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'80 GS1100E rebuild

  • Thread starter Thread starter cavehamster
  • Start date Start date
In this blurry photo, I show off the jig I made up to hold the counter sprocket so I can put a 3 or 4mm dish into the face of it.

IMG_4923.jpg


I had to go figure out how a chain sprocket was made so I could model it so I got the jig right, learning something new every day.

I verified the wheel alignment front and back tonight, and as near as I can tell, it's within 2mm of being centered, so I'm pretty happy. I'm using the stock GS sprocket hub and a 170 tire, and it would appear that I have about 4-5mm of space from both the tire and the frame. To goto a 180, I'd probably need to consider an actual offset counter sprocket and a little frame modification. In the meantime, with the small dish in the counter sprocket, I can move it over enough on the shaft that I don't need to go with a offset sprocket.

I'm going to stick with this rear setup for the time being and concentrate on getting the front together.

Oh, also got the rear brake pretty well bled. Need to go with some new brake lines; it feels a tad spongy, but I can lock the tire up pretty easy, so..

And so it goes on and on... ;)
 
In this blurry photo, I show off the jig I made up to hold the counter sprocket so I can put a 3 or 4mm dish into the face of it.

IMG_4923.jpg


I had to go figure out how a chain sprocket was made so I could model it so I got the jig right, learning something new every day.

I verified the wheel alignment front and back tonight, and as near as I can tell, it's within 2mm of being centered, so I'm pretty happy. I'm using the stock GS sprocket hub and a 170 tire, and it would appear that I have about 4-5mm of space from both the tire and the frame. To goto a 180, I'd probably need to consider an actual offset counter sprocket and a little frame modification. In the meantime, with the small dish in the counter sprocket, I can move it over enough on the shaft that I don't need to go with a offset sprocket.

I'm going to stick with this rear setup for the time being and concentrate on getting the front together.

Oh, also got the rear brake pretty well bled. Need to go with some new brake lines; it feels a tad spongy, but I can lock the tire up pretty easy, so..

And so it goes on and on... ;)
If you do go to the 180, or even stick with the 170 and plan on running at the strip alot, you may want to also consider either making (or purchasing for 170 or so bucks) an outboard CS bearing support. With an offset sprocket, you'll be putting alot of excess stress on the very end of the CS shaft, and when doing holeshots that could lead to premature failure of the CS bearing...would require splitting the cases to replace im pretty sure as I dont see another way of getting it in and out...
 
If you do go to the 180, or even stick with the 170 and plan on running at the strip alot, you may want to also consider either making (or purchasing for 170 or so bucks) an outboard CS bearing support. With an offset sprocket, you'll be putting alot of excess stress on the very end of the CS shaft, and when doing holeshots that could lead to premature failure of the CS bearing...would require splitting the cases to replace im pretty sure as I dont see another way of getting it in and out...

Very true, and I've thought of doing this eventually.

I'll post some photos tomorrow, but I finished up the rear end swap. I ended up taking about 3mm off the face of the 530 counter sprocket and spaced it over on the output shaft just enough so I can still get that lock washer on and biting the splines. The chain has plenty of clearance to the tire and frame, but I still haven't measured it.

I spent a couple of hours messing up and then re-doing a simple chain guard. Not hugely happy with it, but it'll work until I can make up something better, and the local drag strip won't let you in the street legals without one.

I took it out on the interstate. Despite the 30 degree wind, it sure ran out well. Handling feels sure, motor runs smooth. The suspension is kind of rough right now, as I have the preload and damping turned up a bit so I don't lose so much to it at the drag strip.

So, feeling pretty good about things right now! ;)
 
The first photo here is a shot of the pocket I milled as it came out of the machine. I know the spine area looks thin, but that's because the jig has a boss to hold the center of the sprocket, there is more than half of the normal material still there on the actual sprocket.

IMG_4940.jpg


The second one is as it is installed on the bike:

IMG_4949.jpg


My photos of the chain and etc were not coming out last night (silly no light ;) ) but I will post some once I get around to taking some more. I'm going out to the street legal drags tonight, we'll see how it does.
 
Everything went fine, other than me having hell staging. Twice I rolled up, staged the first light, inched forward to stage the next, lit it, pulled back the throttle to be ready to go, and the red light lit without the tree dropping and the other guy went. I'm still not sure what was happening, maybe I rolled past the first stage and the system kicked me out? Ugh.

Regardless, 12.47 was my best time. Not quite the 11.60 I've seen before, but the altitude and humidity and my failure to stage certainly were contributing factors ;)

The chain and etc worked out fine. However, I have an oil leak I need to address. I was hoping the valve cover gasket would seal better, but with the increased oil pressure, it is not happy. In addition, there are a few other places that are seeping a little, ie, the cam chain tensioner, and the oil pressure sensor. So more things to work out.

I think I may put slightly richer jets in for the time being, as the AFR data i collected a while back looked leaner than I wanted it to be. I need some better datalogging though to figure out what is going on. Test and tune at the local strip Wednesday night, perhaps I can throw something together.
 
Cave,
This is a general discussion about front sprockets and not meant to suggest your doing anything wrong.

Next time you have your front sprocket off measure the depth of the spline engagement. I measured a stock 14 tooth 630 Sunstar sprocket and the amount of engagemet was about .65". I measured a 17 tooth PBI 3/8" offset sprocket and it has about .35" to .37" engagement depth. I measured a Kosman 5/8" offset and it has about .55" engagement.

I realize we can compensate by adding and subtracting washers so the nut is tight but I'm starting to worry that less than .5 puts too much stress on the output shaft splines. It would seem the more the better so long as actual sprocket gear is where you want it. There is about 3/4" to 1" inch of exposed output shaft spline to engage with.

I welcome discussion, no worries.

I'm sure you are right about the limited amount of engagement not being a good thing. However, I felt that as long as my sprocket engagement width was the same or better than a 520 sprocket, things should be mostly alright.

My (perhaps poor) reasoning behind this is due to a) I have put about 50 launches at the drag strip on a 520 front sprocket (I didn't have the right tooth count 530 handy at the time), and b) my V-Strom, a 95ish hp large motorcycle, uses a 520 chain and etc and seems to do just fine with it, so, these things combined, I made the assumption that I could get away with it on my GS, at least until I crank up the HP past 110 or so.

So far, there has been no noticeable change to the splines, ie, they have not been twisted at the point of engagement, and sprockets slide up and down them without catching. However, I'm not a huge fan of doing it this way for long ;)

At this point, I will probably go with a standard offset sprocket in the next couple of months once I get the front end swapped out and have time to concentrate on the engine.

I've spent the last week or so concentrating on getting a better handle on datalogging my track performance so I can identify what needs to be fixed up. I already have an Innovate wideband installed on the bike, but the LC-1 does not get RPM data, and I have found the graph to almost be useless without that. Being a tinkering sort of fellow, I have reverse engineered their serial protocol using the little bit of documentation they provide plus a lot of serial port captures and have emulated their SSI-4 box on a microcontroller. I've also got an embedded computer in a small enclosure that will get strapped to the seat and collect data that I can view later. I'll post pictures and further information about this stuff as I get it cleaned up and off the protoboard ;) I also dug up a accelerometer chip in my parts bin that I have working, which might give me some interesting data.
 
So, it turns out I was wrong, my dished sprocket does not have the same bite as a 520 on the shaft, it's the same as a 525, as I forgot my 'template' sprocket was a 525, hah.

Headed off to the strip tonight. I built a small board that hooks to the low voltage side of the coil and uses a low pass filter and optocouple to give me a tach input, built a clone of Innovate's SSI-4 module to get RPM data, and wired it in with the LC-1 for AFR data. I hooked up an old single board computer I had on hand into a small box to interface with this stuff (with an isolated battery to keep it going), and I'm going to strap it to the seat and datalog my launches.

Put one step richer jets in the carbs, as the prelim AFR data I had looked a little leaner than I wanted, but I should get the real story tonight. I'll post pictures/schematics later as I get a chance.

EFI is still coming, though right now I am aiming for it to be a late season/winter project. I'm currently concentrating on getting stuff together to get the front end swapped to go with the updated rear suspension, and getting the seat redone before the next person asks, 'hey, you gonna fix that?' It's become so bad that a friend of mine made a huge stink about it and 'fixed' it trackside with a roll of black duct tape one day, haha.
 
Well, this season of drag racing is over, so I'll have some time to make some further progress on the bike update. I ended up the season running an 11.93 at the local track, and a 11.41 at a track further away that I frequent. Not too bad for 4500 foot altitude on a pretty much stock machine.

Here's a summary of videos from last Sunday, in HD no less.

http://www.youtube.com/watch?v=t1dyztDSGfs&hd=1

I've got mostly everything together for the fuel injection, I just need to get a fuel pump going. I think I am gonna go with a surge tank so I can use a much cheaper fuel pump.
 
very interesting camera POV, it really demonstrates the ****ty track quality you were running on!
 
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