Project '77 Bonneville

[Tri750]

Some may recognize this bike from BARF as it got passed around from one member to another. Well, I ended up with it from a great guy, Cereal KLR who allowed me the time to get my ducks in a row to get it.
It had been sitting I think for 10 years. The brake system was/is shot and I got big help from the previous, previous owner buying quality master cylinders and putting them in the spares box.
I rebuilt the front caliper, cleaned the sludge from inside the hard lines and replaced the rubber lines with steel braided.
I put a set of "Euro" style bars on it since I had them.
It pumped right up so we now have a front brake!
I've cleaned and synched the carbs, checked valves, primary chain, trans level, and today will change the oil and fit the AGM battery, flush the tank, and see if she will fire.
I'll kit the rear brake as well but I want to make sure all is well with the motor and, I'm pretty excited so the rear brake can wait a day or two while I piddle with other details.
It will need tires, some heavy cleaning and down the road I'll put a Boyer ignition on it. The Boyer really wakes these bikes up as the advance curve goes further and setting the points on these can be pretty daunting.

 

[SFMCjohn]

Hey Tri750,

Sweet bike, congratulations, sounds like progress! :thumbup

Thanks for your feedback on my '73 Tiger ... I didn't describe the crank run-out to you very well, it turns out it's moving up and down like an unbalanced tire ... time to replace the main bearings on the crank, we guess ... arty

Hope the '77 Bonnie fires right up! :ride
see you around the campfire,
-- SFMCjohn

 

[Tri750]

Wow, that's a lot.
You're sure that's the problem?
If you don't have a dial indicator, remove the stator and magnet use a piece of coat hanger sharpened like a pencil can be clamped to the engine case using one of the screw holes, the screw and a washer to secure it. Then slowly rotate the engine.
If the crank is that loose then keep the rpms down until you can rebuild it. But that's a lot.

Maybe the end of the crank is bent?

 

[SFMCjohn]

Wow, that's a lot.
You're sure that's the problem?
If you don't have a dial indicator, remove the stator and magnet use a piece of coat hanger sharpened like a pencil can be clamped to the engine case using one of the screw holes, the screw and a washer to secure it. Then slowly rotate the engine.
If the crank is that loose then keep the rpms down until you can rebuild it. But that's a lot.

Maybe the end of the crank is bent?

No, not super-sure what the problem is, except that the stator is being rubbed ... we are sure there is a lot of movement with the end of the crank that should not be there ... (Got a quote from a Triumph restorer to rebuild the engine ... Over $5000, ha. Guess maybe that's where the custom chopper money has moved to ... some of it anyway ... )

The engine is being stripped and I'll keep you posted about what we find ... thanks a bunch for your insight, feedback from someone who used to race one of these engines is pretty valuable! :thumbup

Have fun with the Bonnie project,
-- SFMCjohn

 

[Cereal KLR]

Good to see it end up with the right person. You have lot of experience racing and riding these models so knew it would be better off with you than me. I really liked the bike but did not love it in its stock form which is always a deciding factor for me with moto. I would have taken it all part and made a tracker out of a very nice original survivor which are getting harder to find. Every single one of my friends threatened bodily harm if I did this:laughing

This bike deserved to be brought back correctly and you will make it right.:thumbup

 

[Cereal KLR]

Well how was the first ride?

I had contemplated running it in Production Pushrod 750 class at Bonneville but it had to stay completely original to do so,i.e points ignition etc. The record is sub 90 mph but after thinking about taking it and to try three miles wide open running not knowing a dam thing about these bikes all I saw was a long walk pushing a bike back to the pits :laughing

 

[Tri750]

With a change in gearing, it would comfortably handle 90+ for 3 miles.
Stock gearing, probably fine too on a cool day.
My production racer with large sprocket in the rear pulled 107 at big Willow on the back straight. Fresh but completely stock motor except for ignition.
With a skinny guy, even better.

The bike started 4th kick. Some ticking in the valve train that might get better with time.
It had seemingly new oil in it when I changed it. Valves were set when I checked them, new gaskets on the rocker boxes. Someone was ready to ride.
I took it up the block a few times, bucked and farted a bit. Shifted fine.
Monday, ill clean the wiring harness connectors. Some are pretty nasty.
But the bike seems very willing. Lights work, speedo doesn't.
Step at a time.

 

[Cereal KLR]

Yes!