028AV Super C&P Question

[028AV Super]

Stihl Gurus,
Reserching past threads I decided to disassemble and look at the C&P. As expected, they are pretty bad shape. The heavy damage is on the intake side (is it normal?). I guess that would explain engine bogging (running out of power) down on moderate 15" Doug Fir fire wood cutting. My question is, will a Tecomec C&P kit from MFG Supply ($114.99) best price I came across, ring compressor, and a gasket will do the trick? Any other things I should inspect or replace while I'm in there? I don't have the special clutch puller so I'll let it be. Maybe do a carb kit on it. I'm not sure how old it is but I'm thinking around 20 years old base on 1977 release date of these models. Your tips, tricks, and recommendations will be appriciated. Will cleaning up the new one of burrs and polishing both intake/exhaust ports help? How about chamferring the all edges inside of the cylinder? Thanks,
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[Lakeside53]

I'd just leave the cylinder alone and install it just as it comes from Tecomec. I put dozens of these in and they all work great.

Definitely rebuild the carb, check the fuel and impulse hoses (I'd replace them if they haven't been done in the past 10 years), and open up the muffler somewhat (the old muffler was pretty restricted).

Btw.. it's the flywheel that needs the puller, not the clutch.

 

[Eccentric]

If the heavy damage is on the intake side then I'd take a close look at your air filter. Either it's passing dirt, or air/dirt is getting around it.

 

[Jacob J.]

The heavy damage is on the intake side

Definitely what Eccentric said, the early 028s had a wire mesh filter with flocked covering and the flocking comes off over time allowing a lot of fine dust and particles into the engine.

I would pull your clutch (it should be left hand thread) and check the condition of your clutch drum and clutch drum bearing. The 028 has a beefy bearing so it's most likely still in decent shape. Also check the condition of the oil pump gears. If your clutch has metal shoes, you could sand them a little by hand to give them more "grip". If the drum is a "spur" sprocket type and shows wear, replace it with new. Clean everything real good.

 

[028AV Super]

I'd just leave the cylinder alone and install it just as it comes from Tecomec. I put dozens of these in and they all work great.

Definitely rebuild the carb, check the fuel and impulse hoses (I'd replace them if they haven't been done in the past 10 years), and open up the muffler somewhat (the old muffler was pretty restricted).

Btw.. it's the flywheel that needs the puller, not the clutch.

I guess this means that the new C&P comes assembled? Is assembly lube required on 2 stroke jugs? Also, is there engine break-in procedures? As for the all the rubber hoses and filter, I changed all of them last year with your recommendations (impulse hose was cracked). I did some reserch on muffler mods on the fourm and was wondering what would be the most simple and correct mod you would recommend? Although the double barrel shotgun mod looks trick, I would perfer simple approch without going to the welding shop. Thanks,
T

 

[028AV Super]

If the heavy damage is on the intake side then I'd take a close look at your air filter. Either it's passing dirt, or air/dirt is getting around it.

Good point, I only had this saw for past 4 years and I did replace the filter with Stihl OEM filter when I bought it. I'm sure all the damage took many years of use and I worked it pretty hard cleaning up after 2 acre clearing to build a house. Thanks,

 

[028AV Super]

Definitely what Eccentric said, the early 028s had a wire mesh filter with flocked covering and the flocking comes off over time allowing a lot of fine dust and particles into the engine.

I would pull your clutch (it should be left hand thread) and check the condition of your clutch drum and clutch drum bearing. The 028 has a beefy bearing so it's most likely still in decent shape. Also check the condition of the oil pump gears. If your clutch has metal shoes, you could sand them a little by hand to give them more "grip". If the drum is a "spur" sprocket type and shows wear, replace it with new. Clean everything real good.

Super, I'll check these item for sure. Thanks,

 

[028AV Super]

Connecting Rod Play

Is slight play (radial) okay on the connecting rod to crank main? Vertical play was hardly noticeable. Being that this is a first 2 stroke engine disassembly, I don't know how critical I need to be. Yes, I don't have service manual and going by great tips from the forum, free STIHL (PDF) parts break-down, and avid automotive engine hobby background seems to great help.

I couldn't't stop smiling as I tore in to it yesterday, the cute piston and rings... and they were even highpo pop-up pistons to boot! Gee, only thing I need is a 540 stroke kit, fuel injected bar nuts, 411 posi spur gear drive, double roller full skip chisel chains, and Walbro 850 double pumper with 2" velocity stacks. Oh yea, a chrome 20" bar with nitrated tip (good for .5 hp).:monkey:

 

[Lakeside53]

Radial play is fine. Obviously you'll need a new cylinder gasket. I'm doing exactly the same job this morning, except I recoved my cylinder and I'm just putting in a new piston.
Use some 2 stoke mix oil as assembly lube - I wipe a little inside the cylinder before assembly, and lube the main, big end and piston pin bearing.

 

[028AV Super]

Radial play is fine. Obviously you'll need a new cylinder gasket. I'm doing exactly the same job this morning, except I recoved my cylinder and I'm just putting in a new piston.
Use some 2 stoke mix oil as assembly lube - I wipe a little inside the cylinder before assembly, and lube the main, big end and piston pin bearing.

Thanks for the tip Andy. I thought about cleaning up the old cylinder, which looked excellent and could have saved $80, but I decided to indulge. I'm just waiting on MFG Supply. Last night, I did a backyard unscientific muffler mod. I split the halves and drilled same size holes on the baffle directly front of exhaust port. On the screen side, I drilled single big hole in line of two louvers. One thing for sure, the spark arrestor function is bye bye. Check it out and let me know.
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