V1 Polini Carnage: What do you think?

Hello all,

I seized my bike a few weeks ago at my rally (which was phenomenal by the way) going down a massive massive massive(?) hill...WOT. Very stupid, I know, but I just couldn't help it. The thing was a total beast/wheelie machine and still SCREAMED for a V1 Polini. It probably wouldn't have seized if I didn't do this...the thing was pinned at some dumb high RPM as I was going over 65mph (passed my friend on his Harley ha).

Anyways, upon easing off the throttle towards the bottom, I heard a little ting/snap and the thing immediately felt sluggish. Balls. I killed the engine to let it cool off and it wouldn't start back up...zero compression. After my rescue from the vehicle of shame, I pulled the top end and saw this (attached picture).

Snagged a ring on the exhaust port. Also, burnt oil under the piston crown (never had this happen to me before). In another post, Mr. Motzing had suggested that this only occurs due to too much squish or timing...but HE custom squished my head (attached) and I retarded the timing (with a light, don't have a micrometer) a fair amount...like almost in between stock (23* BTDC) and TDC with it slightly closer to the stock mark (so maybe ~15-16*). I used to run stock timing but I wanted more revs and a safer, cooler-running engine.

So what do you think? Is my logic correct here? What should I do differently besides NOT going WOT down the biggest, longest hill on the planet, if anything? Is this cylinder salvageable with some port cleanup and an overbore (cyl has a lot of miles on it)? Are there any piston modifications that I can do to counter this heat? Swain Tech piston coatings? Run only 1 ring? Custom piston? Etc. etc.

Thanks in advance.

Re: V1 Polini Carnage: What do you think?

Re: V1 Polini Carnage: What do you think?

Other things to add: I spent a long long chamfering the ports after I got a new piston/rehone and I was also running 50/50 93 octane/leaded C-12 to fight heat soak and/or potential predetonation. Thanks!

Re: V1 Polini Carnage: What do you think?

Rob @t ATTN! Burrito /

"...but HE custom squished my head"

i lol'd.

not grahms fault, lower compression for higher revvs, get a temp sensor, handlebar mounted choke

Re: V1 Polini Carnage: What do you think?

Second ring got way to hott! and I see no gas porting holes. Robs, correct. Low psi w/ higher rpms. That's way I said run one piston ring. The atoms can get between the cylinder wall and the piston .001-.002 when it has grew from the heat. 1 ring will be easy to cool.

No stats of the engine/set up. Post them ? (edited)

Re: V1 Polini Carnage: What do you think?

@Rob Haha I'm not blaming anyone here, I just thought it was a little ironic. Graham did a fantastic job...not a single bit of carbon build up either.

@Ed What are these gas ports that you speak of? I am seriously all ears with that. Is it ok to simply use only the top ring? Will I have blow by issues? I'm very hesitant to do anything with the compression as the squish was JUST done a few months ago...I'll check my squish and see if I can be lowered to ~1.15mm (if it's not already) with a thicker base gasket. Or I can run a different piston :) just measured up the Polini one so the hunt begins...

Keep em coming!

Re: V1 Polini Carnage: What do you think?

Oh and engine specs: case matched and rebuilt bottom end w/NOS Minarelli full circle crank (rebalanced/retrued/rebuilt w/INA needle bearings), stock clutch with 80w Golden Spectro gear oil, 47mm Polini kit, full 19mm/25mm intake/exhaust match and polish, custom 19mm ID intake, 19mm Race PHBG w/262 AU atomiser/40 idle/40 slide/W7 needle @ second leanest clip/95 main, Ramesy Simonini pipe w/custom spring mounted header, yellow CDI for CEV flywheel (unmarked, bought from Ed a few years back), BR7ES gapped to .028", approx. ~15-17mm BTDC (used a light, need micrometer confirmation), BRN cylinder head w/countersunk copper head gasket and 47mm squish done by Graham, 32:1 BelRay H1R premix in 50/50 93 octane and leaded C12 fuel, 9x31 gearing aka ~3.4:1 final drive.

Re: V1 Polini Carnage: What do you think?

15-17 timing... Is it hard to start?

Re: V1 Polini Carnage: What do you think?

Oh jeez ha my bad I meant ~15-17*

Re: V1 Polini Carnage: What do you think?

you shouldn't blame graham motzing for your failures

Re: V1 Polini Carnage: What do you think?

@Ryan You should probably re-read what I've said as I specifically said I do not blame him and, in fact, I am very happy with the job he did.

Nice try with the douchebagery, though. Kind of unnecessary, but I guess that comes with territory in forums.

Any other thoughts? Or is it likely my set up was fine and the long hill WOT killed it?

Re: V1 Polini Carnage: What do you think?

@Ed Are you referring to the ring land porting? I'm strongly considering this now.

Re: V1 Polini Carnage: What do you think?

derek: "but HE custom cut my squish" sure looks like youre blaming him. sorry if you find my comments as douchey. i will now stand down. nobody is infallable even graham however i have used his heads for over a year now with great results. good luck in tune land.

Re: V1 Polini Carnage: What do you think?

Ryan, you're failing to read my response to Rob. Thanks though.

Re: V1 Polini Carnage: What do you think?

>>>taykoff [s2m] /

no intake transfer port window in that piston?....add one next time. That should solve your burnt oil problem....

Re: V1 Polini Carnage: What do you think?

Ignore everything written before this. You know why it siezed, you told us. Hone and chamfer that cylinder. Stuff a new piston in and go back to things. Stop bombing hills like that or get a cable choke to pull.

Re: V1 Polini Carnage: What do you think?

Haha thanks Mike.

Re: V1 Polini Carnage: What do you think?

Rob @t ATTN! Burrito /

MikeT, if you choose NOT to ignore reading everything written before your post; you'll see i suggested getting a handlebar mounted choke in the first response.

Re: V1 Polini Carnage: What do you think?

Haha now fellas...

I'm going to try ringland porting and other piston mods, along with getting the skirt and dome coated at Swaintech. Thanks for the help!

Re: V1 Polini Carnage: What do you think?

Re: V1 Polini Carnage: What do you think?

ohhh man thats a good idea... I'm building one of these rinnow.. so i <3 this thread. even though I'm very truly sorry for your loss D.

:s

polini on

Re: V1 Polini Carnage: What do you think?

Overpriced Parts /

Easy peasy just get a head temp gauge and keep under 400 degrees

Then you will know when to back off or whatever

Do all the things you did before, break in good

and run a gauge .

Re: V1 Polini Carnage: What do you think?

Soory there rob, after seeing solutions that include modifying the piston with unfounded tech I start to glaze over it. He knew why it blew, it sounded like he was more concerned with knowing if it was salvagable.

Re: V1 Polini Carnage: What do you think?

For a long time I was of the mind that you built an engine, tuned it, and that was it.. but I've found my engines have lasted much longer when you consider how your riding and what your doing - common sense I know, but I am slow to catch on sometimes...

my puch polini kit has survived only due to the same method that Rob/Michael are describing.. know the relative temp of your head and be able to dump fuel in as needed to slow/lubricate everything - I remember when I put it all together.. fast = hot = main jet fuel dump (jetted typically rich)... slowing down = hot = needle jet = less fuel/oil than main = hot death.. choke for the win

Re: V1 Polini Carnage: What do you think?

i always keep a couple fingers in there when im tucked down to go fast.

they like it! they like it ALOT!

Re: V1 Polini Carnage: What do you think?

Carnage is a fun word. and a Great super villain in spider man.

Re: V1 Polini Carnage: What do you think?

I have seen worse...I would say this is far from "carnage"

what you have is maybe "brutal"

Now this is carnage

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