I'm feeling proud of myself now because I put together my whole bottom end from a pile of parts and it was easy. Only took about 4hrs with cleaning and double checking every part I put on. I don't think I would have figured it out without the downloaded manual I got from this site.thanks. here's some pics of my bottom end and make shift crank puller. If anyone sees anything wrong with the bottom end please let me know.
first rebuild from pile parts
- Thread starter getsum
- Start date
Welcome and Awesome job , First month on the forum and you rebuilt your own bottom end , Nice ! , when you get the top end on there Make sure you do a Leak down test , If your unsure what it is Here ya go !
http://www.blasterforum.com/do-yourself-20/how-perform-leak-down-test-44653/
http://www.blasterforum.com/do-yourself-20/how-perform-leak-down-test-44653/
Looks GREAT!! You can read up on here on how to do a DIY clutch cover polish. That'll clean that side cover right up, where the paint has been marred.
Ya I watched the leakdown video is there a list of parts to make that or how much are they. I need one. As for the top end I'm not sure what to do with it. The cylinder is kinda beat up and I dono if it can be bored or if I have to get a new jug. It looks like the bottom ring came out of its groove so I dono. I took a file to the piston to take the burrs off to see how loose the piston fit. It's real loose I can wiggle it back and forth.
And I was thinking of polishing the side cover because if I paint it its just ganna do the same thing.
And I was thinking of polishing the side cover because if I paint it its just ganna do the same thing.
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now that looks scary,Nice on the bottom end but that piston is toast.As for that jug i would be concerned,only way to know is to measure i guess,A used jug may be cheaper than a resleeve but will still need to be freshened up.I wonder what the cost difference would be between a Resleeve or just a refresh of a new used jug with new piston n rings.hmm,Subscribed to this one for educational puroses hehe.
The piston ring either broke or the pin came out and it spun around to the exhaust side.
Is there still a pin in each groove on the intake side?
The broken or spun end of the ring snagged on the exhaust port and then it was the end of the game.
2.682 inches = 68.12mm is pretty much max for a stock cylinder isn't it?
Resleeve or new or used cylinder are your only options in that case.
This would be the point some people think of going big bore...
Steve
Is there still a pin in each groove on the intake side?
The broken or spun end of the ring snagged on the exhaust port and then it was the end of the game.
2.682 inches = 68.12mm is pretty much max for a stock cylinder isn't it?
Resleeve or new or used cylinder are your only options in that case.
This would be the point some people think of going big bore...
Steve
Ya I think its bored about as far as it would go. I looked up the part number on the top of the piston and its an 80 over and it has a lot of slop in the cylinder and i think they only go 90 over. So I'm ganna have to save up and get it sleeved or buy a used jug or something. I'm thinking sleeve this one so I can start fresh so if it blows up again I have room to bore.
I just got my jug and head I ordered from eBay for $82 and it measured out to be 2.6in. On the dot. I feel like I got a good deal. So I was wondering if I should just hone it to get the crosshatch back and buy a stock size piston? The cylinder looks to be in perfect condition, no scratches or anything.
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For piece of mind, I would want it measured with a bore gauge. A caliper around the top gets you in the ball park but having someone measure it with a proper bore gauge could find that it's out of round or that it's not a true cylinder. You seem to be quiet capable. You should check out the KOR video's on DYI porting and clean up the ports. Since you got such a good deal on the cylinder, maybe there is funds to send the head out for rechambering and having the cylinder power honed for correct clearance to your new piston. Don't forget you leak down test, do a proper break in and dail in your jetting. After all of that you'll have an engine that is making good power and will last a long time. Very nice job you're doing.
If you really want to be a DIYer buy a bore gauge (they can be had for under $100 now) and learn to use it if you think you like this hobby. A hone is under $200 now, not hard to learn to do your own work these days. I paid over double these prices 30 years ago for my tools.
Bore gauge:
If you would rather not, well worth buying your piston from a local shop that does boring and honing and can give you a good accurate measurement. If the bore is close enough to an available size you can just scuff it up lightly with scotchbrite and put the new piston in, but you don't know that until you measure.
Bore gauge:
If you would rather not, well worth buying your piston from a local shop that does boring and honing and can give you a good accurate measurement. If the bore is close enough to an available size you can just scuff it up lightly with scotchbrite and put the new piston in, but you don't know that until you measure.
We use bore gauges like that at work. I wish I could afford to buy the tools and do it myself but that's not really an option now. I'm probly ganna have to just take it to a machine shop and have it measured and probly honed or bored. Do I have to find a motorcycle machine shop or do most auto machine shops do it?
thats a tough question, i've had auto machine shops overbore it by .004, had ken oconnor not caught it when i sent it to him for porting, it would have soon imploded again, it was still another $120ish down the drain, as i needed to bore to the next size and supply a new piston
i've also seen talk on here of "motorcycle shops"
not chamfering the ports after bore/honing, and suggesting heat cycles are not needed ?
i had a yamaha dealership gouge my cases while installing a crank for me = airleak = boom = another $120ish down the drain. (that was before i learned about leakdown tests on here)
it's hard to say wether the shop you decide on will do the work to standards or not, ask lots of questions, and report what they tell you here ?
before handing over your cylinder and $$$
IMO...it is worth every penny of shipping costs, for me to send all my stuff to ken oconnor racing, and have that piece of mind that everything is down to perfection
I was one who has had a cylinder bored and the ports were not chamfered. This came not only from a bike shop but a bike shop that specializes in MX race engines. I agree with AWK about shipping to KOR. I've never had any work from him but from his reputation here and seeing the video's he puts up to help people who want to learn or even try to do the work themselves makes me believe he's a stand up guy who will do you right. If you do look for a shop locally, I would suggest you look for them to specify that they will bore, hone and chamfer the ports and that they have to have the piston in hand to get to the correct size.
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