Big Bertha - Cafe/Tourer 79 Special

[olinrj]

Beautiful progress. The seat and tank combo really go well together. Unfortunately I can't answer any of your questions, but good luck with the rest.

[jetmechmarty]

It looks great! I think you have to take the forks apart. Something is loose or worn out.

[TopCatGr58]

Hey Motobrix,

Looking good! As to the CLICK noise....are you saying that when you pull up on the front end so that the front wheel gets OFF the ground that you hear the click?? You could be hearing the steering bearings and steering shaft and frame bumping/clicking due to being too loose tension setting!?

I didn't reread this build thread, so I don't know of you've done any work on the forks...replaced seals or what?? The inner fork slider is secured to the bottom slider via a hex socket head screw thru the bottom of the fork. However, if it was that loose, I would think you would have a serious fork fluid leak? But perhaps the inner slider is loose a little bit allowing it to hit the side of the slider=click??

T.C.

[motobrix]

Hey Motobrix,

Looking good! As to the CLICK noise....are you saying that when you pull up on the front end so that the front wheel gets OFF the ground that you hear the click?? You could be hearing the steering bearings and steering shaft and frame bumping/clicking due to being too loose tension setting!?

I didn't reread this build thread, so I don't know of you've done any work on the forks...replaced seals or what?? The inner fork slider is secured to the bottom slider via a hex socket head screw thru the bottom of the fork. However, if it was that loose, I would think you would have a serious fork fluid leak? But perhaps the inner slider is loose a little bit allowing it to hit the side of the slider=click??

T.C.

The front wheel doesn't come off the ground, but if you hold the front brake and rock the suspension back and forth it clicks as you're pulling up on it and on compression. If you just compress it from rest it's fine.

I rebuilt the forks in order to powder coat them properly. I replaced the fork seals, and lowered them internally by adding a spacer. I also added shorter racetech springs and a preload spacer made of pvc. The only thing I didn't replace was the bushing (teflon?) underneath the fork seals. So either something is worn out, or I may have installed something incorrectly. Seems like maybe I should just take it to a mechanic.

[motobrix]

For those interested in parts, can someone tell me if this is the stock 79 Special seat? The previous owner told me this was an aftermarket seat or something, but I can't tell. It's in good condition but may not be original.



Here are some pictures of the forks being rebuilt:

The lowering spacers:


Inner tubes, with the bushings or collars that may be worn:


Seal installed:


Retainer ring for seal: The fork seal seemed to sit a bit lower than it used to, with a gap between the seal and the ring.

[bikerphil]

I would think those lowering spacers may be making the noise you are describing, they are free to float around and slam up against the damping rod. It can be very volatile inside the fork with the fluid being forced thru damping holes. It shouldn't be a concern regarding functionability. If the spacers were fixed in position and not free floating, that may cure your 'click'.

The seat you have pictured is a Yamaha factory touring seat, not the original that usually came with your 79SF.

[bikerphil]

Also, those spacers may be blocking your rebound damping holes, it is hard to tell from the pics. Perhaps the oil shooting thru those holes may be making the spacers rattle on the damping rod.

[Rasputin]

I rebuilt the forks in order to powder coat them properly. I replaced the fork seals, and lowered them internally by adding a spacer. I also added shorter racetech springs and a preload spacer made of pvc. The only thing I didn't replace was the bushing (teflon?) underneath the fork seals.

I would wonder why you would replace stuff like fork seals, pre-load spacers made of PVC, if you were going to powder coat them. The heat from a decent powder coat would ruin any new seals put in and any good shop would require they be removed. Kind of a waste of seals, time etc to me.

[motobrix]

I would wonder why you would replace stuff like fork seals, pre-load spacers made of PVC, if you were going to powder coat them. The heat from a decent powder coat would ruin any new seals put in and any good shop would require they be removed. Kind of a waste of seals, time etc to me.

I mean I took everything out, powder coated, then installed new components. I didn't install new parts and then powder coat. That would just be stupid.

The lowering spacers have a hole for the oil to go through. They also have a set screw to keep them locked in place. So unless the set screw got losened, they should be working properly.

[motobrix]

Ok, so it's been a while since I last posted, but I've made some real progress. Getting close to the point where I should be able to start the bike up.

I rewired the entire bike with a motogadget M-unit:




... along with an RFID controlled ignition, with a switch and sensor on the side of the bike:


I also made a front headlight grille type thing to hold the headlight in place:


And finally, here's how it looks with the exhaust back in place:


All that's left is to install ZRX1200 carbs, and clean up the wiring. I might be getting a newer regulator/rectifier from Geezer as well.

[motobrix]

Here's the rear with the turn signals working and side mounted license plate:

[DiverRay]

That's looking nice!

[Mathh]

Very nice!

[Robsweetland]

Cool

Cool

[motobrix]

Just in time for winter, and to put the bike away for storage, I finally got the XS up and running!

All that's left now is to powder coat a few of the raw metal parts, cover the wires a bit more, and get stainless steel lines.

I have zrx1200 carbs installed with 135 mains and 35 pilots, but it's running a bit off. I have a feeling the 35 pilots are too small. I also need to properly test the mains by going full throttle, which I haven't had much of a chance to do yet, and probably won't do until the spring. Right now it pulls pretty hard at closer to full throttle, but it bogs a bit at 1/4 throttle and hangs up at higher rpm before dropping back down to idle.

I have another bizarre problem, which might be do to my wiring and the motogadget m-unit. Every once and a while the horn just beeps randomly. It's really weird. I'm thinking interference somewhere, or maybe it's grounding out somewhow. It only honks randomly when the engine is running. Good way to startle pedestrians!

Here it is in very nearly finished form: