G oog le BadWeB | Login/out | Topics | Search | Custodians | Register | Edit Profile


Buell Motorcycle Forum » Old School Buell » Archive through November 09, 2007 » Domed pistons... « Previous Next »

Author Message
Top of pagePrevious messageNext messageBottom of page Link to this message

Torquemonster
Posted on Wednesday, October 31, 2007 - 12:27 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Preface:

To give you an idea of the type of performance I currently get out of the bike, its mostly stock with only a V&H SS2R exhaust and carb jetting.

Flipped the bike a few months ago- replaced rocker box gaskets and put band-aids on the cosmetic boo-boos. Bike runs like a champ aside from a harder start than before.

BUT....
I found a little bit of oil on the case behind the rear cyl head last week and I cant seem to track down the source. Wiped dry and rode different distances / speeds / styles to see what would bring the leak.

Nada.

Being a fatalist/worry-wart, I feared I would have to split the case. Upon mentioning this to my father in law, who is a cert. ASE master mech and motorcyclist, pops suggested torquing the heads first. Then, if the case had to be split, throwing in some domed pistons.

To give you an idea of the type of performance I currently get out of the bike, its mostly stock with only a V&H SS2R exhaust and carb jetting.

Has anybody here done this?

Is the performance gain significant enough for you to do it again if you had to?

What all will I have to purchase to make this a worthwhile venture?
(sans intake as a forcewinder is in the works)
Cams? Ignition? XB rocker box covers?

Thanks in advance for any advice offered.
Top of pagePrevious messageNext messageBottom of page Link to this message

Djkaplan
Posted on Wednesday, October 31, 2007 - 12:59 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Are you sure the leak isn't coming from the base of the rear cylinder?

I believe M2 pistons had a slight dome in 2000 to match the Thunderstorm head's 15 degree squish band. The only reason for a higher dome is to increase compression ratio. How high a compression did you want to go to... and why? I'm not so sure you'd make any significant gains unless you matched the higher compresssion with more agressive cams and port work.
Top of pagePrevious messageNext messageBottom of page Link to this message

Ducxl
Posted on Wednesday, October 31, 2007 - 02:12 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Domed pistons=artificial displacement.I'm currently installing a set of 13:1 in my 996
Top of pagePrevious messageNext messageBottom of page Link to this message

Sloppy
Posted on Wednesday, October 31, 2007 - 02:15 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Your leak could be from the starter gasket... easy replacement.

As per DJ, your in-law is recommending domed pistons for increased compression. However, since compression is already high enough based on available pump gas, your bike's compression is high enough (or perhaps even too high).

Before you invest in any performance mod first sign up for a riding class. A few hundred dollars there will outperform a thousand dollars of hardware on your bike. Talk to anyone who's taken a riding class and they'll agree.
Top of pagePrevious messageNext messageBottom of page Link to this message

Torquemonster
Posted on Wednesday, October 31, 2007 - 06:34 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

After further inspection, I suspect its the starter gasket. The gasket looks wet, and the seam on the case is dry.

Good point sloppy. The big nut behind the tank IS an integral part of cycle performance. I had forgotten that.

Pops and I were thinking this may be a less expensive way (vs. axtell 1250 kit) to bump up the grunt while weve got it apart anyway.

Looks like riding classes and minor mods are in order here.

Intake, new exhaust (my V&H front hanger broke today), re-jet should get me the fix im looking for.
I imagine cams and an ignition module would be a beneficial purchase too.

Thanks guys. I really appreciate the info.

(Message edited by torquemonster on October 31, 2007)

(Message edited by torquemonster on October 31, 2007)
Top of pagePrevious messageNext messageBottom of page Link to this message

Ducxl
Posted on Wednesday, October 31, 2007 - 10:15 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Torque..i just did the starter gasket and later found the problem was with the stator grommet immediately ahead of the starter gasket.It's wet.How do you seal a rubber grommet? Not much,but a weep...but annoying.
something to consider
Top of pagePrevious messageNext messageBottom of page Link to this message

Bad_karma
Posted on Thursday, November 01, 2007 - 04:06 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Travis
+1 on the course. But before I would opt for the 1250 I would go with upgraded heads, cam, 42mm and exhaust if needed. My 1250 runs better than the 1203 but not that much better. Now if you ever have to split the cases an 88" or 90" is a worth while upgrade.
Joe
Top of pagePrevious messageNext messageBottom of page Link to this message

Djkaplan
Posted on Thursday, November 01, 2007 - 09:52 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

If I had to split the cases... I'd definitely get an 88" kit (1442cc). The top end kits larger than 1250 require the cases to be bored. That would be an optimum time to do it. I bet an 88" kit with everything else left the same (except jetting and ignition timing) would make any engine a mid-range monster.
Top of pagePrevious messageNext messageBottom of page Link to this message

Djkaplan
Posted on Thursday, November 01, 2007 - 09:55 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

"Domed pistons=artificial displacement."

There's no replacement for displacement!
Top of pagePrevious messageNext messageBottom of page Link to this message

Rick_a
Posted on Thursday, November 01, 2007 - 11:56 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

An 88" kit with everything else the same would mean a lot of extra torque and a modest bump in HP. A good cam/headwork/piston combo could do the same less with far less trouble. Now, the best of both worlds would be an 88 incher with properly set up heads/intake and a proper cam...but that's a whole lotta money and a bit more work.

The 1250 kit isn't necessary and doesn't really add much in terms of outright performance but some offer lifetime warranties and they are generally more thermally stable and have better cooling than iron sleeved bores.
Top of pagePrevious messageNext messageBottom of page Link to this message

Torquemonster
Posted on Thursday, November 01, 2007 - 02:09 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Food for thought, as I dont have funds to go all out at this point. Since the front exhaust hanger broke yesterday, Im motivated to just get it back on the road.

I had forgotten about the 88 kit...1442 cc's in a Cyclone?! I get "the grin" just thinking about it... "Scary fun" is probably the general consensus there, and a few courses are definately in line before I make that move.
I'll cross that bridge when I'm "able to" ride over it.
Excellent suggestions, all. Thanks so much.

-Anyone interested in the replacement I get from V&H? Im going with a different exhaust this time around. Not sure what brand I want yet.
« Previous Next »

Add Your Message Here
Post:
Bold text Italics Underline Create a hyperlink Insert a clipart image

Username: Posting Information:
This is a private posting area. Only registered users and custodians may post messages here.
Password:
Options: Post as "Anonymous" (Valid reason required. Abusers will be exposed. If unsure, ask.)
Enable HTML code in message
Automatically activate URLs in message
Action:

Topics | Last Day | Tree View | Search | User List | Help/Instructions | Rules | Program Credits Administration