Huztl MS660

[Racr350]

Bridge Ports are definitely the way to go IMO. You get too wild with Finger porting, and you'll have to flip the piston, as snagging a ring is almost guaranteed. Bridge Porting is much safer and easier on the rings, yet flows just as much as a Finger/Boost Port. The only advantage to Finger Porting is you can truly change where the air/fuel charge hits the combustion chamber. Not worth it to me...

 

[weimedog]

Sounds good. Which 54 has the squish down to mid 20? I'll have to check out that vid I bet it runs strong

Those never made the video's in a big way...had a "Cameo" in this one

 

[davhul]

Not on the 56mm cylinders, pretty much all I did with them 2 year's ago is clean up the ports and add a finger/bridge x-sectional area addition to the transfers towards the intake side and simple muffler mods. Trying to get their R's up a little. I guess that intake horn I got last year is a mod. To be honest those 56mm's are hard enough to pull over as it is. Even though I thoroughly understand the importance of compression & squish relative to efficiency....a man has to know his limitations. My 56mm "bling saw" is at .034 squish so it wouldn't be hard to take another .010 and wouldn't add enough to the free port to matter. "Bling" saw has turned out to be both useful and fun, even though its not "optimal" so I'm going to just run it for a while as is. On the 54's thats another story, as a few have come with .050+ squish and I have put them on the lathe to get them in the mid .020's . BIG difference BTW definitely worth doing along with a clean up & adjusting of the ports. An obvious difference. The good news is unlike the Husqvarna's, you can take a LOT off the base w/o making it too thin. I really try to get the blow down numbers in the 18-19 degree range as now the floor of the transfers drop well below the piston crown at TDC. A low blow down (higher transfer) seems to help offset that along with a steeper angle on the top of those transfers. And also I've kept the exhaust in the 99-100 degrees ATDC even after dropping the cylinder & have the blow down in the 18-19 range. Seems to work pretty well. BUT there are folks here who can give far better advice & better numbers I'm sure, all I can do is report what I've done to this point in time. Also while Brad or Randy do that stuff on a regular basis, its a bit of a PITA for me to go that far & I always question my work, especially when the 56mm's slightly tweaked run as strong as they do. Another "opinion" is I don't like cutting the Huztl squish bands with the plating "spots" with my boring bar. So worked around that either by just shooting for a good squish number to the existing squish band and one I tried a popup. Haven't finished putting that last cylinder on anything yet, have a "Cross" top end that "bumped" it. But plan to have a "timed" comparison of the Cross as delivered vs. a cleaned up 54mm Farmertec vs. a cleaned up 56mm Hyway Top End when I get the time. Have two of the three "comparison" saws built, the Cross MMWS 54mm and HTSS tweaked Hyway 56mm.

I had to reread. Looks like more was add since I last read it last night. Good info

 

[weimedog]

Funny thing shows up in that video I had just posted a couple back....the people factor. Three of those guys run 80-90cc's saws so thats what THEY know how to run, One a 60cc saw. Took BOTH groups a bit of time to figure out the others world....the 60cc guy wouldn't push the 90 and the 90cc guys just instantly stalled the chain on the 60's. THAT was what made that day really interesting to me, watching them adapt. And the one fella has a logging/firewood business and you can tell which one as he figures them out PDQ. The others"fall time" (The season) firewood guys.

 

[blsnelling]

I didn't mind it being on the fat side that was the first real run and at 12,300. For the 2 cuts I did at low 13's I could tell it woke up. I'll find the high end of the tune once I run some gas through it. The other 2 saws I stopped the tune around 12.8-13 because that's all they wanted. I suspect I may leave this one in mid 13's and still sound safe.

IMHO, that's a perfect work tune. Sounds great.

 

[weimedog]

Cylinders that are in the "system" and will show up on the channel over time:

 

[Chris3558]

Just wanted to show my two saws finished. Its been a fun learning experience for sure. Thanks for everyone's help, videos and input. One of the saws has a test chain on it with no cutters just for testing. Both run good, idle and hot start in one pull. Next is to try them in some wood.

 

[chopperopper]

On the flywheel side, looks like there's a bit too much paint and it interferes with the crank counterbalance. I'll have to sand it out a bit. Bummer.

 

[Bedford T]

Have you got that centered?

 

[HoosierS]

Did you get a chance to give her a spin?

I got it fired up, had to replace the chain brake link with oem. It was idling high and die after a minute or two. It runs like a banshee with the throttle down. Hooked a tach up but its a bit tricky trying to tune it. Been busy past few days and pulling a 48 hour shift till Monday, then back to work Tuesday so its looking like I won't get to fiddle with it till Wednesday. This may be a dumb question, but does the B&C need to be on to tune the carb?

 

[davhul]

Yes B&C. I ran it little today at 12,5 and 13. Since it's not going to be mine I'm staying 12,5-12,8 like the others to be on the safe side. He may run a dull chain one day or something else so I like the Insurance. Here's the plug at 12,3-12,5 yesterday so a few hundred extra rpm would still be ok. The vid is uploading from today.

 

[chopperopper]

Have you got that centered?

Yeah, it's centered at .02" gap on each side of the case but the crank can barely turn.

 

[Bedford T]

Someone else had that happen on one. That's the only other time I heard about it. He took a little off the crank beIl i think. He may be by and say something soon.

 

[chopperopper]

Someone else had that happen on one. That's the only other time I heard about it. He took a little off the crank beIl i think. He may be by and say something soon.

Ok. I'm at the point where i need to modify the bell. I was worried that modifying the bell would cause an imbalance. Good to know it's been done before. I must have missed that post. Thanks!

 

[Racr350]

Yes B&C. I ran it little today at 12,5 and 13. Since it's not going to be mine I'm staying 12,5-12,8 like the others to be on the safe side. He may run a dull chain one day or something else so I like the Insurance. Here's the plug at 12,3-12,5 yesterday so a few hundred extra rpm would still be ok. The vid is uploading from today.

Nice & Tan...just how I like my women

 

[davhul]

Here's a couple runs at 13 grand even. It's holds rpm good in the cut but I really like the extra torque at the lower tune. And I liked the plug from yesterday. I didn't check it today.

 

[Racr350]

Man that runs strong. Love how high it will hold the revs in cut. Solid build!

 

[grizz55chev]

I got it fired up, had to replace the chain brake link with oem. It was idling high and die after a minute or two. It runs like a banshee with the throttle down. Hooked a tach up but its a bit tricky trying to tune it. Been busy past few days and pulling a 48 hour shift till Monday, then back to work Tuesday so its looking like I won't get to fiddle with it till Wednesday. This may be a dumb question, but does the B&C need to be on to tune the carb?

Yep!

 

[Johnnybar]

Ok. I'm at the point where i need to modify the bell. I was worried that modifying the bell would cause an imbalance. Good to know it's been done before. I must have missed that post. Thanks!

Have to wonder if the crank is over spec on width at the counterbalances or if they re-milled one of the case halves to eliminate a defect.

 

[grizz55chev]

Have to wonder if the crank is over spec on width at the counterbalances or if they re-milled one of the case halves to eliminate a defect.

Probably not centered, a hard knock on the crank end with a brass hammer, problem solved.