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Discussion in 'Your 250cc Projects' started by Linkin, Feb 19, 2016.
wait till i chrissen your seat.
Picked up the frame bits from Linkin yesterday and home to block up all the important holes. Took to blasters today for a clean up.
Don't remember how I got talked into painting this but must have involved alcohol.
Should have dropped it to me ... I have the perfect solution for it
and i hear sex change operations can be done with a blow torch.lol.
With Linkin away learning how to be a real motorcycle mechanic, I have picked up the reins on this one. Frame has been blasted and painted in two pack silver and I am now working on the engine. Valve and seats have been cut and new seals on order, ports de-burred and waiting on supplies of sanding disc to finish polishing.
The bores are all scratched and worn at the top of the piston stroke, and new O/S piston kits on way, along with new timing chain and gasket sets. These verticle scratchings are what happens to bores when incorrect or no air filters are used.
To get the last three bolts out so I could get the cases apart I needed to remove the rotor. An incorrect threaded bolt had been tried before and had stripped the thread. I ground the end of a tap flat so I could clean up the thread and get the rotor off (some heat from a gas bottle torch helped)
At last they are out.
Cases split and bearings are reasonable, but will be replaced to do the job properly.
A lot more difficult than the CBR.
murdo, you're like a god on this forum, the stuff iv'e picked up and learned from your posts over the last year!! unbelievable stuff, love all the pics they're a great help.
Thanks Beano, I'll try to do more for you.
The cases are a pain on these. Head and barrels off required to split them. Are the MC19/22 different in that regard?
I only have the 19's, but head off, bottom case off and undo rods and push out through bores. Less tricky bolts you have to find when splitting cases too (particulary when you've not done one before and cannot read Japanese in manual).
Do you want to send me those cases and I will clean them up , if you are going to this much trouble with the rebuild then I am happy to do my bit and make them shine
thanks for the offer. murdo can decide.
Thanks Kiff, I don't think it will be necessary.
Doing a bit more on the head today. This is why you DON'T put silastic (or other silicone type sealers) into water fittings (or intake manifolds either). These fittings need O rings for seals, and I can understand using the silicone as a tempory/get home measure, but more is not better.
Imagine if this big lump of blue poo came loose and went into your radiator, how many cooling tubes would it block? Cooked engine anybody?
This is what it should look like. A bit of rubber grease on the seals to help them slide in and all will be good.
Goes to show some people shouldn't be allowed near engine's, or anything mechanical
Some people should not be allowed to buy tools.
But I guess if they didn't then they wouldn't stuff anything up and we wouldn't have any cheap bikes to restore.
If nothing else........it is colourful !!!
Who would have thought that silicone sealer would come in so many different colours?
The Intakes had red and blue on them. Will need some proper gaskets when I put it back together.
Pistons (+0.50mm) have arrived and taken with barrels to be rebored. Cases and components cleaned, inspected, bearings replaced, new cam chain, new seals and gaskets and ready to be reassembled.
When fitting bearings it is important to check on the clearances, but also on the 'crush' of the bearing shells in the rod end. If not enough crush on the shells they may start to 'chatter' and will wear rapidly, possibly spinning in the rod end. To do this tighten the bolts to the correct torque, then release one side and measure how much the rod end has 'sprung' apart. These all came to .005", which is very good (.002" being the limit).
All clean and ready to assemble.
This is not OCD. I like to make sure I have all the bolts ready to go before I start so I don't get caught with drying sealer looking for the right bolt.
All together and waiting for the barrels to come back.
Today I finished with the ports and after a through clean put the head together and set all the shims. Wrapped in clean rag waiting for barrels.
Barrels back and looking good.
Note the white rag with oil on it. My uncle taught me many years ago after a rebore/hone to wash with Kerosene, then hot soapy water a couple of times then wipe a white rag with oil soaked onto it up and down the bores and if any dirty marks appeared on the rag then there was still honing grit on the surfaces and it had to be washed again. Then wipe with another clean white rag to be sure, as nothing will wear a bore faster than leaving honing grit for the rings to grind with.
Pistons fitted and oiled.
Barrels on ready for head gasket. Have to wait as one of the dowels are missing and will be a while before I can get it.
So, who can tell me which one is the genuine gasket and which is the Chinese copy? They are both the same thickness and have same surface coating on them, and all holes line up excatly.