General Category => Engine & Transmission => Topic started by: Ricks on August 03, 2013, 02:25:09 PM
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I just disassembled an engine I have to see what kind of shape it was in. I don't think this motor had any chance of running! Check it out.
Solid aluminum compression plate was too deep, so the rod bearing retaining screws were ground down to make clearance! Who would do such a thing?
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Billet rod was balanced/lightened horribly. This rod has so many stress risers, it would probably let go in short order!
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The piston was also clearanced,balanced/lightened with who knows what!
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An attempt was made to add weight to crank. Don't know how this worked out, but Simplex did this through the years. Also, a repair was made to the key way.
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Not enough clearance for the crank nut? No problem, lets break out the grinder! WTF?
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In an attempt to increase performance, the carb inlet was hacked out. The engine was also sleeved to tighten the intake clearance.
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And last but not least, one of the cylinder mounting bosses was broken off and held on by RTV. Part of the cylinder sleeve is missing, as I only found the one piece inside when I opened it up.
I think this cylinder can be saved by Tiging the broken piece back on and resleeving the cylinder. Guys, what do you think? Is it worth the effort to try to save an otherwise good single sparkplug head?
Oh, the motor pulley is also cracked and has been welded!
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Rick, A call to Bob Kerr should probably be your next move (regarding saving the engine). I never seen so many problems with the same engine. Best of luck to you. Mike
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WOW !!! What a mess .
Do all single plug cylinders have large exhaust ports like that has , Rick ?
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Rick, A call to Bob Kerr should probably be your next move (regarding saving the engine). I never seen so many problems with the same engine. Best of luck to you. Mike
Mike, I think Wayne can provide most, if not all that I need to get it fixed.
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WOW !!! What a mess .
Do all single plug cylinders have large exhaust ports like that has , Rick ?
I don't think so. I think the builder was trying to increase performance.
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I'm no pro engine builder , but it seems to me that the PO went way too far in his attempt at higher performance . But , maybe he was simply experimenting .
Still , there are a couple things that I don't understand : the shaved piston head would decrease already low compression and the added weight to the crank counter weight would slow the RPM gain , robbing power .
Are the transfer ports raised ( opened to the top side ) to make the skirt over cut at least somewhat effective ?
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PD, this is an undersquare engine (longer stroke vs bore), meaning adding weight to the crank is a good thing, as long as the weight of the piston & rod are considered.
This motor can be saved, but the question becomes is it worth it compared to finding another simplex motor.
Mike sal
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The motor will be saved. I will put in a new piston and rod. I will see about saving the cylinder. I think it can be welded, machined and a new sleeve installed. If not, I am on the look out for a single plug cylinder. If anyone has one for sale, please let me know.
The good part is the mag looks great, no problems there.
Did these bikes come with a Brass flywheel cover rom the factory, or did someone make this one?
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"PD, this is an undersquare engine (longer stroke vs bore), meaning adding weight to the crank is a good thing, as long as the weight of the piston & rod are considered. "
Proof that I wasn't lying about not being a pro engine builder . :-[
Thanks for that , Mike . I like learning new things . :)
Rick ,
About the transfer ports , have they been altered ?
Pete . :)
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Rick ,
About the transfer ports , have they been altered ?
Pete . :)
I think they have been enlarged. I don't have another cylinder to compare it to. When I get the engine case finished, I will put the rod/piston back on the crank and check why they cut the piston skirt so much. I removed the bearings so I can't check that yet.
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It wouldn't surprise me if they were hogged out , considering the over the top 'mods' already apparent .
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After bead blasting the case clean, I found out why the cylinder cracked! The case was not originally a 150cc motor case. The builder bored the opening for the cylinder spigot, but not deep enough. The cylinder bottoms out on the sleeve before it meets the sealing surface. As soon as the bolts were tightened, I am sure it cracked.
I measured the base OD of a 150cc cylinder at 2.36", and a 125cc at 2.17".
First 2 pictures are 150cc cylinder, notice how it will not seat.
2nd 2 picture is 125cc cylinder, seats as should.
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Here is the sleeve around the rotary intake port.
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I picked up parts at the Wollard estate about a year before the auction and got a fly wheel cover for my 1941. It was brass also, and I assumed it was factory but I'm not sure. I'm going to polish the brass and use it like that.
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I thought Gary might have made these. He liked to cast things is brass. I am going to bead blast it to remove the powder coat and then sand and polish it. If I don't like it, I will use the aluminum one I just bought from Bill E on eBay.
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I have not done much lately, but as I was cleaning up some of the parts, I noticed that the motor seal didn't look quite right. I like to use a 6mm wide double lip seal, but I have used a 5mm single lip seal when I couldn't find the other. I guess all the builder had was an 8mm seal. These are way too wide and bind up the motor against the motor pulley and case. His solution? Get out the belt sander!!!. Now, this might work, but I don't think for long, as the lip holding the spring in is almost non-existant.
I have sent the cylinder to Wayne, as he thinks he can have it Tig welded and then resleeved. The wall thickness on a 150cc cylinder is very thin, and I am going to have it resleeved back to a 125cc overbore size.
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I spoke with Wayne yesterday, and he said we could not save the cylinder. He said the base had been cut too thin, and that was one of the causes of the breakage.
I am on the lookout for a single spark plug cylinder, so if anyone has one for sale, let me know!
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Rick, I have a cast iron cylinder with one spark plug hole. It has the decompression lever attached. Is this what you are looking for? Mike
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Rick, I have a cast iron cylinder with one spark plug hole. It has the decompression lever attached. Is this what you are looking for? Mike
No Mike, but thanks anyway. I am looking for a late model, aluminum, single plug cylinder. 125 or 150 cc, doesn't matter as I will have it resleeved.
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How is the single plug head different than the double? Did they just pull a core pin cast the second hole solid, or did they have a different design all together with a plug in the middle?
Mike Sal
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They moved the plug to the center of the head. Other than that, I believe they are the same. If I can't find a single plug cylinder, I wil use a double plug cylinder.