Vintage Dirt Racing on a 350 Honda Twin

Discussion in 'Racing' started by LC Garage, Jun 16, 2011.

  1. LC Garage

    LC Garage On Any Sunday

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    I have been posting a little on Oregon Coast's Baja thread regarding some of my own efforts and adventures with vintage SL350's and thought it was time to get off of OC's thread and throw my own out there.

    My current vintage ride is a 1972 SL350 that I had owned in 1985 and prepped and raced in a few grand prixs (they were somewhat like the current motard races and very popular back then). Anyway, I had ridden this bike a few times and then sold to a friend who has had it in his barn for 26 years and recently gifted it to me with the condition that I vintage race it. Done deal! The initial picture is of the bike after being first brought back home.

    When first built, funds were limited and bought the original bike from the local Honda dealer where I worked for $50. Out of the scrap heap we found a set of '73 CR250 forks and front wheel (35 mm and fit SL350 triple clamps), we lengthened the swing arm one inch, put a good set of shocks on also cut off any thing un-necessary and drilled a number of holes here and there, ostensibly for lightening the bike, but probably saved 1 pound off of the original 300!

    The local Honda rep at the time was Adrienne Browning (sp?) and when he found out what I was working on, volunteered that he had a brand new SL350 motor in his garage and claimed it was a spare motor from one of the official Honda Baja efforts. I have no idea if that is true but quickly coughed up the $100. price tag and brought it home.

    The top end was pulled off and a Pow Roll 400 kit installed, and then added TT pipes and later on a pair of RD350 carbs (they never really ran quite right either). After a few races and several trail rides, I had the money for a new RM465 and sold the bike to my friend.

    So 26 years later I have the bike back again and decided it would be a good idea to race in the upcoming vintage scrambles at PIR (6/25/11). It took about an hour of carb & points cleaning to get it running and surprisingly did not smoke. Because of family obligations I waited until last week to get started and now am regretting that I didn't start sooner, there is a lot to do!

    The bike is relatively intact from when originally built, but the TT pipes are gone and now have scrambler pipes. There are a few other subtle differences and I am unsure if it is even the same motor I once built, I won't know for sure until the motor is torn down and checked for the Pow Roll piston kit.

    In the last week, I have cleaned and serviced the steering head bearings, serviced the front forks and changed over to fork gaiters, and last night changed the carbs to a set that Oregon Coast (OC) generously gave me.

    Still to do; grease wheel bearings, new tires, new chain, service rear shocks and swing arm, adjust valves and cam chain, new points, synch carbs and many other small tasks. My biggest worry at this point is that I did not get all new cables and am running out of time, I have a new front brake cable ordered and OC is donating a new throttle cable but will just have to make do with the original clutch and rear brake cables.

    Let me know if you are interested and I'll keep posting some updates and pictures. I've included a link to Smug Mug so that you can look at the original and current pictures of the bike and will update as time allows. http://lastchancegarage.smugmug.com/Motorcycles/SL350-Retrospective/16474080_FMjKs#1239759180_XeUwZ<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:eek:ffice:eek:ffice" /><o:p></o:p>

    Attached Files:

    #1
  2. airgord

    airgord What am I doing out here!

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    Cool!
    #2
  3. oregoncoast

    oregoncoast Racing Like a Noob

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    Great Stuff!! :freaky

    Now don't make that thing run too good, I don't want you to smoke me at PIR on the 25th! :eek1

    BTW, I probably have spare used brake and clutch cables laying around that you can have as back-ups..I'll bring them along.

    I can't wait to see that bike racing again after all of these years. Always sad when an SL is just sitting, rotting away in a barn. :1drink
    #3
  4. LC Garage

    LC Garage On Any Sunday

    Joined:
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    Have been making good progress on the SL, carbs worked great, pulled apart to check and found that one bowl had pinholes but otherwise all in great shape. I also found out that CV carbs don’t exactly fit the SL frame, had to dimple the frame for the choke shafts and also some creative engineering on the intake tubes. The rubber intake boots (LH especially) was starting to tear under the strain of havng been mounted in a bind. I dimpled the frame on each side and then before installing sealed the intake boots with black silicone. Then when I started to tighten the clamps, they were deformed from before and started to collapse. So after thinking about it all day yesterday, when I got home I cut and rolled some little exterior tin sleeves for each boot, so that when the clamp is tightened it spreads the load and tightens evenly, carbs are now secured and even look to be pretty close in synch. Tomorrow I will finish up the front wheel bearings and mount new tire, then move to the actual tune up and get it running, after that I will attack the rear wheel & tire, swing arm and shocks. Whew!!:D<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:eek:ffice:eek:ffice" /><o:p></o:p>
    #4
  5. LC Garage

    LC Garage On Any Sunday

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    Saturday made good progress, but hit a few snags. Started the tune up and began by adjusting the cam chain and then the lh valves, when I went to do the rh valves the tappet cover screw would not budge and I am embarrassed to say I did not have an impact driver (I do now!). Since I was waiting to pick up inner tubes and chain from my friend Brian (Wide Open Motosports) and he was not coming home until 5, decided to go ahead and start breaking down the wheels and tires.

    Started on the front and as soon as I pulled the brake panel off, one of the brake shoe liners fell off in my hand ~ shi*! Had never see a bonded liner just fall off like that, so now I will need to rush order some shoes first thing tomorrow. The tire had not been off for a few decades and was pretty well stuck, so I remembered I had bought an antique iron bead breaker a few years ago at an auction and decided to give it a try. What do you know, it worked perfect.

    Moved to the donor bike and pulled the rear wheel. As I was pulling it apart, I was thinking about what bits and pieces I could use now or as spares and as the brake panel separated from the wheel, one of the brake lininers fell off in my hand ~ double shi*! So I again used my handy dandy bead breaker and dismounted that tire as I needed the rear wheel to replace the one on the race bike as it has 4 broken spokes. After examining the wheel more closely, I came to the conclusion that maybe I better just try salvging the spokes and fixing the wheel I have.

    So now it is close to 5 and I am going to head back to town, I pull the chain from the race bike for a sample and off I go in my old beater Volvo commuter car. Stopped at Napa, bought the impact driver and went to Brian's to pick up my parts. I get to Brian's and since his Blazer "Stinky"
    is not in the driveway, thought that since I was pretty greasy and dirty that I would just wait til he got home and not go in the house and bother the family. I was a little tired, so kind of dozed off. I woke up and a police car was driving by looking at me. Hmmm, not good. He turned around, pulled up behind me and came to my window. He wanted to know who I was and what I was doing. I explained my business and he was cool, just said they had been having some issues in the neighborhood and my presence (greasy & dirty, sleeping in an old beater) had made someone nervous!:evil

    At this point Brian was late and I could not get him on the phone, so decided to head home. I got about a mile from home and the car quit! As I am working on the car, Brian calls to tell me that he is now home and it was his wife who called the police cause she did not recognize my old car! He thought it was pretty funny but at the moment I was failing to see the humor! I finally figured out the problem on the car, hot wired the fuel pump and make it home. What a day!:rofl

    Today I'm planning to continue the tune up and get as far as I can, want to hear the bike run today if at all possible. Tomorrow I plan to do a next day air order on the brake shoes and anythng else I have to have. Stay tuned. More pics on smug mug. I would post multiple pictures on each of these posts, but so far am only able to do one pic at a time, any advice?

    Attached Files:

    #5
  6. LC Garage

    LC Garage On Any Sunday

    Joined:
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    Even though there was a lot to get done on the bike, yesterday being fathers day I decided to put family stuff on the front burner and in the morning we went to town, bought the wife a Rav 4 so that I can now drive her old Highlander and get rid of the cursed Volvo.:D

    In the afternoon the youngest daughter came over for pizza and we decided to break out the dirt bikes and ride. My wife rode a little bit but the daughter and I tore it up for quite a while, I finally went in the shop and worked on the SL350 while the daughter continued riding around the property. It was a great day, we all had fun and still finished the tune up. I can now focus on finishing the chassis, getting it rideable in a day or so and work the bugs out. Time is tight but we will get it done.:clap

    Here is a picture of the front wheel from race bike and rear wheel from donor bike, note the brake linings have fallen off both. A rush order has been placed for brake shoes and OC is also bringing some spares.

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    Here is a picture of the motor during the tune up process (now completed), note the tin sleeves over intake boots that have been sealed with silicone. Previous owner had installed the CV carbs at an angle, deforming the boots and slightly tearing the LH boot. After I dimpled the frame for choke shaft clearance and got the spare set of carbs from OC sitting in the boots straight, each time I tried to tighten the clamps the boots would deform and collapse. The tin sleeves now distribute the clamping force more equally and the carbs are now straight and tight.

    I did end up having to drill out the screw that holds the RH tappet adjustment cover on, the impact driver just rounded out the slots, so I got out the mighty makita out and killed the screw. When I have time I will easy-out the bad screw and reinstall the cover.

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    #6
  7. oregoncoast

    oregoncoast Racing Like a Noob

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    Keep it coming old man :1drink


    I'm glad those carbs worked..they were just sitting there in my garage, having come off this bike:

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    #7
  8. Kootenai Rider

    Kootenai Rider Gentleman of Liesure

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    Cool LC. Good to see another one running. While not an SL or going to be raced, I'm resurrecting a 74 CB 200 for Ladybug.... these are such fun bikes to work on.

    Good luck this weekend both of you!
    #8
  9. oregoncoast

    oregoncoast Racing Like a Noob

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    Well, LC Garage called me and held the phone out and I heard the sweet noise of a vintage Honda Twin singing in the background :clap

    And he rode it around a bit, so it looks like he is good to go for Saturday...just have to wait for an update...
    :ddog
    #9
  10. LC Garage

    LC Garage On Any Sunday

    Joined:
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    KR; its all about the fun!:D

    #10
  11. LC Garage

    LC Garage On Any Sunday

    Joined:
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    Oddometer:
    793
    Location:
    Columbia County
    [​IMG]

    Last night finally fired up the old girl and she ran surprisingly well. After warmed up, I rode up and down the driveway, my wife said she was watching me and I had an ear to ear grin. :D

    Still working thru many details. Since the last post I discovered my new Knechts battery (two months old) would not take or hold a full charge, to fire the bike I charged it as much as possible and then left the charger hooked to it unti it was started. The voltmeter showed the bikes charging system was running at 13 volts, so that is working. Have a new Napa battery ordered and will pick that up tonite, hope it is better than that Knecht cra*!

    In the picture you will notice it has a new front tire, I had decided to get that mounted while I was waiting for the brake parts to come in and as usual I pinched the tube (I have never been very succesful at mounting tires). Grrrr! :cry Brian is coming over tonite and he seems to have a knack for tire changing so we will redo the front and change the rear, hopefully with no more leaks.

    Pulled one shock off and removed spring, the dampening seems just fine, surprising for a pair of SW shocks mounted in '85. Put on a new chain, cleaned the fuel tank and petcock, the gaskets and seals for the petcock are very marginal but much to my surprise as of last night were not leaking.

    After I got it running I called Paul (OC) and held the phone by the exhaust and revved it up a few times, he said it sounded like I had my Yamaha 175 running! Very funny Wise-Guy! :evil

    Still left to do; tires & tubes front and rear, brake shoes front and rear, new plugs, tidy up wiring, operational kill switch, clutch cable & clutch adjust, double check fuel system for leaks (I'm paranoid, you should see the seals and gaskets in the petcock, eek) and replace air filters. Still will spend time going over every nut and bolt and after run it a little more will drain the regular oil and refill engine with synthetic. And that should just about do it, then I'll be ready to practice a little around the barn yard.

    #11
  12. Kootenai Rider

    Kootenai Rider Gentleman of Liesure

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    Awesome. I can't wait to see pics of both bikes in action.
    #12
  13. LC Garage

    LC Garage On Any Sunday

    Joined:
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    First let me say that these last few weeks have once again reminded me why I love the motorcycle community and racing folks so much. The camaraderie is just amazing, the support and enthusiasm from family, friends and sponsors is heart warming. My wife, my brother, and my in-laws, friends (Don, Randy & Brian) my new Adventure Rider friends (Paul, Lonnie, Luke, Al, Sherry) and others have been awesome to say the least.
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    So Friday morning started in on the home stretch of bike preparation. The list included new front and rear brakes, cleaning, greasing and double check of bearings and spokes (we had replaced the 3 broken spokes in the rear wheel at Brian’s shop Thursday night while he was mounting the tires), greasing the swing arm, new air filters, tidying up the wiring, remounting the flux capacitor (the rectifier, just seeing if you are paying attention), new clutch & brake lever assemblies, new kill switch, synthetic oil, clutch linkage service and adjustment (pulled countershaft side cover for that) and a few other small items. As it would turn out, I never did change the oil to synthetic as time simply ran out, but I had already changed the oil once and it would just have to be good enough.
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    By noon the brake shoes ordered from Bike Bandit had not arrived even though ordered on Monday via 2<SUP>nd</SUP> day air, so my brother Chuck jumped in his truck and went and bought a back-up set Brian at Wide Open motorsports had ordered in for us. We never did get the rear shoes, so we just cleaned up the old ones and put them back in. Assembled the front and rear wheels to the bike, paid a lot of attention to small details, and when completed everything was moving free and easy and felt good. Started in on the rest of my final list and was very nearly done about 4 PM when I miss-wired the kill switch to the hot side of the coils (doh!!) and toasted the ignition wiring. I know better, but was getting tired and started making mistakes. So took a deep breath and tore the harness apart and re-did the minimum necessary to get it running and then bundled it back together. It was now after 5 PM and our friends for BBQ were due in an hour, so I just took a few laps around the barn and loaded it up. Well prepared as always (not!).
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    We had a fun evening; many people came to the BBQ/Campfire and enjoyed food, beverage and lots of good story telling. Paul (<?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:eek:ffice:smarttags" /><st1:place w:st="on"><st1:placeName w:st="on">Oregon</st1:placeName> <st1:placeType w:st="on">Coast</st1:placeType></st1:place>) and Lonnie arrived about 7:30, then the bench racing began! While we were looking over the bikes, at my request Lonnie lettered my front fender with “Barn Fresh”. We then gathered around the campfire for some tall tales, my brother Chuck told many stories loosely based on truth and Randy Hess (my former flat track mechanic) threw in some good stories as well. We called it a night about 11 PM, and decided we would leave for the track by 6:45.
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    Bright and early we were up and on our way. We arrived at the track, set up our pits and then walked the track. I think Paul and I were both surprised to see a fair amount of the regular modern jumps being included in the vintage course. This was not going to be a cake walk!
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    Practice was uneventful and both bikes felt good. We signed up and Paul finally convinced me we should be in the Inter-Am class, it is a class for bikes that don’t quite fit anywhere else and as it turned out he was right, we both signed up as Intermediate in Inter-Am and even though this was Paul’s first motocross ever was a good fit for both the bikes and our skill levels.
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    In our motos, we were mixed in with Vintage Expert, Vintage Intermediate, Inter-Am Expert and Inter-Am Intermediate, a good fast group. In the first moto I had a great start and after the first few turns settled into 3<SUP>rd</SUP> overall, 1<SUP>st</SUP> in class, with Paul not far behind. I was passed by Don Matthews (54V, an excellent rider) and made the mistake of trying to race him and nearly took us both out on one of the jumps, so I settled down and let him go. Then the choke lever got bumped on and I lost another position to <st1:City w:st="on"><st1:place w:st="on">Kawasaki</st1:place></st1:City> 125 rider, got the choke back off and continued on finishing in 5<SUP>th</SUP> overall, 1<SUP>st</SUP> in class. Paul ended up 2<SUP>nd</SUP> in class, about 7<SUP>th</SUP> overall. Whichever of us finished ahead of the other in the second moto would win the class.
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    The second moto was about three hours after the first moto so we were well rested and ready (or so I thought) and once again I got a great start, but the other riders were not caught napping and when things settled in was running about 5<SUP>th</SUP> overall with Paul around 7<SUP>th</SUP>. On the second lap, the kick start lever flopped open and started banging my right leg, causing me to take my hand off the throttle and the riders who had been nipping my heel got by, including Paul. Damn! So I gathered myself and charged after him, but by now my legs were going away and I was making mistakes. I also had a great view of Paul doing his thing and he is fast and aggressive. Going into the last lap I came off the back straight jump nose down and landed very hard, smacking my helmet into the handlebar cross bar and the family jewels into the fuel tank! Wow, did that hurt! So at that point I realized I had just better settle down and keep it on the wheels and finish. Paul finished in 5<SUP>th</SUP> overall, 1<SUP>st</SUP> in class and I was a few positions back, second in class. By virtue of the second moto carrying more value, Paul should be the winner (final results not in as of this writing) with his 2-1 finish and my 1-2 finish.
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    No matter the final order, we had an amazingly good time and were surrounded by family and friends for the time of our lives. Even though we were hot tired and dirty, before we left the track we were already making plans for the next race. Stay tuned!

    [​IMG]
    where are those darn brakes????

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    rear wheel after replacing broken spokes, tightening sprocket and greasing bearings

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    hooray, front brake shoes at last!

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    looking better!

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    burnt wiring, my patience was wearing a little thin at this point....

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    campfire and BBQ with friends and family (early)

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    Lonnie & Paul arrive

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    old man and old bikes

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    Sherry, Paul, Rick, Al and Lonnie

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    Family and friends

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    with grandson Brock

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    Great-nephew Orrin (he loves motorcycles!)

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    start of first moto

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    start of second moto (Paul is at far right)

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    Paul jumping onto back straight, this is where I did the face and nutt job...

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    Paul over the table top jump ~ nice air!

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    T98 in flight
    #13
  14. Kootenai Rider

    Kootenai Rider Gentleman of Liesure

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    That is a picture is precious. Way to go LC! Looks like you boys had fun this weekend.
    #14
  15. oregoncoast

    oregoncoast Racing Like a Noob

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    [​IMG]

    That is awesome...that is some serious distance on that table top for a bike with 4 inches of rear travel...you can't even see the beginning of it on the left :eek1

    LC, the fact that your bike was non-running just two weeks ago and had brake linings falling apart and mis-matched carbs, and you had it race ready in time is just amazing :clap

    And the fact that it ran so well is just a testament to how amazing those SL motors really are!
    #15
  16. oregoncoast

    oregoncoast Racing Like a Noob

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    Some more great pictures from LoudAl :clap

    Start of second heat:

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    And here was where I got lucky and passed LC:

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    And some more:

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    #16
  17. Loud Al

    Loud Al .

    Joined:
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    Some more

    Making it fly

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    Close Racing

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    Happy Racers

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    #17
  18. LC Garage

    LC Garage On Any Sunday

    Joined:
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    Thanks Al, great photos, thank you for sharing these and also the support from you and the other ADV Riders!:clap

    #18
  19. LC Garage

    LC Garage On Any Sunday

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    Time to start planning for the next race, the Vintage Nationals at The Farm in Chehalis on August 14th. Here is a link;

    http://www.100megsfree3.com/ahrmanw/aaMX_ChehalisWA.htm

    Lots of work to do on the old bike as well as the old body, no excuses, gotta work out more if I want to keep up with that young whippersnapper OC (Paul)!!!:D
    #19
  20. Ladybug0048

    Ladybug0048 Bug Sister

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    I plan to be there. Watching the vintage bikes and riders will be a good time.
    #20