Forcing Cone Lengthening and polishing

[westley]

I had my early 3800 forcing cones done in around 1986, at that time it was the 'in thing' for reducing recoil. I believe that dropping to 28 and 24 gram cartridges did more on the recoil reduction front,  than any barrel work ever did.

PP

I use BOTH plastic and fibre wads through my 725, which I believe is overbored, without any visual effect on target breaks (I do NOT go in for pattern plating, something I learned to leave alone many years ago). I rely solely on the results,  'out front' on targets,  be they game or clay. IF there is a plastic wad ban, I will not be rushing to get rid of my gun,  I feel maybe THAT would be going 'Overboard'  ! 

 

[schmokinn]

Well

straight off

KH250, then KH650,KHZ1000J1,KHGPZ1100B2,KHGPZX1100, YamahaXT550,Kwasaki ZZR1100, KawasakiZX9R,Honda Fireblade 929RRY and now BMW1200 GS plus a lot of brit bitsas before all of them. But the point still stands I have never had an after market exhaust that did nothing when used properly yes some did need a bit of induction work but now most of they modern sports bikes can uses these things straight off the shelf and change things for a considerable better... the weight saving alone is worth something on its own. The thing about Vale is the most pertainant part of the equation... 99% of road going motorcycle riders do not have the ability to even sense what they are getting they rely on a computer print out telling them ! :lol:

Lot of unknown kh models there!

Can i presume the 650 was actually a 750 and the rest are typos?

 

[jwpzx9r]

Lot of unknown kh models there!

Can i presume the 650 was actually a 750 and the rest are typos?

Clear;ly you know the square root of F all about late 70's and eighties motorcycles BTW I missed a KH GPZ9r off that and an older KH Z1000B2

 

[schmokinn]

Clear;ly you know the square root of F all about late 70's and eighties motorcycles BTW I missed a KH GPZ9r off that and an older KH Z1000B2

Sorry not anal enough to converse in full model numbers with prefixes as not even a dealer would...so was it a z650 or a kh750..?

i do feel from your response i need to tell you to that once you manage to crawl out of your own arse you should wipe the crap from your eyes and read the question above you will be able to correct yourself as they never made a KH650 unless you were prefixing a Z650 without mentioning the Z.

And though it is a long time back i think you will find all those 4 stroke models were prefixed KZ not KH 

 

[jwpzx9r]

Sorry bud the sh*te is blinding me :lol:  The 650 was a KH Z650 all the others were KH Z summat KH being Kawasaki heavy industries.

 

[schmokinn]

Confirmed we have massive thread drift!

QUOTE....1976 BROUGHT A LARGE CHANGE TO ALL KAWASAKI MODELS. A NEW METHOD OF IDENTIFACATION WAS INTRODUCED. ALL MODELS NOW HAD A PREFIX TO DETERMINE THERE INTENDED USE. "KH" INDICATED KAWASAKI HIGHWAY, "KT" INDICATED KAWASAKI TRIAL, "KX" KAWASAKI MOTOCROSS, "KE" KAWASAKI ENDURO AND "Z" INDICATED FOURSTROKE ROADBIKE.EVERYTHING ELSE MADE SENSE EXCEPT THE "Z". LATER 4 STROKE ROAD BIKES PREFIXED "KZ"  :angel:

So are lengthened forcing cones of any benefit....No  :wink:

 

[jwpzx9r]

I have always known them as KH Z whatever BUT to be honest to you the bit about your experience meaning nothing was somewhat rude of me ... but true because as I said although these systems can be very effective the common or garden user just does not he the ability to use the machine to perceive the difference the can make to engine performance. However given to someone who actually knows how to use a motorcycle engine eg. VR, MM etal they would be able to come back in and tell you exactly what difference they make... but these guys are very rare... road users though mostly don't make me laugh yes we all like to dream :lol:   Anyway don't take any offence at my ramblings I mean no harm... but I have a few tea shirts as they say :lol:

like a bit if drift... not too much though :lol:

 

[schmokinn]

I have always known them as KH Z whatever BUT to be honest to you the bit about your experience meaning nothing was somewhat rude of me ... but true because as I said although these systems can be very effective the common or garden user just does not he the ability to use the machine to perceive the difference the can make to engine performance. However given to someone who actually knows how to use a motorcycle engine eg. VR, MM etal they would be able to come back in and tell you exactly what difference they make... but these guys are very rare... road users though mostly don't make me laugh yes we all like to dream :lol:   Anyway don't take any offence at my ramblings I mean no harm... but I have a few tea shirts as they say :lol:

like a bit if drift... not too much though :lol:

Drift is fine as long as it leaves black marks not brown ones!

 

[westley]

Now I am completely confused.......................................so, did N.T. ever make exhausts for KH  Z's then, either backbored or even TOTALLY bored   ?      :???:

 

[matt s]

I’ve never patterned my F3 on the plate but I’m seriously impressed with the kills i get on clays and game(when i hold it straight)best choke combo I’ve found is near enough in the bottom barrel and plenty in the top.?

 

[Davy_B]

 

[Doctor Lecter]

ive got a sym simply 50 cc .      plenty fast enough .   btw  lengthened  forcing cones make jack s***e  difference !

 

[schmokinn]

ive got a sym simply 50 cc .      plenty fast enough .   btw  lengthened  forcing cones make jack s***e  difference !

Wouldn't do its a 4 stroke  :wink:

 

[Jezek]

I'd never found a gun with a lengthened forcing cone to be measurably superior to similar, unmodified ones:



So I did the required test. I counted the pellets in 10 patterns shot at 40 yards, took the gun to a shoot to have the forcing cone lengthened and polished, and retested it with shells from the same flat. Here's the result:



This Remington 870 barrel was probably bought at a gun show for $75 or so. It's the best-performing barrel I have. If I could mate it to a Perazzi, I would. 

Since no one has ever explained how longer forcing cones can be expected to reduce recoil, I will wait until someone publishes a test wherein the lengthened cone is better than an unmodified one before I even start to accept that "there may be something there." So far, there hasn't been.

Neil

There isn't anything to big bores, either...

http://www.claytargettesting.com/Bore_Diameter/Bore_Diameter.pdf

pending counter-evidence, of course.

 

[Wonko the Sane]

Mr. Winston - 

I'm sure that with a proper bore micrometer and a mm by mm trace of that 870 barrel you would be able to discover it's secret.  OK, maybe toss in an exterior contour analysis and harmonic node/amplitude analysis when fired.  Or do like I do, just let the vagaries of the cosmos do their thing and hope for the best hahahaha

Charlie

 

[shootinguru]

Well I don't care what all the " experts" on here say I had my old A1 B25 trap gun cones tapered and it made a lot of difference when shooting Fitasc with 36 grammes was the norm!

 

[Garwood]

Had a 21/2"  s/side taken out to 2 5/8" and cones lengthened yrs ago, it did seem to shoot smoother but it could have been tho good ole placebo effect !

 

[Clynt]

Nigel Teague eased the forcing cones on my Winchester 6500 ...32" Trap gun sporterised ,many moons ago ...smoothest shooting gun I've ever had, and we used 32g all the time in the day ....would be interested to hear views of a reputable gun smith on this ?? have noticed in my Blaser F3 pro that there are areas in the forcing cones that do gather plastic wadd fouling .... was toying with having said cones polished , but this may effect the 10year warranty from Blaser ??  

 

[Jezek]

Clynt, just as you "would be interested to hear views of a reputable gun smith on this," I'd like someone to explain how the angle of a forcing cone, which is in contact with the shot-cup only while the gun has moved about 1/100 inch, can modify the feeling of recoil when the shooter's t-shirt has not even begun to be compressed. 

Remember, too, that if on the downstream end of the forcing cone there were just a solid block of steel that the shot would run into, there would be no recoil at all. The gun would just move 1/100 inch back and stop.

Neil

 

[Wonko the Sane]

Now, Now, Now! ! !   For Shame, Neil !  There is no need to inject any of that nasty old Newtonian physics into this discussion of apocryphal wisdom.