- Foot dragger/Supervision: I think you two need to post a few pictures of your Hangtown days! Back in the northeast we had two events that were pretty wild... Unadilla and Loconia NH. Saw many exciting battles with riders like Rodger D, Hannah, Jimmy Ellis, Pat Maroney, the KTM mounted Russians and others. Fans were very wild too. We made fake pit passes and roamed the inside of the pits and the track. Finally they caught us and turned us over to NY State Troupers on horseback to kick us out. They were nice guy though (and we were young) so they let us go! Loconia in the early '70s was another very wild scene, lots of tits and naked women :eek1 riding by and staggering around, motorcycle gangs, state police with dogs... a real eye opener at 11 years of age! - Ctune: Those are very cool pictures. That is neat they let you put it on the ship. I too am impressed you still have it after all these years! Maybe you have a more recent photo as well? In any case, thanks for sharing these!
43 mm Fork Upgrade Continued... So to re-cap, I have spare '82YZ490, '83 IT490 & unknown year YZ490 disc brake forks to choose from in making the switch from the 38mm to 43mm. In the end, I decided to go with the '83 IT490 forks. In addition to the 465, I also have an '83 IT490 and like the way the forks feel on that bike. Again, these forks have the blow off device that the '82 forks do not have. Another factor in my choice is that I may try the Race Tech emulators in the future. The emulators would make the blow off valve in the '83 forks irrelevent. Because of this, I thought it best to hold back the '82 forks for the Race Tech modification. And I did not pursue the possibility of using the newer internals on the disc fork as I thought I might because of time constraints. For kicks, I have listed damper rod part numbers across the model years. You can see they are all different. Damper Rod Part Numbers<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o> 81 4V4-23170-L0-00 <o></o> 82 5X6-23170-L0-00<o></o> 83 23X-23170-L0-00/ 26A-23170-L0-00<o></o> 84 39X-23170-20-00/ 26A-23170-L0-00<o></o> 85 56A-23170-L0-00<o></o> 86 1LV-23170-M0-00<o></o> 87 2HH-23170-L0-00<o></o> Now, we all know that sometimes parts will interchange even though the part number is different. I did not look to closely at this but did notice the damper bolt holes in the different year sliders were dissimilar enough to make interchange unlikely without doing some real work... Moving on, here the brake side '82 yz490 slider is compared with the '83 IT490 slider. Interestingly, the bottom of the YZ slider is welded on whereas the IT slide is cast as one piece (like the '81 YZ slider). Another difference involves the axle. The YZ axle (top in photo) threads into the slider. The IT axle (bottom) slides through an unthreaded hole and is tightened with a separate nut. The IT forks requires use of the IT axle or machining of the YZ axle shoulder (on left) to match the IT design. Shortening this shoulder allows the axle to move further into the hub thereby exposing the threads per the IT arrangement. Here are a few photos of the IT fork rebuild for the curious. The replacement seals are new from Yamaha. I did not have a tool to keep the damper rod from spinning when removing the damper bolt. The air wrench was essential for overcoming this problem. I found it best to use repeated short bursts to get the bolt to back out of the slider without spinning the rod too much. Make sure you still have the fork spring installed as that is the only thing providing resistance to rod spinning. Note: While the forks were apart I was able to fine a nut that fit into the hex on top of the damper rod. This nut will be used to make a tool to keep the rod from spinning when doing fork rebuilds in the future. Fork caps and springs. Here is a comparison of three different fork caps and 82 YZ490 and '83IT490 fork springs. Even though the parts are different in some way and have different part numbers, they are still interchangeable in the fork tubes. Keep in mind though, the fork caps with the staight valves require use of the offset top triple clamp to keep the bars from interfering with the valves (my understanding is there are 3 versions of the top triple clamp for the 43mm forks). See how overall length is the same for these spacer/spring combinations.
Rear brake stay and expansion chamber. I was a busy bee this weekend! Recall that the YZ490 brake stay I was planning to use was longer than the yz465 stay (21in vs 20.25in) and this was enough to rotate the rear brake plate too far. Solution: Mill off the end on the 490 stay, shorten the aluminum arm and then tig welded the end back on. To my surprise, the brake stay is hollow inside! It does feel pretty light. Top left photo shows the hollow aluminum arm, trick! Top right is a flattering photo of me. Lower left is the arm after welding. Lower right photo is tab welded onto a YZ490 DG pipe I am using. I'll have more to say about the pipe and silencer in a future post.
I have very few pictures of me racing, only a few, I have a hard time turning the computer, if you know what I mean. My Son has shown me a few times but later I can't repeat the same steps, so it goes nowhere. I have another story to tell, you might like. One of my friends I met thoughAHRMA used to be a team Yamaha mechanic, the other day I brought my little IT125 to ride as a pit bike at Holister ca race to spectate off of. He had never seen my IT125 before, and says the thing is so close to a ow27 hanha bike. He said at the end of the year they always turn the bikes to Yama but one year they buildt a spare bike out of parts, and left it with a large Yamaha dealer back east. They new they had to keep it hushed up, and be low key about it. So just a couple years ago he get a call from that dealer, and he says the Hana bike has a broke transmission and if he wants it, because he knows that he'd do the right thing with it. So he had to have a special gear made, and he restored the bike. He knew Bob was going to a some event in so. ca. and he waited though the autograph line to talk to bob. Bob say's, I seen you in the line, didn't think you'd want my autograph, what's up?? Bill took him around the corner, and say's look, your old bike !!!!
Thanks guys! It's been a great bike, I am going to take it out for a ride soon, I'll get some more pics then!
OK, next up is side panels and seat. Like everything else, these items were beat to hell on my bike. Just as well as I was planning to replace the yellow number plates with a style closer to that of the factory bikes. To see what I mean, here's a photo of Bob Hannah's 1979 250cc OW40. You can see the side number plates are of a lightweight translucent type material. It turns out there have been a few different suppliers that made factory look replacement number plates for the 465. Somehow or another I wound up with four different sets that are all a little bit different from each other. The photo below shows them all lined up. I will try to point out some differences. First up is the Maier. These are solid gloss white. I bought these directly off the maier web site. As you can see, they come undrilled. They are solid white, not translucent as on the OW40. The quality appears good however they do not have the molding for the airbox vent (see left side plate) as the yamaha OEM or the other plates do. The next up is DC plastics. These plates are a matte like opague finish. They look durable and fit pretty well. Mine came drilled. I would prefer to get them undrilled so I can optimize the fit to a particular bike. I got the 3rd set of plates off ebay. I have no idea who made them but they are also of very good quality and fit. They are a little bit thicker than the DC plates. These seem to be the closest to OEM in form and finish (except for color). These came undrilled. The 4th set of plates came with another bike I bought. These are the only plates that are translucent like the OW. They are pretty thin and are not formed as well as the others. Being as crude as they are, my first thought was to toss these in the trash. But looking back at the OW photo, those plates are crude too! My plan is to use a heat gun to get a proper fit on the bike. In the end, I will probably use these for display and the DC plates for racing. The other plates (1 & 3) will be saved for the other bikes I now have. Seat. I knew I was going to replace the seat cover but as the rest of the bike was really starting to shape up I decided to replace the seat foam as well. In selecting the cover be sure to check for the lettering on the back side. Some covers have YAMAHA in the sides but not on the back like the OEM cover does. I am happy to report the fit and finish of cover and foam I received were great! I'll try to dig up the supplier info for the benefit of others. The installation itself is simple. Remove the staples, cover and foam. Assemble in reverse order . In my case, I aligned and stapled the front and back first. I then worked from front to back, pulling down and stapling the cover so as conform to the contour of the foam. Here is a progress photo with the cover just laying on the seat. I have removed the tank decals before sanding and polishing the tank. The panels are the number 3 version (photo above). The green ovals and front number plate are from Vintage Iron and are high quality. To brighten the tank up I first sanded it using 400 wet/dry working up to 1000 grit. I then used a buffer with polishing compound followed by new tank decals. Not perfect but much better than what I started with. How about those KYB decals on the forks? Just like the OW . Heikki Mikkola - check out that KOHO Fin fighter mouth guard
So did the OW's come with a aluminum or steel brake stay arm? Does it depend on the year, bike, rider or was it just an option? I always thought the aluminum looked better of course but it's certainly not a show stopper. The steel was probably more durable though.
wfopete: It seems some OW's had a steel brake stay (OW40 above) and some had aluminum like the Rick Burgett OW41. I like the look of the alloy one better So now onto the exhaust pipe/silencer system! Some time ago I picked up a nice (and cheap) DG pipe intended for a 1982 YZ490. I figured the motors are so closely related that it should work fine on the 465 too (displacement wise, the bore on mine will be 1mm oversize and that gives 476cc's, not too far off the 487cc's of the 490). In comparing the 490 pipe to the original, I found the connection to the silencer is made at a different point along the stinger. In essence, the portion of the stinger attached to the pipe is shorter on the 490 version. The overall length of the stinger (pipe + silencer) is about the same. This wasn't such a problem as I was replacing the silencer anyway and would be redoing this connection. I wound up using the same universal FMF turbo core silencer / spark arrestor as used on my it490. This is a good quality part (~$100) and comes as a kit with an extension pipe, a weldable mounting tab and a hanger bracket. The outside is aluminum so it's not too heavy either. The spark arrestor part of it may be a bit restrictive for motocross although I have to say this didn't seem to hurt the output of the IT490 . In any case, the restrictive arrestor section can be removed for the most part by drilling out the internal cone as I did for the 465. This can be done from the end, using a 3/4 - 1in drill bit mounted in a drill press. Below is a pretty good photo of the IT490 exhaust I did last year. You can see how the stinger extention has been welded to the end of a new DG pipe. The silencer is clamped on to the other end of the extension. The mounting tab is welded to the extension at a point where it can be bolt to the original rubber mount. Again, this setup has been working well and so I decided to something similar on the 465. Now for the 465, Here is the pipe and silencer test fitted with the motor in the bike. Yamaha normally uses a rubber coupling/clamp arrangement to attach the silencer the the end of the pipe (the point above the airbox in photo). I never liked this as the joint often leaks hot exhaust gas onto the plastic number plate, sometimes melting it. My plan was to weld this joint to avoid leaks and side plate damage. Before welding, some care was taken to ensure the stinger section was well tucked in. I did not want any possibility of melting my new side panels nor did I want the pipe to rest or vibrate against frame tubing. This next photo shows how tight the routing area really is between the side plate and frame. After tack welding and some clearance checking I welded everything up for the final time. BTW, I should say the front of the pipe is in much better shape than it looks in the photo for some reason. Also, most of the exhaust is isolated using the (new) OEM rubber mounts. The silencer mounting point is partially isolated from the frame with a rubber bushing. With the exhaust taken care of it was time to move the motor back onto the bench for some freshing up. And there was plenty of surprises to be found there (to put it mildly!). But until then...
Ha ha, yeah you can try it... no charge either. Compared to my tax bill this year $10 is a drop in the bucket
Well, I am finally back to the 465 project after taking a break to finish this years taxes ... and yes I had to pay even more, and yes it was very very painful!!! On to to more pleasant topics, I ran across this nice fold out brochure for the 1980 YZ lineup. It has some great illustrations, especially of the rear monoshock suspension where I have been focused the last few days... Next are some photos of various shock absorbers I have in my possession. The 1st photos shows (top to bottom), -1980 YZ465 shock with standard spring and short reservior -1981 YZ465 shock with stiff (marked with blue paint) spring and long reservior -1981 YZ465 shock with standard spring and long reservior -1982 YZ490 shock with Eibach spring and long reservior All the shocks have adjustable rebound damping via the adjuster knob on the left. The 490 shock also has adjustable compression damping via a knob on the right (not shown in this photo). In addition, the 490 shock has a greater number of rebound damping settings from which to choose. My first task was to take the springs off in order to determine overall condition of these units. I found the shafts were good on all of them, however, it was evident that two of the 465 shocks needed a nitrogen charge and all but the 490 shock needed new rubber bumpers. There were a few pleasant surprises too. First, the 490 shock (with Race Tech decal) was in great condition. I also found the springs for the 465 shock fit the '82 490 as well. This is important because of the difference in the 465 and 490 suspension design. The 465 uses a spring made from a tapered wire to get a progressive spring rate. The '82 490 uses a link to give a rising (progressive) rate suspension with a constant rate spring. I found too that the Eibach spring was much, much stiffer than the 465 springs. My guess is that it is much stiffer than a stock 490 spring. Fortunately, there was the firmer (blue) progressive 465 spring (no longer available from Yamaha) also in the bunch. The standard 465 spring felt soft and pretty well sacked out whereas this firm one seems just about right for me @180lbs. Here is a photo of the springs. Left=Eibach 490, Middle=Firm YZ465, Right=Stock YZ465 And here is a photo of a nice looking '82 490 showing the rear suspension link (the '83 on is even more different). It is unclear to me is if the differences in the 490 shock damping action as a result of the '82 link setup are enough to hinder performance when used in the YZ465. In any case, given the very wide and noticeable adjustment range and great condition of the 490 shock, I decided to give it a try. Note that the 490 shock requires some reduction in the front shock bushing width for it to fit in the 465 frame. I also had to insert 0.5 inch spacers in the front tank mount to give some additional clearence for the compression damping knob under the tank. And finally, the 490 shock is about 0.5 inches longer than those in the 465 and gives a wee bit more suspension travel. Here are some photos of the 465 shock setup compared to the 490 shock as they are mounted in the bike. Notice the compression damping knob on the 490 shock. - The 465 shock... - The 490 shock... The tank mount spacers before final machining... At some point I would like to take a crack at rebuilding the 465 shocks. Please send me a note if any of you have instructions on how to do this. More to come...
If your are building a replica bike the OEM shock is ok, but if you are planning to compete, the OEM shock is a bit archaic. Several aftermarket shocks are available that far outdistance themselves from the stock YZ monoshock. Of course you can expect to pay from around $600-$1200 for them. I don't think rebuilding the YZ shock is very complicated but I had Steve Sage (http://sagesuspension.com/) rebuild mine for about $200. Why? Well I'm cheap (I had to pay taxes too!) and I wanted to see how the stocker technology felt before upgrading. Plus I've had yet to start my 465G model that I've been working on, as far as I know it may not start. I hope to find out soon as this time next week I'll be on my way to Diamond Don's Nationals (www.diamonddon.com) for Beta testing. In fact I have to start putting together the bike today, right now the bike is totally stripped down. :eek1 One other thing: Yamaha really boned up the handle bar position and stock triple clamp. They have the bars sitting in your lap which I don't like, but that's 80's tech for you. When I can I'm going to do something about that but it will cost a few bucks. Moving the bars out and up will make this bike better handing and more comfortable as it helps keep rider weight forward over the front end which helps steering input and the front end down under power.
WFOPete: Yeah, I think you are right it is more cost effective to send the shock out for rebuild. My interest in rebuilding one has more to do with cherry picking the best components from the shocks I already have... and I am a little curious to see whats in there! And thanks for link to Steve Sage, he seems to have a very good reputation and price is reasonable too. I dont think I am ready to pony up the big shock money either. In fact, right now I think it is the rider that needs the suspension work as I twisted my back a couple of days ago! I noticed that Race Tech and Pro-Action also have solutions for the 465's. Here is the link to the Race Tech project bike... pretty fancy shock on that one! http://racetech.com/html_files/yz465_project.html Pro-action has their roots in Keystone Yamaha. I remember seeing the Keystone bikes at Unadilla in the '70s http://www.pro-action.com/ I hope you can get it all together in time for Diamond Dons. You will have to keep us informed about this and post up some pictures from the event. Regarding the triple clamps, Yamaha made one with solid mounted clamps that are moved forward. I have one of these on my bike. It came with a set of forks I bought. Not sure exactly which model or year it is off of but it bolts right on to my 43mm 490 forks. Kevin
Motor Rebuild: With a lot of the chassis issues resolved, it is time now to move on to the engine. Over the last year more and more 465/490 parts have come my way. I have to admit...I had lost track of what I had in boxes and tucked away in another building . To get started, I have posted a couple of photos where I am sizing up a few of the various parts motors/cases as well as the original motor on the work bench. From left to right, 1) late model 490 cases, 2) 3R5 YZ465 bottom end 3) 4v4 (81) YZ465 bottom end 4) complete 3R5 YZ465 motor from my bike Not shown is an 83 IT490 engine and 2 more complete 4v4 YZ465 parts motors on the floor! Boy, things really have gotten out of hand here :eek1! As I have been going through all these motors, it has been interesting to observe some common failures as well as design changes meant to address them. The kick starter mechanism is one example of a problem area that I will discuss here and in a future post. There have also been several design changes to the clutch basket through the years. And for good reason too. The early model clutch backet has a pressed on kick start gear that can move over time. In a later 490 design, the gear is made integral with the basket to avoid this problem. I'll follow up with some photos that show all this. In any case, for competition bikes this old, you really need to examine just about every part to be confident in what you have in the end. While most parts in the motors I examined were in good shape, it did seem that all of them had least one or more show stopping issues. And there were quite a few examples where previous mechanics? had gotten in there and hacked things up a bit . Overall though, I think these are well made and very robust engines. Its also cool how Yamaha kept improving them and how many of these improvements can be retrofitted to the original 465 design. The famous kickstarter case leak: So moving on, one of the 1st things I noticed was how many motors had epoxy on them to seal cracks in the engine case at the back of the blind hole that accepts the kick starter shaft. I have come to find this is a very common issue. The only harm seems to be weeping oil which the epoxy is meant to stop. The next 2 photos campares a good case with a case with the epoxy fix. A 3rd photo shows an engine case that has been severely busted out and welded back together, yuk! Good case (notice no epoxy on kick starter boss - upper right) Epoxied case and broken/welded case. Whoah! What's behind all this? ... I have several ideas but I'll have to post that next time
Great pictures!! The one with hanna going by the mechanic area, back to camera, looks like 125, because of right side pipe. Also the guy standing their holding a pit board with long hair, back to camera, looks just like the Yamaha guy I know!!
FJ_Kevin, Yes I talked to race Tech a few of weeks ago; $200 vs $1200. The boingers are EZ but just wait till you get to the jetting part! I'd like to hear what you come up with. You might find this interesting: http://ozvmx.com/community/index.php?topic=21039.0
WFOPete: Thanks for the link, some nice pictures over there. And now we have an inmate building a moates version, neat! Donkey: Funny... yeah I remember that... nice picture. I say keep stirring! Kevin
Kickstart issues continued... Well it took me a little bit to gather up some photos. Recall that among the engines and cases that came with some parts bikes were examples that have the cases blown out in the area of the kick starter shaft. My guess is that this not some fatal flaw in this motors but rather something that can crop up if maintaince is not kept up or if one does not check certain wear points from time to time. First, let me say I don't think the 465/490 has to be a hard starter at all. As an example, my 490 starts within 3 kick cold and one hot. But this only came after elimination of air leaks, a carb cleaning and some careful jetting. Obviously less kicking will greatly reduce the wear in the kickstarter mechanism (not to mention the owner!). Minimizing kickback is also important. Ther are a few sources of kickback but certainly incorrect ignition timing is a big one. This can happen if the stator plate is off the factory timing marks or perhaps from a misaligned flywheel. In fact, one of my parts motors had a bad key and there were marks where the flywheel spun on the crank at one time. If the bike kicks back, it seems the kickshaft shaft can rotate backwards until the paw to jams against the case stop. This is because the gear # 2 is unable to release as it would if the bike had started with normal rotation. Under this condition I think the shaft tries to rotate around the paw. If there is enough energy it busts out the case. It is interesting to see in the photo how the case is broken in a straight line from the paw stop through the center line of the hole for the kickstart shaft. As far as other wear issues, I ran across several. The clutch cover is made of light weight magnesium that is subject to wear in the kickstarter shaft bore. When the bore is worn the shaft can wiggle a bit and the seal can leak. The face of the hole can also wear letting the shaft move in and out of the case more than is normal. As I had a good cover to select from, I made no attempt to fix this for now. In the future I may resize the bore by making a bushing. I found that one of my kick start shafts had rounded off in the paw area. Someone had repaired it by welding up the paw in order to square it off again. I am speculating that the paw was able to jump over the case stop because of excessive play in the clutch cover. Or maybe it was just reassembled incorrectly. Here are photos of the welded kickstart shaft and the kickstart assembly in the engine case. Note the kickstart return spring. I mention the kickstart spring as this needs to be checked also. Here we have 3 springs. The tang on the right spring that goes in the shaft is broken but the other two look fine... But wait, a closer look reveals this :eek1, More to come...