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Old 07-31-2010, 12:09 PM   #46
nella OP
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Quote:
Originally Posted by Rapid Dog
Those look great! Report on how they line up...and post the dimensions for the blocks.

Finally got some time today to get everything together on the front end. Dan at cycleworks expedited me one of his bearing pullers so I mounted some new steering bearings from Alls Balls size 30x52x16 last night and this allowed me to use the GSXR stem.

The rotors line up fine. The spacers are .75" thick and have the stock bolt pattern. The ID and OD are the same as the ATE disc brake washer part BMW number 34111232417. I'm using rotors off a Suzuki GSF 1200 Bandit which have an offset of 19.5mm. They are 310mm discs. I would have liked to use the stock '07 up GSXR discs but it created a set of engineering problems I didn't want to address at this point in time because of the rotor bolt circle diamter.

I had to machine some new bushings for the axle to get the bearing preload right and center the wheel.

Last night I wired up the new left and right controls. Due to the way the Suzuki starter switch is designed I elected to use the "MODE" switch on the right grip for starting. I figure it's going from a non-running mode to a running mode when the switch is depressed, so why not.

I'm very happy with how the throttle works with the single to double pull setup. I've got to make a spacer for the clutch adjustment to work better.

It rides and brakes like a different bike now. I took it for a spin through the countryside today and I'm very happy with it. The steering is much quicker than stock but the bike was stable with no wobble or shaking at all the speeds I was brave enough to try. I have a steering damper but I am not sure if I will install it. Here's a couple of camera phone pics.









Edit: I worked up a new spacer for the clutch adjustment with a slip fit over the OD of the Suzuki adjuster, it's much sturdier and gives the needed adjustment range.

From this:



to this:

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nella screwed with this post 08-01-2010 at 04:51 AM
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Old 07-31-2010, 01:11 PM   #47
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Hmmm...

Now you have me thinking about that modified frame I have hanging in the shop and maybe starting a new project! Lets see... I have the frame, a big tube swing arm, some wheels, transmissions, a tank.... Yep! All I need is a doner bike with a running engine and I'm fat! Next I'll have to drop in on a couple of my sport-bike friends and have a chat.

What year GSXR forks did you source for your project and more importantly, are you having any steering lock issues? I know that with the K-bike conversions, steering lock is compromised substantially.

Lastly, did you measure the difference in the front end drop after swapping the front end? I'd like to compare it to what I have now.

It'll be interesting to see your project develope but I'll bet you never thought that you'd end up with so many questions, huh?

Later,
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Old 07-31-2010, 03:01 PM   #48
nella OP
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Quote:
Originally Posted by mymindsok
Hmmm...

What year GSXR forks did you source for your project and more importantly, are you having any steering lock issues? I know that with the K-bike conversions, steering lock is compromised substantially.

Lastly, did you measure the difference in the front end drop after swapping the front end? I'd like to compare it to what I have now.
The forks came off an 09 GSXR600/750. I found that the '06 and up 600/750s have some of the longest forks and highest spring rates of any GSXRs in the last decade.

Steering lock is not an issue... I'm actually going to have to weld new stops on the bottom triple clamp.

I did not measure ride height before and after. I could take any measurements as it sits now if you want me to.

Best regards,

Scott
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Old 08-24-2010, 06:55 PM   #49
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I renewed the rod and throw out bearing assembly after my throwout bearing failed on a ride:




Tonight I installed these shocks:


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Old 08-25-2010, 06:08 PM   #50
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So I have changed the look of the bike once again. I installed Woodcraft clipons to raise the bars some and have a new tank and seat. From this point on it's just a matter of detail work, including the front fender which I have been working on brackets for.

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Old 08-25-2010, 06:20 PM   #51
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Quote:
Originally Posted by nella
So I have changed the look of the bike once again. I installed Woodcraft clipons to raise the bars some and have a new tank and seat. From this point on it's just a matter of detail work, including the front fender which I have been working on brackets for.

That's purdy!!
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Old 08-25-2010, 06:30 PM   #52
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very cool. i dig the gixxer front end w/the lester.
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Old 08-25-2010, 06:43 PM   #53
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Nella - I see you bought Paul's tank and seat as well ;)

-Craig
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Old 08-25-2010, 06:53 PM   #54
nella OP
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Quote:
Originally Posted by CraigC
Nella - I see you bought Paul's tank and seat as well ;)

-Craig
And Mikunis which I'll try to get on the bike in the next few days. I'm his favorite customer!

Scott
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Old 08-26-2010, 05:46 PM   #55
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So today I installed Mikuni flatslides. They came attached to some 77 R100RS throttle cables so I adapted them to the GSXR twist grip by machining a new ferrule to go into the twist grip to hold then end of the cable securely. The pull is actually less than the Bings so I'll likely go without the crampbuster I had been using.

After adjusting the idle and syncing them I went for a ride. I'm happy with the performance at all throttle positions and constant speeds except at idle, which is a little rougher than I want it to be.



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Old 08-26-2010, 06:03 PM   #56
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Quote:
Originally Posted by nella
except at idle, which is a little rougher than I want it to be.
Could that be due to an unplugged vacuum nipple seen in the photo above? Or is that not a vacuum nipple?
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Old 08-26-2010, 06:17 PM   #57
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That's not a vacuum nipple, just a vent that as far as my research has gone, is to remain open.

Scott

edit: looking into it more I think that the pilot circuit is a little rich. Hopefully I can work on this a bit over the weekend. There's a Sudco Mikuni manual that i need to get, I've found parts of it on the web and it's helpful. These carbs were originally tuned for a R100RS big valve heads with 40mm exhaust, so I should expect it to be rich. What was surprising was how well the bike ran everywhere except at idle.
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nella screwed with this post 08-26-2010 at 06:29 PM
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Old 08-27-2010, 02:16 PM   #58
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GSXR fork conversion details

A couple of people have asked me to outline the GSXR fork conversion, so here it is, in a nutshell:

The big issues in the conversion are: a new axle, spacers are needed to attach the brake discs, and new bearings to allow the GSXR triple clamp to work on the BMW. I used parts off a 2009 GSXR 600/750 for the conversion, but many different years should work about the same.

The axle:

Making the wheel work on the forks was a matter of designing a new 17mm axle that was long enough and the correct size at the ends to work in the GSXR fork lowers. I had a machine shop make it up for me because the bed on my lathe is not long enough. Next time I take the front wheel off I'll snap some pictures of the axle.

I made two axle bushings on my lathe to get the right preload once the GSXR axle lowers are clamped down.

The disc spacers:

I had spacers machined to be able to use Suzuki GSF1200 Bandit rotors on the Lester front wheel and for the discs to line up with the calipers on the GSXR forks. These spacers are .75" wide each and the same inside and outside diameter and bolt pattern as the washer you find on ATE discs, BMW part number number 34111232417. If you just take that washer to a machinist and tell them how thick a spacer you want and tell them you want the same bolt circle as that washer and ID and OD, it's a trivial thing for them to make up for you. I actually should have made these closer to .85" each but they work fine as is. They are bolted to the wheel along with the rotors using 120mm length 8mm cap bolts that I sourced from McMaster-Carr.



Notice I did not use the GSXR rotors. They have a very large bolt pattern and that would require a more complex spacer arrangement to work on the Lester front wheel.

These are the 1200 Bandit rotors:



The stem and triple clamp:

I was able to use the GSXR stem and triple clamps and found bearings in stock at a Suzuki dealership that would work. You need 2 30x52x16 tapered roller bearings to make this stem work in your BMW steering head. The GSXR stem is longer than your BMW stem, so you need a spacer to go between the bottom triple clamp and bottom bearing... I used one of the stock GSXR bearing races and machined it down on the lathe and then had it pressed onto the stem along with the new lower bearing.

Misc. issues:

Wiring: Wiring the controls was simply a matter of finding a GSXR wiring diagram on the net and soldering wires together. I made a chart to diagnose electrical problems later on and for the next owner if I sell it.

Brake lines: The stock GSXR brake line that goes over the tire and between the calipers will not work and you have to source a longer one. It won't work because the diameter of the BMW front is larger than the GSXR front wheel.

Choice of forks: Be careful which GSXR forks you chose if you go that route. Different years have different lengths and you want the longest ones you can find. Also, offsets differ through the years. I have a chart I found on the net that was helpful in figuring out which GSXR forks to use, PM me with your email address if you want a copy.

Misc adapters and ferrules: I also used my lathe to make various adapters to be able to use the GSXR controls with the stock throttle and clutch cables. I adapted a mid-80s single to double pull BMW R100RT throttle cable to work with the GSXR throttle twist grip (those are parts 10, 15, and 17 in the fiche image below).





That's it. Lots of hours, measuring and experimentation and machine shop costs plus the cost of the GSXR front end. Having your own lathe and ability to make small parts will save you lots of money and honestly I know of no off-the-shelf way to make the clutch and throttle work with the GSXR controls without making your own parts. If you want to keep your stock BMW controls you will run into the problem of what to do about the brake master cylinder.


Scott
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nella screwed with this post 08-28-2010 at 07:39 AM
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Old 08-28-2010, 05:33 AM   #59
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how about a couple more pictures including a full length side view of that bike?
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Old 08-28-2010, 02:56 PM   #60
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It looks like the choke lever isn't all the way down in the photo above. It also appears to be bent, which could account for not being all the way down. But it could also be just the magic of photography and everything's fine.
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