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Well, 1st off 2 strokes are not the same as 4 strokes, and like another member said. Should have bored it to 1st size over. Then installed new pistons. That way your clearances would be within tolerance, and your bore would be straight. What you have gone and done is honed an already questionable bore. The original bore could very well have been worn a little oval. A visual inspection will not reveal that. Then you went and honed the bores clean. I bet it wasn't done on a honing machine. The only honing that is to be done with a hone, and drill is a quick in and out to provide a cross hatch. If you use the drill method, and you try to remove all the verticle scratching you end up with questionable tolerances, and an hour glass shaped bore. Then you go and put used pistons back in. Your pistons are cast aluminum, and are a wear item which are to be replaced on a fairly regular basis. They are cheap! Why not replace rings and pistons together, especially in a 2 stroke? That way you know your engine is good. When you break a skirt off you better hope it's at start up when your pistons are loose and slapping, 'cause if you do it while riding, all that pretty paint is going to get fucked up when your bike hits the ditch.
While I tend to also think an overbore woulda been good, I believe you're taking "....had the cylinders LOOKED AT..." far to literally. If they were checked and deemed ok to use then that's the end of that don't you think?
I appreciate the input. I should have mentioned that the guy who "looked" at It has been riding and working on Yamaha 2 strokes since the 70's. He saw no problems. However it's never too late and since it only takes about a half hour to yank the motor I may go back and Do the over bore once I'm done and Can see where I'm at.
Wow, Its only been a week and I'm kicked to the bottom of the 3rd page! Man, a lot of great work going on right now.
Alright boys and girls she's on her feet. I took the bars off another bike I have and I really like the look. I got the tires mounted and "tacked" it together so I could roll it out for some pics. It is by no means assembled at this point.
Seeing it at this point has helped me solidify my color scheme. I am going to paint the oil tank, side cover and headlight and ears gloss black the tank will be orange going with the original theme. I'm liking the black and silver thing that is going on and I think by continuing it a little further I will get a real vintage brit bike feel on this which given the distinctly Jap lines to this bike should be kind of cool.
I do have one concern, well I have more than one but lets take it one at a time;
The hoop is looking great but I had a flat bracket welded across the frame over the rear tire to provide some more stability and give me a place to mount the seat. But I'm worried about clearance with the rear tire. I bounced on the suspension with all my 220lb.s and it doesn't hit but still it gets to within an inch or so. Chris, how did you deal with this?
The seat is going to sit about an inch above the bracket on a couple of rubber discs so I could have another plate welded that comes up an inch or so and over. Any thoughts from you metal gurus out there?
Here's some pics. they are crappy i-phone pics I'll get some better ones up soon.
And I started the body work. I wanted smooth side covers and the R5 has these raised emblem panels but I discovered that they come off and leave an indentation. I filled the deep spots with filler then glassed over that and skimmed the whole thing with more filler. Just waiting for it to dry then I can sand that smooth. I think they are going to come out real purty.
The motor had good compression before I tore it apart. I checked that when I got it. I tore it apart for cleaning and inspection purposes and because I knew there would be some carbon build up on the top of the pistons and in the tops of the cylinders. He did do some measuring but the compression test and visual inspection played in to the decision. I am strongly considering the over bore now anyway just to be safe.
two strokes are very cool but there is a reason that 4 strokes dominate the street. I can't wait to ride this around though!
That 350F has been my daily rider this summer. great little bikes. It quit on me a couple weeks ago though. Elctrical just shut off while I was riding along. I think it was some kind of short with the turn signals though as it did some weird stuff when I used the signals for a day or so before this happened and it quit (luckily) as I was rolling into the parking lot at work. I haven't had time to dig in to it yet. My yard is full of wrecks right now. That 350F, I also have a '72 CL450 a CB200 and an XS650. My girl has a '68 Benelli 125 all of them awaiting attention. So much to do, so much to do.
Thanks for the great comments guys! The pictures of the cylinders are before I had it honed. It looked really good after the hone. I got the spokes off eBay from that guy in Thailand. I think it was $75 with express shipping to get them here in two weeks. He was very prompt and easy to deal with. I hear you on the motor I do like the cylinders black though. I think the covers look tons better with the yamaha logos blacked out. Let's the design and paint pop. I have made a bunch of progress this week and will have more pics up soon.
Just caught up on this build and it is looking great, as the consensus shows. I especially like the idea of blacking the logo's, should make for a really clean ride. Nice choice on the bars too. I definitely agree with PJ on bringing out the fins, breaks up the black and adds visual interest. The jugs are a pretty complicated shape and it seems that shinning up the fins gives the eye some balance and flow to follow.
Okay, haven't updated in a while but lots of progress. I got the body work and paint pretty much finished and I also got my seat finished. I'm really happy with the seat!! I started putting the wiring back together and though its a simple system there are a few questions. but I think I'll have it worked out this week. I've got some photos and I flirted with making everyone wait til I had a chance to take great pics but I'll show you what I've got and show you the pretty pics later 8)
body work started and stance of bike mocked up.
seat cover in progress. Its not that hard fellas. Thanks to Go! for the tips.
Tank in paint. I have not yet wet sanded and buffed this. The paint was a little tricky as far as finding its "run" point but well worth the effort. I will be building a paint booth in my garage soon!
Here is a blurry photo of the almost finished look. The seat in this photo is only tacked on the pan for a trial. the final seat sits down on the frame and shows the hoop better. Still some work to do lads! Check out the bobbed fender I think it works!
I still have a lot to do before I even start this but I am inspired by what is coming together! Almost everyone who has seen it calls it a hornet and I know thats what its going to sound like so I'm calling it that at this point. I've got some YAMAHA decals on order and will be adding those to the tank. Im thinking about some sort of hornet for the side covers, think WWII so if anyone has any ideas let me know!!
Thanks guys! I agree on the decal stuff I'm looking for just the right stuff for it.
The paint came out as well as can be expected with out a booth. there are a few "air born debri spots" I laid the clear coat thick enough that they should sand/buff out. Nate (cb200remix) gave me some tips on laying the clear as thick as you can before it runs to reduce orange peel. I tried to do that but it ran on me. the first time i waited and sanded it down and re-shot. this time it ran as well but down low on the tank so I just laid it on thicker so that it ran all the way down the tank. worked out well. in some spots it is glass smooth but there are some areas that show some peel so I will sand and buff. I think paint is all about set up and experience so I will keep at it.
Chris, I thought about clubmans but with out rear sets I find them really uncomfortable. The seat will sit about a half inch off the frame. I have no choice as I need clearance for the rear tire. I looked at your build and it looks like your loop is shorter which avoids this problem for you. Your frame is a bit different than mine I guess.
I have a couple things to work out. I didn't think about the oil tank fill tube and I am going to have to adjust that somehow and there seems to be a lot of play in the front forks. we'll see.