| Author | Message | ||
     Jetlee |
I'll post up pics this evening. Didn't take many, cause I was too excited, but I got a few. The thing runs GREAT! Hard to keep my right hand under control and let the rings break-in. I've always been of the opinion "Break it in like you're gonna drive it!" It worked on my cars. The power is amazing. | ||
| Styxnpicks |
i'm jealous... | ||
| Jetlee |
 | ||
| Styxnpicks |
now I really need to get mine running.. what jetting are you using? | ||
| Jetlee |
46/175, air screw 1-3/8 turns out. I've also got a Yost tube and using the Yost blue needle on the second-from-top notch with a Yost shim below it. | ||
| Ezblast |
He just uped the main to 180 - to stop the tinkle - lol EZ | ||
| Gearheaderiko |
I didnt lie did I!!! I dont know if you're using a stock piston, but you're likely way too rich (as evidenced by 1 3/8 turns). I dont know the set up you're using, but I dropped my main down to a 150. I'm sure you'll figure it out, I just wanted to give you a heads up as the XB combustion chamber is a lot more efficient and uses a leaner mixture. I'm sure you'll have yours running way better than mine! I'm jealous too  | ||
| Gearheaderiko |
But you're cam timing may have affected things in a different manner. I also couldnt get the midrange lean enough, no shims required! (Assuming you're running XB cams, as I remember). | ||
| Ezblast |
Cool! | ||
| Jetlee |
I'm using XB cams, yes. The 46 pilot jet will go down to a 45 when I have the bowl off next time. It's at 1-1/2 turns out now. I had to up the main to a 180 though to get rid of the tinkle, as EZ said. With the 175 I was hearing a tinkle noise at low rpm's that was bugging the hell out of me. Reading about the the XB's, this was a fuel mapping issue below 3k rpm, which is pretty reflective of what I was experiencing. I changed my ignition map back to a stock-similar map, no change. Retarded it ~9 degrees, same tinkle. Took it back to my custom advanced map, still no change. Finally upped the main to a 180 and the tinkle disappeared. Advanced the ignition back up a little bit more and got the performance from it again without the tinkle. Kinda weird; I'm at the same ignition advance I was with the Blast equipment with a 180 main instead of a 170. It kinda makes sense, I always knew with automotive engines that higher compression needed more fuel. | ||
| Gearheaderiko |
"with automotive engines that higher compression needed more fuel." I disagree. If you mean soaking pre ignition with more fuel to subdue it, I dont think thats the best way to solve the problem. The big advantage with the XB combustion chamber is better performance and better mpg. I would've drowned with a 180 jet. Below 3000 rpms (with stock cam timing) the XB cams are pointless, thats not where they run or why you install them. What you might find though is now that you have a full XB top end, everything you learned jetting/tuning a Blast goes out the window. One example is that shimming the needle resulted in even worse midrange as the midrange was already too rich. I bought every needle I could find and experimented until I found the best one (which still wasnt good, but the best I could do). I did figure out a way to solve the problem, but never had a chance to try it as the 515 piston came apart (and finances imploded shortly thereafter)  I'm confident you'll get it tuned right, but I'll reiterate what I've said for years: once you install the XB top end, forget what you learned about tuning the Blast top end. It's different, but thats why you put it on in the first place! I look forward to hearing what you come up with. FWIW: You might want to get it broken in first before you get too carried away with tuning. Get it safe and stable. | ||
| Jetlee |
Most of what I've learned tuning-wise was one 4-bangers and old school V8s. Whenever you heard a tinkle or knock, you pull timing first. If that doesn't fix it, go back to original timing and add fuel. That's what I did. Stock Blast stuff was always giving me issues and wasn't making sense. Standard tuning procedures just didn't seem to be working properly. (I tune a lot by feel) I had been reading that the 515cc kit runs leaner than the stock Blast; but I'm not running the 515cc, just 492cc. I was weary at first, so I went up from the 170 to the 175 for the first try. That's where it was tinkling. No amount of retard got rid of the tinkle, even to the point the engine barely ran. I even tried different timing maps to pull timing at low rpm but retain the top-end; it just wasn't having it. I put my ignition map back in, set the timing back to where it was, put in a 180 ... VOILA! No tinkling. Way better top-end too. I advanced the entire curve another couple degrees, still no tinkle and better mid-range. I know that below 3k is out of the power band, and that's not where I typically run. But around town putting, to keep the decibels down I have to, and it sounded BAD. If I had a wideband sensor I would get the jetting dialed in perfect then adapt the timing, but I don't, so I'm going to have to rely on my butt-dyno and ear-sensor until I can either get one or get it to the dyno shop for a proper tune. Re break-in: I've always been of the opinion, break it in as you intend to drive it (in this case, ride it). It served well on the cars. (Message edited by JetLee on April 11, 2012) | ||
| Crackhead |
The 515cc kits for the Blast have a different piston shape that matches the squelch band angle in the head. The stock piston has the squelch band angle that is mismatched from the head and will push the fuel away form the the center of the combustion chamber. While the 515 kits have the correct squelch band angle and push the fuel towards the center of the combustion chamber, also the 515 kits typically up the compression ratio. The XB heads/ pistons use a flat squelch band and make sure you order the XB style pistons/jug if you ever upgrade to a big bore. | ||
| Jetlee |
With the thinner gaskets (.010"/.030" base/head), theoretical compression ratio is ~10.5:1 up from 9.2:1 stock Blast. I didn't clay the piston, so running solely on results of math based on specs for that number. So, do the 515cc XB parts have the angled squish band that pushes fuel to the center like the 515cc Blast parts do? Or is that an inherent property of the stock XB's flat squish band? I ask because, if Erik's 515 XB setup had an angled squish band that pushed fuel to the center, and the stock XB hardware does not do so...that could be why I have to run richer jetting. Just trying to understand why mine is requiring the richer jet to prevent pinging. (Message edited by JetLee on April 11, 2012) | ||
| Jetlee |
Erik, what cams were you using with your XB setup? Did you have a Dial-A-Jet? (Message edited by JetLee on April 11, 2012) | ||
| Jetlee |
So turns out one of my buddies works at an oil/fuel company. They normally sell C10 for $9.50/gal, he'll get it to me for $8.04/gal. Mix a little of that with the 91 crap at the pump and I can have 93-94 octane. He can also get me C16 for $12/gal. | ||
| Gearheaderiko |
Okay, now I'm really confused. Crackhead: Are you saying there are different XB pistons available? XB "style" pistons and other XB pistons? I never saw any differences listed and could never find 'stock' replacements in anything other than overbore or 515's (which are apparently different). We are strictly discussing XB top ends in this thread, is that what you are discussing? Am I missing something? | ||
| Gearheaderiko |
Stock XB9's were 10:1. Aftermarket pistons for the XB9's are commonly found as 10.5:1 My first piston was a CP 10.5:1 .015" overbore. With the Buell Pro Series and the 45/175 jetting it was strangled. Switched to a Why Bothers exhaust and leaned the jetting out. I had it on 3 Dyno machines and they all basically said the same thing: a 150 main was about right (ballpark). The a/f ratio followed the same pattern too. Honestly I never bothered with anything much below 3000 rpms. I never had any problems there, except the powerband was "dull"! The bike had 2000 street miles before it saw track only duty for at least the next 5000 miles. And it ran good! XB cams (SE XL'04 cams-same as the XB grind). Used stock CV Keihen jets and needles without any aftermarket add-ons or carb modifications. I mainly focused on handling which became much more important when everybody was running WOT through much of the course (and the Blast hybrids were coming out). I do believe there was a lot more to be had with some creative carb tuning, I just hadnt gotten there. We pulled it apart because the rings finally wore out. I did ask a few posts ago what piston you were running? If its a stock XB piston, that might be the difference. Might also be your cam timing, exhaust or intake too. My comment about break-in wasnt concerning how you do it, its just if the rings arent seated and the compression isnt up to normal running, you'll pull your hair out trying to get it tuned right. I ran the XB 515 solely because it was the fastest way to get the bike track ready in 4 days. I consider it a waste of money (and considering the piston came apart, it was a lot of wasted money). It had more power than the .015 over CP piston but it certainly wasnt a "bolt on" mod as advertised. It might have been because the XB's had fuel injection, so they had an automatic way of adjusting for anomolies. It turned out to be different than the .015" piston (515 is .063" over) in tuning. I just think the XB top end needs a little creative carb tuning since it behaves differently than the Blast top end. But its entirely possible yours needs it rich. I've conversed enough with you to know that you know what you are doing. I currently have a factory stock (and bore) XB piston and jug, but it only saw minimal use as the head needs the valves 'reseated'. All 3 CP pistons look the same (without a detailed examination), but are easy to tell apart from a Blast piston, high compression or not. It doesnt matter what jug you use as long as it fits. Blast, XB, 883, XL they all work. They are just designed a little differently. The XB jug has A LOT more fin area though! | ||
| Jetlee |
I'm using a stock XB9 piston/jug/head. I'm using the jug for two reasons, it's already matched to this piston, and I want the raw aluminum jug as opposed to the Blast black. XB9 cams timed as stock. I am using thinner-than-stock gaskets though, which calcs out the compression ratio from stock XB 10:1 up to 10.5:1. Crackhead threw a wrench in the machine and confused me. For the best idea of what I have, here goes... Front half of a stock XB9R engine, Force exhaust, velocity stack on carb, Yost tube and blue needle, 46/180 jets, Denso Iridium Racing plug, Ultima ignition (Dyna 2ki). "I've conversed enough with you to know that you know what you are doing." Thanks! That means a lot coming from one of the pro's! Even though at times I don't do exactly as you guys say, it doesn't mean I'm not listening or being arrogant, I just think outside the box as much as possible. Sure it takes longer to come to the same conclusion, but I enjoy the journey just as much as the destination. (Message edited by JetLee on April 11, 2012) | ||
| Gearheaderiko |
Velocity stack, yost tube and blue needle. With a grain of salt: I dont trust the velocity stack. I've seen too many variables and people having trouble with it. But maybe you are flowing enough air properly to need it richer. Yost tube: I'm not familiar with it to know exactly the effects of where and when its altering the a/f mix. Blue needle: I have no idea how this compares to stock CV needles. However, the needle profile can really fine tune the carb and some guys will actually sand their own needles down. The 'Jet Kits' will use very different needles from stock. If "The Force" flows as good as reported, maybe that accounts for some added 'richness'. The goal is to get more fuel into the cylinder and burn it as efficiently as possible. Take a compression test. From my experience 175 psi is great for a stock Blast. The 10.5:1 usually hits around 205psi. The lower your compression, the richer the mixture you'll need. I stuck with Badweb from early on because of the free interchange of ideas and experience without condescending BS or the "do it my way or you aint *dirt*" attitude some have. If at least any one of us wasnt contrary on a regular basis, we wouldnt learn anything! | ||
| Gearheaderiko |
FWIW: EZ is running 45/150 on 'Vader'. Though a different piston/head, I believe the reason its so lean is the compression? | ||
| Ezblast |
DAJ - lol - running 45/160 with the stocker with B50 cams - same reason - lol EZ | ||
| Jetlee |
I'm not liking the velocity stack placement right next to my knee, I hate that I can't tuck my knee in tight. It's not a true Force, but recreated to same measurements. I'll dig on the BRO site later and link some measurements I did of the Yost red and blue needles compared to both the Blast stock needle and the DynoJet needle. I don't have a NOK needle or Sportster needle to measure for comparison, or I would add it to that thread. | ||
| Gearheaderiko |
EZ, So you're running the lean main because so the DAJ can make it richer (or adjust for it)? | ||
| Jetlee |
Here's a good read on the emulsion tubes and needles, as I mentioned above. | ||
| Spade115 |
The motor (Pic added above) Looks real good, and This seems like a reasonable mod then buying the 515 kit. (Seems safer as well) I was wondering is going this route have better mpg/power results then just a 515 bolt on? | ||
| Crackhead |
Sorry for confusing your guys. Basically, if you are using the XB head and want to go big bore (515 or 600), make sure you order it with the XB style pistons. Since the XB head uses a flat (0 degree) squelch band, you would need pistons with a flat squelch band. Now if you are ordering high compression XB style pistons, they will have a dome. The OEM Blast head has 10deg squelch band but the piston came with 15 degree squelch band. (5 deg difference in the wrong way) Lighting style head but with a thunderstorm style piston. So, if you order a Blast 515 or 600 BB kit, you should get a 10 degree squelch band piston with a larger dome. Ok, back to how it effects the tuning. The OEM Blast reverse squelch band forces fuel away form the center of the combustion chamber. This makes us jet the Blast richer to make up for the fuel begin in the wrong place. If you are using OEM Blast parts and omit the base gasket, it should make things worse. So, just switching from Blast piston/head to XB piston/head, should allow you to jet down. You can have the XB head machined to have a 15 deg squelch band. This is aftermarket mod. Adding the squelch band should force the fuel to the center of the combustion chamber allowing for a more even AF ratio in the chamber (less lean spots) compared to the 0 deg squelch band. Since there are less lean spots, the AF ratio can be run leaner, since you are not trying to compensate for bad fuel distribution. Does that make sence or am I smoking again? | ||
| Jetlee |
That makes sense, Crackhead. Still haven't found why I require the 180 to prevent pinging, though. Anyone have a wideband sensor/gauge I could borrow and really get it taken care of? | ||
| Jetlee |
Erik, what ignition and timing curve did you use? I can replicate it on my Ultima to play with, and adjust from there. When I was hearing the pinging with the 175, and with the timing retarded a LOT (Ultima curve 4, last page, module turned back ~3mm/9º from crank notch centered in window), the engine dieseled for a couple strokes once. It was then that I decided I didn't have enough fuel. The curve that I've been using, and really enjoyed, was a hybrid. It's based on the SE ignition curves. I've read where most engines like setting #5. I took the part-throttle map of #0 with the WOT map of #9 from here. I have a middle-ground map made that should be close to the #5 map, but I'm not using it. (Message edited by JetLee on April 12, 2012) | ||
| Ezblast |
Even at idle the DAJ will add some fuel, so you must lean out to compensate for it, I like to keep my DAJ so that it is barely having to work and jet accordingly. This way it actually helps gas mileage. EZ |
