'99 SV650 track rebuild
- Thread starter doc_rot
- Start date
A common performance mod on these bikes is to lighten the starter clutch plate. I recently completed a control system retrofit onto an old CNC bridgeport and this is literally the first part to be made/modified on it. It came out ok, not totally happy with the tool finsih but not bad for the first try. This reduces rotational mass on the crank by 355g / 0.78lbs. check it out next to a stock one. I am also going to trim some fat off the generator rotor for about another 189g / 0.4lbs. all in this is about 1.2lbs off the crank!
That's rad. Pretty significant amount of weight reduction.
I got the engine wrapped up and back in the chassis. I ended up using the stock pistons with 2G piston rings. The heads were done by Spears with his valve springs and a supersport valve job. He bead blasted the heads and I did an OK job of matching the paint with some random Gun Kote that mixed from other projects. I used 2G cams on both intake and exhaust - shimmed the head on the bench - so much easier than doing it in situ. I also got my lightened rotor and starter clutch in there. I wanted to slap a drop dial on the cams and see where the timing was at for future reference but I'm running out of time and just need to get this sucker done - maybe next year.
I got a second set of fairings that were in a bit better shape than my existing ones but they still needed a bunch of work - mostly fixing previous repairs. Sanding through the paint it seems like they've been painted a dozen times or more. They are mostly prepped at this point, all patches complete and new 1/4 turn fasteners. I striped the old paint job on the tank and started prepping that as well.
At this point The bike is like 95% ready. I hope to start it up tomorrow. and then finish the fairings at least enough so they are mounted and in primer. My first track day is May 11. I'd love to get this on a dyno for the break in and to check A/F but getting a dyno slot this time of year is tricky.
I got a second set of fairings that were in a bit better shape than my existing ones but they still needed a bunch of work - mostly fixing previous repairs. Sanding through the paint it seems like they've been painted a dozen times or more. They are mostly prepped at this point, all patches complete and new 1/4 turn fasteners. I striped the old paint job on the tank and started prepping that as well.
At this point The bike is like 95% ready. I hope to start it up tomorrow. and then finish the fairings at least enough so they are mounted and in primer. My first track day is May 11. I'd love to get this on a dyno for the break in and to check A/F but getting a dyno slot this time of year is tricky.
First day at the track was a complete success - the new engine performed flawlessly and is a major improvement. The old engine would fall on its face after 8k, now it makes power all the way to red-line and watching the needle fly from 8-10k is crazy, Ive had to adjust my style to keep up with shifting because it revs so fast now. The engine never exceed 78c/172f on the track. it would creep up to 83c /181f cruising back to the pits.
Only issue of the day was I had to fiddle with the shifter to keep it from binding and that was it. Reconnected with a bunch of people there and had a great time. Doing a double track day this weekend in Oregon!
its earned the nickname "jawbreaker" for the time being.
Only issue of the day was I had to fiddle with the shifter to keep it from binding and that was it. Reconnected with a bunch of people there and had a great time. Doing a double track day this weekend in Oregon!
its earned the nickname "jawbreaker" for the time being.
Did a 2 day event at Oregon Raceway Park this weekend. Its a really fun track, a bunch of elevation change and blind corners. They run it the opposite direction on day 2 to keep it interesting. I was feeling really comfortable on the bike, and have gotten a lot more confident with passing people which is aided by the new engine. I was on the fence about getting a different bike last year but after the engine build I am very happy with this bike, is crazy how some small changes can completely transform the character of an engine. At this track I get good drive out of the corners and can keep up with the better guys on liter bikes in my class. They obviously will ditch me on the big straights but I can usually real them back in once we get into the tighter sections of the track.
During the sessions I starting hearing a popping sound, it only ever seemed to be apparent when I was chasing someone down. I thought it was just their exhaust or auto blipper or something. On day two I realized it was the fork brace hitting the fairing. I was nearly bottoming out the forks - you can see how close I was to bottoming out these forks - check the zip tie under the lower triple. When I would load up the front the fork brace would come past the inside of the fairing and then catch it on its was back down. Finally it literally broke part of the fairing off and thats when I realized what was happening. I taped the fairing to hold the edges back and took it easier for the rest of the day.
I haven't experienced this at other tracks before and I'm wondering if my skills have progressed far enough to need stiffer springs, or if its a by-product of the track at ORP, or some combination of both. ORP has several sections where you are braking down hill into a bowl or banked corners which really let you load up the suspension. Do I need stiffer fork springs? maybe just more preload?
I'm not quite sure how to proceed with the fairing issue. Both fairings I have rub badly here on the fork brace. If I cut out the offending section that will remove the leading edge radius which is giving these fairings quite a bit of rigidity. I'm contemplating making some notches in the fairing for the forks and glassing it in. suggestions?
During the sessions I starting hearing a popping sound, it only ever seemed to be apparent when I was chasing someone down. I thought it was just their exhaust or auto blipper or something. On day two I realized it was the fork brace hitting the fairing. I was nearly bottoming out the forks - you can see how close I was to bottoming out these forks - check the zip tie under the lower triple. When I would load up the front the fork brace would come past the inside of the fairing and then catch it on its was back down. Finally it literally broke part of the fairing off and thats when I realized what was happening. I taped the fairing to hold the edges back and took it easier for the rest of the day.
I haven't experienced this at other tracks before and I'm wondering if my skills have progressed far enough to need stiffer springs, or if its a by-product of the track at ORP, or some combination of both. ORP has several sections where you are braking down hill into a bowl or banked corners which really let you load up the suspension. Do I need stiffer fork springs? maybe just more preload?
I'm not quite sure how to proceed with the fairing issue. Both fairings I have rub badly here on the fork brace. If I cut out the offending section that will remove the leading edge radius which is giving these fairings quite a bit of rigidity. I'm contemplating making some notches in the fairing for the forks and glassing it in. suggestions?
3d printed a plug, took a positive off that and glassed it in. I decided to make a few minor cosmetic improvements as well since i was using fiberglass. I filled both vents on the fairing lower with scrap from my old fairing. I also made a inner fender/panel for the tail. I feel like it cleaned up the look - I didn't like how it looked like something was missing. fogged the lower fairing with some scrap paint and sanded it back to not disrupt the track-rat aesthetic and you can barely tell i modded the lower.
I did another track day today and did some fiddling with the suspension. Turns out I didn't need new fork springs, I added some preload to the gold valve emulators to increase compression and added 15ml fork fluid and my bottoming problem issue is solved. I also did some adjusting on the shock and got that working better.
I feel like im close to moving to the A class. ocassionally i will see those guys in the intermediate class and i can keep up with them in the corners and but not the exits and straights
I did another track day today and did some fiddling with the suspension. Turns out I didn't need new fork springs, I added some preload to the gold valve emulators to increase compression and added 15ml fork fluid and my bottoming problem issue is solved. I also did some adjusting on the shock and got that working better.
I feel like im close to moving to the A class. ocassionally i will see those guys in the intermediate class and i can keep up with them in the corners and but not the exits and straights
Attachments
Last edited:
I bought a used slipper clutch off ebay. I didn't realize it when I bought it but the slipper clutch I bought was actually the race version that requires a billet basket and extra clutch plates. I didn't have the correct basket with the sale. Luckily, Gregg Spears was able to get me one from his supplier and with a new clutch stack I am in business. Thank you Gregg for saving me from a misinformed purchase! The Ebay seller was apologetic and gave a partial refund so all in it ended up being about half of what this setup costs new. I'm still chalking it up as a win even if it meant i spent more than I wanted to.
I haven't had a chance to ride the bike with the new clutch yet as I'm waiting on UPS for a clutch gasket. Hopefully it comes tomorrow because I have a 2 day track event sunday/monday. May have to goober on some RTV and call it good for now.
I haven't had a chance to ride the bike with the new clutch yet as I'm waiting on UPS for a clutch gasket. Hopefully it comes tomorrow because I have a 2 day track event sunday/monday. May have to goober on some RTV and call it good for now.
Track Day Report: Slipper clutch is fricken awesome - the bike is waaayyy more composed on corner entry. Confidence boosted and I passed a lot of people by braking deep and tipping over late. Day one had good weather and I felt great on the bike. The track-side photog got some decent photos of me so I shelled out. Day two the weather was not good - light rain all day but relatively warm, so not too bad. I didn't have a rain coat that fit over my leathers so i bought a cheap poncho. I didn't think i could look any worse at the track until now. Only got in a couple sessions before I started running on one cylinder with water in the front spark plug cap. Some frantic thrashing (i was convinced it was a fueling issue) and I got back out a couple times but kept having issues so I packed up early.
Back home I replaced the cap plugs, and did some other maintenece. This time at the track the bike seemed to be running louder and louder to the point of being obnoxious. Once back at the shop I cracked open the can. I must have packed it with cotton candy because there was absolutely ZERO packing left in there from when i repacked it with ceramic fiber last year, still in disbelief of where it went in about 15 track days. This time around im trying 750g of "moose racing packing" we'll see how it fairs.
Next track day is oct 11-12 at Oregon Raceway Park and is the last of the season. I got a few small things to change up like new tires and a 45 tooth sprocket. Im hoping for good weather - froze my ass off there in the spring.
Back home I replaced the cap plugs, and did some other maintenece. This time at the track the bike seemed to be running louder and louder to the point of being obnoxious. Once back at the shop I cracked open the can. I must have packed it with cotton candy because there was absolutely ZERO packing left in there from when i repacked it with ceramic fiber last year, still in disbelief of where it went in about 15 track days. This time around im trying 750g of "moose racing packing" we'll see how it fairs.
Next track day is oct 11-12 at Oregon Raceway Park and is the last of the season. I got a few small things to change up like new tires and a 45 tooth sprocket. Im hoping for good weather - froze my ass off there in the spring.
Last edited:
That looks light to me. I machined my flywheel most I dared. Never done it before but didn't do the starter clutch and together they were 1872g which I was happy with
Quote Reply & Quote
Report
Last track day weekend of the year. The weather did not cooperate - it was cold, damp and windy - and I still had a great time. It was a good lesson on adapting to track conditions as I wasn't able to get much heat in the tires being so cold. I practiced tipping in later and faster to minimize time at lean, and really tried to focus on memorizing reference points and being more consistent. My goal this year was to move to the expert class. This weekend a couple different people told me I was ready for the expert class without solicitation. I switched to the expert class halfway through Saturday and was surprised I wasn't that far off some of the riders pace, even had a guy I really respect tell me I was looking good out on the track. Mission accomplished - I can't wait for next year!
Luugo86
'73 CB350, '78 XS650 Cafe Killer
Hell ya man.. It's probably 10x better knowing that you built your bike from the ground up and didn't just throw money at a new one. I've been shopping around for cheap Yamaha R3's.. thinking about getting some instruction and trying to get on the track next spring/summer; it's been a pipe dream for a while now and seeing you go for it has lit a fire for me.. Congrats on the jump to expert class.
I wanted to do it for years and always found reasons why it couldn't happen. I wish I would have started doing track days so much sooner. Its the most fun I have had on motorcycles in years. Plus the community aspect of it is really cool. Your surrounded by a bunch of like minded people that won't roll their eyes when you talk about the nuances of suspension design.
It doesn't need to be a well planned out and expensive endeavor, you can rent typically rent suits, bikes and whatever you need from track-side vendors if you just want to dip your toe in before fully committing. My only advice would be just get out there and do it!
It doesn't need to be a well planned out and expensive endeavor, you can rent typically rent suits, bikes and whatever you need from track-side vendors if you just want to dip your toe in before fully committing. My only advice would be just get out there and do it!
ex119x
Been Around the Block
Rather than go with an R3, I'd recommend an SV650. First gen if you want the carbs and second gen if you prefer EFI. They both have their advantages depending on what you want. I think an R3 at track days is at too much of an HP disadvantage and you are going to be forever giving away position on the Straights and being held up in the corners.
There are tons of SVs available that are basically track ready for not much money or you can get a really cheap street bike and build it yourself for not too much more.
