Just_Alex

@Wonky the beast lives! Nice. 🤩

10 hours ago, spudulike said:

You can use a brake bleeder kit to produce a vacuum, a bicycle pump for pressure and use a Gunson low gauge as I did for a bit but the Mityvac does it all for you but obviously at a cost and there is the rub. I have used mine a few hundred times and it has saved me loads of hassle finding issues and ensuring my customers get a saw that is perfect and won't go pop in the next few years.

In your position, you are likely to use it once or twice and that is the issue, someone running a business needs this sort of kit and can invest in it amortising the cost over many repairs and unfortunately, you can't unless you enjoy this sort of work and start your own business etc etc......

 

Maybe a simpler method is the saw should die if you turn the L screw all the way in, if it doesn't, it most likely has an air leak.....it takes a bit of experience but is an indication!

Thanks @spudulike I’ll mull those options over, nice thing with your last method is it requires a screwdriver which I already own  

1 minute ago, spudulike said:

Not done the oil pickup on an 038 before but from what I can see, you push the rubber pickup on to the metal elbow that goes through the oil tank wall. Generally pickups push through from the clutch side oil tank wall but this one looks like two flexible hoses go either side of the solid elbow. 

try it, forceps are generally a good tool for this sort of thing.

Much obliged @spudulike, I’ll try it! On another note, I’ve been musing if I can fashion some kind of pressure/vacuum testing kit or if there’s not much point? Maybe a bit of flat bar as a seal on the exhaust side of the cylinder, and some kind of tyre valve fitted to flat bar mounted to the intake? This way I might be able to attach a tyre pump to pressurise… not sure what to do about a vacuum test, need to find a way to suck out the air….

Anyhow im sure it’s all possible, just not sure it’s worth it or if running the saw will tell me in other ways if there is a seal issue. Eager to hear your thoughts  

23 minutes ago, spudulike said:

The suspense is climbing...not much to live up to after 12 pages of posts

@spudulike waiting on parts now- might not get everything needed right away as a couple are on back order from Stihl. Hope I can do it justice!

Did a bit more cleaning today and wondered if it’s possible to replace the oil hose through the oil cap somehow, have you ever tried that? The manuals seem to think it’s possible but I’m doubtful I could reach in there. Is it just a matter of pulling off the old hose & filter and shove a new one on with long nose pliers?

God I hope the crank seals are still good after all of this 😂

Small update. Rebuilt the carb as best I could. Not a super duper high spec carb kit I fear but at least it’s new and it’s had a clean. 

before

after

Thanks everyone, this has been super helpful and I’m glad I asked. L&S will be glad too, since this has resulted in a rather lush order of parts 😊🤩 The only thing I really couldn’t find on their site was a Bing 48A carb repair kit, so sourcing that is the next mission. I’m keen to see how rebuilding the carb goes, those components look finicky and it’s very possible I might mess it up the first time. 
 

I’m starting to get a little bit concerned I won’t be able to put it all back together without having a dozen bits left over🙈. Is there a general rule of thumb in terms of the order people put the saw back together? Put piston and cylinder back on case with new gasket, then put carb (once rebuilt) back into the handle part and then marry the handle part back up with the crank body?
I want to add a few things which others may think of as “cosmetic” such as new fuel line, fuel filter, air filter, air prefilter (won’t be able to do a new oil line or oil filter because we are keeping the case closed), the carb rebuild of course…. My assumption is it’s pointless to fit a new shiny piston and then mess it up with contaminants from ancient intake components. Is this a good approach?

Oh and should I bother with a new exhaust, or try to get it to run first? I’m not sure what to look for in terms of criteria too judge a muffler etc by, I can’t see much rust for example. Any tips on this?

Anyway, wishing you all a pleasant evening 🙂
 

Thanks @openspaceman, yeah that’s the one. I’ll send them a wee message or see what happens when I place an order.  
Quite keen to get the rubber parts from L&S as they have some of the original Stihl parts (AV stuff for example). 
 

Really useful info @openspaceman, thanks  Still trying to settle for a piston kit but the nicer quality ones don’t seem to have the 50mm available, and I look at the £10 ones and think… is this going to be decent enough? is it made of cheese?
 

I’ll keep looking 🙃

Morning all. I have a potentially very naive question for our brain trust: How come most overhaul discussions revolve around replacing the entire piston, rather than just making sure the cylinder is in hood shape and then putting new piston rings on the existing piston? What are the reasons to go with a whole new piston & rings set over just new high quality piston rings? Surely new rings would give the head and existing piston new life?

I’M not trying to be a cheapskate or anything, I’m trying to understand the engineering reasoning (also if good replacement 50mm pistons are hard to come by, maybe keeping the OEM piston plus new OEM rings is mechanically a better option?).

Many thanks for improving my knowledge, I’m really really grateful  

EDIT: I think this answered part of my question. The part of the question around what is better- low quality piston & rings versus old OEM piston and new OEM rings I would still love your thoughts on  

For those with too much time on their hands (and might be interesting for @Wonky and other future readers of this thread), found this 028 service manual which according to the introduction also largely applies to the 038. Some cool info in there. 🤩

STIHL-028-038-Service-Manual.pdf

<picks up wood chisel again with trembling hand> phew! I used a chisel a tiny bit but said to myself “Alex, don’t be a fool now, best ask what Spud does first!”

thanks Spudulike. Will inspect the breather tube. Clear is better, I get why it’s designed this way. 
 

Another thing I noticed is that the rubber grommet thing on the oil pump looks pretty perished, so potentially that could be refreshed too. 
 

I’ll see if I can obtain original Stihl parts for anything rubber, but yes as you point out sometimes it seems tricky to find bits for these old creatures. 
 

@Stubby Thanks, I try! Although the rat could be winning this one, jury’s still out!😂

Good thing I have a 5L container of WD40, because: more cleaning today. It’s starting to look like saw parts again, and not like a pile of muck.

I could not see any perishing or cracks on the boot, my guess is this saw has sat for a decade or two and has not seen much action and the oily gunk has preserved it like the precious fossil it is! 😄
 

Carb is a BING 48A / 101A and I’ve decided to make a list of potential spares to order first before placing a bunch of orders. As tempting as it is. 
 

@spudulike is the breather hose materially different from the 038’s impulse line hose? It looks like a red (maybe was clear once?) hose. Was super clogged with gunk all around so not sure if it needs replacing or if that’s a non-issue. Or maybe I can just use a bit from the meter-length black hose L&S sell….

Here’s another million dollar question: how does one go about shifting the head gasket off the crank case? It’s pretty much baked on there I think. I don’t want to make any marks on the aluminium so for now I’ve just gently shifted one side of it and when I couldn’t move the rest I soaked it in WD40. Will that do to soften the material? Any tricks of the trade?

Pictures below. Aside from the head gasket and flushing the whole crank case and the crank bearing with methylated or pure WD40 to flush out any potential gritty bits that may have made their way down there, I feel like it’s at least at a point now where I can start to plan ordering the components and then have a few weeks of sleepless nights worrying about whether or not I’ll remember how to pit this old hornet back together again….

9 hours ago, peatff said:

 I think the 044 is a longer stroke than the 038. 

This makes sense thanks @peatff 👍🏻

Thank you Spud, sounds like I’m vaguely ambling in the right direction. Tomorrow I hope to clean and inspect the head a little closer, I’ll see what acids I can get my hands on too. I’ll remove the carb to see what type it is and hopefully unseat the boot. 
I checked out of curiosity and sadly L&S don’t have 50mm piston kit listed in stock as far as I can see. Where do I go - eBay? Not sure how rife it is with imitations of the replicas (as a novice I don’t want to end up buying a piston that says it’s Meteor but ain’t, if you see what I mean).  
I’m trying to work out if the 50mm piston from the 044 will fit the 038 av super, but maybe that’s just the Google algorithm confusing me…

If anyone has a trusted source of parts and could link me to their website that would make me eternally grateful. I really like the way this site collates the 038 parts but if I can avoid import duties / get better quality parts that would be great 😂 https://shop.saegenspezi.de/Passend-fuer-Stihl-br-038

Thanks all!

Well, perhaps time for an update, as I have spent some quality time with the old hornet today. I’m fairly certain there is no axial or lateral wobble on the crank shaft, can feel nothing move at all. Clutch is still attached though, not sure if that makes a difference. 
In the end I could not get to the impulse line (clumsy fingers) so I did take the tank off (wanted to clean under there anyway) and as far as I can see there is no visible crank case seal oil leak anywhere, but maybe it’s too early to tell, as there is still plenty of gunk to get rid of.

Impulse line removed and inspected. Aside from stiffening over the years there was nothing wrong with it, to my surprise. I have ordered new tubing from LS. 

I also had a careful look at the crank shaft bearing by rotating it all the way with a pointy thing to make sure the race is not broken (poor @Wonky!). Bearing race looks good. 

Questions I have: 

1. Boot- can I remove that from the cylinder side by tugging/gently prying? Or do I need to work from the carb side and remove the carb first? ( @spudulike if I proceed to the MotoMix side I’ll need to remove the carb anyway…). I’m having a hard time inspecting the boot for cracks in position so would like to replace it I think. 

2. The crank case / tank case mounting: are the black rings supposed to be attached to the plastic tank assy or are they broken off “slices” of the rubber AV mounts? 
 

3. Good idea to replace the river AV mount grommety things all over I assume? 
 

4. is there supposed to be any fleece filling inside the air filter? Looks like nylon webbing front and back but is empty inside for me which I found odd, but maybe it’s intended this way. 
 

5. The drive shaft on the sprocket side- I can see some tempering colours on the steel- from dark straw to blue and back to straw. Is this caused by normal operation or is this a symptom of overheating in the past? 
 

6. The oiler set screw at the base of the crank case seems a bit weepy, is that normal? I’ve not tried unscrewing it but maybe there’s an o-ring in there that might want to be replaced?

Anyhow, I am rambling. Thank you all for all your input, I’m trying to learn as fast as I can, and am actually enjoying this. If it weren’t for you I’d probably have sold the saw in parts or something, I don’t know. I might still fail here to get it back to life but I’ll have learnt a lot. 😊

9 hours ago, spudulike said:

The intake damage on the piston is often when the build up of transfer on the exhaust side pushes the piston backward and against the inlet port side causing a mini seize.

A bad bearing is more likely to scuff the sides of the piston.

If the machine is going to get some serious use, you want to learn a bit and are a bit masochistic, fill your boots, otherwise, just check for play like I said.

You could pull the clutch side seal to check the cage further but up to you and your ambitions. Splitting and rebuilding a saw is generally a bit beyond most unless you have been around engines a good time.

Thank you @spudulike, I’ll have a wee bit of time with it this weekend and will check play and hoses. From what I’ve researched it seems to do that properly I need to remove the handle/tank from the crank case, right? 
Couple of other questions: assuming the cylinder is serviceable, which grit do you recommend using in terms of sandpaper? I have a bunch of higher wet-and-dry grits here, just not sure how high to go. Also, do you wrap the paper round your finger or perhaps use the old piston as a template for a “sanding block” of sorts to not accidentally overdo any one area? 
And when it comes to the piston itself, we are replacing that, correct? Or just sand and new rings? Any links to recommended / favoured piston kits to use? I’ve been searching online and getting Option Paralysis 😂, and I saw you recommend Meteor etc before but I’m not sure which retailer to go through (same for OEM auf that’s the case). 

You said in an earlier reply “You then need to rub the cylinder to roughen the bore” and I’m trying to digest this- do you mean we use chemicals to get rid of transfer, then abrasive to make even and smooth, and then use a different/lower grade grit to make it a bit rough again? If so- why do we do that and which grits would you recommend for each step?

I’m also planning on using MotoMix - are there any other rubber parts I should consider at this junction? Fuel line / filter I assume as well?

So many questions. I apologise. You’re a saint for putting up with me. 

This is as far as I got @spudulike et al - the cylinder to my untrained eye looks like it may have some deposits but to me it does not look very scored. What should I be looking for when taking in the heady sights and smells of a head assembly soaked in oil and WD40? I’m gonna take a break until the brain trust has spoken (please remember I know nothing, in fact, less than nothing, and any advice is mega welcome!).

cheers all 🙂 

Ok kids before I upload lots of detailed shots of the cylinder and piston outside and in - is the crank supposed to have as much wiggle as this? Hoping videos are allowed here. More pics to come. Cheers

@Wonky you fill me full of hope 😂 

thanks I need all the advice I can get. 

I’ll blow it somehow or other, the bets are gonna be on how. 😂 thanks Dan!

Evening all. Torx key arrived, first evening with a bit of time, hold onto your braces!

@spudulike and others I might need your advice- dare I pull off the head before I clean this whole machine down somehow? Or just flush out the case with petrol later if several buckets of carbon solids make their way in there? What’s a good solvent to use - I have a big load of WD40 here, and a toothbrush? Or am I over or under thinking what feels to me like open heart surgery? 
 

As always, much obliged for your input, team. 😊

Torx key ordered, thank you Spudulike 🙂

I also saw you recommending doing the rubber swap dance when starting with MotoMix which is what I plan to do for any saw(s) I get since I’m a “very occasional” user. 
 

Even if this saw ends up in bits on the floor I’m going to try to soak up all the knowledge I can do thanks all for your help 🥳👏😇

7 minutes ago, spudulike said:

They typically split, just done a Red Eye 066 that had done similar. Best to remove it to inspect it or just replace it as it isn't expensive.

This is how it goes isn’t it, “just let me undo that set of screws to take off one more thing” and before you know it, there’s piles of parts everywhere and a spring in your eye? 

ok will get a set of long torx and see how far I get this weekend.  Thanks Spud  

28 minutes ago, adw said:

The impulse actually creates a positive and negative pulse due to the action of the piston movement, this is transferred to the pump diaphragm which creates the pump action.

Located the impulse line, but it’s hard to see if it’s perished or not without disassembling at least a tiny bit more… I’ll also take a look at the air intake grommet thingy on case that’s also 35 years old and wheezing like crazy. 
thanks all I learnt so much already, thanks for being patient with me! 

4 minutes ago, adw said:

Oh dear, we have are work cut out here.

I’d pay good money for someone to do the honours rather than you having to watch me work out which way round to hold a spanner 😂

dunno… it’s already in a box… boxes are used to ship things… any takers? 😅