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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    Since the donor bike came with a pair of fairly new looking Works Performance shocks that would be a huge upgrade over the old SW's, I'm determined to have these on the bike for Chehalis. On Monday morning I called Works Performance to order rear shock springs and as always, when working with phone reps it is the luck of the draw. The guy I got did not want to hear what I needed, instead launched into a long speech about everything they did and how he was going to help me. When he finally took a breath, I quickly interjected that yes, this winter when I'm done riding the bike you can rebuild everything, but for now I just need some softer springs for an upcoming race. He finally began to listen and asked a few questions and began to take down my measurements. I gave him everything I had; spring lengths, diameters, wire size, everything. He then asked if I had the swing arm and shock mount lengths so he could check geometry. I said no, but would get them and call him back the next morning. He also told me to get a dgital caliper so I could give him a more exact wire diameter on the coils. No problemo.

    The next morning called the same rep back and began relaying the final bits of information. Much to my surprise, he then said "we don't have any springs in the length or size you need, we can't help you". I am sitting there on the phone a little puzzled, but forge on, explaining that they were indeed Works Performance shocks, clearly had the WP label and were just a pretty standard spring set up, and what do you mean you can't help me? He stuck to his guns, saying they could not help me, so I realized that I needed to hang up before I lost my temper. :fyyff

    I then called OC and asked who did he use, as I remembered in his Baja blog he talked about a suspension guru that had been a great help. He said I needed to call Alex at Konflict Motorsports as he had been a great help to Paul in setting up the front and rear suspension on his SL350. I called Alex and what a difference! Super helpful, knowledgeable and ready to get to work! Just what I was hoping for. He took all of my measurements and said he would have springs custom wound to fit both the bike and rider weight as well as the bikes geometry. He said it takes about a week to have them wound, powder coated and shipped. :clap

    In fairness to Works Performance I have had other riders tell me they received great service and had I started over with a different rep might have had a much better experience. :huh

    The plan now is that at whatever point we are done riding vintage for the season, Alex will take my forks and shocks and give them a complete rebuild including dyno testing. He said that the forks will require custom emulators to prevent cavitation and he had some ideas he wants to try on them. I'm looking forward to seeing and feeling the progress and am already excited to tear the bike down this winter and go completely though it. :D

    Post Script; just talked to OC on the phone and told him I was going to work on making the bike as light as possible for next season, he said it was like taking Ugly Betty and trying to turn her into a super model! Well that is just the kind of encouragement I need, Ugly Betty indeed! :freaky
    #41
  2. LC Garage

    LC Garage On Any Sunday

    Joined:
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    Alex at Konflict Motorsports is having the new rear springs custom wound in Okahoma, and is pretty confident they'll be finished and here by early August. Whew! The old spring rate was about 120 lbs/inch and Alex has calculated a new rate of 85 lbs/inch. That should soften things up a bit! :D

    In the meantime I've finished stripping the donor bike and decided that I'll definitely be converting to the stock slide carbs. The CV carbs may make a little more power, but the bike was definitely boggy coming out of the tight turns. What I lose off the starting line should be made up for in rideability.

    Got my pre entry in for Chehalis, signed up for the Sportsman 500 Intermediate, I'll probably have my hands full of snarling CZ's! :puke1

    Not much progress for the rest of this week, too many honey do's! Next week I plan to be out in the shop every night, should make a ton of progress, so stay tuned....
    #42
  3. never2old4fun

    never2old4fun Been here awhile

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    Yes,
    Getting rid of the CV's will help, but I was wondering if you had done any other work to the engine?:D
    #43
  4. LC Garage

    LC Garage On Any Sunday

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    Pretty sure the motor is bone stock, I do plan a full rebuild this winter with 400 kit and some other goodies. Any suggestions? I see the road race guys have some neat stuff, it looks like pow roll no longer does the 350 twin parts though.

    Also planning to freshen up Oregon Coast's 350 motor, but he has told me he wants to keep it stock for reliability in Baja.

    Anyone know where to get TT pipes?

    #44
  5. never2old4fun

    never2old4fun Been here awhile

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    It's sad that Powroll doesn't make hop ups for the 350 anymore.
    That TT/ scrambles flattracker I built had there 375cc kit with the 12.5 to 1 pistons in it and there 12,000 RPM cam.
    You might try Mega Cycle for a cam, I understand they will grind a wilder cam for the SL 175's I'm working on.
    Also Honda Twins. net may have some info for you, too.:D
    #45
  6. oregoncoast

    oregoncoast Racing Like a Noob

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    TT exhaust.

    Rick, if you find a proper source, let me know. I have done exhaustive (pun intended) searching and although there is stuff available for the CB/CL, like here http://jemcoexhaust.com/downloads/Jemco_Product_Catalog.pdf The late SL's have the twin downtube frame and it is uncertain if many of these aftermarket ones will fit.

    I almost bought a pair of these http://cgi.ebay.com/ebaymotors/Hond...ccessories&hash=item2a055d2a09#ht_1748wt_1167

    [​IMG]

    but was uncertain if the 360 flange was the same as the 350 motor...and whether they would clear the frame due to their design.

    This is why I suggested we find someone local to make pipes for us. This is also why I have been hoarding SL exhaust pipes, because they are rarer then hens teeth. I still want to find someone willing to make a 2 into 1 coming off the right side..this fixes the issue with drive chain contact with the pipe, and will be good when I dirt track the sucker :wink:

    I hope you do find something that works..heck, for $119 bucks, those 360 TT pipes might be worth trying...I could always buy them from you for my CL350...if they don't fit and would fit the CL head. :1drink
    #46
  7. LC Garage

    LC Garage On Any Sunday

    Joined:
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    If memory serves (and that is questionable) it seems as thought the old 350 twin TT pipes fit any frame. I threw that question out in the previous post cuz you never know who may have a source. I'm still in for having some pipes made and have already talked to my buddy that works at Laser Cutting Service in Tualatin, about making several sets of the header flanges so we can eliminate those god awful heavy factory things and have also been pondering how to either use or not use the original clamp technology to hold the pipe in the head. We will have to iron out those questions when we go to build the pipes.

    Everyone take care and have a great weekend, headed to Alsea Bay for crabbing trip. :freaky

    #47
  8. LC Garage

    LC Garage On Any Sunday

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    At long last, some quality time in the shop! Tonite's goal was to put the new rear brake shoes on, extend the rear brake arm and put the 15 tooth countershaft sprocket on.

    First a side view of the brake set up, note the lengthened swing arm (originally lengthened exactly one inch) with stock brake arm and how it causes the brake panel to rotate backwards when the shocks are fully extended, throwing the cable in a bind. Combine that with the worn out rear shoes and the rear brakes were almost worthless.

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    Next is a view of the stock brake arm, along with the aluminum flat stock used to make the new longer arm.

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    From eye to eye measured 14.5 inches, but I decided to make the new arm 15.75 inches eye to eye to ensure the cable did not bind when the suspension was fully extended (imagine you come off a jump and the rear wheel binds, which could pitch the nose down, something I did experience in the last race!)

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    Next is a picture of the new shoes mounted on the backing plate. I used my new digital calipers to measure the shoe thickness and although they only appeared to be .010" thicker than the old shoes, I had to back the adjuster way off to get them into the drum, a good sign. Note; the picture is deceiving, they really are the same size shoes!! In this picture you can also see how far down the adjuster had been tightened in a vain attempt to get the worn rear shoes to work. After installing the new shoes, this adjustment was backed off almost 1 inch. :wink:

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    Last picture is with the rear wheel back on and the new longer brake arm in place.

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    With the rear brakes completed, I pulled the countershaft cover and swapped the 16 tooth countershaft sprocket for the 15 tooth off the donor bike. This will help keep the rpm's up and allow a little tighter spread thru the gearbox. Still lots to do and counting the days until the new rear springs arrive. :clap
    #48
  9. LC Garage

    LC Garage On Any Sunday

    Joined:
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    Tonite I decided to get the carbs changed. The CV carbs that I borrowed from OC worked well but seemed a little boggy coming out of the corners, so wanted to give the stock slide carbs a try. Their smaller size may cost a little power on the top end but should more than make up for that with their quicker response. We shall see! :D

    [​IMG]

    Pulled the CV's, cleaned up the slide carbs from the donor bike, pulled the bowls, gave everything a quick check and then bolted on the smaller manifolds (bonus, they are in much better condition than the CV manifolds) and slipped on the smaller carbs.

    [​IMG]

    These carbs also came with an aftermarket quick throttle and at first I thought that might be a good idea, but the throttle turns so hard I might have to go back to the stock slow turn throttle or maybe find some lighter slide return springs.

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    Also finally got around to changing the engine oil and putting in the synthetic. Next up; putting the electrical system back together. Two weeks to go, starting to feel that time crunch again! :eek1
    #49
  10. never2old4fun

    never2old4fun Been here awhile

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    Going with those carbs will help, but just so you know on my old flattrack/ scrambles/ TT bike Ihad 32mm mic's on it.
    More is info is always good.:D
    #50
  11. LC Garage

    LC Garage On Any Sunday

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    If I had more time and deeper pockets, might have opted for the Mikunis, but that will have to wait for this winter. I had the stock slide carbs and we are told they were working good and they looked fine inside, so should get me thru this race. Did you get your Mikunis new or find some used ones that worked? My friend Brian seems to have good luck with Keihins, any knowledge on those? I probably won't go as big as the 32mm, maybe 28mm or 30mm.

    Definitely going to make some improvements and step up the power this winter! :evil

    #51
  12. LC Garage

    LC Garage On Any Sunday

    Joined:
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    Today was wiring day. Finished pulling all the old electrical off and did a quick comparison to the harness off the donor bike. Less stuff is good.

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    I began installing the "new" harness and as expected, found all kinds of loose connections, bad wires etc and repaired as I went along. Also removed anything that was not absolutely necessary. The toggle switch on donor bike had been mounted behind the motor, down low, but when I looked at the bracket I realized that it had been made to mount on the handlebar mount. Extended the wires and it fit perfect. Staying true to the barn fresh theme, I resisted the impulse to clean up, shine or otherwise beautify the bracket.

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    I also took the opportunity to pick the smallest rectifier of the three available and mounted it tight and inside, out of the way. With the slide carbs installed and the cleaned up wiring and smaller rectifier, should have room for the side panels now.

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    After it was all back together, turned on the switch and kicked it over with the plugs out and connected, and had spark. Success! :clap

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    Last shot,the debris field. Why do I show these shots? Maybe it's kind of the same reason we have been leaving the bike raw and rough, it is the reality of the process, greasy hands, busted knuckles and an array of parts and tools spread everywhere. Tomorrow I'll clean everything up, get organized and begin again. :D

    [​IMG]
    #52
  13. Ron Peck

    Ron Peck Been here awhile

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    I raced one back in 1968/69; great bike

    [​IMG][/url]
    #53
  14. oregoncoast

    oregoncoast Racing Like a Noob

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    Duh!
  15. never2old4fun

    never2old4fun Been here awhile

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    The 32's I had on my bike were new, but at this time you'd be paying premium for them now and if you are looking for more torque the smaller carb's will most likely work better for you anyway since you don't have high comp pistons, head work, or a big cam.
    #55
  16. LC Garage

    LC Garage On Any Sunday

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    Ron, was this Ascot (TT with jump)? Can't tell from the black and whites photos, but that looks like red numbers on a white background, were you an AMA Novice in these photos? I rode a 350 twin as a novice (1973), have some great stories from that old beast!

    Looked at the photos of your street tracker (66 Triumph), that is an amazing piece of artwork. Thanks for checking in on my humble project.

    #56
  17. LC Garage

    LC Garage On Any Sunday

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    By next summer will have a 400 kit, but probably stick with a stock or nearly stock cam with a better exhaust system and possibly ignition. Keep looking at those 350 twin road race bikes, lots of trick parts to be found there.

    #57
  18. Ron Peck

    Ron Peck Been here awhile

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    LG, red numbers on white plate; district 36 AMA novice. Picture was from Triple M Speedway Marysville, CA. Those were the days my friend.
    #58
  19. oregoncoast

    oregoncoast Racing Like a Noob

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  20. Ron Peck

    Ron Peck Been here awhile

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    I found another pic

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    #60