You might remember I bought a MS660 recently that turned out to be absolute junk. I got my money back and returned it. Since then I bought a 066 Magnum from another AS member. It was complete minus the piston.
Hmmm. Sounds like a candidate for a big bore kit right off the bat to me
Well that's exactly what I did. The saw was completely disassembled, clean, reassembled with all new gaskets and seals, and painted. I got the BB kit yesterday and went to work.
I originally thought I'd port it right off the bat, even before I ran it. I decided against that incase something would be wrong. First thing I did was install the P&C with no rings and no base gaskets. It seems like one of the main complaints on these is lack of compression so they probably have a large squish. WRONG!! It wouldn't even turn over. At this point I decided to go ahead and put the saw together and run it stock. I had to install with a base gasket to get a good squish measurement, so why not go ahead and run it to establish a baseline. I'm glad I did. The squish is .018" on all four corners. Nice and consistent.
It started right up. I ran it for about five minutes in the garage about 1 AM last night. It was mostly idle with some throttle blips. I wanted to get it good and warm for its initial heat cycle. I pulled a compression test first thing this morning and it was a nice 155 psi. At least on my guage, that's a very nice reading. This was with only about 5 minutes on a brand new P&C with no load time on it.
Now to set the H needle. Where does this thing want to run. I wasn't expecting much since this is just a cheap aftermarket kit. I started with good compression, so I can't expect much in the way of RPMs. That would be asking too much. Again...WRONG!! This thing wants to turn a screaming 14,700-14,800 RPMs. I detuned it down to 14,500.
I will mention a couple less than perfect points about the kit. The finish on the ports is indeed ugly. It looks like lumps of sand in the casting, although it's just the texture left by the sand casting. This is no biggie to me since I'll be grinding the ports anyway. Also, the decomp and spark plug holes are not perfectly aligned with the holes in the plastic. I didn't have to trim any plastic but it is close. Again, not a big deal, but I want to give a fair evaluation. I might also mention that SilLoggers findings on the skirt length is correct. I did not measure, but they are probably 1/8" shorter than OEM. And it does indeed free port the exhaust at TDC. It's only a few thou, but it is there. I've talked to a builder that uses these and he said this is not uncommon and not a deal breaker. It's something I've always been told to watch for when porting, but evidentally not a deal breaker. I'm just glad the squish is good and I'm not looking to lower the jug any more. It is not my intention to pass judgement on how good or bad this is. I don't really know. I just want to pass the information on.
I'm flabergasted at this point. I was expecting a large squish and less than stock RPMs. I got neither. Instead I've got 98cc with good compression and excellent RPMs. I can't wait to stick this thing in some wood and see how it compares to my ported 066 RL. I'm putting my dibs on the BB
Hmmm. Sounds like a candidate for a big bore kit right off the bat to me
Well that's exactly what I did. The saw was completely disassembled, clean, reassembled with all new gaskets and seals, and painted. I got the BB kit yesterday and went to work.I originally thought I'd port it right off the bat, even before I ran it. I decided against that incase something would be wrong. First thing I did was install the P&C with no rings and no base gaskets. It seems like one of the main complaints on these is lack of compression so they probably have a large squish. WRONG!! It wouldn't even turn over. At this point I decided to go ahead and put the saw together and run it stock. I had to install with a base gasket to get a good squish measurement, so why not go ahead and run it to establish a baseline. I'm glad I did. The squish is .018" on all four corners. Nice and consistent.
It started right up. I ran it for about five minutes in the garage about 1 AM last night. It was mostly idle with some throttle blips. I wanted to get it good and warm for its initial heat cycle. I pulled a compression test first thing this morning and it was a nice 155 psi. At least on my guage, that's a very nice reading. This was with only about 5 minutes on a brand new P&C with no load time on it.
Now to set the H needle. Where does this thing want to run. I wasn't expecting much since this is just a cheap aftermarket kit. I started with good compression, so I can't expect much in the way of RPMs. That would be asking too much. Again...WRONG!! This thing wants to turn a screaming 14,700-14,800 RPMs. I detuned it down to 14,500.
I will mention a couple less than perfect points about the kit. The finish on the ports is indeed ugly. It looks like lumps of sand in the casting, although it's just the texture left by the sand casting. This is no biggie to me since I'll be grinding the ports anyway. Also, the decomp and spark plug holes are not perfectly aligned with the holes in the plastic. I didn't have to trim any plastic but it is close. Again, not a big deal, but I want to give a fair evaluation. I might also mention that SilLoggers findings on the skirt length is correct. I did not measure, but they are probably 1/8" shorter than OEM. And it does indeed free port the exhaust at TDC. It's only a few thou, but it is there. I've talked to a builder that uses these and he said this is not uncommon and not a deal breaker. It's something I've always been told to watch for when porting, but evidentally not a deal breaker. I'm just glad the squish is good and I'm not looking to lower the jug any more. It is not my intention to pass judgement on how good or bad this is. I don't really know. I just want to pass the information on.
I'm flabergasted at this point. I was expecting a large squish and less than stock RPMs. I got neither. Instead I've got 98cc with good compression and excellent RPMs. I can't wait to stick this thing in some wood and see how it compares to my ported 066 RL. I'm putting my dibs on the BB
I love every chance I get to run them.
