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Post by oldgeek on Sept 3, 2023 19:23:02 GMT -5
Dove in today and made the squish band area deeper and wider, it went well. Decided to make the combustion chamber larger because it is inevitable Lol. It took a long time but It also came out great. Started out with roughly 12cc ended up with about 17cc in the end. Yeah I went a little too far maybe.  Before  After  Side by side with modified head from 103cc project.  |
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Post by 190mech on Sept 3, 2023 23:13:42 GMT -5
Nice to have an in house machine shop ain't it!!  |
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Post by oldgeek on Sept 4, 2023 19:48:54 GMT -5
I am kicking around cutting the squish band deeper into the head, for a couple reasons. 1)I really dont like the steel head gasket that comes with this kit, I just dont have faith in its ability to seal. I could eliminate the steel gasket if I cut the head deeper. 2)It would lower the head volume a bit which may be a slightly large now. I guess calculating corrected compression is the only way to find out for sure. Steel head gasket  |
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Post by Lucass2T on Sept 5, 2023 0:05:52 GMT -5
Nice work OG.
Have you also measured the radius of the piston crown so that the squish band is equal?
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Post by 190mech on Sept 5, 2023 3:51:14 GMT -5
I think a gasket will be needed, either steel,copper or aluminum (or O-rings) to seal a LC head..The steel should do fine with copperkote, it has those embossed beads to aid sealing, likely a 1 time use gasket..
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Post by Lucass2T on Sept 5, 2023 4:43:54 GMT -5
OG you could consider using bigger studs and torque the head down a little tighter.
What are they, M6 (hope not), 7 or 8?
That head gasket is probably fine if both mating surfaces are surfaced and clean.
You might need to torque it down a little harder.
I know the Honda MB8 motors (80cc) are M8 studs and they work fine even for the 125cc big bore kits.
My Suzuki 50cc watercooled motor has m8 studs and they are torqued to I think 25nm (18.5 ft-lbs).
It has a car style head gasket and I did use a light coat of RTV to make sure it's sealing.
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Post by oldgeek on Sept 5, 2023 6:49:57 GMT -5
Nice work OG. Have you also measured the radius of the piston crown so that the squish band is equal? I have not but the solder I use to check squish is near equal thickness the entire width of the squish band. I was very suprised to see that. I think a gasket will be needed, either steel,copper or aluminum (or O-rings) to seal a LC head..The steel should do fine with copperkote, it has those embossed beads to aid sealing, likely a 1 time use gasket.. I was thinking of using just copper spray between the head and cylinder. If it is a one time use gasket, It is already done because I have torqued it down several times now. I dont think these gaskets are available anymore. OG you could consider using bigger studs and torque the head down a little tighter. What are they, M6 (hope not), 7 or 8?............................. They are only M6, and there is hardly any room for them. However I did deepen the holes by 8 - 10 mm and re tap the holes so the studs would have more grip. I also use red thread locker on the studs in the engine case. The head looks pretty flat, the cylinder its hard to tell. I have been trying to check the flatness of the cylinder with my diamond credit card style files but they are a little small for the task. Maybe some glass and sandpaper would work better.  I have a horizontal mill, I guess I could try to destroy flatten the cylinder using it. Gotta get a fly cutter for it though. I could always see how well the steel gasket works and if it does not, change to plan B. |
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Post by 190mech on Sept 5, 2023 14:13:54 GMT -5
If you are going to try no gasket, I'd give UltraCopper RTV the go, still gotta wonder if it will seal combustion gases and water, guess time will tell!
Glass and wet sandpaper with WD40 works great for getting surface true..
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Post by oldgeek on Sept 6, 2023 21:14:12 GMT -5
Decided I will leave things as they are, no more work on the head. I will use the metal head gasket with some copper RTV to seal the head and some motoseal for the base gasket. A .54 base gasket will put me in the low 60's for the squish, maybe mid 60's after the motoseal and RTV. The .80 base gasket lands me in the low 80's with the squish, maybe mid 80's after motoseal and RTV. I should probably find some .60-.65mm gasket material to make a base gasket from. I checked ring end gaps on all four 54mm ring sets I have, looking for .009 The one set I have that checks out to .009 came with a Tadia replacement piston kit. The other three set of rings are kinda wide gapped.  The radiators I ordered were waiting on my porch today when I got home. They were $38 shipped and the quality shows it, I hope they hold water. I went over to the shop after dinner to see where they might fit the naked Kymco. I tried several locations but the only place they work kind of easily is where I have them in the picture. Not too bad and removable for when I put an AC motor in the scoot. For the water pump I think I will order something 12v off of Amazon. They have some automotive pumps for inverter coolers that look just like some of the ones you see for scoots, but they are much cheaper. Anyone have any recommendations?   |
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Post by Lucass2T on Sept 6, 2023 23:21:07 GMT -5
I would be very content with a 0.8mm squish on a 100cc motor!
0.6 is pretty tight...
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Post by oldgeek on Sept 7, 2023 19:21:48 GMT -5
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Post by oldgeek on Sept 10, 2023 20:21:15 GMT -5
Well I got over my last post and pulled it back apart to see where things went wrong during assembly. I cleaned up the gasket surfaces, it sits ready for inspection, some time this week when I get a chance.  I looked but could not find the info 90GTVert posted on electric water pump tests. I just ordered a cheap one from amazon for a Prius If its no good I haven't wasted much money. I also ordered some heater hose to plumb it all together. I was thinking about installing a thermostat but I cant seem to find a thermostat or a housing for a scooter. |
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Post by 90GTVert on Sept 10, 2023 22:00:20 GMT -5
This is probably what you were looking for : 49ccscoot.proboards.com/thread/23915/water-pump-flow-current-drawThis is the pump that I've been using : amzn.to/3Pz30UcI never looked into thermostats too much. Some of the Minarelli stuff has a spot built in, but the actual thermostats aren't easy to come by. I think it's too hot anyway. I'm perfectly happy if my coolant temp will stay around 120F. Seems to run quite strong. It won't do that in the summer. Then it's gonna get to 140+. Winter could see below 100F, which is not ideal, but most people aren't going to ride in very cold weather. |
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Post by Lucass2T on Sept 11, 2023 0:37:49 GMT -5
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Post by oldgeek on Sept 12, 2023 6:45:15 GMT -5
I pulled the head off the cylinder and I have to say I have zero faith in the steel head gaskets ability to seal. Assembly oil from the bore had wicked everywhere between the head and the cylinder.
I am thinking about getting some soft 1100 aluminum sheet and cutting a gasket from it on the scroll saw. Good or bad idea?
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I have a horizontal mill, I guess I could try to 
