Questions on mixing parts between years

Discussion in 'Airheads' started by Bh867, Nov 7, 2018.

  1. Bh867

    Bh867 Adventurer

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    I've been a long time admirer of the airheads but I am still quite new to the game and as such I have a few questions I'd like to ask with regards to a Frankenstein bike I'm building. I have a 78 r80 with r100 jugs. The front forks are off of an 80's model and has the dual Brembo brakes. It also has a 5 speed trans with kick start. I bought a /5 tank and would like to build it to look a lil more old school /5 ish. Some questions I had are wether anyone knows if the brake distribution block that mounts under the tank for the Brembo equipped bikes will clear the /5 tank? I know the hydraulic master cylinder for the dual brakes won't as I've tried that :)
    Also I'm curious wether the front timing cover for a /5 and the intake boots will fit on this setup, I have the stock 32mm bings from the r80. Any help would be appreciated thanks!


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  2. Plaka

    Plaka Brevis illi vita est

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    you don'r want the /5 timing cover. Very poor ventilation and the diode boards overheat. Grind the stripe off a later one and bead blast it for a more old school look..

    The brake splitter ought to fit without the ignition heatsink fitted to it. Depends on the tank. The later big /6 touring tank is a better choice. The cloissone roundels can be glued on and the cut-off /r screw heads glued into the badge.

    The polished /'5 turn signals will fit. The dipstick will with slight modification. Keep ( or source) the deeper /7 oil pan. The larger /5 chrome grab handle is a bolt-on.

    The air filter housings should exchange, old for new. But you will need the air tubes that go with the filter housing and the correct (or bodged up) windage plumbing.. The newer filter housing is superior but is not quite the old school look. Don't know when they changed.

    The polished aluminum fork caps will fit, you may need to change out the fork tube top nuts. The polished aluminum bar mounts are the same as the painted ones but the painted ones are unpolished castings and a lot of work to convert.

    I have a lot of /5 on my '83 /7 but the emphasis is on polished aluminum and anything shiny. Where /7 aluminum could be polished out that was done, like all the foot controls, etc.
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  3. Warin

    Warin Retired

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    On the brake splitter .. those are fairly small .. won't make much visual impact, put it somewhere that is not in your face.

    A '78 will be points - you don't have a heat sink ..
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  4. Bh867

    Bh867 Adventurer

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    Awesome info, thank you very much. Do you have a pic of your bike by chance!


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  5. Bh867

    Bh867 Adventurer

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    Also I have been thinking of picking up a /5 or /2 headlamp bucket and fitting a newer gauge in the stock opening. I'm sure I'm not the first to want to do this.
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  6. Disston

    Disston ShadeTreeExpert

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    Some in depth threads here on this particular modification. The search engine will help. But since a lot of the wiring on an Airhead is in the headlight bucket it gets involved. And the switches on the older bikes are older school. They are often a challenge to make work, can be hard to find parts that work well, new is often not available or too expensive.

    Here's a short spiel on the subject: https://advrider.com/f/threads/5-headlight-onto-6.1185945/
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  7. Bh867

    Bh867 Adventurer

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  8. Plaka

    Plaka Brevis illi vita est

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    I don't know if that block had the stilling chamber with the exit at the front. The /5 windage is through a disc poppet valve that goes to a hose directly down t R. intake. The /7 has a reed vale ( interchanges with the disk. Use the reed) That, at least by '83, Goes into a little cover that dumps the gasses into a stilling chamber cast in the top right side of the block.

    You do know you need a new top cover, right?
    #8