I am looking to put Hi Compression Pistons in my Carb'd Monster 900. I have my eyes on the JE 11.1:1 kit that CA-Cycleworks has.
What all do I need to know before "diving in" to a project of this magnitude? It seems incredibly straightforward, which is how I know I'm missing something.
As it appears to me, the project involves:
Pulling heads, pulling old pistons, putting in new pistons, putting it back together, wondering why a bunch of screws are left over, taking it back apart, putting it back together correctly, and then: [moto]
Like super-advanced Legos. What am I missing?
There's a lot of good info on Brad's site
http://www.moto-one.com.au/performance/900carbhighcomp.html (http://www.moto-one.com.au/performance/900carbhighcomp.html)
I put those in my bike about 9-10months back. The job was pretty easy. Before you tear it down make sure you get the base shims (gaskets), and o-rings that go between the jugs and heads. You should also replace your belts and adjust the valves while you have everything apart. Also make sure you have the proper wrench to remove and re-tourqe the heads and some molly lube for re-assembly. A inexpensive ring compressor and piston pin puller are needed. just make sure you get all of the tools and parts ahead of time or you'll delay the re-assembly process. Just take your time, label and bag the parts and double check your work.
Don't expect a big change. On my install the low end power was much more noticeable. (easier power wheelies and lifting the front exiting slow corners) Top end still drops off in the 8-8.5k range. Mine is a carb model but I have 41mm Flatslides and the Igintech module and Dyno tune so your's should be equivelent. I would recommend the dyno tune though as the infamous butt dyno lies and low speed throttle response improves immensely.
Ok, good deal. That's the info I was after.
I'm not expecting a world of difference, but the guys at the old shop I used to go to used to sing high the praises of hi-comp pistons and would always say there's really no downside. I figured that was two-fold, no rideability downside because it was only a slight bump in power, and the install wasn't all that involved - no machining etc.
higher compression = need for higher octane
TXduc's post is right on.
Tools I've used when JUST replacing pistons:
- splined sockets for head nuts
- ring compress tool (i have a cool ratcheting band type). you put the piston in the jug before installing the piston onto the rod for best results (well, i do)
- something to tap out the gudgeon pins. You can use a socket, but don't use your best set.
- wood mallet. i don't like using a plastic one as it ends up breaking up some. you need to tap off the jugs and even the heads sometimes.
besides replacing all the belts, gaskets and base o-rings, i would also get snap rings with heads rather than the POS wire they usually include for the pins. they are easier to remove and hold 1000% better than the wire clip.
don't forget to video the whole thing and post it on utube so we can all criticize and monday-morning-qb the whole thing.. [evil]
actually, if you've never done it before, it might be a very good video to do so you can show what a knowledgeable but inexperienced (with this particular job) joe can do with their bike. I bet Chris would like that video too!
i would seriously consider a set of Nichols Cylinder Head-Studs from http://www.nicholsmfg.com/ (http://www.nicholsmfg.com/) as well. Some of the older 900 motors had weak studs that tended to break. Higher compression puts more stress on them.
Wow. Ok, I would need to budget extra for those, the site lists them at $240 - and it shows 4. How many would I need? Is it four per head or two per head?
The fine print says "Qty 8." which would be enough to do one engine.
A lot of the parts available at Nichols Manufacturing were developed by Jon Nichols for his own bikes. He blew up four engines in his 955cc 851 before finding a combination that would survive. They mostly only make the stuff you can't get anywhere else. And it's usually the best quality that you can get anywhere.
Quote from: ScottRNelson on March 31, 2009, 01:20:41 PM
And it's usually the best quality that you can get anywhere.
+1
I gotcha. I have his breather on my 900 now. I will make sure to wait till I can do it all at once then. I would rather not have skimped on $240 and end up with a blowed up motor.
Don't forget to order squish wax when you order the pistons. And be prepared to dis and re assemble several times while adjusting and checking the squish.
You may even have to make custom base gaskets or machine the jugs to get it just right. Feel free to ask me how i know this.
Howard
Where might i need to machine? I guess I don't understand - same diameter pistons, do you mean to the heads?
Quote from: ato memphis on March 31, 2009, 04:25:40 PM
Where might i need to machine? I guess I don't understand - same diameter pistons, do you mean to the heads?
Didn't mean to be vague.
The (squish) is basically the size of the combustion chamber, measured at the edge of the piston at TDC. You may have to move/shim the cylinder & head assembly up or down in order to get the correct measurement. If machining is needed it should be done on the bottom surface that is going to be in contact with the base gasket and engine block.
Oh, ok! I gotcha.
its beginning to look a little more like a shop-procedure... however, it seems like something that would be fairly routine for a ducshop to do.
The Ferracci hi comp piston kits are SUPPOSED to be a drop-in. Setting squish accomplishes several things, i.e. setting compression, equalling compression, checking clearance, etc. I know ppl who have put those pistons in with nothing else and been fine. their compression between the cylinders may have been off a little but they probably didn't notice it.
Quote from: ducatizzzz on March 31, 2009, 07:09:35 PM
The Ferracci hi comp piston kits are SUPPOSED to be a drop-in. Setting squish accomplishes several things, i.e. setting compression, equalling compression, checking clearance, etc. I know ppl who have put those pistons in with nothing else and been fine. their compression between the cylinders may have been off a little but they probably didn't notice it.
The kit i used was Ferracci. Maybe i'm a bit anal about such things, but why go to such trouble and expense without maximizing the benefit?
ATO, you can do this mod yourself. It's a hell of a good way to get to know your bike inside and out. Just be patient and it'll work out fine.
And you'll know that no one was cutting corners when you weren't watching.
Quote from: hooligan machinist on March 31, 2009, 07:29:51 PM
The kit i used was Ferracci. Maybe i'm a bit anal about such things, but why go to such trouble and expense without maximizing the benefit?
ATO, you can do this mod yourself. It's a hell of a good way to get to know your bike inside and out. Just be patient and it'll work out fine.
And you'll know that no one was cutting corners when you weren't watching.
oh, i agree, i was just adding that the kits are good enoug hthat you can put them in without the tweaking.
i feel its best to set and equalize squish.. i also am of the opinion it's best to replace anything you can get your hands or or any disreputable part (ie. the studs)
Quote from: ScottRNelson on March 31, 2009, 01:20:41 PM
The fine print says "Qty 8." which would be enough to do one engine.
A lot of the parts available at Nichols Manufacturing were developed by Jon Nichols for his own bikes. He blew up four engines in his 955cc 851 before finding a combination that would survive. They mostly only make the stuff you can't get anywhere else. And it's usually the best quality that you can get anywhere.
I have the Nichols engine mount bolts and head studs. Both *quailty* products. You get what you pay for.
Quote from: DesmoTull on April 01, 2009, 10:10:30 AM
I have the Nichols engine mount bolts and head studs. Both *quailty* products. You get what you pay for.
i bought a $1 lottery ticket once and won $300
i would like you to share. pleeeeeaase. That will cover my nichols bolts and buy you a few cases of beer.
Quote from: ato memphis on April 01, 2009, 12:28:24 PM
i would like you to share. pleeeeeaase. That will cover my nichols bolts and buy you a few cases of beer.
sorry, i already gave it to some craps dealers and titty dancers