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Lornce
| Posted on Tuesday, January 29, 2019 - 03:17 pm: |
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I bought these parts here on BadWeb about 8 or 9 years ago from a guy in California, iirc, and he'd had them on his shelf for 10 years before that. He originally bought them from NRHS, I believe when Aaron Wilson was involved with NRHS. Am I correct in understanding Aaron was the brains of the operation back then? Anyhow, I've got a few questions about the pieces and would love the benefit of the experienced among ye. 1. Does anyone have a stock Thunderstom Head kicking around they can measure between the head's mating surface and the rocker box's mating surface? I'm trying to determine how much material was milled from these heads. 2. .536 cams. What's the ideal application and expected service life of these .536 cams? 3. Push Rods. How much deviation from stock height (ie: head milling, thinner head gaskets etc.) can the stock pushrods and lifters accommodate? 4. Valve Springs. I'll guess these heads were prepared by NRHS with the .536 cams in mind. I'll guess they're pretty stout. I'll guess they may be over-kill if I ran these heads with the stock .497 Lightning cams? What says all ya'all that know? Are these over-sized valves heavier than stockers? May seem obvious, but maybe not? 5. How durable would this combination of parts be if used on the street by a mature rider with no interest in attracting the wrong kind of attention? I'm a conservative guy worried about the aggressive cams undermining reliability of a pretty cherry low-mile '98 S1. Valid concern, or am I over-thinking this? 6. I'm liking the idea of the 1250 Nikasil barrels, pistons and heads. Just not sure about the cams. Does anyone forsee any issues using these heads with stock .497 Lightning cams? 7. Maybe this stuff would be wasted on me and I should just move it along and find some healthy stock Thunderstorm parts? Gurus, I beseech thy wisdom.
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Jayvee
| Posted on Wednesday, January 30, 2019 - 03:53 pm: |
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There's a push rod discussion on both NHRS and Hammer Performance web sites. So it probably would be useful to know the height compared to sock. Maybe somebody selling a stock head could measure for you? There's always adjustable pushrods. No original packing list/manifest came with it? 5. Over-thinking. |
Sportyeric
| Posted on Thursday, January 31, 2019 - 12:57 am: |
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My heads were 3.690 stock on my silver S2. Not Thunderstorm heads but I think the basic casting is all the same. The decked Thunderstorm heads that went on it were 3.668. I bought pushrods that were 30 thou shorter as a reasonable guess. Working out fine. |
Lornce
| Posted on Thursday, January 31, 2019 - 01:45 am: |
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Thanks, gents. Just looked at Hammer Perf's website (where Aaron currently works) and they offer custom length pushrods - which is a big part of this puzzle. Just need to verify decking and gaskets to determine required length. The rest should be fairly straight forward. |
Falloutnl
| Posted on Thursday, January 31, 2019 - 04:51 am: |
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Got a picture of the S1 they're going on? |
Phelan
| Posted on Thursday, January 31, 2019 - 08:04 am: |
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Those are a lot older than 10 years IMO. That level of head work later would have have more decking and a cnc cut squish band. Nonetheless, not a huge deal per se. .536 cams are not a huge deal for the street. They are less aggressive as far as valve train wear than the stock .551 E grind cams in the XBs, which run hundreds of thousands of miles often before needing replacing. Those springs are overkill for the street and cam, but they won't have have a significant impact on valve train life unless you plan to put 40k+ miles on the bike after building it. I say run the stuff as is, anything else isn't really cost effective. You can measure the heads with a caliper; stock height is 3.690 for all stock 91-03 XL and 91-02 Buell head castings. For the record, XB and 04-up XL1200 head castings are 3.670" tall stock; 04-up XL883 head castings are still 3.690". (Message edited by phelan on January 31, 2019) |
Lornce
| Posted on Thursday, January 31, 2019 - 11:45 am: |
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Let's recap: Bought 8 or 9 years ago from a guy in CA who had them on a shelf for 10 years, so that's 1, 2, 3, ... 18 or 19 years. Yep, older than 10 years. Reading are hard. .551 E grind cams which are operating smaller, lighter valves controlled by lighter beehive valve springs... Details are important. 40k miles would be around the average mileage of the 16 bikes in my garage. If these pieces won't last that long, they may not be much use to me. Thanks for the head dimension. That was useful information.
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Sportyeric
| Posted on Thursday, January 31, 2019 - 12:36 pm: |
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As I think about it further, if the valves have been recessed, that will affect pushrod length also. That was an error I made on my red S2. Had to disassemble and further shorten the pushrods. In hindsight on that one, I think having an adjustable pushrod to use as a measuring device would have been wise. |
Phelan
| Posted on Thursday, January 31, 2019 - 01:28 pm: |
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My point was simply that the cams themselves are not inherently bad; they are a better performing cam than the 551s. I missed the 8 or 9 years portion. That explains a lot. The springs, cams, valves will probably last longer than 40k miles. But those Ferrea springs are heavy and tend to wear out lifters prematurely. You will likely be replacing lifters in that time frame, for clarification. |
Lornce
| Posted on Thursday, January 31, 2019 - 10:52 pm: |
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Good thinking, Sportyeric. I'll need to talk to Aaron and see what he thinks. Turns out Hammer Performance is down in Idaho just a few hours south of here. Thanks, Ross. Appreciate your input. I'll need to figure out how much pressure is being developed by those Ferrea springs. At this point I'm half way thinking to have the heads redone with newer thin stem valves/guides and beehive springs/retainers. Seems crazy on a brand new set of heads, but it might be money well spent in the long run? Plus I have another set of stock Thunderstorm heads needing new guides, valves etc and that's the route I planned to go with them. Maybe do them all at once?
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Phelan
| Posted on Friday, February 01, 2019 - 09:24 am: |
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I much prefer the 7mm valves; I did a set of Thunderstorm heads for Eric that way (HD 7mm valves, guides and beehive springs). But essentially paying for the work twice; I would be more inclined to sell the heads as they are and have another set of heads done. Porting has come a long way in the last 19 years. "Impact" porting on a set of XB heads (or impact on Tstorms but with 7mm conversion) would almost certainly outperform the heads you currently have. (Message edited by phelan on February 01, 2019) |
Buelliedan
| Posted on Friday, February 01, 2019 - 12:42 pm: |
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Actually if you are thinking they were done 18-19 years ago (2000) that would have been when Brian Nallin was still running NRHS. Pretty sure Aaron took over 2 or 3 years after that as I believe Brian went to Revolution Performance in 2003. I could be off a year or 2 though as that was before my time. I came on at NRHS in late 2005. |
Buelliedan
| Posted on Friday, February 01, 2019 - 12:43 pm: |
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If you want Nikasil barrells you will need to get those from Revolution Performance though as NRHS and Hammer do not offer those. |
Steveford
| Posted on Friday, February 01, 2019 - 01:00 pm: |
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I think they were having problems with the Nikasil coating which is why NRHS dropped them. That's not inherent to the coating so maybe that's been resolved by now? |
Buelliedan
| Posted on Friday, February 01, 2019 - 02:18 pm: |
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yes you are correct. Here at NRHS we had lot so problems with the Nikasil plating which is why we dropped them. |
Lornce
| Posted on Friday, February 01, 2019 - 02:20 pm: |
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Okay, so that leads to my next question about these old Millenium Nikasil cylinders. As I now understand it, there was a period when Millenium were having QC issues and their cylinders were problematic. Does anybody know when that was? Does anybody know how to identify date of mfg\r on Millenium's cylinders? Long shot, I know, but you have to ask. Best evidence I have for mfg'r date is the March '03 Denver Post packing material in the Millenium boxes. Which is odd because Millenium Technologies were in Plymouth, Wisconsin. I guess NRHS added packing material before shipping? So that just tells me approximately when they shipped, not when they were made. I guess the million dollar question is how do you identify the cylinder batch that was problematic sixteen years after the fact? Arrgghh.
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Firemanjim
| Posted on Sunday, February 03, 2019 - 01:04 am: |
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Just use them, never actually saw any bad cylinders in all the ones we did. |
Lornce
| Posted on Sunday, February 03, 2019 - 04:00 am: |
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That's encouraging to read, Jim, and likely what I'll end up doing. Roll the dice! My only experience with Nikasil barrels is with old Airhead BMW's and on those things they last forever. |
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