High Quality Chainsaw Bars Husqvarna Toys

Unlimited coil for ported husky 450?

isaaccarlson

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I ported a husqvarna 450 yesterday and it hits the limiter like a hammer even after fattening it up. Is there an unlimited coil available for it? It’s a pretty easy saw to work on, but boy is there a lot of metal to take out of ‘em.
 

beaglebriar

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Not sure on this. I wonder if the aftermarket coils are limited?
 

Terry Syd

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I use the 13,000 rpm limiter on my 450 as the 'dull chain indicator' - works great.

My saw likes to cut between 12,000 and 12,500. If you find a source for an unlimited coil, I might be tempted to have a pop-up made for the saw.
 

legdelimber

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Has anyone made a thread on modding the 450?
Seems I recall, from somewhere, Terry Syd doing some work on one of the larger brothers 455/460?
I have a 450 that's just collecting dust for now, But I am curious what anyone has done to them.
I did swap in an oiler from the 455/460 series in place of that non-adjustable one. A handful of parts some bar plate shaping & done.
 

Terry Syd

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I should put the 455 oiler on mine. The stock one is pathetic and I use 10-40 motor oil in order to keep the chain oiled.

Yeah, I did a long thread over on AS on modding the 450. Mine is now a 'pocket rocket', the weight of a 45cc (11.8lbs) saw that thinks it is 60cc. I ran it against a couple of 036s with 3/8 chisel chain (I use semi on the NK chain) and it was like running a race saw against a couple of stock saws. The guys were a bit crappy about it and complained that I cheated with the NK chain.

Modding the 450 takes a LOT of work. The biggest problem is that it is based on a 45cc engine and the transfer ports are already too small by 9%. I then made the transfer port opening 12.5% wider, which then compounded the too small transfer tunnels.

I had to grind the back out of the transfer covers and re-build the backs with fiberglass and GB Weld. Take 9% add 12.5% and you can see I was already 21.5% too small. It took a lot of work (measuring, grinding, measuring, etc.) to get the transfers to flow the way I wanted them.

I also matched the strato and intake timing. The stock strato timing is 10 degrees longer than the intake. I just increased the intake to open with the strato. The piston needs a bit of work to increase the strato flow.

I then removed the stock 11mm carb and put on a 13.5mm carb off of a 570. The choke rotated the opposite way, so I had to grind out the old one and build up a new stop. I dropped the pre-load on the metering spring to bring in the fuel a bit faster with the larger carb - it works like a light switch.

With all the increase in flow, the stock filter is a restriction and I had to go to a nylon mesh filter. Even that can begin to clog up on a cutting session (just wash it out with fuel - good to go).

I also widened the exhaust port to 65% of bore and raised it 2 degrees. I also used the trick of filing the top of the piston to the curve of the exhaust port to get an equivalent extra 2 degrees of blowdown while maintaining the trapping efficiency and compression of just raising the port 2 degrees.

I used the bolt tubes on the muffler as part of my muffler mod. It is a little quieter that way, but not by much as the entire exhaust port opens at once and there is a fairly sharp exhaust note as a result.

As you can appreciate, it was a lot of work, but the saw will be the last one I sell.
 

Terry Syd

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Oh yeah, forgot to mention something else. With all the mods I was making the engine was getting hotter and hotter. The plug was running very hot and the piston was expanding all the way to the crown. I thought I might have to put a 'clearance band' in the top of the piston to keep it from seizing.

Then the light came on!

The 'air injection' system sucks air off of the flywheel. The more power I was producing, the more air I was pulling off the flywheel. I was compounding my heat problem - the more heat I produced, the less cooling air I had available.

I blocked off the air injection system and put a couple of holes in the back of the air box to pull in cool air. The plug temperature dropped right back to a nice chocolate brown and the piston was running cooler.
 

legdelimber

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I need to see if I still have the images from mine.
Along with clutch shell, You'll need the bar plate from a 455/460. The hole around the oiler drive needs to be "dimpled" different. But the 460 plate needs a little trimming at the rear and then the lip reformed to fit in the groove on the plastic case.
Let me look for some pics and come back.
 

legdelimber

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I found some of the pics from the oiler change.

you'll need the 460 clutch shell, so as to have the drive notches for the new oiler worm.
The pump itself is a direct swap in after you remove the original.
It fits the rubber parts and all.

The backing plate is the only problem!
The 450 plate has a different dimple shape where the clutch driven oiler gear~worm needs to be.
Then the two plates have slightly differing curves towards the rear of the saw case.
You can see in the pic of the plates, where the shapes of the two plates differ.
I took a new 455/460 backing plate and did a little bit hammer work, on a vice body, to get the shape to fit the 450 case groove.
It then needed a little file work to trim the excess and deburr.

Be very careful of getting the backing plate fitted in the groove!
Any excess lift of the plate will cause binding at the oiler worm and undue sideways pressure on the clutch assembly.
This will damage them.

I had already added a screw, ( as seen in the lower left of pics) to hold the lower rear corner of the 450 plate against the case.
So I carried that screw fitment over to the 460 plate.
Reason being, Sawdust was allowed in the gap there, as the factory had left the design.
Just remember to use a machine thread and not one of those coarse screws that resemble drywall screw threads.
Always gently backspin the screw upon assembly, to find the thread starting point.

edit: Added a pic of the original 450 clutch shell and oiler worm gear, to show difference between it and 460 shell.

Oh and yes, I like dollar store fingernail paint to dope the fasteners in plastics.
 

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longleaf

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I don’t know much about the 450. Would a 455 coil fit?
 

legdelimber

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Hey folks, my apologies for the oiler derail.
I can't answer the question of the igniton coil swap, but here are some pics in case they help.

1st frame shows the numbers on my particular coil.
2nd frame is just pulled back to see the shape of things a little better.
3rd frame shows the flywheel numbers on the magnets ( 120425 -01 )
4th frame shows the factory sticker and model information.

The ignition coil screws look to be 1.75" apart if checked in a strait line from screw to screw.
The flywheel looks to be about 3.9" diameter across the magnets.
This is just a quick & dirty check with plastic calipers.

Guys, I'm Sorry that I don't have any really useful info about the coil.
 

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