Відео

No it has a light interference fit, comes off easily😉

It's a 125cc kart pipe modified to fit this engine and frame

Yes, correct. I used a copper soft jaw on one jaw, which turn out to be the right thickness for the offset i needed

@@genk94 thanks - exactly what I was thinking. Thanks for your video, now I’m going to do the same to my carbs.

@@genk94 how much did you open the carb up after you were done? Start size vs finished size?

@@kiltedmoto You're welcome man, glad you found It useful👍🏻

@@kiltedmoto the native bore was 38mm, for the finished size somewhere in the video there are 2 photo where i measured with caliper the new sizes in both directions

Yes it's a hss lathe tool bit that i've grinded with the radius i need, actually i have made 4 tools with different radiuses for this job. co10 stands for 10%cobalt in the alloy

It depends, you have to analyze your carburetor and find the setup that will work better for you. Not sure what you mean with the 2nd question

Thanks, great result almost 2mm. I have to stop because where the carb connect to the rubber manifold there isn't a lot of thickness. Interesting the test on the increase of Power. Do you have the graphics? Will be cool to see a before and after comparison. Btw i'm subscribed to your channel, good stuff 👍🏻

@@genk94 I checked the results... In my defense it was 7 years ago I did the mod. I actually only got 1.3hp increase and they were in fact bored to 27.5mm. I've added the graph to my community tab and tagged you into it. Hopefully you got the notification?

@@AutoBeta2T Yes, I received the notification and replied on it👍

@@genk94 sweet - the system works 😃

@@AutoBeta2T hehe, yes it seems to work

Yes, the engine seem to have a higher peak power, and It pull stronger, especially from 10000 rpm. I didn't notice any decrease in torque on the mid range, I think there are some gain also there. About jetting i haven't done anything yet, but i think that more fuel will be beneficial considering the hypothetical increse in air flow, i'll try increasing it. In general i think that you can give It a go with your car, for sure this is a mod suitable when an engine Is already well tuned and need to find something to make it even better, a loss of time on a stock motor

Thanks, glad you enjoyed the process

Unfortunately a bearing with a smaller ID it's not available for this application, if there was yes of course will be the easiest choice. But you've to consider the diameter of the balls and all the others specs of the bearing, i think that's the reason why the bearings normally don't make small jumps in size

Sure, It's very simple. You Just need a round stock threaded with the same thread as the head, M14 and you're good to go. It works for any head that have a central sparkplug hole

@@genk94 when you mean round stock threaded you mean something like a bolt with the same threads?

@@exormos a round stock that you put on the lathe and cut the thread on It so you can grab the head on the chuck. It works for all the head with central sparkplug. For the head with lateral spark plug hole you'll need a special setup

@@genk94 Thank you for your explanation my uncle has a lathe and i did it today on my AM6 50mm piston engine

Hehe yes there are troll everywhere and most of the time they have no idea what they talking about. I fully agree with what you say, doing it this way, without the rotor leaving the chuck from start to finish, it's pretty much the same thing, the last step in the process is to light skim the hub contact face, so it's like it was bolted to the brake lathe. Glad you enjoy the video, thanks for watching ;)

Glad you enjoy the process, I subscribed to your channel too.Thanks for watching 👍🏻

No, it bounces which creates chatter depending on rpm and depth of cut as well as port map of cylinder. Cast iron is quite nice, nikasil not so nice..

Not really, this type of cast iron Is really soft. Also this cylinder has only 1 transfer per side, so It's stiff. Some minor bites will disappear with the chamfering of the ports.Thanks for watching👍🏻

​@@MarkhamMotorsport Yes, i agree👍🏻

Hi, for this job i used some carbide tips, but i think you can get the job done with hss co10. cast iron Is very abrasive on the tool tip, i think that's the reason why your foreman said that. If you can use carbide It's for sure better due to it's higher wear resistance.

@@genk94 thanks for the input sir!

@@borneoaxiadriver no problem man 👍🏻

I always use tungsten carbide tipped tools. Lower R.P.M. gives less vibration. Getting the thickness parallel is crucial

Yes It's a really challenging repair to do, but with patience and some skills It's possibile to do It that way. Thanks for watching 👍🏻

@@genk94 make video how to repair house bearing kruk as... That big problem too😱😱

Glad you enjoy the process, thanks for watching 👍🏻

Never heard something like that before, can you explain what you mean? Probably have something to do with the boundary layer theory?

I have researched this as well and all I can find is in relation to fuel in "fluid" form, not gaseous. Since the pressurized gas mixed with air is ignited prior to TDC and don't come into contact with with the surface of the head, I am not sure it would condense. This is of course, a theory and not proven as of yet. I can say that of all the years I have modified engines and polished heads, power valve parts, and exh ports, (basically anything that sees combustion), all it really has done was make for an easier time in servicing the cyl and removing carbon build up and offers no performance gain or performance decrease.

Ya that's not true and testing has shown that any rough surface in the combustion area is a spot that may cause pre-ignition. Combustion chamber temperatures will also prevent "condensation" of fuel. This heat is also a factor that requires richening of the fuel charge due to heat evaporation losses in the intake tract. This effect is rarely directly adjusted for but done in the overall jetting of that engine.

Si esatto👍

Hi, that's for transpose all the ports higher, increasing the timings. Then raising the cylinder with an alu shim to compensate and obtain a proper squish height. Then from there i tweak manually all the ports sections and timings 👍🏻

Hi thanks. Yes that's the way to find the best compromise regarding the liner ports position in relation to the ports on the cylinder. And go from there to match and eventually modify the sections, timings and angles. Regarding the cost what you think it's a good price for this repair?

Yes, i don't have find any video here on youtube showing this way of repair a worn out motorcycle crank. I have find someone repairing with welding build up, but i think that the heat in this type of steel is not good, especially on a solicited point like this. Thanks I appreciated, glad you enjoyed ;)

In the first phase a smooth finish was not needed because then the bush was pressed on this surface to restore the diameter. I obtained the ideal finish after pressing the bush and restoring the diameter for a proper shaft to inner race coupling. If you go at 13:53 you can see that the finish of the repaired journal finished to size, match really well the rest of the shaft

Si, quello è in generale l'obiettivo primario di qualsiasi preparazione

@@genk94 Mica tanto , le marmitte tendenzialmente la spostano, la testa pure.

@@dimmacommunication Chiaro, ma non hai parlato di spostare la curva, ma di aumentare la potenza nella curva. Logico che per ottenere notevoli aumenti di potenza, automaticamente si ha una traslazione della curva verso l'alto, specialmente considerando che con l'aumento dei giri la potenza aumenta in modo esponenziale e non linearmente

Yes i think i'll make one in the future, can become handy. For this type of work the methods i use work very well for me. The little chatters is not a big deal because i'll clean anyway with some emery paper. For the volume also the radius cutter is not really helpful in my case because i don't make maths to calculate the volume, but i measure directly few times in between, and with max 2-3 measurements i reach the desired volume, considering also that almost every head that i machine isn't with a full radius. For the piston dome, yes, using a radius cutter is the way to go. Thanks for your thoughts ;)

@@genk94 I can send you a picture of one I made if it helps

All heads I did so far, I did them with just 2 form tools (plus a facing tool and an ER16 grooving tool to form the O-Ring gland if required), and it worked a lot better than trying to blend a radius between 2 other cuts with a radius cutter. The finishing pass is one move with the compound to set the depth and the angle where the combustion chamber meets the squish band, and then an inward move with the cross slide. You can either face it all the way to the spark plug hole, or leave a protruding spark plug with a small radius around it, for a toroidal shape combustion chamber. If 2 conical surfaces are required I would generally try to get at least one of them from the tool itself, but then the hardest part is to find the proper reference points for measuring while still on the machine, but you can easily get a twin chamber head within 0.1mL of each other just by eyeballing a set of calipers over the features you are machining). Of course my method works better on my 2 ton TOS SN50 (a real monster of a machine, an absolute joy to work on and impressively precise for a 37yo machine, which more than justifies the fact that it's still being produced), but you can break up chatter even in small machines by picking around the shape in different directions, and if I couldn't use a form tool at all, I would rather use a freehand tool rather than a radius cutter for combustion chambers (I have modified combustion chambers even by just holding a freshly faced head with just the squish machined on it on a drill press, and using a hand turning tool with the table as a tool rest, to freehand turn the dome and then blend and polish it with emery, and got some really fantastic results).

@@Sketch1994 sorry don't agree with you there but whatever works for you, far more flexibility with a radius cutter and even more with cad cam cnc, have a look at my UA-cam channel shorts

@@marcusbrown2493 A CNC is almost always the most universal in terms of what you can do with the least amount of tooling, but when it comes to having just a manual lathe, and having to turn a dome in a pinch every now an then, I can grind a form tool from a carbon steel planer blade within less than 20 minutes, and it can machine multiple radii and ellipses, blends and angles at once. A single pivot style radius cutter attachment will only work well for cutting a spherical segment, often smaller than a hemisphere when in bore (which is indeed a decent design in some cases), depending on the size and shape of the toolholder, Many, if not most modern, combustion chambers aren't hemispherical anymore and they have either a radius or an elliptical shape, blending a cone with a face around the spark plug (the small part right out of the squish zone is practically just a taper, then there is a blending radius that gets larger as it gets closer to the center of the combustion chamber) PS: Nice work BTW. Most machine shops just nag and refuse to install aluminum sleeves and send them for plating...