hi there,

I have a very specific question ...

I have a XRTT rolling chassis that uses a WM3 borrani rear rim ... I know that that was stock on the first XRTT's in 1972 ... looking at the pictures I have from 1973 XRTT's (Rayborn, Pasolini and Brelsford) it's obvious they are using wider rims. Some look like the 2.50x18 high flange rims, other look even wider and look like low flange rims.
Now my question: what rear rim would be period correct for a 1973 XRTT with the Honda disc setup? Its quite obvious that I can run wider tires on wider rims, so I would like to go for a wider rim. I have a akront 3.50 rim that I would like to use, otherwise the Sportster 2.50 or a borrani 3.00 ...

any comments appreciated ...

ralf

Hi Ralf;
I would use the akront as it is strong and you can use a wider tire with the sidewalls in the correct position. The HD rim from Varese would be the next choice. Borranis are light as a potatochip (but about as strong)lol
I obtained a Magnesium 18"x4" Morris mag for my project. I have a picture of Cal Rayborn's XRTT. Send me an email address and I will send it to you.
I have a friend who might still have some billet honda rotors he had made. They are correct and legal for WERA. I think he also has a billet tripple tree assembly for ceriani or marzocchi front ends.
Tschuss;
Bill

Hi Bill,

thanks for your reply ... the main question for me is wether 3.50" for a rear rim is period correct or not (in 1973) ... I did some more research and I definately can say that most of the riders were using a special "low flange"-"drop center" rim at the rear (or the morris mags) -- but I have no information on the brand or the width of the spoked wheel ... actually the chassis came complete despite the rear shocks with a stock Honda CB750 front wheel hub and brakes.

A second issue is the spokes ... my spokes (original) have a light surface rust (not to much) and they are cadmium plated. unfortunately I can not have them replated with cadmium in germany (toxic), but want to keep them ... have you restored or replaced your xr spokes?

Anyway -- what kind of projekt do you have? A XRTT? Or Lucifers Hammer like? Not to much people around working on a KRTT or XRTT ...

best regards

Ralf

Hi Ralf--
I'd replace the spokes with new ones; it will give you some peace of mind vs. using older spokes. Try these folks (no affiliation ) : http://www.buchananspokes.net/

Me, I'm looking for a primary chain for use with a 34T front motor sprocket. Anyone?

Hi Ralf;
How are you today? A standard 1957 to 2003 sportster or buell primary chain is for a 34 tooth engine sprocket. A K would have the correct chain for a 30 tooth(optional) XR sprocket. Did you just buy the $76 dollar (64R )30 tooth sprocket on Ebay?
I hope all is well. I am at work will write more later.
Talk to you soon;
Bill

Actually, it's not Ralf. But I did win the 34T motor sprocket, after searching for about 6 months. It's for a Bonneville project; putting a XR750TT together for the salt. Also have a 24T transmission sprocket and a 36T rear, so now, if anything, I may be a little too tall for my motor.

Hi;
Sorry about that. I am working my ninth 12 hour shift in a row. I would look for a 30 tooth engine sprocket and underdrive the motor a little . Using a chainfall as an example,the outer chain heel is 4x as big as the inner. When you pull on the chain it feels easy due to the torque multiplication(leverage)
An (early)XR will make it's best power and live under 7,000 rpm. To figure your theoretical top end multipy 2.96 times tire diameter times rpm divided by overall gearing times 1,000. Eg a 30 tooth engine sprocket x 59 teeth on the clutch with a 22 tooth countershaft sprocket(fits with no grinding) and a40tooth rear sprocket will give you a 3.58 overall ratio. Using a 25 inch tire diameter with this formula would give you 142 mph at 7,000 rpm.
Keep in touch as I am building a killer Nallin XL powered XR framed streetbike.
Bill

With the tires I'll be using (851 revs/mile), the formula I'm using comes up with 137.92 mph for those gears and rpm. I had been using a bit higher rpm, but even if you use the 22T trans sprocket with the 36T rear, that bumps it up to 153+. The record I would be chasing is 132.45 (BMW). With the gears I do have, the tallest combination (34T motor/24T trans/36T rear) reaches 189+ at 7000 rpm. I won't be going initially with a motor that will pull that mph, but the first year is a "get your feet wet" year anyway. After that, a real motor....

I have a very rare set of Sputhe heads (mid 70s)on my 62 XLCH, Allan Sputhe says I have one of maybe 10 sets left in the world. 4 are on bikes in his showroom and I have located 2 sets on bikes in North Carolina. Anyone know where there are any more? I dont even know if I can put a value to this motor of mine. Sputhe heads, Drag Specialties cylinders (63ci), sifton cams (C grind, XR pattern, early XL shafts). Everything on this bike is vintage rare or handmade to bring it in at a curbweight of 360lbs. Kimtab Snowflake Magnesium wheels (8lbs), Ceriani roadrace forks, Tomaselli clipons. One off Mikuni butterfly carbs made for me by Mikuni. I have recently in the last 10 years modified a set of 4 piston Hog Halter brake calipers to the original triple disc setup ( cant have too much brakes)

http://i253.photobucket.com/albums/hh79/o1racing03/DSCN0193.jpg

http://i253.photobucket.com/albums/hh79/o1racing03/DSCN0195.jpg

[QUOTE=o1racing03;2334978]I have a very rare set of Sputhe heads (mid 70s)on my 62 XLCH, Allan Sputhe says I have one of maybe 10 sets left in the world. 4 are on bikes in his showroom and I have located 2 sets on bikes in North Carolina. Anyone know where there are any more? I dont even know if I can put a value to this motor of mine.
/QUOTE]

I would love to find a set of these heads. I'm building a bike for a crack at The Australian National Title, Period 3 Unlimited. Basically A Sportster motor in a featherbed frame. As an example of the cost to build just the rear brake alone was $2,500. Magnesium Manx Norton mirror imaged.

Even the loan of a set so measurements etc could be taken to get some more sets cast up ? Or has someone already done a cad drawing of these ?

Put a value on the motor. I'm selling my house, you never know !

Re alloy wheels (Post Original) consider using Morad - new rims that look the same as the Borann's. You can turn the flanges off, which is probably what those guys did back then. The flanges add very little if anything to the strength and it's a way of dropping some weight. While they are doing that they can also "skim" the inside of the rim. This gives the tire a little more room to spread and gives a better contact patch. Check very carefully the rulebook on rim widths as some classes specify sizes. Also work out which tires your going to use beforehand - you may find the tire you want is not available for the rim width you want in the compund you need.

Cheers
Gene

I have been trying to located the 3 sets of missing heads for about 20 years now. Allan Sputhe who designed and built these in the 70s has 4 sets on bikes in his showroom, last I heard they were all for sale. I have posted a link to a late model XL with the XR style head. I was able to speak to the builder of that bike and as he explained it to me, the engine builder is in Japan and associated with Pops Yoshimura, you give them your motor and they build it with the heads that they redesigned with differant valve angles, porting, etc.They make between 105-125 rwhp. I understand they are quite expensive and selling the house might be a viable option if you are interested. It might be cheaper to buy one of Allans bikes , just to have the heads. I am awaiting more info on the Japanese motors(Sundance Racing Project)


]http://i34.tinypic.com/16axnye.jpg[/QUOTE





[QUOTE=Ferrous Head;2336347][QUOTE=o1racing03;2334978]I have a very rare set of Sputhe heads (mid 70s)on my 62 XLCH, Allan Sputhe says I have one of maybe 10 sets left in the world. 4 are on bikes in his showroom and I have located 2 sets on bikes in North Carolina. Anyone know where there are any more? I dont even know if I can put a value to this motor of mine.
/QUOTE]

I would love to find a set of these heads. I'm building a bike for a crack at The Australian National Title, Period 3 Unlimited. Basically A Sportster motor in a featherbed frame. As an example of the cost to build just the rear brake alone was $2,500. Magnesium Manx Norton mirror imaged.

Even the loan of a set so measurements etc could be taken to get some more sets cast up ? Or has someone already done a cad drawing of these ?

Put a value on the motor. I'm selling my house, you never know !

Re alloy wheels (Post Original) consider using Morad - new rims that look the same as the Borann's. You can turn the flanges off, which is probably what those guys did back then. The flanges add very little if anything to the strength and it's a way of dropping some weight. While they are doing that they can also "skim" the inside of the rim. This gives the tire a little more room to spread and gives a better contact patch. Check very carefully the rulebook on rim widths as some classes specify sizes. Also work out which tires your going to use beforehand - you may find the tire you want is not available for the rim width you want in the compund you need.

Cheers
Gene

I can't run XR style engines but I could get away with the Sputhe type heads. Our Period 3 class rules nominate 1963 as the cut off date. I can get away with things that look like I could have modded to back then but won't extend to the Thunderheads or XR style heads. I could for example just run Panheads on it. Two front heads with the rear one reversed. Might be a bit of shove and push to get the Sputhe heads passed but I'm pretty sure I could do it.
Cheers
gene

Hey guys I have access to a set of these sputhe heads and sputhe cylinders which are even more rare than the heads,possibly a whole stroked engine, Type sputhester in the gallery page: thats my bike. Contact me if your serious. Sputhester@gmail.com

dang, I thought I had found another of the missing 3 sets, but you and I have spoken in the last year and yours are one of the 2 sets I mentioned in N.C. You never did follow up with pics of your mechanics bike that you said had them also. What do you figure these heads/cylinders are worth. I can't even begin to put a value on my heads, or my bike for that matter. I see one thing you did on yours that would solve a problem I have and that is knee clearance on the front filter, by running your manifold forward. What size are the cylinders? Ever dynoed it to calculate HP/torque?Hey guys I have access to a set of these sputhe heads and sputhe cylinders which are even more rare than the heads,possibly a whole stroked engine, Type sputhester in the gallery page: thats my bike. Contact me if your serious. Sputhester@gmail.com

Yes,turning the front carb with an elbow is the only comfortable way to set these up if you want to be able to really ride. 10.5:1 ,Bore is stock, but stroke is 5": 80CI/1340cc. We welded and machined crank scrapers in the cases, and ran exterior drains. Runs awesome! What xr cams are you running? Any extra sets of cams? Im from Mass by the way.

I have a very rare set of Sputhe heads (mid 70s)on my 62 XLCH, Allan Sputhe says I have one of maybe 10 sets left in the world. 4 are on bikes in his showroom and I have located 2 sets on bikes in North Carolina. Anyone know where there are any more? I dont even know if I can put a value to this motor of mine. Sputhe heads, Drag Specialties cylinders (63ci), sifton cams (C grind, XR pattern, early XL shafts). Everything on this bike is vintage rare or handmade to bring it in at a curbweight of 360lbs. Kimtab Snowflake Magnesium wheels (8lbs), Ceriani roadrace forks, Tomaselli clipons. One off Mikuni butterfly carbs made for me by Mikuni. I have recently in the last 10 years modified a set of 4 piston Hog Halter brake calipers to the original triple disc setup ( cant have too much brakes)




...how did you feed the lights? Cant see a generator o it.
Regards,
Andreas

I run a small battery in the tail section that runs all the lights, total loss system , good for about 4 hours of day time braking and headlight , then plug it in the charger...how did you feed the lights? Cant see a generator o it.
Regards,
Andreas

After speaking with Alan Sputhe yesterday on the phone, getting heads seperately from him was actually more of an accomplishment than getting heads . Apparently I got one of the few sets of prototype head sold without the cylinders and heads or full motors. Alan also has a motor for sale with his heads and cylinders.Hey guys I have access to a set of these sputhe heads and sputhe cylinders which are even more rare than the heads,possibly a whole stroked engine, Type sputhester in the gallery page: thats my bike. Contact me if your serious. Sputhester@gmail.com

I run a small battery in the tail section that runs all the lights, total loss system , good for about 4 hours of day time braking and headlight , then plug it in the charger

... same did I on my street legal XR. thanks,

Gene;
How did you fit a XR-750 to a Norton Featherbed frame?
Retards;
Franz

I believe my cams are custom grinds from Sifton. They can make you anything you want. I dont know the numbers on them, but I think all they are are C grind-XR pattern on early XL shafts.Yes,turning the front carb with an elbow is the only comfortable way to set these up if you want to be able to really ride. 10.5:1 ,Bore is stock, but stroke is 5": 80CI/1340cc. We welded and machined crank scrapers in the cases, and ran exterior drains. Runs awesome! What xr cams are you running? Any extra sets of cams? Im from Mass by the way.

I meant more of an accomplishment than getting heads and cylinders.After speaking with Alan Sputhe yesterday on the phone, getting heads seperately from him was actually more of an accomplishment than getting heads . Apparently I got one of the few sets of prototype heads sold without the cylinders and heads or full motors. Alan also has a motor for sale with his heads and cylinders.

I know of a Sputhe motor for sale, serial numbered heads 790017/790018, making them the 9th set made in 1979. Motor was built in 1980 and has never been fired, been sitting in a machine shop all this time, owner has a baby on the way and is letting this historic piece go for less than its valued at. Contact me if you want to make an offer. Complete motor with Sputhe heads/cylinders and its in a frame.

Everything is doable with little imagination and some fabrication skills. Just fill the space between the frame and the engine with a custom fabbed mount. We have Kawasaki H2 750 in a Norton Manx frame ( Kawaton/ Norasaki), you want to talk fast and well handling.Gene;
How did you fit a XR-750 to a Norton Featherbed frame?
Retards;
Franz

XR-750 in Norton Featherbed frame: Yes, imgination is the attitude. Have seen some XR-750 Hartons from: Dresda, McIntosh and Egli. The rear support of the engine is the moust complicated, because the size and shape of the primary chain case (clutch, side) and you want a short wheel base.
Regards;
Franz606

Gene;
How did you fit a XR-750 to a Norton Featherbed frame?
Retards;
Franz

The rear motor mount was not difficult at all. But it does require some fabrication skill. My frame had a mid and bottom tube across the frame so I just fabricated a square section which was elded to these two tubes and drilled holes for the mounting bolts.

The hardest part is the rear brake. I have a mirrored image Manx type cast in magnesium. The Harlet motor is right side drive and Norton motors are left side drive.