Matching the barrels - MJ's Secret tuning tips!

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mj43
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Matching the barrels - MJ's Secret tuning tips!

Post by mj43 » Sat Apr 14, 2007 9:57 am

This is a little bit of tuning that you can do easily with a dremel some patience and a bit of care.

Make sure that the exhaust port is round and no discontinuities - I have a ring made up that allows me to see which bit needs trimming back
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This barrel isn't bad but could do with just a bit of a tidy up in the area marked by the green arrow
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Next match the transfer tunnels. Put a stock gasket on the barrel and see where you can see metal - this lot needs to be trimmed back. Just to prove the point put the same gasket on your crankcases - gaskets match the crankcases well but not the barrels.
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A few minutes with the dremel and the barrel is now a good match to the gasket and hence the crankcase :D

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You can also rework the web that divides the transfer tunnel but more on that another day.

I reckon that little bit of work is worth 3 to 4 hp on a stock motor :D

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Post by corky » Sat Apr 14, 2007 10:03 am

cheers mj that was spot on out to play on a set of my barrels now...
keep them coming....
kr1s project wanted
aprillia rs125 track bike
03 r6 race/trackbike
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plus a few more......x7,kdx125 etc

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mj43
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Post by mj43 » Sat Apr 14, 2007 5:31 pm

Batteries went flat on the camera.

The other bit that is easy to do is the exhaust. At the front where the round bit is welded to the header there is usually over weld and a step smooth that out. Again you can do this easily with a Dremel.
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There a couple of easy mods to give your KR a bit of zip without compromising reliability or spending a load on special tools. Remember to clean up the barrels properly and blow the metal cuttings out of the exhaust. Any left over metal could damage the engine. I can not stress enough how important it is to clean everything properly other wise you will damage the engine or even seize it.

If you want to do any more you need to get proper tools such as these.
The chunk of steel above the tools and in front of the barrel has been designed to slide into a barrel. I can lock it off at any length and use it as a guide so that all my ports are the same height. Also if I slip it reduces the chance of damaging the plating.
The long cutter in the straight tool I use to get right down the transfer tunnels and up the exhaust into the kips ports. The right angle tools are what you need for doing the ports. Along with this you need a selection of diamond tipped tools, stones and cutters.
Image

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Post by rc46 » Sat Apr 14, 2007 8:40 pm

Awsome MJ if anything else its always intresting to see how its done, Not sure i have the balls myself to do that sorta work!!!
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Post by Cliff » Sun Apr 15, 2007 7:57 am

Thanks for the tip Mark. I will check it out at my next top end overhaul, you would like to think this work would have been done at the factory :roll: .

What is the best way to clean up the finished barrels, i would probably give them a bath in heating oil (kerosene), what do you think?

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Post by mj43 » Sun Apr 15, 2007 8:18 am

If you have a bubbler put them in there for an hour.

If not degrease them - I use thinners but that is dangerous so I can't recommend it - Gunk or similar would do.

Then in hot water with lots of washing up liquid and a small brush (tooth) clean all the ports etc. Rinse throughly in hot water, shake off excess and towel dry taking care to get all the water off the plating especially if stock plating. If you used hot water the barrel should now be very warm. This plus the fact you have toweled it will mean it will dry very quickly without leaving any water stains.

When it is dry run your finger down the transfer tunnels and through the ports. If you pick up any silvery bits repeat the exercise - bits get stuck in the pores in the casting and don't always flush out first time.

Take your time and don't rush it. That applies especially to the cutting - you can't put metal back. I normally do 5 to 10 minutes of cutting then walk away for 5mins otherwise I get impatient and start cutting to much.

If you are not that comfortable get somebody like Graham File to do it for you 01303 262222

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Post by nate » Sun Apr 15, 2007 9:29 am

Cheers Mark,

Was going to have a play with my spare engine today anyway as its wetter than a wet thing outside...

Top tip and really interesting to see how its all done!!!

Wish me luck.


Cleaning the swarf out sounds like a very important 'pain in the arse job'...

Nate

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Post by mr_bungholeo » Sun Apr 15, 2007 10:38 am

also if you angle the transfer ports to throw the gases to the center of the piston crown or towards the exhaust port it washes out the burnt gases better and helps to get the freshest charge in, but it wastes a bit more fuel....
bring a ding ding i'm a throttle happy chappy...:)

you cant beat a bit of blue haze...
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mj43
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Post by mj43 » Sun Apr 15, 2007 11:07 am

The purpose of this thread is to show what can be done to tweak your KR sensibly and easily using the tools people can obtain easily. It isn't aimed at replicating my race engine.

I will put some piccies up of what I do with the transfers and kips ports soon - but that is aimed at either you asking your tuner to do it, or you buying the correct tools. If doing your transfers use the proper tools otherwise you will do more harm than good. You cannot do the transfers properly with a Dremel I know I tried then bought the proper tools - they are cheaper than re-plating a barrel.

The info is aimed at usable power with a good spread using standard pistons. It certainly won't involve angling transfers to put fresh charge towards the exhaust port :evil:

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mr_bungholeo
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Post by mr_bungholeo » Sun Apr 15, 2007 11:11 am

sorry ive been playing with 2 strokes for20 years n a mechanic for 10...i use air powered files bent angled....but yep jumped in there didn't i....sorry... :cry:
bring a ding ding i'm a throttle happy chappy...:)

you cant beat a bit of blue haze...
danny harris.....R.I.P
gone but totally forgotten...:)

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Post by the kid » Mon Apr 16, 2007 5:28 am

Great Post :D

Am I correct in thinking that the transfer tunnel has been sharpened up around the outside of the bore as well ?

Can't wait for the next post along this theme .
Thanks Mark

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Post by KwakOn » Mon Apr 16, 2007 7:22 pm

8)

great post, think I'll have a go at that myself too. Never sniff at a few horsies :D

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Post by mgtkr1 » Mon Oct 29, 2007 8:19 pm

here you go matty, loads of tips above you can do for nearly bugger all, from the man himself aswell! the gains outweigh the cost of the mods more than a tuner getting 70hp quite considerably!

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Post by Matty21 » Thu Nov 01, 2007 1:09 pm

Cheers mg :)

I rekon il have a go at it after my first trackday so i can compare power and difference.

Would this extra 3-4 be throughout the rev range or is it just top end or bottom end?

Cheers!

Matty#21 :mrgreen:
23, Racing a zx9r in Aintree race club.

Ex Kr1 owner.....one day again.

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Post by mj43 » Thu Nov 01, 2007 1:41 pm

The red curve is the blue engine with the barrels moddified and the crankcases flowed. Gain is at all revs with no loss.

MJ

http://i104.photobucket.com/albums/m197 ... g/all3.jpg

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Last edited by mj43 on Sun Mar 06, 2016 1:57 pm, edited 2 times in total.

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