XLCH/XLR Hybrid build

Classic short-frame models

Re: XLCH/XLR Hybrid build

Postby JerrryR » Sun Jan 09, 2022 9:12 am

Congratulations Ralf, I am in awe of your mechanical abilities and vision. Your build is beautiful. Swap meet season is coming up, if you're on the hunt for any parts let me know.
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Re: XLCH/XLR Hybrid build

Postby panic » Sun Jan 09, 2022 3:12 pm

I appreciate your dedication to accomplish all of this fine work.
It doesn't have to please anyone but you, but what's the goal?
With your kind permission, a few remarks on what I see as mixed signals.
1. A CR transmission (designed to prevent a highly tuned 48 hp engine from falling off the cam) is a life raft for the bathtub. I suspect you will select numerically low driveline ratio to keep piston speed and vibration down while cruising, a close 1st gear will need more clutch from a stop than I would like. Given "tall" gearing, I would try for much greater progression and wider range between 1st and 4th to take advantage of huge engine torque.
2. Ball bearings reduce parasitic loss at the expense of much shorter service life. They have a significantly lower load capacity than a comparable roller bearing. Read Branch, throwing them away on a schedule (rather than waiting for a sign of mileage or condition) was common.
3. The low RPM (stroke length) and low gram weight of the stroker pistons make the rods overkill.
4. That front brake was dangerously undersize when new. More on drum brakes in my articles here: http://www.victorylibrary.com/tech/harley-2LS.htm, http://victorylibrary.com/brit/2LS.htm, http://victorylibrary.com/brit/SLS-TLS.htm (sorry, some information appears twice).
5. The entire fork is too small; the tubes will go out of parallel any strong steering motion.

In short, the engine and chassis are developing in opposite directions.
[url="http://victorylibrary.com/L-BK.htm"]The Linkert Book[/url]
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Re: XLCH/XLR Hybrid build

Postby xlh59 » Mon Jan 10, 2022 7:29 am

thanks Jerry for the heads-up and thanks panic for your comments!

"what´s the goal?" is a very valid question and is sort of easy to answer:
I bought my first Ironhead (the XLH) in 1992 in Chicago. I actually wanted a Panhead, but I was running out of time and my cash was limited -- so the first rebuild was an attempt to look like a big twin (very common, I know). After I realized how fast the sportster was and that actually friends with Panheads were frightened to drive that "thing", I went more into handling. I used a 38mm fork and double 300mm disc brakes in the front. Then I was attracted by the flattrack design ... drag bike ... you name it. I ended up in a lenghty process of restoring all the original parts (which I luckily kept) and getting the ones missing. I even prefer a used part from a colony reproduction. I like the original patina, as you can´t buy it.

So whats the point here? I am addicted to the history of a bike and not necesarily the original factory appearance. There will be a "no limit" build (in regards to "original" or "period correct") some day, but this bike had a history, so I needed to respect it.

As far as a pile of pieces, its hard to tell what was part of the bike and what not. On the other hand, this bike has been run before, so there is a history to it. The pistons where seized, but were correct for the KH flywheels and cylinders -- and someone modified the KH flywheels to accept the 55R crankpin and rods. The cases were modified to match the pistons and ball bearings ... I just wanted to make that thing run again! -- Simply that was the goal.

Your comments in regards to chassis vs. engine are 100% true -- but honestly speaking, I would most likely never use the potential of the engine. My idea is to use the bike on vintage flattrack races, but I want to drive there! No Trailer! And my flattrack capablilties are also limited :D

I changed the ball bearings to metric rollers on the cam side and the superblend barrel bearings on the primary side. That should add some lifetime to them. The close ratio transmission was there and although they are not needed for a stroker, I assume they would not hurt. The bike came with a 30t motor sprocket, but for street use I changed it to 34t, which caused minor interference problems with the chain tensioner.

For the 35mm Ceriani fork, I am actually quite satisfied ... used a similar fork in my XLH and had no complains. The front brake is "empty" by now, because I am really considering a 2LS conversion, like you describe in your articles. But keep in mind, that this is the -54R conical brake, which should be stronger than the stock brake?

Thanks for reading and your comments! I really appreciate it!
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Re: XLCH/XLR Hybrid build

Postby chuckthebeatertruck » Mon Jan 10, 2022 11:17 am

Congratulations on completing this long saga.

I wanted to share some of my experience running the same alloy cylinders on the street.

I've been running mine for two seasons -- and they are the oddest things I've had on a motorbike. Put simply, the expansion rate between the cylinders and everything else goes helter skelter for a few minutes as everything comes up to temperature. For me, it happens between 7 and 10km from my house. It isn't what you think. Basically, the valve lash grows and when you increase the lash on the exhaust cams you're running -- the motor takes on a hard edge. It's hard to not want to crush the throttle when you feel it . . .and hard to remember the motor is still warming up.

Pay close attention to your head bolts and base nuts. They will move around a lot more than iron cylinders and will likely not settle down until after you have crossed 1000km. Similarly, pay close attention to the sealing of your exhaust push rod tubes. I had to do some serious work to get mine to seal reliably -- again due to the expansion. I wound up grinding down two shovelhead clips and grinding the OD of the middle cork to ensure the top tube could slide easily and maintain a strong seal.

Also, these cylinders shed heat -- a LOT of heat. So much so I literally melted a plastic body fuel filter that was almost 3/4" of the cylinders:
Image

I've run these filters on many bikes over the years and sometimes with the filter body sitting right against a cylinder. I never saw this happen before and the motor was not overheating. It boiled the fuel right out of the filter and gave me an instant vapor lock on the side of the road. I had to stop, release the fuel line to break the seal, and then get the bike going again. I managed to do that on a roughly 35C day and was not even beating on the motor very much. Unlike iron cylinders, these ones just transfer the heat fast to the fins -- they also "ring" as they get hot and you get on the throttle. You'll also notice that your exhaust system moves around . . . again all the expansion. Check your clamps at the 500km mark.

With regard to your starting -- it's partially a function of what you have going on. Try an extra prime kick or two - and then consider a different carb. I found with the -/- exhausts I need one or two extra prime kicks from "stock" bikes or bikes running P/PB cams regardless of whether I'm on the +h intakes (small stroker) or the -/- intakes (mid sized stroker).

while Dr Dick was doing surgery on a GBL for me - I ran a DC linkert on my 78" alloy cylinder bike. It was OK, but the bike woke up considerably with the GBL. I just put a Super B on it and found a little more "around town" but not as much top end. In other words, you've got a good package and an OK carb ... but part of your issue will be working around a rather small carb on a mid-sized motor. It will work . . . but it won't live up to the potential of your bike.


Finally, if you used copper head gaskets, keep an eye on the oil returns. One thing I learned is that it can be difficult to keep them from weeping on the alloy cylinders. A swap to fibre gaskets solved that without issue. I was warned by the national champion who sold me the cylinders they only used fibre gaskets on the alloy cylinders themselves and I thought I'd be smarter . . and learned the hard way to listen to this advice. If you do run straight copper, anneal them well and copper coat both sides before install. That "might" work -- but again, you'll find out around 700 to 1000 miles in what the final score really is on your choices.

Sometimes, having unusual stuff is fun -- but makes you work for it.

Speed Safely
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Re: XLCH/XLR Hybrid build

Postby chuckthebeatertruck » Mon Jan 10, 2022 12:04 pm

panic wrote:With your kind permission, a few remarks on what I see as mixed signals.
1. A CR transmission (designed to prevent a highly tuned 48 hp engine from falling off the cam) is a life raft for the bathtub. I suspect you will select numerically low driveline ratio to keep piston speed and vibration down while cruising, a close 1st gear will need more clutch from a stop than I would like. Given "tall" gearing, I would try for much greater progression and wider range between 1st and 4th to take advantage of huge engine torque.


As someone who has a bike with a "life raft for the bathtub" -- I have been told or heard many of these same things.

I haven't found them to be true at all and instead have come to believe the c ratio is great for life in the real world. I've come to prefer it over my other ironheads with stock boxes. I have also ridden C ratios at different displacements and enjoyed all of them without fail.

You don't notice the "tall" first gear. Most of the wet clutch conversion kits for 900s make you slip the clutch a lot more to take off and almost all 1971 up wet clutch ironheads make you slip them as much if not more. I actually mess around and ride my 78" c-ratio bike in town like a big old trials bike. I have no issue rolling around at a walking pace, pulling figure 8s with one or two finger friction zone control, etc.

What happens is that you fall in love with the closed up 3rd/4th gap, especially if you live in areas where the average speed limit is 40-50mph.

YMMV
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Re: XLCH/XLR Hybrid build

Postby dlxl66elxl » Mon Jan 10, 2022 1:09 pm

I'll share my experience with the transmission gearing. I have a race kitted XR1000 and a XLCR with a stroker motor and Andrews V9 cams. I have the Andrews M ration 3rd gear and wide ratio first set in the XLCR and a C ration in the XR. The XLCR gearing is somewhat complaint free. The C ratio is too closely geared, but better that the big 3 to 4 jump with OEM gearing. I am in the process of going back the M gears in the XR. I ride canyons mostly, so I get a lot of gear changing, one first gear 25 MPH hairpin.
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Re: XLCH/XLR Hybrid build

Postby panic » Mon Jan 10, 2022 6:25 pm

believe the c ratio is great for life in the real world
And I don't
[url="http://victorylibrary.com/L-BK.htm"]The Linkert Book[/url]
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Re: XLCH/XLR Hybrid build

Postby xlh59 » Wed Jan 12, 2022 4:34 am

thanks a lot for sharing the information on those cylinders! I will definately have a closer look on all the nuts and bolts involved. As far as I remember, mrmom hsa also used these cylinders on one of his XR750 replicas? Other than that I have not seen them before.
When you used the Linkert DC on your 78" bike, was ist stock diameter or a version with the 9x throttle plate (hence 1,5" diameter)? I use the Linkert because it would be the correct carburetor for a bike in that period -- I know that it is a bit to small. If I switch to another carb, I will propably first test my 40mm CV (which I feel is the smoothest carburetor I ever used) and also a 40mm Dellorto (which is propably "closer" in regards to period correct). From my understanding a 40mm carb should be the correct choice for a 77" bike? Any S&S would eventually still be to big?

Cheers, Ralf
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Re: XLCH/XLR Hybrid build

Postby chuckthebeatertruck » Wed Jan 12, 2022 11:50 am

Your memory is pretty close. I bought the cylinders I'm running from Don Rothwell. He tried them in different configurations and really wanted to put them on a thunderhead equipped stroker -- but there isn't enough material to move the bolt pattern. So -- I wound up with them and put the Dytch cylinders I intended to use on the shelf. The big mistake I made was not listening to Don about the head gaskets. I wound up swapping them out a couple of months ago because of the oil weep from the returns. Lesson learned.

There's relatively few people running what you've got going on. Please keep that in mind. You not only have an old stroker - you have an old stroker with unique, major parts that affect how it runs and behaves compared to stock or other stroked bikes. I've found mine to be more challenging than other strokers I've had a chance to work on and/or ride because of the cylinders. A few people have asked me if I would recommend them -- and my honest answer is no. Other than the cool factor and the very light weight -- there really is no advantage. Though, it is cool to ask guys what happened to make your cylinders loose magnetism :-)

I am happy to share all of my experiences with you in the hopes they short cut your learning curve. Put simply, these cylinders are funny and fun. For example, as you get down to working on your overall timing and your plug gaps -- you'll discover that the ringing of the cylinder fins on hard acceleration is very close to the sound of part throttle detonation! To quiet it down and trace some oil dripping, I stuffed paper towels between every other fin. Did the trick -- but again something iron cylinder riders haven't had to contend with to the same extent. Conversely, the cylinders don't get raggedly looking as the paint fails. They just stay a lovely silver -- which means as you approach 1000 miles your heads will start becoming a different color than the cylinders. Mine went silver/gold while the cylinders stayed silver/grey. It looks sorta funny but not too bad. I tossed on a turtle tank for more range -- and it makes the color change almost imperceptible.

To your question; the linkert I used was straight off my 1959 XLH. I was po'ed I wasn't riding the bike and so decided to put the Linkert on. No special modifications. I simply juggled the needles and the idle speed a bit. I only ran it a couple of weeks like that before the GBL came back and went on. It was enough for me to be unimpressed, but not long enough to really sort it out.

With regard to the carb; the linkert will work. My comments were more about the enormous difference moving from the linkert to the GBL made for me on a bike that is very, very similar to yours. I don't really have any knowledge about carburetor sizing for strokers. Instead, I cheated and quizzed the grey beards with a lot more saddle time than me.

I have come to really, really like both the GBL and Super B over the past two years. If you cruise a lot - the Super B is lovely. If you live somewhere that finds you accelerating frequently from a stop -- the L series is wonderful. But, the L series does take some time to get right. I've been in and out of the carb more times than I care to admit finding the right float level for ease of starting and snappy low end. The Super B is much faster to set up and in my limited experience as stone axe reliable as they come. I have found that raising the float level of the Super B just a little bit so it almost, but not quite drips at idle results in better starting and a smoother throttle response on the big inch bikes. If you want period correct -- I'd be going here. I have no experience with dell ortos on ironheads. I have run a CV on a stock 1980 1000 and on my stroked flathead. I do like the carbs, but think they look a little funny on ironheads. Given that genuine OEM CVs are getting to be $150-200 for good cores; I just assume buy $100-150 super b.

I'd suggest quizzing some folks with strokers or lots of stroker experience on what they have found the best all around for street riding. Then compare that to your bike and the type of riding you do.
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Re: XLCH/XLR Hybrid build

Postby wz507 » Wed Jan 12, 2022 3:17 pm

Here’s another carb data point for reflection. In 1976 I built a 76” CH fit with a 44mm Mikuni VM carb. The bike ran well, always started 1st kick, and would run an 11.70 sec ¼ mi at 117 mph. There was however, the occasional issue with this carb that related to a particular combination of air temp and relative humidity. On rare long summer evenings when temperature was dropping and nearing the dewpoint, the slide would stick, i.e., would not return to an idle. I never knew if this from icing or from moisture formation in the carb, all I knew is that it happened and wasn’t pleasant. It never, ever happened mid-day or in dryer weather. If you are not an evening rider in such conditions, likely a non-issue, or you could employ a carb from Mikuni’s HSR flat slide series that would be far better and absolutely wouldn’t stick.

As you can well image if you were accelerating away from a stop and on the way up wacked the throttle open in 2nd gear, only to find it stuck at WOT, some serious sphincter tightening would be in order. I’m sure the look on my face at that moment would be akin to seeing the "white of a horse’s eye" – an image foretelling that danger lies ahead.
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