| Author | Message | ||
     Ratbuell |
...if any of youse guys end up with a spare front thunderstorm head...I need one for my S3 Defender restoration. Just figured I'd toss that out...  | ||
| Rocket_in_uk |
To add to my last post, with reference to the confusion over stem size on the different heads. First off, stem in the UK means the long round section of the valve body. As it states in the above document, stem size is 7mm. I assume they are not talking about the valve stem but the valve guide itself. The valve guide is likely 7mm and not the valve stem! Then there appears here to be confusion as to the affect or not of the different size valve GUIDES used between the 04 up XL 1200 head and the TS head. If following the words from the company that state the XL head offers more HP due to the difference in port design over the TS head, yet they both flow the same rate, remember they are claiming this is the case for stock heads. If I were building a high performance engine, even just for a mild performance increase, I would never do so without flowing the heads. Not to flow is just a waste of time as all it leaves to the tuner is a choice of slightly bigger bore cylinder kits and / or a change of cams. That to me is a bolt on upgrade and likely a waste of money all things considered (like stripping the top end to install etc etc, paying someone to do it). You are only left with a carb and exhaust upgrade there after. So what is the point in looking at the later XL1200 head or a TS head if leaving them stock? The only point I can see is if someone were to put XL heads on a TS engine then they will have the alleged 4 or 5 HP increase is all. That's an expensive 5 HP if that's all you're going to do. There is no point in going for more performance without flowing the heads, no matter which head you have already or which head you choose to source for whatever you're intending. The stuff above from that company does not say which head offers the best performance when flowed. This information would be of much greater value to the researcher and prospective performance seeker. I suspect there's nothing in it when the magic has been worked is possibly why the information is not there. Anything less than the magic being worked toward is at best just a reference point and nothing here is telling me which of those heads works best once flowed. I do suspect once flowed turbulence and velocity will be appropriate to the kind of performance the engine builder /end user is working towards, therefore it will likely not be as critical (not that 4 or 5 HP is anyway) as the difference is at stock level. The crucial point here is this. Do your homework and trust in what you do or someone is doing for you! Rocket in England | ||
| Buellistic |
Are we discussing building a "TORQUE" 0r a "HIGH RPM" engine here ??? | ||
| Airbozo |
Well, My sportster is rocking an S&S 89" Stroker kit. Last dyno was 101tq and 96hp. It's a rocket in the straight a ways, but could use some help cornering. I had to re-learn how to ride that bike as it tended to want to pull up on takeoff. Even twisting the throttle coming out of a corner can be a bit scary if you don't realize the power it has. | ||
| Rocket_in_uk |
Is there such a thing as a high RPM engine in our world of tube Buells? From my limited experience you have to try hard to build a high revving engine if you are wanting to produce its preferred peak power high up the rev range. There is an abundance of great info in the BadWeB archives going back to the when the tubers were current models and we were all looking for more of this and more of that! I mention the archives for obvious reasons, and I am reminded of when some of the BadWeB community went crazy on posting up their dyno charts, and how the search for the perfect flat torque curve was all the rage along with a steady rising power line like the side of a steep peaked roof! It's all still there no doubt. You just have to go search. Rocket in England | ||
| Mikeyp |
Excellent help and a lot of great info here guys. I really appreciate you guys coming out of the woodwork, especially you Blake Rocketman! Seems like the old days indeed! Since running my own business takes alot of time, im squeezing in posting when i can. I still have a fair amount of tear down to do, and ill take pics as it goes. Im thinking to keep costs down, i'll stick with the 1250 and possibly go with XB heads if my Thunderstorms are too far gone. Thanks boys! PS. to whoever needed the front head, bear with me..i'll know in a few weeks if my rear head is beyond repair. | ||
| Kc_zombie |
A high RPM engine in the world of tube frames Buells is sort of an oxymoron. The design does not lend itself to that. Even today a Pro Stock Buell Engine redlines at 8500 rpm. Just sayin... | ||
| Buellistic |
Anybody remember the XBRR that ran "i" think only once at DAYTONA ??? Think it was maxed at 9000 RPM ??? | ||
| Radon30 |
High RPM is a matter of reference, of course 9000 is a high reving pushrod vtwin, hell 7500 is high. If you compared that to inline 4 of course its not, its about half of that. I think we've moved pretty far past what the orginal OP asked. I went with th 90" , its a blast to ride , haven't had any issues. I don't put as many miles on most, but sure puts a grin on my face when a ride. With that said, I think either will make you happy, but for the most part its not a plug and play, you will have to make some other mods to compliment the higher cubes. I am a believer nothing replaces CI's, but it will come at a higher cost. I have a hard time believing a 1250 kit will out produce power of 88/90 kit, maybe hp not tq and thats what these engines do best. I think when I was dyno tuning , I was over 110 ftlbs and the clutch was slipping alittle, don't remember was a few years ago. Never went back after that, Engine was running fine so no need. | ||
| Rocket_in_uk |
A high RPM engine in the world of tube frames Buells is sort of an oxymoron. Yeah why not. Oxymoron as a higher revving low revving engine I think would work. Rocket in England | ||
| Rocket_in_uk |
Mikey, the head should be ok. If it's chewed a ring and spat broken piston all over the place, the head will likely be scored and pitted. This type of damage will clean and polish out to a perfectly usable finish. Check valve seats for damage. Seldom do they suffer they being hard material. Valves and valve guides can be replaced (as can seats) if need be. Even a badly damaged head can be welded and machined though it's unlikely you'll be faced with such from a piston failure. Post pics if in doubt. If you do decide on XB heads you'll illiminate the puke issues some of us suffer with, should be a consideration. You may be better searching for a used pair with the rockers and covers etc, otherwise buying new might prove much more expensive. It's entirely possible you might be fortunate and turn up a complete top end. Even a gas flowed set at that. Search the right places I'd imagine. Rocket in England (Message edited by rocket_in_uk on November 14, 2013) | ||
| Phat_j |
There is no replacement for displacement.... go big if your already taking the cases apart, why wouldn't you? | ||
| Blake |
Expense and diminished strength. | ||
| Radon30 |
It is expensive, but I havent heard of anyone that had issues with the bigger bore on the street. I'm not road racing so I'm not flogging my bike at sustained high RPM's. | ||
| Rick_a |
XB heads, 1250, and N9 cams here. Also port work by Cycle Rama. 100hp and 90+ ft-lbs in a still untuned state. It averages about 45mpg and required such a delicate touch to ride that I purposely put a carb that's a bit too big on it (HSR-45). It was wheelying and sliding everywhere, wheelying more in the summer, sliding more in the winter, at low throttle openings. Buellistic must not have had his glasses on comparing the Thunderstorm and XB heads. The exhaust ports don't look all that different but the chambers, intake ports, and bowl areas are worlds apart. When my bike was stock I was really flogging it for all it's worth to get around in a hurry. It bounced off the limiter frequently. The way it is now, I rarely have to push it past 5K. I think the best combo would be big bore and de-stroked to 3.125." If I had the bucks, that what I would've done. | ||
| 2003xb9r |
I'm with Blake but would like to add... I have a stock 1200 S1w & an 88" S1w so can directly compare. The two bikes handle quite differently even though are otherwise set up the same. The 88" (all iron cylinders for strength) is a heavier engine, weight carried higher & it is noticeable to me when riding them. The stocker is definitely easier to flick around tight twisties. The 88" feels more planted & steady in fast gentle curves. It wasn't like this before fitting the 88". The 88" hasn't ruined the handling, just changed it. A 1250 with head work etc should be more than enough for the street. If you're into wheelies, the necked out stock cases for an 88" are scary thin, the case bolt between the Vee virtually non existent. I found getting over sized pistons etc a slow involved process when I rebuilt the 88" recently & seriously considered going to a stock cases/1250 combo. | ||
| Rocket_in_uk |
Rick, if we consider the performance gain from the XB head over the TS head, according to info from that company they claim only 4 to 5HP. That I'd wager is somewhat moot on the street. Whether it is or not, what that company don't say is what performance gains the two heads offer when flowed, and if one is better than the other. Without this info it's somewhat ridiculous to champion the XB head as the better head if tuning the finished motor for more performance where a gas flowed head is part of that tuning. Commercial reasons would have a company wanting to sell a customer XB heads as they're available new. TS ones are not. If fitting XB heads on a pre XB Buell you'd also find yourself having to acquire the rest of the XB top end, which is a great way to go and stops the puking of the XL head, but it does add more expense. Thus if you have a TS head equipped Buell already and you are going to gas flow as part of your performance enhancing efforts there is no reason to change to XB heads despite the difference in port shape from what I can see. Perhaps yes, change to XB heads if you don't have TS heads, but not if you do. The TS head puking can be prevented by fitting XB rocker covers at little expense. Speaking of your bike Rick, are you running stock US pulleys? Rocket in England | ||
| Rocket_in_uk |
I wouldn't personally go with cast iron. I've never had an issue with my AAC at stock bore. I've not heard of failings or problems from going 1440cc in alluminium from reputable manufacturers. Distortion or expansion issues are not known unless things have changed since I last researched. In fact the opposite was true during the early 2000's as material, technology, and quality had risen significantly. The case machining is not such a consideration either as a street ridden bike isn't going to stress the cases like perhaps a full on drag bike engine might. Rocket in England | ||
| Rick_a |
Well, the Thunderstorm seem to be preferred for big bore builds as the chamber is easier to work with. Stock vs stock there is no comparison. The peak HP/TQ figures are not dramatic, but the XB heads make a lot more power "under the curve," as they say...and people spend a lot of money to get that last 4-5hp. The valvetrain set up is superior, as well. My current gearing is 23/49, I think. | ||
| Radon30 |
I run the all aluminum cylinders, I haven't had any issues to speak of. For the first 2 years of its life I beat it at the drag strip regularly hitting 7200 . Now its just ridden on the street mostly drag strip when I have time.....Damn kids :-). I stated earlier if you have TS heads and are doing head work don't waste your money buying xb heads and doing head work. | ||
| Rocket_in_uk |
Under the curve is very important as that's where a lot of riding will be done on the street. In fact, likely most of the riding. Is this really proven for the XB heads over the TS heads, or is it more seat of the pants claimed and the foundations of such based on the odd few known better results? I've seen some pretty flat torque curves for TS headed tubers that would appear hard to improve upon. Do we have any XB headed tuber comparison dyno charts supporting the XB head as a consistently better performer when looking at the torque line to determine the under the curve power delivery? Sorry to sound a little sceptical but I am! I doubt to be honest there's much in it at all once either TS or XB heads have been flowed. Is Pammy not here these days? She would know for certain. Rocket in England | ||
| Diesel_lv |
Just my .02, I have a NRHS 1250 with XB12 heads on a 94 hardtail. S/E536 cams and stage 2 headwork. 98.98 hp and 87 lb/ft trq. More than happy with it. I had a 120" twin cam and due to large bores and short piston skirts, I had to rebuild engine once a year because of piston slap. I average 15,000 miles yearly. If you don't ride many miles, the 88" is a great setup, if you put on a lot of miles, then the short piston skirts in the 88" kit will probably cause the same issue. | ||
| Rocket_in_uk |
If you don't ride many miles, the 88" is a great setup, if you put on a lot of miles, then the short piston skirts in the 88" kit will probably cause the same issue. I wouldn't say a short skirt piston is necessarily a cause for concern. It would come down to a few factors. Not least of all what piston in what cylinder and how the engine was set up and running. Maybe if you're looking at high mileage use, don't choose to go with a short skirt piston. And of course, what is considered to be a lot of miles. 20000 hard miles? How many oil and filter changes? What oil? What weather extremities? I'm no authority on 88 inch engines but there seems to be a great deal of suggestion they're unreliable when coming from a 1200 original displacement. That's just rubbish. The unreliability of such conversions is always down to the individual build and its given use. Build it right and treat it right and it'll be as reliable as the 1200 it was made from. It really is that simple in my opinion. I'd be happy to put mine and my money where my mouth is, and still might do so one day. It is after all true what American's say. There ain't no substitute for cubes, right? Rocket in England | ||
| Diesel_lv |
Due to the stroke and piston diameter on the 88", the piston skirt has to be short so the pistons don't hit each other at the bottom of the stroke. Not sure on the 88" of they are also clearanced as the pistons on the 120". I'm sure they are reliable, but with the cylinder wall being worn from the piston slap, I would think that the cylinder would need to be honed and new rings every year. I could be wrong tho. On my 120" it was new rings and hone or new cylinders and rings once a year. But that was on 15,000 miles a year. And yes, it was hard miles. Why else have the extra power and Cubic Inches... | ||
| Mikeyp |
Rocket Check out the damage to the heads and the rest of the motor. Think the heads are repairable? https://www.facebook.com/mike.palladino1/media_set ?set=a.10150407199805188.626759.542860187&type=3 | ||
| Radon30 |
Damn wanted to see the pics but don't have facebook | ||
| Rocket_in_uk |
Damage to the heads? All I see is chics chics and more chics Mikey? Rocket in England | ||
| Radon30 |
What???? ...I want to see too!!!!! | ||
| Rocket_in_uk |
And yes, it was hard miles. Why else have the extra power and Cubic Inches... Well, because a big inch motor should offer a lot more torque, it's not all about giving it a hard life. Quite the opposite actually. As mentioned earlier, riding under the curve a well set up 88 inch motor will make for a lot of fun without it being ridden hard to near death. We can go big for reliability and not just performance, and many do. Rocket in England | ||
| Diesel_lv |
Hard miles, Not flogged miles. Yes, the 120" offered a lot more torque. 130 lb/ft, but at over 4k rpm. It was in an electra glide. I rode it from Vegas to NY to Jersey, VA, AL, TX and back every year. That and riding 6%+ grade mountains on a regular basis. I haven't seen the torque curve of the 88" so I don't know where the torque comes in. But, "a lot more torque" doesn't do any good if it's not in a usable rpm range. Cycle Rama did a write up in Night Rider about a 100/100 motor. That logic would also apply to the 1250 engine. A 95" motor pulling 100 hp and 100 lb/ft of torque. The torque comes up to 100 at about 2500 rpm and stays flat till over 5k. That's usable. |
