Post by Chuck78 on Dec 16, 2019 21:59:12 GMT
I was considering boring out my new to me very well worn '83 PE175D much larger and having the cast iron cylinder Nikasil plated, and thought that perhaps if I was going the very tough long lasting Nikasil treatment that can be re-plated back to original 1st plating specifications if it ever wears out, I would perhaps be good boring it out to the 2nd largest size of compatible TS185 piston. I was thinking about cylinder wall thickness quite a lot, and wondered if a TS185 cylinder would drop right on and be compatible with the PE crankcase and head? This would give me much thicker cylinder walls, but also drastically different cylinder porting. Perhaps if it did fit, I should compare porting of the DS185 and TM185 as well, and pick the one that would take the least professional porting work to get to modified PE175 specs?
I have read that these cylinders are very thick to begin with (the PE cylinders), but was trying to find a middle ground of big bore vs metal mass to dissipate heat. If I bore it too thin and remove a large amount of thickness aka air cooling heat sink material, then the compression ratio and octane requirements will be a bit temperamental or hampered, so I would not be able to increase the compression ratio as much if going thinner - as thinner means it will run hotter, and it is intended to be a slow going tight woods bike as required, which will be often, but will see some wide open high speed areas as well.
Can anyone comment on the cylinder compatibility? Perhaps my money is better spent just having the PE porting touched up a little or doing some research and some slight DIY porting alterations?
If I go to at least stock 185 or slight 185 overbore, I should have pretty similar air-cooling capacity still, but reap the slight benefits of the "There's no replacement for displacement" slogan.
I also plan to send some heads to RK Tek aka 2StrokeHeads.com for their combustion chamber re-shaping (possibly with welding up the chamber to give more material to machine and re-shape), milling, squish band modifications, etc. This will improve combustion significantly, and boost compression ratio slightly or perhaps quite a lot depending on how much they can mill it, or if the aluminum alloy is weldable (they have welded some Full Floater RM heads, but state that the RM465 alloy is not a weldable aluminum alloy, and therefore what they can do is slightly limited on that head. I have to submit a head as a test piece that may or may not get ruined trying to weld it. However they say some head chamber designs do not even need welded up, and this chamber may be of this variety, as it is not as deep of a bowl as some vintage heads that I have seen. RK Tek mills fancy fluting patterns radially into the head that do something with the harmonics of the air-fuel molecules which vastly improves the combustion process. They have a patented design that they base all of their work off of, and it gets fantastic reviews, particularly just over someone comparing a milled head that only has the added compression ratio as the benefit.
