| Author | Message | ||
     Strato9r |
So, I've been collecting parts for a Blast- based project, having determined that my Firebolt runs too darned good to be pulling apart (yet). Somewhere, I came across a thread regarding building up the cases around the cylinder mounting area and fitting the engine with a 4" bore cylinder, but no specifics were given. This seems like a pretty slick idea, especially considering that there is no rear cylinder to complicate things. Any insight into what pieces were used for that setup, or if a Twin Cam cylinder (and head) could be used, would be gladly appreciated! | ||
| Clutchless |
I'm pretty close to positive that you need to use a sporty or buell jug and head for this. The twin cam jug would be ginormous next to your blast cases. Not saying that it cant be done, but you will find easier results sticking to some 1203 buell parts, or just boring out the old. I have seen and rode a blast with 1 xb12 jug and head setup, so you can pull it off if your crazy about your blast. | ||
| Blake |
I think that you can use the big twin cylinder, but of course doing so requires some serious work to the Blast cases to get it to mate up as the bolt pattern is different; not sure about oil passages. I think I once read one of EZBlast's posts where he mentioned that Revolution Performance had said it was possible. You might try contacting Brian Nallin there about that. This would definitely be a project for an experienced engine builder. | ||
| Jlnance |
What would the displacement of that be? Someone already makes a 616cc kit for the Blast. | ||
| Blake |
I've seen a bolt on 515cc kit and a 600cc kit (case boring required), both of which retain the stock Blast crank/stroke. Using a longer stroke XB12 style crank, the Blast can support what amounts to half of a 1250cc kit. No case boring is required for that. From there, you can still retain the stock cylinder mounting scheme and go as high as half of a 90" (1,474cc) engine kit, which would yield 737cc in Buell Blast Thumper form. This also requires using a longer stroke XB12 crank and also requires case boring for the 3-7/8" bore cylinders. Above and beyond that, then you are talking about drilling, tapping and boring the cases for a larger base bolt pattern and larger cylinder, a big twin cylinder. That's all I know based on what others have shared. I have no idea if you could make it all fit in the stock Blast frame or not or what other issues may arrise. Sure sounds like a fun project though.  (Message edited by Blake on March 10, 2008) | ||
| Strato9r |
Thanks for the responses thus far, this project is getting more interesting, and educational by the moment. I've laid out a template of the stock cylinder base of a twin cam engine, and it is do-able as far as gaining some extra bore potential, but with 3.813" bore size available with the stock stud layout, it hardly seems a worthwhile effort. I gotta admit, I'm impressed that the Blast has a 7.44" long rod with such a short stroke; definitely a Smokey Yunick approved rod to stroke ratio at just under 2.4-1! That, along with a crank assembly that is WAY lighter than I thought it was going to be, has me thinking that a 3.813"x3.125" combination (587cc) is worth considering. I'm still collecting parts, so we'll see what pops up; I'm taking a look at some decent, low mileage Sporty cranks this weekend, and a guy who was in our shop today is checking to see if he still has a set of 4.312" Truett and Osborne flywheels in his stash pile. (806cc!!) As far as machining and assembly goes, no sweat, we've got a really well equipped shop, and do the cylinder and case boring as well as full radius valve seat work for the local dealer and the better independant shops in the area. I pretty much had to come up with a project so that I could finally say "NOW" to the people constantly asking me when I was actually build something for myself! This little Blast powerplant has got to be the most ridiculously overbuilt engine I have ever seen! There is soooo much overkill in the thickness of the cases, clutch and transmission capacity and nearly stress-free engine geometry, I would imagine that not many of these things have any sort of problem under normal operation. Which is exactly why I'm driven to see what I can do with. I have been collecting parts for a couple of years now, and although I love the street tracker look, the way I'm starting to see things shape up is just as minimalist as a flat tracker, but with clip-ons, rounder, more sculpted tank and tail section and very little polished metal. And, skinny. Like old Indy roadsters, or 50's midget racers. No fat tires, as a matter of fact, the wheels that I'm mocking the bike up with are 19", front AND rear, and will probably be fitted with 4.10"x19" Avons. What the heck, if I'm going to build a really unique engine, might as well wrap a really unique bike around it!! | ||
| Fast1075 |
Did anything ever come of this project??? Inquiring minds want to know.... | ||
| Strato9r |
Yes, the project is ongoing, but on hold for the moment. Our shop is undergoing some long overdue upgrades, so my spare time is at a premium, especially since my evening job (Fender Guitar repair tech), keeps me busy for at least a couple of hours a night as well. The machine that the engine will be fitted to is close to being tested, however. Comprised mostly of Yamaha parts (for the sake of convenience at the moment; they were cluttering up my garage, anyway), the test mule is actually a stock XS400 inline twin in it's stock frame. The rear swingarm is off of a late 70's Yamaha dirt bike (a 400 single 2-stroke) monoshock setup , sprung with a Buell XB coilover. Up front, an XS 650 fork setup is there for the time being, but I'll probably end up using a non-inverted Buell tuber front end on the final iteration of the bike. Wheels are 19" Yamaha cast 7 spokes, a stock XS650 unit on the front, and an XS1100 front wheel, which has a beefier hub for mounting a drive sprocket to, on the rear. The frame that I'll be using on the Blast powered machine is another XS400 frame that has been modified to fit the big single, as well as beefed up with a lot of the same upgrades that SR400s being raced in Japan receive. It is actually a decent little frame; lightweight with the bulk of it's strength in the upper tubes, allowing me to ditch the single downtube and lower section, and use the Blast engine as a stressed member. I've got to admit that the inspiration for the project is that nasty little blue and yellow street tracker photo that keeps popping up around here (Thanx, EZ!!). As for the Blast engine itself, I'm dealing on a complete, running stocker right now, just to expedite the project, as I'd really like to ride the thing, until such time that I get whatever engine I'll ultimately use completed. Final version is still somewhat up in the air; I've got some truly sick possibilities lined up, including machining up a custom cylinder and drive setup to mount a Honda XR600 cylinder head on the thing, or a prototype Desmodromic setup that I've come up with for a stock cylinder head. Right now, though, it's simply a matter of having too many irons in the fire, and that's a sure fire formula for getting nothing done at all. I promise I'll keep you posted as things progress. Right now, I just wish it was warm enough to ride my 'Bolt! | ||
| Fast1075 |
Good luck on the project Strato...I'll keep my eyes peeled for future development. | ||
| Cvc |
Ok it's been another year and the winter weather is keeping us indoors Has there been any progress on your giant blast motor? | ||
| Strato9r |
Well, I had a nice collection of parts together, but unfortunately, my wife lost her job last fall and we ran into a bit of a cashflow shortfall. I sold the cases, tranny and crank assembly to a decent kid who owns a Blast that had a trashed bottom end. I more than doubled my money on what I ended up selling, and he's got a good running machine now, so even though that project is gone for the time being, all is good. I've had to sell cool stuff before, and what the heck, it is just stuff, and it's always worked out better in the long run. I've still got my XB, as well as my BMW, so i consider myself lucky, especially when I see folks down in the States that have been put in terrible financial situations by the screwed up economy, and have been forced to sell wonderful machinery for pitiful amounts of money. My girl has some good prospects on the horizon, so I'm sure I'll be able to continue the project when things get a little better. I'm one of those people who tends to be a little hard on myself when I don't finish something I started, so this is something I'd love to get back to! I still have the frame, forks and wheels, as well as some other neat pieces to use, so the only thing that has to be replaced is the engine, and there are still lots of those around. I really appreciate your interest in the project, though, CV, thanks for asking! | ||
| Cvc |
Sorry to hear about the bad luck But glad you were able to make"lemon-aid of life's lemons" on those parts. I have a blast with a trashed crank and top end. and need to do something with it. Looking for Ideas. bike has a salvage title and 1600 miles see the thread above this on for explanation. |
