98cc Villiers on a 1945 Sears Roebuck

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indian22

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Periodic de-coke is such a good maintenance practice Harold & on engines that have significant buildup often results in quite impressive performance improvements. As I don't know what the replacement parts availability for the Midget is I'd be reluctant to break the cases until absolutely certain it's required. Making gaskets is quite easy & seals can be found, but if the cranking pressure is within parameter & the cases are holding that pressure I'd leave the bottom end intact. The China girls holding 135 to 160 lbs. are good to go. Youtube videos may mention specs for crank case pressure on the Little Villier's which is good info to know if you plan on keeping this little beauty. Rick C.
 

Harold_B

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May 23, 2012
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I'm really hoping there's not a leak in the cases or for that matter the seals. That would have me tearing it all apart and after three years that'd be a real bummer. Not the end of the world but disappointing.
Thanks for the link Ludwig. I've added it to the bunch of links at the start of the thread. I also added this one:

https://www.oldlawnmowerclub.co.uk/book/export/html/247

Glad all of this info is out there. I had no idea the flywheel nut was captured. I'll get back to it in a day or two which will give me plenty of time to over think it all. This did give me time to drain the gearbox fluid again. Lot more rusty gunk coming out of there. I'll refill it and drain it until I'm getting clean oil coming out. After running the engine and spinning it a lot with the kick starter there's a fair amount of oil sprayed in a nice straight line from the chain and sprockets. I'll be wanting guards to keep my pants oil free.
 

indian22

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Thanks to both Ludwig & Harold for the links. Not fully understanding how an engine type works leads to all types of care and maintenance neglect, to say nothing about poor operation practices.

I wonder how many engines have been damaged because of a lack of design knowledge as correct dis-assembly is just as important as the proper assembly of devices; though I've been guilty of both on more than a few occasions.

"Captured nut" is a good find Harold...something to chew on. The proper de-coking info in the great Villiar's link Ludwig posted should help those who are perhaps performing this important maintenance procedure for the first time etc.

Good read guys! Rick C.
 
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silverbear

The Boy Who Never Grew Up
Jul 9, 2009
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I've been away from this site for too long, fiddling with sail canoes and playing on the water. Harold, you've made wonderful progress on your bike which is truly looking great! I've read back several pages to catch up a bit and am mightily impressed. Your progress makes me want to get a couple of my old projects further along, both of which use the Villiars midget engine. You might even remember them. One is an elderly 1934 Elgin lady's step through bike and the other is a hybrid trike with the villiars in back and an electric hub up front. I love these engines. As I was running my eyes over your bike's very nice lines I 'm pretty sure I heard it say "ride me". And what a day that will be when you ride it off into the sunset. Woohoo! Well done, sir...
SB
 

Harold_B

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Glad to see you back SB! You should know you are missed when you're not around. Both of your builds are referenced on the first page / first heavily edited post. I have good intentions of editing the entire thread to replace the photos and verify / label all the links but just haven't had a chance. My old iPad just can't help but crash frequently.

Thanks for the feedback on my build. Slow and steady will finish the race. The race now is with the cold and snow.
 
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Harold_B

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Since the time where I was able to video the engine running to post about the backfire it hasn't run. Not even a lousy sputter. I have a new coil and condenser on order and I've managed to remove and adjust the flywheel. Nothin'! When I have the flywheel loose and give it a spin with the spark plug laying on the top of the jug I get a so-so spark. Maybe the new coil will give it more oomph. I had also read where if the rings are stuck the engine won't fire. The test was to put some oil in spark plug hole and wait a bit, then kick it again. I have plenty of compression as far as I can tell. Drained the case while I was there. It's supposed to be nice next weekend and my parts should be here by then.
 
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indian22

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Sorry to hear you've had no luck getting her started to this point. with new parts coming that may soon change, but in the meantime have you put a new plug in? Are you absolutely positive you've a solid ground? I can't tell you the number of times I've tried everything & it turned out to be one of these two basic things. Also do you have a way to turn this old girl over that does not involve kicking her repeatedly? If not I'd dream up a way, no point in inducing a heat attack while fiddling her to life. (I've not yet had to suffer the indignity of sensitivity/reprogramming & I'm not at all conflicted over descriptive issues of gender or any others at this point in my life)

Is this engine fixed timing on ignition and are flywheel key and key way tight & in perfect condition? Just a few things to occupy your mind while waiting on the postal service. I
I'm certain you'd like to have a ride before the snow flies & I for one will applaud & cheer!

Rick C.
 
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Harold_B

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Thanks Rick. The plug looks nearly new and is the one that was sent with the engine. When I measure the resistance between the spark plug connector on the HT wire and ground I'm getting around 4K ohms. Nominal is supposed to be 5K with acceptable being anywhere from 3.5K to 5.5K so I'm pretty sure the coil is working like it should (just maybe not as well as I need). I had masked off the threads in the jug before paint but I'll double check that I have good contact between the spark plug and ground ASAP. I might invest in a spark tester to be sure I'm getting good spark under compression. A spark plug socket fits the flywheel nut but my drill won't accomidate the extension/adaptor. I might just hack one off so it will fit the chuck. Fortunately the kick starter works fine. I'd hate to be trying this with a rope starter.
The flywheel is not keyed. Turning it on the shaft is how timing is set.
 
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indian22

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Testing electrical components under load & static bench observation can & do vary dramatically. I replace rather than test the inexpensive elements. Including all that's been mentioned as well as the spark lead, cap and any and all ground straps. Coil leads are quite fragile and easily damaged.

One more variable on the ignition side is the magnetic which may need to be excited to induce proper voltage and current. I'm hoping the coil/condenser is the culprit though. The fact that it ran and then wouldn't start indicates , to me, an electrical problem. It's always amazed me how an IC engine can run just great and after shutdown won't even offer to fire, no matter how hard you try. until the faulty electrical component is replaced. A mystery to me... Rick C.
 

Harold_B

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Thanks again Rick. It's a mystery to me as well. I'm taking your advice and replacing pretty much everything that goes "zap". Just ordered a new plug and I'm looking at contacts too. The HT wire and connector are new but the spring loaded contact between the end of the wire and the coil is "vintage".
I'm not letting it get the best of me although my arms are getting a little sore working the kickstart by hand. Won't matter though when it's finally running!
 
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MEASURE TWICE

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I'm adjusting the valve lash on my engine as I have restarting running the engine in warm to hot weather needing to let the engine cool off. I heard heat expansion of the valves can have them stay open too long. Only reason why I mention is that my arm trying to restart the engine had in the past been exercised beyond belief.

Oh of course I will be measuring the gap again, but I let it be even when I first got the used engine as it ran, and you know, if it ain't broke don't fix it rule.

Also not likely for my engine is a weaker spark when the magneto gets hot. I have heard of that too. The engine I guess gets hotter than when it is being run. The latent heat from within the cylinder and no electric fan like on new autos, that causes problems in this case.

A so so spark eh. I have heard that if you can crank the engine fast enough and you have the spark plug still in the cylinder with that spark tester connected in parallel, and you see a spark in the tester, you for sure have enough juice.

I have seen ads in many auto parts stores online showing those tester for cheap less than 10 to maybe 15 at most. An adjustable calibrated dohicky to use while the plug is out, an easier pull, or in your case foot crank.

You had it better, I was in the woods with 95 degree heat and trying to see if it would restart after cooling an hour. Some times I was a bit far from camp. Nice though that there are some if not just infrequent passing by of the ranger or those living in the National Forest Lands. A guy was going on a diesel fuel run for his generator, as they have no electric lines, and offered me a ride back to my camp. I offered some compensation brew, but he was happy to help and not but 2 miles out of his way.
 
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curtisfox

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MT. You have something else wrong. probably need to reseat the valves, lap them in. And if it is getting that hot, need more clearance The old school was 8 intake & 10 exhaust, but shouldn't get that hot in the first place. Do you have shrouds on? Do you ample gasket between the carb and engine( heat shield )? Tecumseh carb right? Running to high rpm's or blockage of the fan?..........Curt
 

Harold_B

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Yup MT I have it good as far as being close to home. In my own garage is a pretty comfy place to work on my bike. The build I tore down and partially sold prior to this one was a four stroke and it had a lot of the issues you're talking about. Over heated enough times to burn up the rod bearing/bushing after the oil total broke down. Several of my favorite pics of that bike were taken along the road after it decided it was done for the day. Hooray for friends with pickup trucks!
I'll look into buying a spark tester if it won't fire after I install the new parts. Pretty cheap on eBay and delivered to my house. Perhaps I shouldn't be so cheap and just buy one before I need it.
So much for beating the snow. Chance of accumulation tonight.
 
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MEASURE TWICE

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I don't want to hog the thread on my trouble shooting, but will let you know when I get gaskets and the rain and snow is stopped to put back the engine and on the bike after adjusting intake valve gap. Exhaust was supposed to be between 0.007 inch and 0.009 inch. I had a 0.008 that fit just OK. The Intake which I suspected was what I recalled being too tight and left it be as a new used engine may be better to not mess with. I got stuck with the engine when trying to restart it out in the woods now too many times. Not good. An as I thought most likely from reading about valves expand with heat I would have best adjusted the intake valve when I just got it. I also did read about heat shields to help with vapor lock but though not. Spark I remember was good when engine was hot

Yup, but it ran and I let it go.

The data is that the intake valve is supposed to measure between 0.005 inch and 0.007 inch. How small, OK it was not zilch but was 0.0015 inch so close to it. No more will there be a possibility of Venturi effect in the opposite direction with compression leaking out the late closing intake valve and wetting with gas the paper air filter. It happened on my prior 3hp Briggs. This is the 3.5 Briggs upgrade up from 8000 series to 9000 series. Paid 70 dollars for it about 2 years ago.

I can go back to pleated paper now as I should not have to worry about the soaking of paper and cutting off of the air through the filter. For the prior engine I modified a paper filter putting in a foam one and using the special oil as the cost of going through so many paper air filters was costly. I still would get stuck for an hour while I was waiting as the engine cooled. But it was even worse as the filter was getting sprayed wet gas.


I have a video up on Vimeo of that other older 3hp Briggs where I pull the recoil with the ignition off and the filter removed. I filmed gas spraying out the carburetor the wrong way.


Anyway now I can expect a lot more power, but will keep from getting a fat head and see how it re-assembles. I cleaned the carbon off inside and also did a little lapping with fine grit for both valves in their seats. Kept everything plugged from getting down in oil and wiped with oil tack rag and dried over and over.

Cold in the AM, got through by Sunset though even starting very late at about 11am. Windshield picture shows it! Hey maybe some one can date the truck picture?
 

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Harold_B

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New coil and new plug have arrived. Condenser is on the way. Weather and time permitting I'll take another crack at it this weekend. Time to get some oil-dry on the garage floor too.

MT - no problem posting here. The topic has strayed from my build to the weather, work, health, family, standard units of measure, and other members builds. On the other hand if you are looking for feedback I think pulling up your own build thread or starting a new one will get more attention. My guess is most of the people looking at this thread are specifically interested in the Villiers two stroke (and I think I've lost a lot of their interest since this has taken so long). Like I said, no big deal just depends on what you want out of the post.
 
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indian22

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Beautiful bikes likes yours get plenty of attention Harold, perhaps we just run short of quality superlatives along the way. I'm crossing my fingers on getting her up and running this weekend. Rick C.
 

Harold_B

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Thanks Rick. I didn't mean to go fishing for compliments especially since your feedback is always appreciated as is everyone else's that has offered an opinion along the way. I'm aware that the longer these threads tend to go the more there's a few core members with more interest. I think it has to do with the specifics of a build. There are several I pop in on but don't comment because I have nothing to offer but really like the build. I also think it's driven by questions vs updates where questions will get a lot more participation (and I think that's cool). The main point I was hoping to make was for MT to consider how many people might be seeing his post and of those how many might be knowledgable about vintage Briggs engines and therefore able to give meaningful feedback like I get on my build.
 
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