spudulike

I meant that some bike tuners cut the front edge of the crown of the piston where it interacts with the exhaust port thus giving a very similar effect to lowering the exhaust port. I also recently found it on a Wiseco Dominant piston I was asked to fit to a 372XP.

Yes, correct and I always ensure the owner knows this and really prefer at least 10 tanks through the machine first.

That is one reason I don't push the revs beyond the manufacturers maximum recommended specification. An air leak or just a well used engine can also peak out of this specification and have had to pull many limit caps to get the saws back in to the black but the safety reason is one area I am careful about. In answer to your question - ported/modified saws should only be used by the owners of the saw and in no way would I recommend or condone giving a modified saw to an employee. As an employer you have a duty of care to your employees health and safety so it isn't wise to give them a ported saw. In my world, my customers ask for a saw to be ported, I don't sell it to them, they ask for their saw to be modified. When it is done, I check out the safety devices on the saw, cleaning, lubricating and servicing them. I have asked many when their saws were last serviced.....I usually get a blank look on that one. Coming from an engineering based manufacturing past, we used to have to check all heavy plant safety devices at the start of each shift, carry out preventative maintenance, training etc and log the lot. If the H&S get involved in a serious accident, I would imagine they would question when the saw was last maintained and by whom........now that is probably a big grey area judging by the state of most of the chain brakes on the 200s I get in!

Pretty much so. Manufacturers work with EPA regs (that is a BIG part of it), they have to make less than 118db noise and will work with a much narrower set of parameters on port size, shape, opening. Motorcycle manufacturers were getting 20hp out of a 125cc engine back in the late 80s.......the MS880 makes 8.6 Hp so chainsaw technology is a fair way behind. Even the NEW fuel injected MS500....Bimota did that in the 80s as well on motorcycles, it finished the company but that is another story.

It is what it is. My customers always seem pretty happy and don't believe I have had any issues with any of them. I try to treat customers how I would like to be treated. It is a simple model but I guess other people in the same industry have some catching up to do!

Well, the toms, cucumbers and courgettes are beginning to come up in the propagator. Something rather basic and spiritual about the first signs of life from your seedlings that will hopefully feed you this summer. Always an uplifting feeling coming out of winter. God, I sound like a hippie

It is done, can't say it is riveting reading but it explains what I do, what my customers get and the reasons why. I think most of my customers glaze over even when I explain even the simpler stuff but there you go, you asked and you got!

Here is my more commercial view on what I call porting: - Most of the saws I get in for porting are anything from knackered to new....mostly "Well Used". Most need a good 45 min clean and an hour service. Things like the fuel system and pressure and vacuum testing of the saw are important if you are going to get more out of it and failure to do this will result in the saw not lasting. In my world, I look at £200-250 as being what the general fella with a saw for porting will spend, most will accept this as being acceptable on a MS200T up to a MS880, small MS150s and MS201s are different in so much as a muffler mod and ignition advance make such a big difference, I don't do a full port but do a muffler mod and ignition advance/service for around £100. So, what I do is clean the crap of the saw and get it as clean as I can. I strip it down, inspect its bits replace what is needed, make sure the fuel system can provide what is necessary and then do a muffler mod. This can be a simple increasing of the outlet hole area or letting in a secondary outlet port but always look for a "Rorty" sound and increasing flow rather than an ear splitting row likely to piss the owners customers off. I then try to increase compression and widen/reshape ports and do piston work to improve flow in the engine then finally tune the carb to keep the saw close to manufacturers limits but not to exceed them. This won't give max power but will ensure safety of the owner and the saw. The chain brake and chain catcher are cleaned and inspected and on all top handle saws, the cover is stripped, cleaned and all components inspected to make sure it works as the manufacturer designed it to do - those that have had me do your MS200T/MS201s will have seen this!!! My modifications give at least 25-35% increase in performance and I avoid changing port timings as it is time consuming for the reasons in my previous post and I tend to aim for getting the 80% of relatively easily achieved gains rather than spending hours achieving timings that will give a relatively smaller increase in performance compared to the simple modifications (simple in my world) that I do that make a real difference. I don't tend to measure the performance from what I do but I did have a customer who was competing in timber-sports with a 372XP. He was all over his saw and sport and already had a jungle muffler on the saw. My mods to ignition advance and ports (without taking the jungle muffler increases) gave him another 30-35% increase in performance.......his figures not mine. In short, when I mod a saw, I aim to get the easier 80% and avoid the difficult 20% gains so my customers get a good working saw with enhanced performance, that is safe and will last. Call it what you like, that is what you get!

In response to various comments on porting, Porting is viewed in different ways....here is perhaps a purist view and will follow this post with what my more commercial business take is: - You take a two stroke engine, you put a timing wheel on the crankshaft, many use a drill chuck as it makes it simple. You affix a pointer to the engine that points to the outer part of the timing wheel. You insert a piston stop, you rotate the engine clockwise and anti clockwise moving the timing wheel until you match the degrees in either direction meaning that when the pointer points to zero degrees, you have TDC (Top dead centre). From this point, you can measure the important parts of the engines timing....these being "blow down timing" - the timing between the top transfer ports top and the top of the exhaust port - shorter is perceived as more aggressive and found on higher revving saws plus the higher the transfer port is, the longer the fresh fuel charge is entering the combustion chamber. Followed by exhaust port timing - the point the exhaust port opens (where the top of the port lies in regards to TDC. The higher the port is usually means the saw revs higher but it has less compression due to the piston having less travel up the bore to make compression. And finally, the inlet port duration, that is how long the inlet port stays open thus charging the crankcase with a fresh fuel charge. So, for the purist, you have blow down time, exhaust port timing and inlet duration. You then try changing these figures by ...getting figures used by other tuners or developing your own figures and get to them by grinding the top of the transfer ports, top of the exhaust port or bottom of the inlet port to achieve them. Some machine the squish band of the cylinder and the base of the cylinder to allow more compression and greater scope of changing the port timing of the engine. Then there is the "pop up piston", the outer part of the piston machined as is the base of the cylinder where the middle part of the piston goes higher in to the combustion chamber making much more compression with 220 psi being pretty much the most you would want as more will slow the combustion process. Some motorcycle tuners used to port the piston rather than the cylinder as it was easier and cheaper to test timing figures by changing the timing by grinding the lower skirt of the inlet side of the piston and grinding the crown exhaust side of the piston and then try different pistons rather than scrapping cylinders if it didn't work out. So to meet a set of pre determined port timing figures you have to sort out your compression/gasket/squish first of all and then keep fitting your cylinder, measuring your timing with the wheel and then removing, grinding and repeating until correct to your figures. This is time consuming but it is an effective method of modifying an engine to achieve the exact figures you have developed or "borrowed" and know will work. One set of figures will not work on all saws....it doesn't work like that and all tuners will have their own approach to these figures, what they mean and we haven't got on to the general basics of modification yet! More to follow.............

OK, I will put it up over the next 24hrs.....if may get long!!

Going back to yesterdays debacle about the art of tuning, modifying, porting saws.....is anyone actually interested in the technicalities of what the issues were because if they are, I can clarify on my porting thread otherwise we can just smile and get on with having another beer!

How the decadent live😉

It is for his harem and three extended families......and a large savaloy on the side

Yes and you can take back £50 for a fish and chip supper

Blimey, been in the workshop all day, just sat down and have missed all the fun....what the hell happened Second time this has happened to me now on AT but thanks for the support from those that gave it. In life you reap what you sow and is a good basis of how to live your life and treat others

Best ebay them for parts, O84s are still out there and lots of parts are obsolete. Shame it couldn't be sorted...some are like that unfortunately.

I was about to but TBH, can't be arsed......did you ever get that 084 sorted.....long time ago

Not being funny but Garden kit is based in Devon and not sure exactly where the OP is based but it may be worth popping in to Gardenkits business (just Google "Gardenkit") and get an honest opinion from a fella that knows his business and isn't just trying to flog you the mower he makes most on or has the most stock of. I have known Barrie for a long while and is a decent honest bloke.....think we call it "Old School" not many of them around now!!

Where are you getting this "World Beating Hotsaws" thing from, It isn't from me because I don't big myself up, never have, never will, don't need to, not interested. If it is from my customers, I can't control and have no influence what they write and what views they have. Apparently I am mentioned all over Facebook....I don't even have a Facebook account I just do stuff customers appear to like....is that wrong? Cut to the chase....what is the issue?????

Andrew, you are correct but have personally only found this on one specific model, the MS150 where the shearing of the flywheel is a real issue. I haven't found it on any other machine although I use a small 1/4" gun on most saws and keep the big banger for the larger ones. I have seen it so accept your opinion and do use a socket and wrench on smaller saws

You can put some of the issues down to preconceived issues with some members views of what you are, what you represent, your principles and how you conduct yourself on the site. Very difficult to judge from a distance and lambaste someone for no good reason without knowing the person involved. Arbtalk has been a good forum for me, it has given me a business and have met with a load of good fellas, many that I have known for years now and are always welcome for a chat, advice, a cuppa and a helping hand where possible. Unfortunately some forget that you get out of this forum exactly what you put in to it.

Tis the way it is, lots of it around here!! If you are busy....you know the options If you are not, bend and brace for

Excellent, you should be OK then. Hope it works out.

Different micron counts on the nylon mesh filter - just choose the mesh you want in the filter. Yellow or Black are the common ones!

The bigger the house, the tighter the wallet.....was that Issac Newton