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Thread: R100GS frame modified

  1. #1
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    R100GS frame modified

    I'm working on a basket case over the winter. I really want to simplify this bike and turn it into a bare bones street bike. I saw a picture of a GS frame with 2 inches removed from the front down tubes. It didn't show the engine installed.
    I installed the complete motor today (minus starter motor and cover) just to get a feel for clearance. It seemed a bit tight getting it in. The question is, if I cut 1.5 inches out of the front tubes and pivot the frame forward above the swingarm pivot, by anybody's best guess, would the motor still fit?

  2. #2
    Douglas Williams
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    Mark a spot 1.5" down the front tube and pull a string back to the rear and see if everything will fit under the relocated top tube. If it does then I'd guess you could install the engine without the oil pan. Add it afterwards. I'd ask why, but then I'd have to face up to some my own mod attempts. Good luck.
    Doug
    Sent from a Galaxy, far, far away

  3. #3
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    Hi Doug

    Yes I was able to confirm, using a variation of your method, that it will fit. Thanx. My concern is removing and replacing engine intact. It was more of a bugger to get out than expected judging by the gaping hole left after removing trans, airbox and all that other stuff. Oil pan off would have made it so much easier. I was hesitant to remove the pan because I didn't want to risk damaging the fiddly bits underneath while wrestling the engine out. I'm going to look at making some sort of low profile protecting plate under the crank case to ease install.

    The other clearance issue would involve removing front cover with engine in place. I see people raising the engine mounts quite a bit, at least equal to shortening down tubes 1.5". Are they able to service the front in that configuration? I've googled all this, not so easy to find.

    I'm doing this as an alternative to raising the engine mounts. Then I can lower the front suspension slightly to level it out. Also 19" front wheel.

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    There is an egine raising kit for airheads

    I can't remember who makes it or where to buy it but I've seen a vendor in the MOA that had adapters to raise the motor. No welding just a bolt on item. I personally wouldn't cut the frame without a jig of some sort to make sure you got it back straight and welded nice and strong.

  5. #5
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    Yes I've seen that kit mentioned, and if memory serves, the jury is still out on the strength of it. I believe the threading into the aluminum is thin. And filter access would be a hurdle.

    I have a well established frame shop lined up for the work.

  6. #6
    Outlander Omega Man's Avatar
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    This sounds interesting, it would be great to have some pictures.
    OM
    "Well they say.. time loves a hero but only time will tell.. If he's real, he's a legend from heaven If he ain't he was sent here from hell" Lowell George
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  7. #7
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    I talked to a beemer guy in the pits at Barber Vintage Festival with a raised engine. He said the oil filter access was nearly impossible. He said something about making a section of the frame removable, but he did not like that becauswe ow weight and rigidity. He had a pretty machined front mount pump and spin on filter that fit in place of the alternator I think. For short races you can run total loss on the battery. So it appears the answer to your question is yes, it messes up the oil filter access.

    Rod

  8. #8
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    Quote Originally Posted by ragtoplvr View Post
    I talked to a beemer guy in the pits at Barber Vintage Festival with a raised engine. He said the oil filter access was nearly impossible. He said something about making a section of the frame removable, but he did not like that becauswe ow weight and rigidity. He had a pretty machined front mount pump and spin on filter that fit in place of the alternator I think. For short races you can run total loss on the battery. So it appears the answer to your question is yes, it messes up the oil filter access.

    Rod
    Any time the motor is raised the filter access is a problem. He may have had the spin on kit from Motoren-Isreal. I'm thinking of that as well to get rid of the oil cooler, not sure yet tho.

    I saw the chopped frame idea on Advrider. But not the finished bike. This is not my original idea but I really like it.

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    It would not be hard to make the stuff

    You were considering cutting your frame and re-welding it as part of a project. It really shouldn't be that difficult to make your own engine mount tabs (out of steel) to raise the motor and I have seen more than one type of remote oil filter mount and filter assembly. I've mostly seen them on airhead sidecar rigs and I know they are much more affordable than the Motoren-Isreal set up. If you have a good straight frame with a title I would think twice or even three times before I cut even a mounting tab for the battery box off. Keep the frame whole but go to town on the rear sub frame and other stuff that can be replace easy if and when you decide to change directions and goal.

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    Post

    Quote Originally Posted by 69ZEFF65 View Post
    You were considering cutting your frame and re-welding it as part of a project. It really shouldn't be that difficult to make your own engine mount tabs (out of steel) to raise the motor and I have seen more than one type of remote oil filter mount and filter assembly. I've mostly seen them on airhead sidecar rigs and I know they are much more affordable than the Motoren-Isreal set up. If you have a good straight frame with a title I would think twice or even three times before I cut even a mounting tab for the battery box off. Keep the frame whole but go to town on the rear sub frame and other stuff that can be replace easy if and when you decide to change directions and goal.
    Interesting. What would be a good reason to not cut it up? I have complete faith in the the shop I'm taking it to. 40 yrs. in business and they sent pictures of a much more radical airhead vintage racer frame. Either way, the bike won't see the road without bracing.

    Just to be clear, I have five bikes. All projects that I would lose my shirt on if trying to sell. I consider it a privilege to be in the position to do that. It wasn't always so. I will climb as high as I'm willing to fall. I can fall $5000. per bike.

  11. #11
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    I must admit I'm a purist at heart

    Its your bike and money so have at it, I was just offering the 2 cents you inquired about. Instead of making some sort of pivot point or removable section in the frame ask your welder if he could fabricate a section that gives clearance for the oil filter section and have that welded in. Maybe a small section flat steel as you may already have the frame cut for your modifications. I have seen one Airhead race bike photo in which the builder cut the frame in half (front and rear) and installed fastener plates so that the frame could be disassembled for quick and easy engine remove and install. it was a very slick and well thought out modification that the owner claimed worked very well for all types of track side repairs.

    What ever direction you take good luck, enjoy the ride and by all means post some photos.

  12. #12
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    I think I probably worded my question wrong. Rather than talk about shortening the down tubes I should have said raising the engine mounts to top of frame rails as seen many times. Six of one, half dozen of other.
    If anybody has raised mounts, are there any clearance issues with front cover access? Anything else? The filter we know about. thx.

  13. #13
    Douglas Williams
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    Quote Originally Posted by BERNII View Post
    I think I probably worded my question wrong. Rather than talk about shortening the down tubes I should have said raising the engine mounts to top of frame rails as seen many times. Six of one, half dozen of other.
    If anybody has raised mounts, are there any clearance issues with front cover access? Anything else? The filter we know about. thx.
    It would appear that raising the engine by shortening the down tubes would avoid oil filter clearance issues. It may present other issues that'll show up when you try to fit the engine and components into the modified frame.
    Sent from a Galaxy, far, far away

  14. #14
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    Frame mods finished

    I just received the frame. I think they did a good job. I can't post pictures but I could email them to somebody who can. I hope that doesn't break any kind of forum rule.

  15. #15
    Registered User lmo1131's Avatar
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    BERNII, if you can email a photo to a friend then you can easily post them here yourself.

    Just go the the "Manage Attachment" button located below the blue line under this text frame in the "Additional Options" area ...

    When the pop-up screen opens click on the "Add Files" button (1) in the upper right hand corner...

    the "Upload Files from your Computer" window (2) will open...

    click on the "Browse" button (3) ...

    How to post image.jpg

    the usual Windows "File Upload" window will open... the same window that opens when you want to send a photo using your email.

    Open the Folder that your picture is in ... select it, and click on "Open"

    File upload.jpg

    the "Upload Files from your Computer" window will re-open... at that point click on the "Upload" button (4) ...

    Give it a few seconds to transfer the data... it may take a while, depending on the size of the image.

    When it is ready you will see the file name at the bottom of the screen in the "Attachments" window ... click on the little box (if it isn't already checked) to indicate that you want to post the file (5) ...

    Click on "Done" (6) ... and, you're done.

    To check if the image posted, click on the "Preview" button to the right of the "Submit" button.
    Last edited by lmo1131; 03-08-2014 at 10:59 PM.
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