and #3 arrows).

If you can't find any GS500 cams when you do your head gasket, let me know. I have some GR650 cams that will detona ........I mean "wake up" your engine. Ha!

[pete]

Hahaha ok that sounds cool! Waking up the top end... considering the 450 only really gets going over 6K RPM then that might be very cool indeed!

How much different are the 650 cam's?

Since my ride on Saturday where I rev'd the ring out of the little beast constantly, the weep seems to have slowed if not stopped, so I'm wondering if the new oil has sorted that out for me... may not need to do the head gasket so soon if at all now, but time will tell.

Either way, new cam's with a bit more spritely performance is definitely an interest! Especially if it's only the high RPM's because that won't compromise anything for the commute...

Edit: Hmmmm... $US51 shipped to me...

http://www.ebay.com.au/itm/04-05-06-07-08-09-Suzuki-GS500-GS-500F-Cam-Shaft-Camshafts-Cams-OEM-/400692951827?pt=Motorcycles_Parts_Accessories&hash=item5d4b293b13&_uhb=1

[landshark]

Edit: Hmmmm... $US51 shipped to me...

http://www.ebay.com.au/itm/04-05-06-...b293b13&_uhb=1

Just Do it!

[pete]

Hahaha don't worry I'm tempted! Although a bit strapped after the recent stator, R/R, starter motor, and tyre purchases...

[Big Rich]

Hahaha ok that sounds cool! Waking up the top end... considering the 450 only really gets going over 6K RPM then that might be very cool indeed!

How much different are the 650 cam's?

According to the Twins wiki that Mekanix has......a good bit. The GS450 intake cam has .330" lift, exhaust cam has .320"......both GR650 cams are .364" lift. I wouldn't try it without a LOT more research, and a spare engine laying around "just in case".

[pete]

Yeah I went back and looked through the Wiki...

Seems we don't have duration for the stock 450 cams... I'll have to check my factory repro manual to see if it's in there anywhere.

My 450 went onto 1 cylinder for about a minute on the commute to work again yesterday so I need to work out what the hell's going on there (again) before doing anything else... I really hope it's not yet another Dynatek module. What are the chances of that? I mean sheesh... but it could be coil or I could have pinched a wire putting the tank back on or anything...

Once I get that sorted I will probably look at picking up some GS500 cam's, I'm all for a little more pep up top without a large expenditure

[pete]

One thing I neglected to ask...

I notice eBay ad's have the 500 cam's as '88 to '03 or thereabouts and other ad's have '04 to '09 or so... any idea if there's a key difference here that I need to worry about?

If the only difference is for example the tacho drive then I don't care as I don't use it...

[Big Rich]

Hmmm.... I know the tach drive is different for the late model electronic tachometer. I think that's the big difference. There is a problem with camshaft float with the early GS500's, but I don't know if Suzuki changed anything, or it was just a bad production run...... Ben2Go would have a better idea about the cam float than me though.

[pete]

Hmmm ok, will see what Ben has to say if he jumps in here otherwise I'll PM him... one thing my 450 doesn't have is camshaft float although I know they were susceptible for it as well, just not as bad.

Was in the garage yesterday and completely forgot to check the factory manual to see if it had duration in it

[Big Rich]

And it's done!



Here's the jetting info for anybody that may be searching for it......
First generation GS500 carbs on a GS450:
K&N lunchbox filter (part # RU-2970)
Pilot jets: stock 37.5
Mixture screws: 4 turns out
Jet needle: raised by .040" with washers (2 washers per needle)
Main jets: 132.5
MAC 2-1 exhaust with a 3" Supertrapp universal muffler (with 9 discs installed)

I would like to get some #40 pilot jets, possibly some 135 mains, and a different muffler. But for now, it's just time to ride the tires off......

[tkent02]

Excellent! Now ride it!