SELLING 58mm big bore project for ms660

[Nutball]

Any interest in a 58mm Hyway big bore cylinder I started work on converting to fit a 660? It should end up at 105.6cc. I thought I would have gotten back around to it by now, but have been busy with other things, and have less motivation with no local GTG.

 

[Maintenance Chief]

Whays been done to it? Grinding ect...

 

[Nutball]

Mainly grinding the fins so it will fit on the case, as well as some measurements related to squish and porting. Still lots of work left.

 

[Maintenance Chief]

Mainly grinding the fins so it will fit on the case, as well as some measurements related to squish and porting. Still lots of work left.

Send me some pics.

 

[Cerberus]

I'm surely outta my depth posting here but the title caught my eye and, on the odd chance I do have the ability to work-with this, I may be interested!! I just finished going to 56mm on one of my two units and, having "confirmed it", was intending to go to 56mm on my other unit...but 58mm is insane!

Some Q's:

- What cylinder is it, specifically, and "in general" do cylinders tend to have universal mounts, I'm referring to the size of bolt-holes and the spacing? Obviously it'd vary by displacement-class and all but guess I'm curious if there's more commonality, or if it's mostly proprietary (to models, or to brands)
Seeing new(awesome) youtuber "dyno joe" showing a 590 with a 440 head was pretty crazy, couldn't help wondering if cylinders (and/or pistons) are typically "plug&play" between brands, or if say the 12mm gudgeon pin on a 660 is for the 660 and no it won't fit some other saw's con.rod!

- Would fitment of exhaust, and intake, be more "mcguyvering" or "fabrication"? I guess I'm comfortable shimming stuff but not building mounts Put another way, "i don't weld"

- As displacement increases on a 660, what do you anticipate the 1st "choke point/weak point" would be? I'm very surprised to have seen >10HP figures on (piped)660's at 54mm so I guess I'm thinking that for raw power it's "how much displacement before [something] cannot keep up anymore", based on the carb bore size (and relative intake-port that should allow), it seems the carb should be fine for a bit over a 100 if not over 110, would be curious what 'choke points' you foresee (and what swaps you'd be looking to)

Thanks for indulging anything here, am very much into the idea of pushing 660's but gonna guess this kinda project is levels beyond me, still very very curious both Re yours and in-general (the 590 with 440 head that I mentioned, still trying to figure out if such things are all entirely fabrication jobs or if maybe there really is just 2 or 3 mounting patterns for jugs&slugs, allowing far more inter-powerhead swaps than I'd ever have guessed!)

 

[Ketchup]

I'm surely outta my depth posting here but the title caught my eye and, on the odd chance I do have the ability to work-with this, I may be interested!! I just finished going to 56mm on one of my two units and, having "confirmed it", was intending to go to 56mm on my other unit...but 58mm is insane!

Some Q's:

- What cylinder is it, specifically, and "in general" do cylinders tend to have universal mounts, I'm referring to the size of bolt-holes and the spacing? Obviously it'd vary by displacement-class and all but guess I'm curious if there's more commonality, or if it's mostly proprietary (to models, or to brands)
Seeing new(awesome) youtuber "dyno joe" showing a 590 with a 440 head was pretty crazy, couldn't help wondering if cylinders (and/or pistons) are typically "plug&play" between brands, or if say the 12mm gudgeon pin on a 660 is for the 660 and no it won't fit some other saw's con.rod!

- Would fitment of exhaust, and intake, be more "mcguyvering" or "fabrication"? I guess I'm comfortable shimming stuff but not building mounts Put another way, "i don't weld"

- As displacement increases on a 660, what do you anticipate the 1st "choke point/weak point" would be? I'm very surprised to have seen >10HP figures on (piped)660's at 54mm so I guess I'm thinking that for raw power it's "how much displacement before [something] cannot keep up anymore", based on the carb bore size (and relative intake-port that should allow), it seems the carb should be fine for a bit over a 100 if not over 110, would be curious what 'choke points' you foresee (and what swaps you'd be looking to)

Thanks for indulging anything here, am very much into the idea of pushing 660's but gonna guess this kinda project is levels beyond me, still very very curious both Re yours and in-general (the 590 with 440 head that I mentioned, still trying to figure out if such things are all entirely fabrication jobs or if maybe there really is just 2 or 3 mounting patterns for jugs&slugs, allowing far more inter-powerhead swaps than I'd ever have guessed!)

58mm Big Bore is probably a 395 jug. The bolt patterns are different 395 to 660. So is the wrist pin diameter. IIRC stroke length is 40mm on 660, 38mm on 395. Muffler and intake track will need fabrication. Seems pretty complicated, but somebody should pick up the torch!