polishing intake ports

[Rooster]

So I have a 1989 FZR 1000 that came in boxes and was in a real rush to put it back together and fire it up but then I figured a slower approach might be better. What I want to know is if any one here has polished the intake runners up to the valves and did this have an effect in overall performance or is it just an extra load of work to remove the rough sand casting in the intake ports? I have the engine apart and the sleeve for cylinder #4 was replaced after being cracked from broken clutch basket debris, it came with new piston rings, a rebuilt second gear, a new clutch, gaskets and a few seals. I want it to be a good solid runner and am in the process of cleaning off the grime and grunge from all the engine pieces and want to deal with all the possible internal mods that I can do before buttoning the engine back up. btw I suck at posting pictures I tried but I am almost ready to make an example of my computer to all the other electronics in my house.

[banner001]

its a 100% myth that polishing = performance.

surfaces that are very smooth have large boundary layers where the air transitions from moving to not moving. slightly rough surfaces (think swimmers wetsuits from a few years ago, shark skins etc...) encourage smaller boundary layers, this means that the air you try to get in your engine is not pulled back so much by this boundary layer, a really smooth inlet is something to show off to your mates...it will probably hinder performance.

getting the head properly ported is a different matter, and if the tuner has the correct flow measuring equipment he can look at possible areas of casting to remove that are prohibitory to the air/fuel flow...that will be your best bet, proper race head porting and flow optimisation...its not just a matter of making it shiny

last paragraph http://en.wikipedia.org/wiki/Flow_separation

[Rooster]

so no bling on the inside cause its just for show

[banner001]

so no bling on the inside cause its just for show

if you only want it shiny then yes its just for show...a proper head tuner will have a flow bench, get the head properly ported then look at getting the flow sorted, this will probably involve some polishing, but it wont be super-shiney...i will get mine done at some point. a different set of cams and the bike will be cracking, i have never had a head-skim done on a road-bike...too likely to blow a HG or munch a piston/valve...

[Rooster]

yeah no it wasn't intended for show just more go, I lack the necessary flow bench so likely I will not go that way and possibly screw up a good head. By the way does anyone have a spare seat for an 89 FZR 1000 they'd like to sell I keep missing them on ebay and my boxes contained no seat. But I actually have hard bags for an FZR which was a wierd anyone on the European side of the world see an FZR 1000 with hard bags on the sides?

[banner001]

yeah no it wasn't intended for show just more go, I lack the necessary flow bench so likely I will not go that way and possibly screw up a good head. By the way does anyone have a spare seat for an 89 FZR 1000 they'd like to sell I keep missing them on ebay and my boxes contained no seat. But I actually have hard bags for an FZR which was a wierd anyone on the European side of the world see an FZR 1000 with hard bags on the sides?

if you can part with the head for 2-3 weeks and send it to a tuner you will probably see a few bhp from it without a head skim.

remember that the heads are a precision piece, already at 95% of their max performance...it is very difficult to get a few more bhp, but very easy to lose it.

[Rooster]

Yeah it is 1.5 degree's Celsius this morning in great old central Alberta so I think I can live without the head for a couple of months The worst part is the loss of any hope of riding for at least 6 months. What jet size do you suggest for about 850m above sea level? I still have my 79' XS11 that runs so I can still take advantage of a few warm afternoons.

[banner001]

have not taken my carbs for the fzr apart yet, but general rule of thumb is for every 2000ft of elevation go DOWN 1 jet size, so a 125 becomes 122.5 etc...but for every 10C drop in air temperature go UP one jet size, so for you at ~2000ft elevation drop 1 main jet size, but consider also going UP 1 main jet (so cancelling yourself out).

if the bike is fuelling correctly and not surging/bogging then its probably fine, consider tweaking your needle clip position and main jet when you get the head back from the tuner, it will probably like a bit more fuel, maybe stick a k&n/pippercross filter in there as well.

[Rooster]

I was thinking that I was over fueling mainly because the valves were so horrible when i flipped over the head to inspect it, the exhaust valves actually had to be ground down back to metal and the build up was making a polished mark on the pistons. I thought originally bad fuel but with only 28k on the odometer I figured the really carboned up combustion chambers were going to be a guessing game for me until I made contact with someone knowledgeable. Why do you think there was such a large build up on the exhaust valves?

[banner001]

I was thinking that I was over fueling mainly because the valves were so horrible when i flipped over the head to inspect it, the exhaust valves actually had to be ground down back to metal and the build up was making a polished mark on the pistons. I thought originally bad fuel but with only 28k on the odometer I figured the really carboned up combustion chambers were going to be a guessing game for me until I made contact with someone knowledgeable. Why do you think there was such a large build up on the exhaust valves?

rich mixture, so too much fuel in the system, combined with the fact that a rich mixture results in lower engine temeratures will all lead to excessive carbon buildup...remember though that the engine will get a small film of carbon over it within the first 100 miles, so no matter how clean you get it, it wont be that way for long

[Rooster]

When I get past the fact that I am a techtard and can finally upload photo's I'll show what I mean it was quite disturbing.

[DonTZ125]

No personal experience, but I am given to understand that polishing the EXHAUST ports can have benefits in reduced heat transfer and reduced fouling. YMMV

[Rooster]

got a photo in the gallery of valves how does one move it to this thread with a mac not a PC

[reelrazor]

here:




It's just that hole? The other two that can be seen are not so bad........not great but not horrible.

How's the cylinder wall in the hole look?

[Rooster]

They were all like the one on the left, most cleaning was done with varsol, there was a ring like clean mark on the pistons where the exhaust valve reliefs are on each piston. #4 piston had a chunk of the skirt missing so I bought a replacement from my local Yamaha dealer who said it was collecting dust for years, the sleeve in #4 was replaced because it was cracked when the clutch blew up. So all the cylinders were honed to clean up the light surface rust and to get #4 cylinder ready for the new rings, and yes the second gear problem was fixed and it came with a brand new clutch basket.