Engine rebuild

heyhi

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I'm going to be rebuilding an Laura m48 case and adding a motomatic batavus M48 airsal 43.5mm 60cc cylinder I have a few questions.
This is the first time I'm doing this so please give me any type of information that will avoid me making mistakes and damaging anything later on.



With this kit I have to bore the crankcase 1 mm, what should I use to bore it? Can I use a bore /hone tool from harbor freight or advanced auto? or Dremel? I don't want to make any costly mistakes. I also read somewhere that the reason these Pistons have an arrow and have to be faced towards the exhaust is because they're not actually truly round is that true?

Should I replace the crankshaft with something stronger?
Does anything need to get upgraded on the clutch?
As I'm lubing everything can I just use two-stroke oil?
When I'm replacing the seals and bearings do I put any type of specific lube on?

Am I going to need any type of three finger puller to take off the clutch hub or pretty much anything else on the bike? I also ordered a 11 tooth sprocket that goes on the drive pulley how does that come off? I haven't taken the pulley off yet but from pictures of other pulleys it looks like the sprocket is fitted on there pretty tight.

Before putting on the cylinder should I clean off anything inside there with a file to avoid catching the piston rings and damaging anything?
 

Chainlube

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I'm going to be rebuilding an Laura m48 case and adding a motomatic batavus M48 airsal 43.5mm 60cc cylinder I have a few questions.
This is the first time I'm doing this so please give me any type of information that will avoid me making mistakes and damaging anything later on.

I need this seal and can't find it anywhere. Can I reuse the seal? I'm going to be putting the case in the oven so I could split it. And it's also like 40 years old not sure if I should reuse the existing one.

With this kit I have to bore the crankcase 1 mm, what should I use to bore it? Can I use a bore /hone tool from harbor freight or advanced auto? or Dremel? I don't want to make any costly mistakes. I also read somewhere that the reason these Pistons have an arrow and have to be faced towards the exhaust is because they're not actually truly round is that true?

Should I replace the crankshaft with something stronger?
Does anything need to get upgraded on the clutch?
As I'm lubing everything can I just use two-stroke oil?
When I'm replacing the seals and bearings do I put any type of specific lube on?

Am I going to need any type of three finger puller to take off the clutch hub or pretty much anything else on the bike? I also ordered a 11 tooth sprocket that goes on the drive pulley how does that come off? I haven't taken the pulley off yet but from pictures of other pulleys it looks like the sprocket is fitted on there pretty tight.

Before putting on the cylinder should I clean off anything inside there with a file to avoid catching the piston rings and damaging anything?
Do you have any pictures of your engine?
 

heyhi

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I removed the clutch, I'm waiting for the flywheel puller to come in so I can remove the flywheel and get the case off. I'll post pictures when I get everything in the mail. But as far as honing/bore. I need to bore the crankcase not the cylinder.The kit comes with a cylinder/piston and it's 1 mm bigger. Hopefully you guys can guide me through this with pictures.

Here's a picture of the clutch side seems like it was leaking or is it just dirty?
Another thing I noticed here with the clutch, there's three versions of this engine, a 20 mph,25,30 mph . I have the 25 mph. On the 20 and the 30 there's an extra washer inside the clutch. What would be the purpose of this washer?
 

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DieselTech

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I removed the clutch, I'm waiting for the flywheel puller to come in so I can remove the flywheel and get the case off. I'll post pictures when I get everything in the mail. But as far as honing/bore. I need to bore the crankcase not the cylinder.The kit comes with a cylinder/piston and it's 1 mm bigger. Hopefully you guys can guide me through this with pictures.

Here's a picture of the clutch side seems like it was leaking or is it just dirty?
Another thing I noticed here with the clutch, there's three versions of this engine, a 20 mph,25,30 mph . I have the 25 mph. On the 20 and the 30 there's an extra washer inside the clutch. What would be the purpose of this washer?
Spend the money & buy the case splitter / installer, it's well worth the money & you lose the risk of breaking cases during splitting them & putting it back together. They also make a cutter to cut your engine cases for your big bore kit. It can be done without the case cutter, but need to be extremely careful & precise.
 

heyhi

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I don't mind spending the money and buying the right tools. I was looking into case splitters. The reason I didn't get one yet is because the videos I've seen have the bolts on the side so you could grab on to them and split the case. But on this engine case the bolts are on top so I wouldn't be able to grab it and split it that way. Do you know which case splitter would work? And as far as honing the case I'm not sure which tool to get. They have the ones they sell at harbor freight or advanced Auto but it seems like those are for deep cylinders .
You look at where the Piston is I don't have that much room to go down so I'm not sure what tool would work. I only need to go 1 mm. I'll take off the Piston later on when I get out of work and show you a better picture. Don't Mind that oversized stud hole, that half of the case is going to get replaced.
 

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DieselTech

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I don't mind spending the money and buying the right tools. I was looking into case splitters. The reason I didn't get one yet is because the videos I've seen have the bolts on the side so you could grab on to them and split the case. But on this engine case the bolts are on top so I wouldn't be able to grab it and split it that way. Do you know which case splitter would work? And as far as honing the case I'm not sure which tool to get. They have the ones they sell at harbor freight or advanced Auto but it seems like those are for deep cylinders .
You look at where the Piston is I don't have that much room to go down so I'm not sure what tool would work. I only need to go 1 mm. I'll take off the Piston later on when I get out of work and show you a better picture. Don't Mind that oversized stud hole, that half of the case is going to get replaced.
What's your cylinder stud spacing. Measure diagonally across 2 cylinder studs & report back when you got time. But this is a case cutting tool for cutting cases for a big bore cylinder kit. This will work on multiple engines, that's why I'm needing cylinder stud spacing.
Screenshot_20221018-112253_Google.jpg
 

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heyhi

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Yeah I seen that tool. The spacing is 1.75 inch or 45 mm. Is that the only tool available because that one is pretty expensive
 

DieselTech

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Yeah I seen that tool. The spacing is 1.75 inch or 45 mm. Is that the only tool available because that one is pretty expensive
Yes there is other companies out there making a case boring tool/ case cutter for big bore kits. That's just the 1st 1 I stumbled across.
 
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