'80 GS1100E rebuild

[posplayr]

Do you have a 5/8 inch offset sprocket? If not, that is why you are thinking it won't line up. Ray.

I mentioned that earlier but he wants to try with the stock countersproket. :-s

 

[cavehamster]

I mentioned that earlier but he wants to try with the stock countersproket. :-s

I'm sorry, I didn't mean to imply this. I know I will have to offset, I knew this going in, but what I meant in that previous post is that I would like to think about a way to use a stock sprocket with something that will offset it, so that when the sprocket eventually dies, I can just buy a new sprocket and not a whole new offset unit for $$$.

I'm probably not going to be able to manage this, but hey, it's worth thinking about.

I'm listening closely to what you guys have to say here, I would never have made it this far without having your excellent posts to go off of. It's a fun engineering challenge, and I appreciate folks who view it in the same way.

Regardless, as I mentioned just prior to this post, looking at the wheel I chose, I'm not convinced I can make it work. I'll post a pic in the morning and hopefully you'll see what I mean. As I said, to get the wheel close to bike centerline, the chain would have to go through the frame, at least eyeballing it. I'll steal a couple of HeNe lasers from work to verify, but I don't think it will happen with what I have

 

[posplayr]

I'm sorry, I didn't mean to imply this. I know I will have to offset, I knew this going in, but what I meant in that previous post is that I would like to think about a way to use a stock sprocket with something that will offset it, so that when the sprocket eventually dies, I can just buy a new sprocket and not a whole new offset unit for $$$.

I'm probably not going to be able to manage this, but hey, it's worth thinking about.

I'm listening closely to what you guys have to say here, I would never have made it this far without having your excellent posts to go off of. It's a fun engineering challenge, and I appreciate folks who view it in the same way.

Regardless, as I mentioned just prior to this post, looking at the wheel I chose, I'm not convinced I can make it work. I'll post a pic in the morning and hopefully you'll see what I mean. As I said, to get the wheel close to bike centerline, the chain would have to go through the frame, at least eyeballing it. I'll steal a couple of HeNe lasers from work to verify, but I don't think it will happen with what I have

Unless you have someone else do the conversion for you, you really need to understand all the ins and outs of the alignment issues involved. No body ever figures out the fastest and best solution to a problem the first time through. The important thing is to be able to keep learning and checking your own work till you get it right.

I have seen plenty of examples (much more the norm than the exception) that there is a personal attachment to a particular solution because of the effort someone expended on getting to that point even if it is really "sub-optimal" if not outright wrong. The ability and personal discipline to move beyond those situations is the most important.

I think there are many examples of putting a 180/55-17 with 17x5.5 wheel on the back of a GS even with the stock swing arm. It is tight but is has been done plenty of times and in different ways. Mine is a 170/60-18 even though it is on a 18x4.5 wheel and it fits with plenty of room.

 

[cavehamster]

Unless you have someone else do the conversion for you, you really need to understand all the ins and outs of the alignment issues involved. No body ever figures out the fastest and best solution to a problem the first time through. The important thing is to be able to keep learning and checking your own work till you get it right.

I have seen plenty of examples (much more the norm than the exception) that there is a personal attachment to a particular solution because of the effort someone expended on getting to that point even if it is really "sub-optimal" if not outright wrong. The ability and personal discipline to move beyond those situations is the most important.

I think there are many examples of putting a 180/55-17 with 17x5.5 wheel on the back of a GS even with the stock swing arm. It is tight but is has been done plenty of times and in different ways. Mine is a 170/60-18 even though it is on a 18x4.5 wheel and it fits with plenty of room.

I appreciate that, and I am trying my best to build off your work and others to come up with something that works for me. I experiment here and there, but I'm not married to any solution until it works.

That said, take a look at these photos. I lucked out and found the cable for my camera in the basement.




As near as I can tell, the order of operations to getting this thing lined up is:

1) Align swingarm with offset to clear the rear brake plunger (check)
2) Align the wheel to the centerline of the bike (in process)
3) Align the sprocket to sprocket, using offsets on the engine side (to do)

If any of the latter is too far off, wiggle the others until you get it, but the key key key is that the rear wheel is on the centerline of the front, and that the chain clears the tire, frame, and shock spring.

Note that I have re-installed the engine so I can look at the front sprocket, as suggested.

With that said, visually, I cannot line this wheel up so that it both sits on the bike centerline and the chain will clear the frame. You can see from the top photo that it looks like the chain will work, but in the bottom photo, it is not centered on the bike. Again, I need to borrow some lasers and check this, but I don't think this wheel was a good swap.

From the wheel rim to the face of the hub, I measure 25mm. The Bandit wheel looks like the hub tucks in a lot further, am I wrong?

So, right now, just trying to work through getting the proper wheel and getting it aligned. Again, I am open to suggestions and advice, and I probably will experiment as the mood strikes me

Thanks!

 

[posplayr]

1) Align swingarm with offset to clear the rear brake plunger (check)
2) Align the wheel to the centerline of the bike (in process)
3) Align the sprocket to sprocket, using offsets on the engine side (to do)

I think you are on the right track. I would say though that you need figure out what type of tolerance you are trying to achieve, because to a certain extent when you are fiddling to get something to work you are encroaching on those error tolerances.

I did my wheel alignments last weekend and spent some time going back through the old calculations.

On item #1 above the minimum offset required was 4.5mm so instead of 6mm/6mm top hat spacers I had 10.5/2 mm spacers. This pushes the left fork 4.5mm further to the left. And allows just enough room for teh plunger to fit between mt ED frame and teh Bandit swingarm.


On item #2 above, You should reverify this but I think the left swingarm fork is 3/16" (or there about) further to the left. In other words if you split the difference between your swingarm forks the wheel center will be 3/16" to the left (towards the sprocket side). As mentioned before Katman used a jig to measure that. I used a straight edge and a T square measuring left v.s. right side of the swing arm. He may have measured it as 5.2mm v.s. my 4.8mm. remember offset needs to be measured along an axis that is parallel to the swing arm bolt.

Using his numbers you need the center of your wheel at 9.7mm to the sprocket side of the center of the swingarm forks. Of course the tolerance could be 9.7 +/- 2.0mm and not notice any real issue. In a pinch you could go as far as 9.7 +/- 4.0mm.

To achieve this you will need a left and right hand spacer along with using the stock brake arm and spacer.

As it turned out I accepted a 2.3mm offset and went to a 1.004" spacer and did not need a brake side spacer for the 88 GSXR 1100 3 spoke 8x4.5" wheels. The numbers would be different for a 17x5.5" wheel.

Finally for Item #3 above, the counter sprocket alignment probably needs to be within about +/- 0.125 (1/8") and probably no more than 1/2 a sprocket tooth width to insure you have no way of hopping a sprocket.

With my 170/60-18 I'm using a 3/8" offset sprocket and I'm still 5mm from the frame with a 530 chain. Most 180 rear tires require 5/8" offset which would put a 530 chain basically into the frame (5mm of room and 1/4" extra offset). So to avoid grinding down your frame, a 520 chain is recommended. The 630 has almost no way of fitting it is too wide. Kataman has posted different measurements of 530 chain thickness. Heavier tensile strength chains are beefier and almost no size benefit. You need a tin 530 or 520 chain.

With the above you will need to do something like the string alignment to get the front and rear wheels in alignment.

Hope that helps; anybody got any issues with the above

 

[rapidray]

Cave, call me at 714-356-7845 & I will go over some things with you & tell you where to go to look at something. Ray.

 

[GregT]

With a 520 chain you can machine a little off the sprocket carrier to pull the chain line in as close as possible to the tyre.
This gives you a little more room to work at the motor end.
With the wheel on center - and actually in alignment - I like to see the sprocket edges lined up with a straightedge. Tolerance here would be max of .015 in IMO - unless you can float the chain by narrowing the front sprocket.

Greg T

 

[Guest]

I have always had to cut and plate the inside of the frame to get a 5/8 offset sprocket chainline to clear without hitting.I usually cut almost half the tube away and gusset like crazy (dragbike with suspension)

 

[posplayr]

OK Looks like we brought out the experts on this one.


GregT

Tolerance here would be max of .015 in IMO - unless you can float the chain by narrowing the front sprocket.

Wow that is pretty tight tolerance +/- 0.015". Is that for racing or just a street cruiser? I asked around at work what would be a good number. The best answer I could get was to have as much overlap between sprockets as practical to make skipping chains difficult.

IIRC, Katman says he has seen 0.100" out chains running with no problem on the street. Hopefully he will chime in and correct my memory .

NoBars,

I have always had to cut and plate the inside of the frame to get a 5/8 offset sprocket chainline to clear without hitting.I usually cut almost half the tube away and gusset like crazy (dragbike with suspension)

What chain we talking about? What rear tire/wheel size? I know Ray talks about a fair amount of frame cutting as well.

Anybody else got comments on tolerance (qualify for street or drag or other) for either:

1.) Rear wheel off center of frame tolerance
2.) Sprocket to Counter Sprocket out of alignment or out of plane (chain alignment)
3.) Rear to front wheel alignment

Tone already weighed in on the #3 item.

http://www.thegsresources.com/_forum/showthread.php?t=147705

When checking the wheel alignment do not use the ajusters at all ! leave them completely slack & push the wheel all the way forward within the slots & nip it up, the reason for this is that the marks on the ajusters are notoriously poor & the wheel will not be straight if you use them & the front edge of the ajuster slots is usually a fairly accurate place to start your measurements from while with the rear it is not always the case

summary .... 4mm of misalignment is just about acceptable but personally i wouldnt be happy with that
1mm or less is the ideal but not always acheivable
2mm to 2.5mm is the most misalignment you should be aiming for in my opinion & if that is not acheivable you did something wrong somewhere along the line

I find he also discussed the chain tolerance as well.

As posplar says a small misalignment can be tuned out by ajusting the wheel slightly more on one side than the other, the chain will allow you to do this by around 1mm without adverse effects on chain or sprocket life, although it is always better to avoid this if possible

Until Katman shows up, looks like we have for chain alignment tolerance:

• GregT (Objective tolerance) +/- 0.015"
• Tone (Threshold tolerance) +/- 0.040"
• Posplay Guess (Sloppy seconds) +/- 0.100"

 

[cavehamster]

Evening gents,

More updates. I borrowed a couple of 10mW HeNe lasers from work. These guys are lab grade lasers that have very good coherence out to many meters. Complicated choice? Maybe so, but I didn't have any good straight edges to use.

I placed the two lasers in front of the bike, and aligned the front forks to be perpendicular to the frame for an initial position. The tire measured out to be 10cm wide, so through out the procedure, I kept the lasers coaxial down this 10cm separation, give or take a mm. My spot size went from about a mm to about 2 or 3mm at the back of the bike, so obviously this is not absolutely precise.

Setup:



I made an assumption in all of this, namely, that the frame is coaxial along the length of the bike, that the centerstand is centered, both in construction and placement on frame. I measured these assumptions as best I could and it looked right.

To align the lasers, I made up a sheet of paper that I stuck just behind the centerstand that marked out 50mm on each side of the center point, and then made sure the lasers were 10cm apart out of the emission aperture, just barely striking the front tire, and 10cm apart at the center stand. This gives me about a meter of distance over which I have control of how coaxial my beams are. I adjusted the front wheel slightly so it was not interfering with the beam, and the beam was striking the tire in two places on each side.



Looking good so far. I installed the wheel I bought on the axle, shoved it far forward and made sure the face of the wheel was parallel to the swing arm. I then moved the wheel so the laser dots were equidistant on the surface of the wheel (which worked out pretty easy, the dish in the middle is about 10cm wide):



So, now we had the wheel straight behind the front wheel, with some margin of error of course, but I felt good about it. Visually, it looked good.

Next post has the results for the hub and etc.

 

[cavehamster]

Now, note that the swing arm itself has been offset with my machined top hats. It is set over 3mm on the left side, and 11mm on the right. The fit between the frame mounts is absolutely dead on, with no play. The swing arm itself has about a mm of play side to side.

From plate to plate on the axle way on the swing arm, I measure about 250mm. Now with my lasers, I see that I am hitting the axle (as viewed from the rear of the bike) 82mm to the left, and 68 to the right, which is 14mm difference. If the swing arm was centered in the frame, I would have an offset of 7mm on a side, so I show that the swing arm itself is offset to the left side about 7mm. That's fairly close to the 4mm everyone else is measuring, so I am pretty happy with my results so far.



Now, how about that hub?

Using a generic construction laser that has an optic in it to give me a flat line perpendicular to the floor, I lined up the little guy with the hub surface of the wheel, with the wheel centered, and shot it in towards the engine sprocket. Looks like it could work, without the hub installed in the wheel at least...



However, in order to maintain this spacing, the hub would have to look like this:




Eeep. Not sure I want to try to make that fly.

At this point, I plan on getting the rear brake caliper and arm off ebay next week, as well as a Bandit style wheel with the hub that sticks out. I figure at least that way, I can machine a bit off the face of the hub if I need the room. With what I have got, well... that's what I have got. Nothing can be machined as it sticks right in there. On the current wheel, the actual hub stick-out of the wheel itself is 28mm. Does anyone have a measurement of what the stick out to the hub face is on a Bandit-style wheel?

Hope this info is useful to someone, and as always, I appreciate your feedback/flames!

 

[posplayr]

Having tried to do something similar and also finally doing a string based wheel alignment last week, I think the laser method is really an inferior method as the beam divergence is significantly less accurate than a simple thin piece of thread of string. I'm very confident that I aligned my front to rear wheel to within about 0.5 mm given whatever was introduced with the rear tire run out which is really a fundamental limitation in what accuracy is required.

I generally follow the measurements you are making, but I am left to guess as to what distances you are really trying to measure. If you are trying to determine where in the swing arm the center of the rear wheel should be, then I think that you have corrupted that measurement by all of the uncertainties making measurements from the front wheel not to mention the increased uncertainty of the lasers at that distance.

I think based on the measurements Rob and I did previously the Bandit swing arm is offset is closer to 5 +/- 0.3mm if you add your 3.5mm pivot offset, then you should be at 8.5 mm which is a full 1.5mm off from your approximate 7.0 mm measurement.

After going through this previously I became convinced that the most straight forward way to determine the wheel center in the swing arm and then the spacers was to measure swing arm offset directly relative to it's pivots instead of introducing all of the other errors you have introduced measuring from the front wheel.

Of course you need to do a final front to back alignment but that doesn't help determine the wheel location along the rear axle. You are operating at an accuracy disadvantage when you try and measure the length of the bike to determine a lateral offset. These measurement uncertainties can cause you to go around in circles.

IMO, the rear wheel offset should be measured using the swingarm alone and where you intend to mount it in the frame. The chain can then be aligned roughly with an offset sprocket and fine tuned with milling the counter sprocket. A straight edge either against the rear sprocket or against the rear tire seems to work well.

Final front to rear wheel alignment is easily done to within 1mm using the string technique.

 

[cavehamster]

I generally follow the measurements you are making, but I am left to guess as to what distances you are really trying to measure. If you are trying to determine where in the swing arm the center of the rear wheel should be, then I think that you have corrupted that measurement by all of the uncertainties making measurements from the front wheel not to mention the increased uncertainty of the lasers at that distance.

I'm trying first to determine the offset of the swingarm for myself, as a sanity check. I already know what you guys are measuring, so if I am in the ball park, then I know I am going in the right direction. Once I am confident of where the swing arm is in space vs the front end, then I can dispense with measuring off the front each time and just measure off the swing arm. Regardless, these are not laser pointers I am using here, the beam width at the back of the bike is hardly more than 2mm, and I can live with that.

I think based on the measurements Rob and I did previously the Bandit swing arm is offset is closer to 5 +/- 0.3mm if you add your 3.5mm pivot offset, then you should be at 8.5 mm which is a full 1.5mm off from your approximate 7.0 mm measurement.

1.5mm is pretty good. Seeing as stock bikes can measure up to 4mm off (as read in other posts about this topic), I'm pretty happy with that. Plus, I lack string right now, but no lack of lasers.

After going through this previously I became convinced that the most straight forward way to determine the wheel center in the swing arm and then the spacers was to measure swing arm offset directly relative to it's pivots instead of introducing all of the other errors you have introduced measuring from the front wheel.

But this is what I did, don't you see? I sanity checked where my swing arm is in space, compared to what other people were getting and was looking pretty good, I thought. 1.5mm is not bad, overall. From here on out, I don't need to complete the exercise, I can just go off the swing arm. Hey, I'm not second guessing your methods, I just need to be able to work out for myself what it is everyone is saying so I understand what I am doing, yeah?


So, moving on, does anyone have a measurement of how far the hub on a Bandit wheel sticks out past the rim?

 

[cavehamster]

Turns out I'm still alive here

Getting the tank ready for some new paint:

I'll be painting this an 'electric blue metallic', maybe it will look good, maybe not; it's mostly an experiment and so I can seal this tank to use on the bike soon.

Going to pickup a chain and sprockets today to move forward on the rear end swap. Temporarily I am going to use the stock swing arm while I am getting the tabs done on the new one so I can hit the drags this weekend at least before they close for the season. I'm using a 170 tire right now, but the clearance on it is great, estimating about 35mm of room for the chain between the tire and frame, so I might just stay with a 170.

Also have new clutch parts on order, with any luck I shall see them today or tomorrow. Just hoping the weather holds out at the drag strip for Sunday, wheee!

 

[cavehamster]

Got the bike back together for the time being, still waiting on a paycheck or so to get the tabs welded onto the swing arm to get the Bandit swinger in there. The Bandit wheel looks like it will work awesome.

The rear on my V-Strom is cooked, and it's a 150, so I shoe horned it onto the stock rim for the time being, so I can at least hit the last drag race or two of the season.

The tank is painted up and at least it looks like a million bucks, haha. I still have a decent amount of work to do on this guy, but it's running great. I have a new chain and sprockets on it right now, a 530, and I put in some Barrnet heavy duty clutch springs, 3 instead of 6. We'll see how that does at the track tomorrow. Last time I was getting mid 12's, but the back tire was so old that I was spinning the rear end all the way through the 60 foot traps no matter how low tire pressure I ran or how hard I burned out. I'm hoping the newer rubber on the 150 will help with that, plus I'm bringing some VHT. Gotta lot po-dunk tracks that don't bother with the stuff

So, here's where we started:

And here's where I am right now:

It's an improvement, more or less

 

[cavehamster]

Broke into the 11's today, best time was a 11.81. Going to mess with the sprockets and a few other things for next weekend, which is probably going to be the last drags of the season, then I can get serious about EFI and getting a new front end together.

 

[cavehamster]

Last drag of the season, managed a 11.71.

Video of the run is here

Now it's time to get busy taking it apart. Going to pull the engine and get the crank welded before something bad happens, probably replace the rings and valve guide seals as it is blowing a tad much smoke right now.

The tank and the tail have been painted, just need to dig up a new left side cover and get the covers sanded and painted up.

The rear suspension just needs the tabs welded on and it will be done. I'm on the lookout for a front end too.

The final thing is going for MegaSquirt for FI this winter, hopefully the budget can allow for everything

 

[67fire]

Nice! I couldn't get the video from breaking up though.

Eric

 

[jwhelan65]

I saw that pic. I decided I wanted to replace the top hats with new ones rather than put bushings in the old ones. We'll see if that is the right approach or not, I'm not sure of the loading these guys see, but I think the 6061 aluminum will be alright for it.

3mm on one side and 11 on the other was a tight fit. There is no slop at all, what with the spacer tube in the middle of the swing arm and all. I'm going with a 17 inch, 5.5 rear, so hopefully I can make it work, otherwise, I'll be headed to a 4.5. I guess I mostly just have it in my head that I want a 180 back there

You went with a 520 chain, correct? I've been reading your threads with great interest, seeing what I can apply.

Also, did you hack up and use the swingarm chain guard the Bandit uses? I think I can make that thing go in there with some healthy cutting, hehe.

Thanks for the info!

Here is what I did on my chainguard, after I boogered up to two Bandit guards ...

 

[cavehamster]

Here is what I did on my chainguard, after I boogered up to two Bandit guards ...

Nice and simple, I like it.