| Author | Message | ||
     Xb12s |
I'm going to upgrade my XB12S with a 88 ci kit from Axtell, and in addition, I'll have the heads machined and the cams changed. BUT exactly what should be done with the heads, and what cams should I run? Any recommendations for street driven bikes? Axtell recommends to replace the injection with a Mikuni carburetor. However, I'd rather go with the injection tuned with ECMSpy. OK, the throttle body is a bit on the small side, but I'd rather swap some high rev power (provided by the carb) for driveability all through the engine's register (provided by the injection). Any comments on this? Recommendations? | ||
| Blake |
Tell the performance experts what kind of performance you are wanting and what kind of durability you want, and they'll advise you accordingly. My strong recommendation is that you have ALL they work specified and performed by the same performance shop. Talk to Hal's, Cycle Rama, JET, Revolution Performance and others listed in our sponsors section. | ||
| Bad_karma |
Patrik As Blake said ask the experts. What I did with my S3 was redshift 630/585 cams, Zippers head work. This motor makes power all over. It is very streetable running smoother and no hotter than the original. I have the HSR45 installed, it works very well out of the box. I thought it was pinging so I went up two jets, not happy way too rich. It turned out to be my belt about 2-3 mm too lose. But with your desire to stay with fuel injection I feel you need to talk with some one that has done it. I believe that there is a Buell tuner in Europe that has an 88" with the stock fuel injection. As a fact the is a post in here concerning this subject, good searching. Joe | ||
| Alex |
XB12S, You can not fit a 45 Mikuni on a XB model as it has a downdraft intake system. Furthermore replacing a 49mm injection system with a 45mm carb is probably not an upgrade. Keep the stock injection. Furthermore I recommend to keep the stock cams. They deliver excellent power and torque for street riding and safe You from many problems (You don´t need different valve springs and camtrain stress will keep stock guaranteeing a long engine life). Additionally You can stay with stock compression. Bad_karma speaks of a European tuner. Maybe he is thinking of me as I have posted some dyno graphs of my engines here on Badweb (sorry I can´t remember where). Do a search (maybe by using my name as author). If You find the graphs be sure to read the hole story carefully as numbers may be misleading. If You can´t find the graphs simply tell me. I will try to post them again or send them by e-mail. Thanks. Good luck with Your project. Alex M-TeK Engineering Germany | ||
| Alex |
Me again, You should find my posting here: http://www.badweatherbikers.com/cgibin/discus/show .cgi?tpc=32777&post=1001608#POST1001608 | ||
| Alessio66xb12r |
Freespirits team used on their 2007 supertwin-class xb 1250 race bike a modified 45 carb . he told me it was a real pain to fit it because of the downdraft design of xbs . anyway i agree with Alex this is not an upgrade . they told me about some difficulties to tune the xb injection .... Alex (a lot of questions for you...) have you experienced different fuel pumps pressure regulators and injectors in race(track not drag) engines ??? i heard somethings about mods on the stock fuel pressure regulator to obtain a little bit more pressure in the fuel line ....do you know something about ??? bye Alessio | ||
| Firemanjim |
There are upgraded fuel pressure regulators available as Terry had some for the Vallejo roadrace XB 1208 motor.Ping Buelldynoguy.Might have had upgraded injectors also,but cannot be sure.You can have throttle body bored out,also. | ||
| Xb12s |
Thanks for all the input! I'll have all the work done at speed shop here in Sweden, and I'm confident that they'll do a great job. However, their specialty is Harleys (the guy who's gonna machine the heads build Harley drag racing engines). They've been doing this for like a gazillion years, so I know they've got the skills needed. They asked me to do some searching/asking on Buell forums first, even though they have some ideas for cams and what should be done with the heads. Always good with some input and advices before you get started. I'll forward a link to this thread, and a link to Alex's thread to them. Thanks again!! | ||
| Alessio66xb12r |
thank's Jim i bored my throttle body and mainfold(one piece on xbs). i'll ask to Buelldynoguy . right now my engine seems to run regular and even cooler than ever , but i really don't know how much life stock injectors have in this conditions(27%more "opening time" at wot from 5000 to 7000 rpms). Jim i saw your new bike on this forum.... COMPLIMENTS. bye Alessio | ||
| Xb12s |
Alex; when you built those engines, did you do balance the crankshaft? I've heard that it's hard to balance the stock cranks after '03 due to the construction, and that one could swap to an older type to be able to balance it. I guess the bottom line is: Is it necessary to balance the crank when you swap to a 88 ci kit? | ||
| Alex |
XB12, yes, all my crankshafts are balanced. The new style crankshafts are a press style construction but if You know how to do You can disassemble them, balance them and reassemble them. And yes, I would recommend to balance the crank (even balancing it for a stock engine is a good idea). Alessio, I do not have any experience with different fuel pump regulators or injectors as I always got along with the stock components. One easy method to increase fuel pressure would be to squeeze the stock regulator metal body thereby increasing the spring pressure that acts upon the regulating valve inside (unfortunately this would be a rather rough and unexact method). Regards Alex | ||
| Xb12s |
Thanks for the quick answer Alex! Balancing sounds like a good idea, I'll look into it. | ||
| Bombardier |
Perhaps an inline tap to increase fuel pressure as required. | ||
| Alessio66xb12r |
hi Alex squeeze the stock pressure regulator is exactly what i did on mine ( 1,3mm) . right now i'm pretty satisfied with my engine i found a good fuel map , after a lot test rides . i think i will stay with my stock components , when they will last i'll look around. i agree with you again : balancing the crank for me is VERY important maybe the most important step to do even with stock components , i know that it is a no popular choice and people are not happy to hear this because is not easy to do but its true. an 88 square motor with a well balanced crank has less vibrations than a stock 1200 , this is what i experienced. i'm working on a new front end ,i got all the parts i just need some time (not only time) to adapt it on my frame. when i'll finish i'll show you some pictures of a NO-BUDGET 88xb race-bike. thank you bye Alessio | ||
| Aeronp1 |
Hey,guys i am totaly new to this.I own a 2003 xb 9r and i need to get more power out of the motor.I have a guy that tells me to do just the heads,not the cylinders. And another one who tells me to do the cylinders (big bore)and live alone the heads.A third one tells me to do both.I am just about to go creazy any ideas??? | ||
| Xb12s |
Alex, one more question (I'm a pain in the ass, I know), did you keep the stock connecting rods? If you kept the stock con rods, did you do anything with them? Weight matched, magnafluxed them etc? | ||
| Alex |
Yes, I normally keep the stock rods. I do match the upper part for same masses and sometimes give a little more running clearance to the lower part. Never had a problem with it in a street engine. Alex | ||
| Xb12s |
OK, thanks again for all the answers!! | ||
| Alex |
You´re welcome. | ||
| Xb12s |
Alex -> I've got (yet) another question for you. This time it's from the guys who's building my engine at the speed shop. They're wondering what balance factor (not sure of the correct term in english) you used when you balanced the cranks. To be honest I'm not exactly sure what that is, but I guess it's how much you have to balance the crank. (This is one of the reasons I didn't do the job myself.  ) They've balanced my crank now, and thought it could be interesting to have some other figures to compare with. | ||
| Alex |
Ask them what balance factor they use and I will tell You if it is close to mine  | ||
| Xb12s |
Ha ha ha, well they've used 58%, but they think the vibrations at 5 500 rpm are a bit irritating. Is this close to the balance factor you've used, and what do you think of the vibrations at 5 500? Normal? | ||
| Alex |
XB12s, I use 58% most of the time,too. Irritating vibrations at 5500 may have a lot of reasons (You normally balance the crank, but there are many more moving/rotating parts inside the engine like clutch basket or the sprocket) but I don´t think the balance factor is the reason in Your case. Most of my engines really smooth out with rpm with 58%. Regards Alex | ||
| Xb12s |
Thanx (again)!! I'll talk to the speed shop and give them your input.  | ||
| Alex |
You´re welcome. | ||
| Pikeslayer |
Xb12s, Keep us posted on the build. Is it running yet? | ||
| Xb12s |
Hi, no it's not running yet but I'm hoping it will be in the near future (1-2 weeks). I'll get back with the dyno chart, and when I've put some miles on it I'll get back with some impressions. Stay tuned for more rock 'n roll! |
