Vintage Dirt Racing on a 350 Honda Twin

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

  1. Old fart

    Old fart Keen AG100 rider

    Joined:
    Oct 21, 2006
    Oddometer:
    841
    Location:
    South By Southwest near the dotted line
    The SL sounds like problems other than carb. The smaller Honda's require a battery to run, the alternater/generator can load up and the bike won't rev like yoo describe.
  2. LC Garage

    LC Garage On Any Sunday

    Joined:
    Mar 18, 2011
    Oddometer:
    790
    Location:
    Columbia County
    SL350 with OC's skid plate setup. RH pipe has been rotated clockwise as far as possible while still leaving frame clearance. LH pipe will be cut, rotated clockwise and joined into RH pipe. Single pipe will emerge from under brake pedal pivot area. Some type of light, durable low restriction muffler will be used, possibly a super trapp.

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    View of area where 2 into 1 pipe will emerge.....

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    SL350 "Scrambler" project, before disassembly on Saturday afternoon;

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    "After" on Sunday morning. Have a rough idea what I want this to look like, I am thinking black and silver with scrambler pipes, maybe an older tank and fenders in the style of the old 305 scramblers....

    [​IMG]
  3. drdubb

    drdubb OFWG

    Joined:
    Dec 13, 2009
    Oddometer:
    493
    Location:
    Raleigh, North Carolina
    What material is that skid plate? Thickness?
  4. LC Garage

    LC Garage On Any Sunday

    Joined:
    Mar 18, 2011
    Oddometer:
    790
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    Dale,

    The skid plate is a piece of art work built by OC and his crew, not sure of aluminum specs, you can hop over to his thread and ask him. He told me they mocked it up with cardboard and then built. It is made of three pieces and bolted up beautifully, impressive work. :D

    There are other threads here on ADV where they discuss "old school" skid plates, one design mentioned was to take an aluminum scoop shovel of appropriate dimensions, fabricate brackets and bolt on. For the right bike it could be kinda cool.

    Take care


  5. LC Garage

    LC Garage On Any Sunday

    Joined:
    Mar 18, 2011
    Oddometer:
    790
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    I'm happy to report that the SL100 continues to progress and the charging system is now working fine. As reported earlier, The stator had checked out (there are differences of opinion on how to check, I used the method checking for continuity between the three possible wire pairs and also ensuring that none go to ground) and then tested the rectifier, which showed to have one bad diode. I decided to try out the Oregon Motorcycle Parts rectifier, it is tiny in comparison to the original unit but is supposed to be far more durable. I used the original mounting bracket and location, installed the wires into the connector to match original configuration, put it all back together, started it up and.....nothing???? Still not charging. WTF? :cry

    So I'm looking at the way it is wired, it does have a ground wire leading to the base, I had cleaned the base and mounting plate, should have a good ground, but then I realized the rectifer mounts to the air box and it's mounted on rubber grommets! Ok, so I make an auxilliary ground wire, hook it up and suddenly she is charging beautfully. With key off it was at 6 volts, key on and engine running at 7.75 volts. Just for grins I decided to try something I had read about, pairing the yelow wire with the white wire and the running voltage jumped to over 8.5. I decided that since this unit does not use a voltage regulator to only go with the factory yellow wire. :D

    Old rectifier

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    New rectifier (with auxilliary ground)

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    The increased voltage definitely helped the performance but still had a pretty good burble in mid range, so I took the slide out, dropped the needle to the bottom adjustment and tried again, now it is running pretty good with only a slight mid range burble. The new needle and nozzle should arrive have next week. :clap

    I'm now tidying up the wiring, getting ready to pull and clean the clutch plates (they are stuck) and turn this bike over to the duaghter so she can ride it! With this phase of the project winding down (remember it is going to get hot rodded for Vintage MX) I will start shifting my focus back to the 350 twins again. :D
  6. oregoncoast

    oregoncoast Racing Like a Noob

    Joined:
    May 15, 2007
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    4,544
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    Duh!
    I would not worry about the Oregon rectifier. They are damn good units at damn good prices...and they have a great warranty.
  7. LC Garage

    LC Garage On Any Sunday

    Joined:
    Mar 18, 2011
    Oddometer:
    790
    Location:
    Columbia County
    Since I'm waiting for the carb parts to arrive, last night I decided to tear into the stuck clutch issue so that when we got the carb dialed in she would be ready to ride. It turns out its a good thing the clutch wouldn't break loose (I tried all the normal tricks first) as the plates were pretty nasty. I also found that (once again) all the bolts and screws were relatively loose. I'm really not sure how this thing ever ran.

    Before (note heater buddy, it's gettin' cold at night in the hills of Oregon)

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    Note gunky oil & grungy crankcase, another benefit of tearing into this, I had not changed oil yet (my bad)

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    Tear down was fairly easy as the majority of all fasteners were already loose. The clutch pack was firmly stuck together in one rustly lump

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    Clutch plates were very rusty and bonded together, it took a lot of persuasion to peel them apart

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    The friction plates were lightly buffed on wire wheel and then got more agressive with the steels, they looked pretty good when finished, then began the reassembly, this is as far as the reassembly got last night

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    Less than an hour left to finish asssembly, when carb parts are here, this bike should be ready for riding, stay tuned. I promise we will be getting back into the twin cylinders soon. :D
  8. LC Garage

    LC Garage On Any Sunday

    Joined:
    Mar 18, 2011
    Oddometer:
    790
    Location:
    Columbia County
    This weekend I finished up the SL100, at least the first phase. My intention has been to get the bike running properly in stock form, so my daughter could ride and enjoy it before boot camp, and then later as time allows will modify and improve for when she rides it in vintage mx.

    After finishing the clutch, I went back to the carb. The new needle and orifice needed installed, so once again I took the carb apart and with some gentle persuasion had the orifice out. One look under the magnifying glass told me the whole story. No wonder I could not get this thing to run right! The orifice was rough, worn and egg shaped, the needle somewhat less worn but still showing signs of a long hard life. Put in the new pieces and fired it up. It was so lean now it would hardly run. I tried raising the needle one notch which helped a little, but it needed more. When I originally rebuilt the carb I'd put in a 105 jet that in some books is shown as the stock size, but in others it shows a 110. I had a new 110 so put that in and it really started to come around. A few finer adjustments and at last a decent running 40 year old baby thumper!

    The old worn parts, towards the bottom of the orifice you can see that it is egg shaped;

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    First ride on her "new" bike;

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    That does it for now. Back to the vintage twins! :D
  9. oregoncoast

    oregoncoast Racing Like a Noob

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    Duh!
    Cool, I'm glad to hear you got the 100 running well. Now I just need to get you the CL350 so you can get that going to sell to pay for improvements to another 350 twin :lol3

    :1drink
  10. LC Garage

    LC Garage On Any Sunday

    Joined:
    Mar 18, 2011
    Oddometer:
    790
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    Columbia County
    Amen brother! :freaky

    My next move is to get back on the exhaust project, stay tuned for updates!

  11. Ladybug0048

    Ladybug0048 Bug Sister

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    Oddometer:
    11,533
    Location:
    Spokane Valley, WA (the dry side of the mountains)
    :clap:wings:clap:wings:clap:wings:clap:wings:clap

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    Nice!!!​
  12. Kootenai Rider

    Kootenai Rider Gentleman of Liesure

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    Hillsburrito
    Looking good Rick.

    Got any tips for a stuck carb? I'm working on a CL100 right now....tried WD40, tried brake cleaner, vinegar, etc.

    Just got some special new WD-40 rust desolver stuff, we'll see if that works. Haven't tried boiling it yet.
  13. LC Garage

    LC Garage On Any Sunday

    Joined:
    Mar 18, 2011
    Oddometer:
    790
    Location:
    Columbia County
    Assuming you mean the slide is stuck in the bore?

    Something I have not tried but keep hearing about is coca cola. Apparently it is very acidic, and just might work.

    Here is one of many links describing in some detail why this can be effective;

    http://www.antique-engines.com/rust-coke.htm

    Although this is touting primarily for removal of iron oxides, it may still be worth a try.

    Would love to hear back if this actually works??? :D

  14. Kootenai Rider

    Kootenai Rider Gentleman of Liesure

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    I'll report back about the new WD-40 I used.

    I'll try the coca-cola trick, and yes it is the slide that is stuck.

    White vinegar worked very well on the rusty tank.



    *edit* - Yup..new WD-40 formula worked very well. Got it free tonight without much effort.
  15. LC Garage

    LC Garage On Any Sunday

    Joined:
    Mar 18, 2011
    Oddometer:
    790
    Location:
    Columbia County
    This weekend was able to spend several uninterupted hours out in the shop and decided to get busy on the bike trailer, so I can haul the various 350's around to get worked on as well as hauling them to events and races. I do have a truck, but it has two major flaws; it is a big gas hog and pretty tall, making loading bikes in the back a real chore. The trailer is low and easy to load and can be pulled with my rice burner and save gas money. :D

    Before, not sure what this trailer started life as, we are thinking maybe it was a tow dolly? Previous owner had added some good and bad touches, most of which will be dispensed with using the "hot wrench"...

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    After initial surgery with torch and grinder (Industrial Therapy!) :1drink

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    After more surgery and new center rail welded in

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    With outer stub rails tacked in place, decided since the original wider side rails were an intrinsic part of the structure it just made sense to leave them in place, but trim back a bit and install smaller extensions. Next step will be to finish out the front wheel racks and build on some kind of storage box and maybe a gas can holder.

    [​IMG]
  16. oldairhd

    oldairhd Adventurer

    Joined:
    Nov 16, 2009
    Oddometer:
    52
    Location:
    Jimbobway, Oregon Outback
    Must be a sickness of some sort. Here's mine. Since I'm too old and busted up to race anymore, mine has no purpose but to amuse and entertain. At 10,000 RPMs on a country road with the Snuff-or-Nots turned out, it puts a big grin on my face!

    Got it for "free" from a local AHRMA racer's collection of parts bikes. Spent a winter getting it to run right. Added kill switch and NOS Honda Redwing shocks from Omar's. Needs more frame tabs removed and a paint job, I guess...

    1971 Honda SL350
    1976 Yamaha TT500
    1884 Honda XL125S
    1985 Yamaha TT600
    2005 BMW R1200GS

    Attached Files:

  17. LC Garage

    LC Garage On Any Sunday

    Joined:
    Mar 18, 2011
    Oddometer:
    790
    Location:
    Columbia County
    Your bike has a great look to it, just add number plates and go flat trackin'!!!!!!!

    These bikes do have a great sound of their own, glad you shared you with us!

    You are right, it is some kind of sickness but the good kind I think. Have met several nice people thru this site and am going to Baja with OregonCoast (Paul), Luke & Paul Jr to help with Paul's SL350 in the 2012 Mexican 1000, it will be the adventure of a lifetime. :D

  18. oldairhd

    oldairhd Adventurer

    Joined:
    Nov 16, 2009
    Oddometer:
    52
    Location:
    Jimbobway, Oregon Outback
    Thanks for the kind words. Anymore, I mostly just ride to BMW rallys and do the annual dual sport Sheetiron 300 and a bit of local trail riding. Haven't raced for 35 years, but love to go to the occasional National--dirt track, road race, whatever.

    2012 Mexican 1000 sounds like a great adventure. How far south will the course go? I love the Mulege, Loreto and La Paz area. I'll be watching this thread for your reports!

    Rod

    Klamath Falls

    P.S. If the SL350 sickness progresses, I know where a 1972 model with the 21" front wheel and an old 400cc conversion lives, unloved.
  19. Kootenai Rider

    Kootenai Rider Gentleman of Liesure

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    We're stopping in Loreto for an overnight assuming they keep the same pace as the last two years. The race ends in La Paz right at the Malecon.

    <a href="http://s1234.photobucket.com/albums/ff409/psusbauer1/?action=view&amp;current=Mexican1000andFamily644.jpg" target="_blank"><img src="http://i1234.photobucket.com/albums/ff409/psusbauer1/Mexican1000andFamily644.jpg" border="0" alt="Photobucket"></a>
  20. oregoncoast

    oregoncoast Racing Like a Noob

    Joined:
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    Duh!
    :ear

    We (LC Garage and me) are always looking for orphaned SL350's. PM's work great :wink: