what is this frame?

Discussion in 'GS Boxers' started by kellymac530, Nov 18, 2012.

  1. kellymac530

    kellymac530 motorcycle addict

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  2. LaurelPerryOnLand

    LaurelPerryOnLand Long timer

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  3. boxermoose

    boxermoose Now fully goosed

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    HPN - they usually do airheads in a Dakar sorta flair...there are threads in airheads/old school

    If you look you will see that this oil head has been converted to carbs (Bing) ans as such to moronic has been stripped out of it
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  4. kellymac530

    kellymac530 motorcycle addict

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    Laurel,
    THanks for that link. Good pics there of a similar bike and an explanation that it is a prototype HPN frame, so I assume it is NOT available to a person in the general populous...unobtainium?

    That is a different bike though. Very similar but different in the tank and airbox area.

    I have a good running R1100RT that I am bored with and am wanting to build something cool. I like the tubular frame and standard forks over the heavy forged frame on the GS/GSA frames and the A-arm/monolever frontend for any dirt stuff.

    I have an '86 R80G/S that I was thinking about building an HPN replica bike out of, but am not sure if that would make as good of a longer ride on the pavement bike and dont think it will have the power I like without some big rebuilding of the motor at a big expense.

    When I saw this frame I thought, Man I have alot of parts that would translate over to a frame like that and give me bit more modern driveline....I know I know you Airhead guys are screaming at your computers that an Airhead is as good or better than my Oilhead....but whatever.

    Does anyone know if there is a frame builder that builds a frame like this anywhere that can be purchased by a clown like me?

    I have good fab skills and a full fab shop here but not enough to build a full frame and set up all of the geometry stuff. I can build airbox, tank mounts, and modify stuff like a sub frame.....but If I could buy just the trellis front/upper frame section with the steering head all set up I would buy one for sure.

    I already have a built set of KYB full cartridge 46mm forks with new seals and heavy springs and a 21" Excell front wheel. The seat/tank/....could easily be pieced together. Man I am jonesing for that frame.
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  5. kellymac530

    kellymac530 motorcycle addict

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    That would be a personal choice to do carbs. I could run the FI set and just strip out the ABS brakes and stuff I do not need but keep the FI and ignition pretty easily. I do not care about ABS on a more dirt oriented bike like that.
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  6. LaurelPerryOnLand

    LaurelPerryOnLand Long timer

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  7. kellymac530

    kellymac530 motorcycle addict

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    Oh yeah, I have been there many times since I bought my R80G/S. I just feel like the R80G/S is worth as much or more leaving it alone over building it as a replica HPN and I am still not sure I will LOVE it. I would kind of rather buy a frame like this for my 1100 and do something fun and different.

    I LOVE the HP2 bikes from a couple years ago but could not afford one. Building one of these out of my 1100 would a close style of HP2 wannabe.
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  8. Whale Rider

    Whale Rider Been here awhile

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    You have to make your own here is my interpritation. I need to get back into the shed.
    WR

    [​IMG]
    Bike1 by boGSer, on Flickr
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  9. kellymac530

    kellymac530 motorcycle addict

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    Whale,
    Very nice.
    So now we have 1 home made bike and at least 2 HPN custom fabbed frames. Those 2 in the first 2 post links are different bikes and they are privately owned since they have different license plate numbers on them.
    Somebody has to make them.

    You can buy a custom hand crafted Norton Slimline or wideline Featherbed frame in nickel plate with almost any mounts for various engines already in it for under $2000.00 USD so I am sure someone could make a trellis frame for an oilhead for that or less.

    I am considering buying a YZ....or whatever frame and using that as a jig for geometry and building off of that....big project there though.
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  10. kellymac530

    kellymac530 motorcycle addict

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    Whale, what is the distance from the front axle center to the swingarm pivot shaft center, if you dont mind?
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  11. larryboy

    larryboy Chopper Rider

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  12. Ua the Destroyer

    Ua the Destroyer Been here awhile

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    This place sells a front subframe so you can mount regular forks on the front of an 1150. Don't know how that would translate to an 1100. You'd have to make your own rear subframe.

    http://www.bakker-framebouw.nl/products/motorbikes/bmw?lang=en
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  13. Ua the Destroyer

    Ua the Destroyer Been here awhile

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  14. Whale Rider

    Whale Rider Been here awhile

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    1100 & 1150 motor mounts for the front subframe are the same so it will fit an 1100.
    The bike in the first 2 post where built by HPN and BMW to race and win Paris Dakar if you google 900RR & HPN there is plenty of information out there. The HP2 Enduro came about from these bikes. I have studied alot of photos before I drew up my frame. Have a look at the links for some information

    http://www.motorcyclespecs.co.za/model/bmw/bmw_r900gs_rally%2099.htm

    http://www.rallye-tenere.net/bmw.html#900rr2001

    I am using parts off a YZ donor bike but the frame is way to small for the BMW engine as for steering head angels look at KTM 950 990 Super Enduro to get some ideas the YZ has about an extra 1 Deg steering head angle.
    I will measure the distance from the front axle to the pivot point for you.
    WR

    Rough but close measurement 108cm
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  15. kellymac530

    kellymac530 motorcycle addict

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    Thanks guy for the links. That Bakker frame would be a perfect start for what I want to do.
    I am really concerned though. The GS frame is not in their price list but some of their other frames run right about 3.500 Euros....holy heck thats a butt load of money for a bit of tubing bent and welded together in a jig...
    3.500 was just the frame, the rear subframe was another 1.000 I think so we are looking at close to 5k Euro for a frame...that is well over $7000.00 USD....Im out at that.

    Whale, That 900RR is exactly what I would like to build :clap:wink: Like many folks I am sure. Did the Dakar have a 900cc engine limit that year or what? Why did they go with 900cc instead of the standard 1150 motor?
    I know somewhere around that time they dropped to 650cc singles and later to 450cc.
    I know the early airhead HPN bikes were the 1050cc kit on the 65/80 motors.

    Whale, I have been looking for a few days and I can not find alot of pics of any custom frames like that, just the frames and any specs. I like what larryboy did, that is what I am thinking of doing. He sounds alot like me....hold it in place and tack weld.
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  16. kellymac530

    kellymac530 motorcycle addict

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    Whale, I am staring at your pics more and noticing something, did you turn your TBs verticlewith an elbow and run them up under the tank?
    If so, I love that idea..

    I have a donor 2003 YZ 125 donor front end and can get the frame as a start point. I know the frame will be short, but combining your style and larryboys is possible.

    I just wish I had an 1150 with the 6 speed trans. I have an R1100RT that I may use for this project.
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  17. Whale Rider

    Whale Rider Been here awhile

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    Yep back then CC rating was limited to 900 and as for the $7000 I would hate to add up the hours that I have spent on this so far but I suppose it is a one off and I have made everything in my shed for it so far from scratch.
    Yes I have turned the intakes up 90Deg and swapped the throtle bodies from side to side to get the injectors pointed back in the ports again. The air intake will be up by the steering head and a fuel tank is next to be made to fit where the airbox used to be.
    This bike will be for trails and I had a gearbox with the pivot point broken out of it so I cut the rest of it off with the angle grinder and now the swingarm pivots in the frame.
    I will be running an 850 to start with which will have a 3.36 final drive ratio I think the 5 speed box will be better because the ratio split is a bit wider the 6 speed box ratios are pretty close so with a low final drive you would be changing gear all the time.
    As for the HPN 900RR if you study the engine it is way from Std all the sump is cut off the engine and extra oil tank fitted under the gearbox an alternator on the front of the crank like an airhead motor, remote oil filter and the list goes on many things to take in. Rear shock on top of the gearbox at a 45Deg angel. I have kept mine vertical.
    R900 RR the dream machine never to be made by HPN for the public unlike the previous airhead models
    As for the YZ parts go for it anything is possible all that is required is time and inclination good luck.

    P.S. if you click on my photo you will see some previous photos of the frame. Still a way to go before the big fire up but the major stuff is done once I get the tank made.

    WR
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  18. kellymac530

    kellymac530 motorcycle addict

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    Very cool Whale.
    Thanks for all of the input.
    I got in touch with Bert Duursma last night and it is much better than i thought. The subframe is not available at all, not sure why, but I think the stock BMW subframe will bolt up to the custom frame and if so I believe that there are aluminum subframes on the market for a stock frame.

    The price is WAY better than I thought, the frame is VERY simply in design so the price is better, not cheap, but better.
    Bert sent me an email that the frame is *about* 1650 Euro shipped which only translate to about $2200.00 USD.
    That is doable imho. I just need to verify if their steering head will fit with the YZ triple clamp. I think I can get some bearings that will work either way, but it would be nice if I could get the exact head diameter that the YZ has for simplicity.

    I am just really torn. I am one of those guys that have TOO many Ideas, TOO little money, No time, and BIG dreams....lol
    I am torn between building my R80G/S into an HPN replica or building the 900RR replica. I want a bike I can tour long distances on when on the highway, but is reasonably capable on things like the TAT or the Rubicon trail type of rides.

    I like the idea of the oilhead for HP, stock it is at 85-90 ish and smooth, where as the Airhead is only 50 ish HP and is old, It would require alot of work to get the motor fresh and up to snuff for a long distance trip. The oilhead I have is road ready, fairly low mileage, and a know good running commodity.
    Apples and oranges, but tasty, but one makes a better pie and one makes a better cocktail....lol
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  19. Whale Rider

    Whale Rider Been here awhile

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  20. kellymac530

    kellymac530 motorcycle addict

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    WR,
    Thanks for those links, that gives me a great head start on what I am looking at doing. Great info there and some different approaches to a similar end result. Big help.

    I am really condsidering using the ugly stock RT tank with no tupperware. Looks are not my biggest concern. I wish the glovebox pocket was different but I may make something to fill it, like a reserve tank. The tank is not really heavy, unless full of fuel, it carries the weight pretty low down near the cylinders, and best of all it is free...since I already own it. Also the screw holes could make for some nice tank back attachment points etc...

    Rear shock and suspension is a big area of concern, an Ohlins GSA shock is out of the question. A WP PDs is possible, but will have to research the fitment issues. Then some sort of a front frame goosneck, whether I buy one from Bert Duursma or build my own, either way I have the whole front end already and the '96 RT is is good shape so I can sell alot of parts if I do this, the build could be almost cost free, just time.

    I am leaning towards trying a Trellis frame similar to the Bakker frames Bert sells, no real risk, if I can't get it right then all I am out is an $80 YZ frame that I cut the gooseneck out of, then maybe an aluminum attemp at cutting the stock one with a CR gooseneck, then last resort drop the cash on a Bakker. Lots of playing around ahead of me and I am sure alot more questions from me and request for info help.

    My only issue right now is my bad neck, but on Dec 5, 2012 I am getting a NEW plate and new Ti screws to fix the one that got broken....somehow, and refuse the C6/7 joint that did not fuse. 6 months after that I am in to do a big project.
    #20