| Author | Message | ||
     Nillaice |
i'm re-building an 1125 motor and i am looking to increase the compression. i plan on running this bike on the track this year but would like to have it as a streetable bike too. has any one else done this? 1) can anyone advise how much material can have machined off the heads/jugs and 2)about what the compression would/should be? 3)should i have the heads or the jugs machined? 4)does it matter which? 5)should i use Cometic/other-brand head gaskets? or will OEM work for this application? 6)who else makes 1125 head gaskets? 7)also, how will this affect the valve timing? will it advance or retard them, and how can i compensate for that? 8)is there anything else i should know/change in doing this? | ||
| Stirz007 |
Give Michael Richter or Micheal T at EBR a call (or email) tech@ebracing.com. The DSB spec 1125 motor is at about 14 to 15:1 compression, involves milling. - but as you increase compression, you also increase chance of detonation and may need to run higher octane go-juice to head that off. | ||
| Jdugger |
EBR is the ticket. A high compression stocker will produce a fair bit more power than showroom, given the right fuel and exhaust. Over 150HP at the rear wheel using the belt drive is not an unreasonable expectation | ||
| Avalaugh |
Anybody Dyno'd one of TM(Dris) maps on a stocker yet ? They claim about 150 whp I think with there exhaust and intake stacks ? | ||
| Sprintst |
What are you planning to use for fuel? | ||
| Nillaice |
i e-mailed EBR, but just thought i could 'poll the audience' while i wait for a response and i was hoping to get away with just 93 pump gas. am i octane/detonation limited? | ||
| Sprintst |
yes compression always effects detonation, unless you mod the chamber typically, you need to up the octane when you up the compression, or you'll get detonation and bad things happen | ||
| Jdugger |
> i was hoping to get away with just 93 pump gas You might. You might not. Mine was milled .020 I think and after timing put the compression at around 14.8:1. It worked for a while, but I did start to have some trouble with detonation, or at least, it just didn't run all that great, on 93. I re-mapped to Sunoco GTX100. It's a 49-state street legal fuel, with a tiny bit of oxygenation and 100 octane. VP-100 is pretty similar. The bike runs WAY better, has a lot more spunk, and I picked up a few HP in the process. On our dyno down here, I dumped 155 to the wheel on a hot summer day. | ||
| Nillaice |
Jim, with .020 did you have to adjust/compensate for your valve timing? you said re-mapping ... was that for just the head-work or for other reasons? 14.8:1 sounds very impressive. i want but ... i might have to settle with something less than that for longevity and streetability concerns. there has to be a way to calculate the compression ratio ... anyone handy with a TI-86? i didn't pay enough attention in high school math class. if stock is 12.3:1 and .020 yields ~14.8:1 soooooo .010 splits the difference? it can't be that easy. ... it's an exponential ratio, right? | ||
| Two_seasons |
Isn't there some sort of "squish" plate that has to be accounted for when re-milling? I thought I read somewhere where the squish plate thickness can be whatever you need (within a reasonable +/- of the original) to accomplish a compression change. | ||
| Slaughter |
You have to know the combustion chamber volume . Take the volume (cylindrical) of the bore x stroke. The ratio of the two is the compression ratio. You will reduce the volume of your combustion chamber by machining 0.XXX off the head/base and that reduces combustion chamber volume by XXX. Recalculate. You MIGHT be able to look up combustion chamber volume somewhere... otherwise it can be directly measured (oil method - pic) or new optical scanning systems can do it "high tech" (had that done at CP/Carillo when making custom high compression pistons for my modified heads  | ||
| Jdugger |
> with .020 did you have to adjust/compensate for your valve timing? > you said re-mapping ... was that for just the head-work or for other reasons? You need to talk to EBR. What you want is a "DSB-Spec" build. It includes the milling and timing service. Basically, a DSB-spec build is the same thing as a superstock build in most racing classes. The remapping was to get the bike to run its best on my selection of fuel in hot, thick Texas air. It's NUTS. The power difference is not subtle. I have a quick-turn throttle and that motor, and the other day I got on my "new to me" CR for the first time and thought to myself "good gosh, this thing is tired..." It's that much difference. If you are in Texas come by... you will soil your leathers. | ||
| Stirz007 |
JD - they had to swap out the rear cam on my DSB build to get it 'just right'. It's still too cold around here to fire the beast up and see what it feels like - sounds like I need to head to the store and get some "Depends" before the first sessions of the spring. Have you firmed up dates for the Tejas track party (I remember something like 4/21). J-Money | ||
| Jdugger |
> Have you firmed up dates for the Tejas track > party (I remember something like 4/21 The problem with that weekend is I may be in NO at the new track there. I don't know yet. We could just sign up for that... April is pretty hit or miss in North Texas. I'd recommend late June or July. It's hot as hell, but the odds of rain are pretty low, and the beer tastes that much better. If we can get around 20 bikes, I can get the track on a Monday or Friday for just us. I've done it in the past with some friends from a local bike club. We just need to pick a date and work it from there. | ||
| Stirz007 |
It's about 36 hours from here to the Big Sleazy, not pulling a trailer. I'd really like to hit the new NOLA track, too, but I want to take my bike. I have a race weekend here on the 21st and 22nd. NOLA calendar shows the 28th being an open bike track day, which is also JazzFest first weekend. Tentatively I could leave here on maybe the 23rd and start heading back on May 1 - that would get me back for track day at MMP on the 5th (and burn two weeks of VaCay). It would also put me in your hood on April 25 and May 2, both Wednesdays... Higher Compression - back on topic (sorry for social interaction hijack) (Message edited by Stirz007 on January 26, 2012) | ||
| Rodrob |
Here are the specs I got from EBR for my 1125R race bike. I have yet to do it. .005 off cylinders. .010 off the heads. Piston to Valve min. for reference 1.9mm exhaust 1.3mm intake Squish no less .033" Measure carefully! | ||
| Timebandit |
is the motor an "interference" or "non-interference" design? | ||
| Kruizen |
Jim, what did you use to set up your quick turn throttle? | ||
| Jdugger |
G2 throttle w x50 cam. R6 or r1 throttle tubes work ok too | ||
| Avalaugh |
This is how I did my QAT http://www.badweatherbikers.com/buell/messages/290 431/603783.html?1289870422 | ||
| Avalaugh |
This is how I did my QAT http://www.badweatherbikers.com/buell/messages/290 431/603783.html?1289870422 | ||
| Nillaice |
RodRob, was there any mention to how it would affect/effect valve timing? | ||
| S21125r |
Nillaice, I crunched some numbers on a sticky note - Assuming approx 3" dia cam sprocket lowering the cam .015 toward the crank would retard the cam 1.14 degrees (crank degrees). I don't know what the actual dia of the sprocket is but gotta be pretty close... .015"/(3"*pi)*360 = .57 cam degrees = 1.14 crank degrees. Will ~ 1 degree retard make a difference? Dunno. If anything I would think that it would push the torque up the RPM band slightly. Possible that EBR already uses an adjustable cam sprocket on their race bikes for the purposes of shifting the band around for different tracks. | ||
| Avalaugh |
Ar'nt the stock pully's adjustable anyway ? alright they dont have markings on but the right person could easily fine tune them. |
