| Author | Message | ||
     Forevernow |
anyone know if cam needle bearings have a advantage, or create exter problems? | ||
| Blake |
I saw this question posed elsewhere. I don't think anyone is confident enough to say. The stock bearings are not problematic so I guess my answer would be along the line of... "if it ain't broke, don't fix it." I seem to recall you saying that your mechanic installed the needle bearings. I would be suspicious that he had buggered the stock bushings/bearings and as an easy fix installed the needle bearings. But I'm a suspicious kind of guy and my honest answer is that I really don't know. | ||
| Torqd |
Had a friend that did that (installed needle bearings) and after a season the bearings were gone and the cams messed up...And yes it was done at a reputable dealership that races Buells at a high level...I think that I would stay away from that setup. | ||
| Madduck |
Needle bearing in this application are not for the faint of heart. They fail with great regularity. The main advantage they have is that they require less oil pressure to operate, hence you can reduce friction losses. They can theoreticaly tolerate higher rpm operation. Race only would be my take on this question. Paul | ||
| Panic |
Not familiar with the bearings used for this conversion, but the older Sportster needle bearings are drawn cup crowded roller Torringtons with no separators or inner races for maximum load area. Unfortunately, the needles rotate against each other, which increases friction and local oil temperature, and limits maximum RPM to about 5,000 (engine 10,000). These needles replaced the older higher capacity plain brass bushings used 1937-57 and had acceptable life for the lower speed iron Sportster motors. A conversion to cage-separated (INA?) rollers would involve either enlarging the case opening for a larger OD, reducing the journal OD, or both, to get more load capacity with fewer rollers. | ||
| Buellistic |
Ball bearings on the ends(both) of the cams do !!! In BUELLing LaFayette | ||
| Panic |
Ball bearing = lowest load capacity for size. | ||
| Panic |
http://victorylibrary.com/graphics/BUELLer.jpg | ||
| Samc |
I just stumbled on this and think it pretty funny that the MoCo went from crowded roller Torringtons, that worked mostly OK, to cage-separated INA's in evos, with consequent increase in failure rate of inner cam bearings; and has had numerous problems with the cam outer balls (now rollers in the rear cam outer) on twinkies. The current configuration, supposed to fix the problem for twinkies, is plain-element bearings, like in Sporties. | ||
| Buellistic |
Smac: The was the "WAY IT WAS" from the WR, KR, to early XLR's ... The way to go "NOW" is needle bearings ... In BUELLing LaFayette | ||
| Hobanbrothers |
As I dig through the KV I keep on coming to these interesting conversations and have to throw my .02 We have done this on race bikes for a while now, both new and old motors when a bushing may have spun and basiclly made cases junk unless bearing converted. I do not know who Frank knows of, I hope it is not one of ours that I do not know of as I do not know of one failing. There are tricks that you must pay attention to as it could easily be messed up with great consiquences! I have spoke to HD engineers about this and they have asked me about HP numbers before and after, but unfortunately, I have never done an independant study to just isolate the bushing to bearing conversion and as I told them, until they pay us to do just such a test we will never know! Regardless, it can and is being done, we have yet to have one fail and can save a lot of dollars if you were to have a bushing spin in the case that can not be repaired. On a side note, it is funny how some things change and stay the same... 37-57 cam bushings 57-I believe 90 cam bearings 91-present cam bushings 52-56 K model pressed together flywheel (straight pin) 57-I believe 99 / tapered crankpin 00-present straight pin pressed together crank I could go on with a couple more, but we will stop there... | ||
| Blake |
Darn engineers keep second-guessing themselves.  Very interesting and informative post; thanks! | ||
| Panic |
Close: 1957 XL has bushings, 58 has needles inboard. 1952-53 K is straight pin, taper begins in 1954 with KH. Why would they ask about power increase? Has nothing to do with cam bearings; major failures from spring load and RPM increase. | ||
| Hobanbrothers |
To race engineers, power is everything. Failures from spring load is what I believe takes out the bushing also. We do not subscribe to bigger is better theory here though, we run Ti 7mm stuff and do not overcam and actually run a pretty mild spring kit because of such light valves. We have run our race bike for 2 years (same cases, cam bearings and cams) turning consistantly over 8,000 RPM, Daytona 2x a year and that is absolutely the toughest enviroment for any street orientated motorcycle. The newer style caged rollers have failed with much greater rate in BTs and are an automatic for changing when cam upgrades are done. | ||
| Blake |
Jeffrey (Panic), Roller bearings, including needle type, typically yield significantly lower parasitic/frictional losses than bushing type bearings and thus can increase power delivered to the rear wheel. | ||
| Buellistic |
What about BeeHive valve springs and needle bearings on the cams ??? After all the tappets have needle bearings(FOR YEARS !!!) ... In BUELLing LaFayette | ||
| Panic |
That was a joke, I assume? Or were you going to explain the wheel next? | ||
| Hobanbrothers |
You know, I never even thought of the tappets, and I would believe there is much more force exerted on a smaller set of needle bearings there than a cam supported on both ends, good point. I guess I am on the fence regarding beehive springs. When the beehives were first introduced, we ended up getting wierd harmonics going on at about 7,200 rpms, depending on what cams we were running and I was told that beehives work great in their intended and designed use, but you step out of their intended use and you can get some bad mojo going on. So, with that knowledge in hand, how can the XLs run the exact same spring that the Buells do with no issue and pretty different cam profiles and lift. I do believe we butted up against it upper limit with cams and stock beehives, we ended up shimming spring a bit to get some more seat pressure and that moved the harmonics up to where it really did not cause and more goofiness. Since then we (actually Mike Perry @ Kibblewhite Precision Machining)have designed new valves with a spring kit that works well with the 7mm valves and does not cause problems with cam changes. I do not believe you have enough spring load from stock beehives to cause any concern with Torrington bearings on cams given you have not shimmed or gone exotic with cams. | ||
| Blake |
"Why would they ask about power increase? Has nothing to do with cam bearings;" I thought I was answering your question.  If you like, I can also explain the wheel to you. | ||
| Buellistic |
IMO after 6800 RPM the engine should have insert bearings on the rods instead on roller bearings ... BUT we will never get them with a bicycle evolved engine !!! In BUELLing LaFayette | ||
| Buelldyno_guy |
Here at H-D Buell of Vallejo we agree with John and have stayed with bushings. How ever we do listen to Brian and follow his suggestions on valve train items such as valve springs and now his new RP roller rockers. We also turn to 8200 so we try and keep everything as light as possible. There a few places where we might open up the clearance to the loose side of the tolerance. ... Terry |
