Ghetto Bobber

[Tonkaman]

Last week I picked up a 1978 Yamaha xS750 that @Herzog generously donated.

All I know about the bike is that aproximately 5 years ago it was a running bike. It got sidelined to become a cafe racer project and has sat outside since that time. The build progress didn’t get further than cutting off the back of the frame, and removing most of the body panels.

Here’s how it looked once it got home

 

[Hickey]

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[Tonkaman]

Yamaha XS750 Frame Conversion Kits

Z1 Enterprises is the leading destination for Yamaha XS750 Frame Conversion Kits. With a large inventory of vintage motorcycle parts and same day shipping in the continental US, we can assure that all your Yamaha XS750 motorcycle needs will be met here.

www.z1enterprises.com

Awesome, thanks!

I’ve done lots of different dirt bike projects over the years, but modifying a road bike is all new to me.

 

[N-Smooth]

Looks like a fun project. My bro had a ‘8x Yamaha Seca which looked pretty similar to that and I had a ‘83 Virago 750. I miss the days of the old ghetto bikes.

 

[Tonkaman]

I pulled the carbs and tore them down for cleaning. They are in terrible condition! I’ve seen worse as far as old fuel and ethanol, but never seen so much internal damage to the parts.

2 of the 3 air screws have the tips broken off inside the carb. I ended up having to drill out the carbs to get them out. Unfortunately I can’t get those screws from Yamaha anymore so I’ll have to find an aftermarket solution


1 of the diaphragms looks like it got hot enough to melt somehow. Considering it’s $200 to replace I think I’ll try to reuse it.

One of the towers that holds the float pin is broken off. The float was also bent out of shape, but easily bent back. I’m hoping I can use it even the the float won’t have a stopper when open.

I’ve never seen a needle that has gouges and dents all over it either.

 

[Tonkaman]

I have no idea how a float pin gets bent, but here’s proof that it can happen.

The plastic tees for fuel between carbs are all cracked. These are on a long back order, so I’m hoping they will hold long enough to verify the engine will run.

The intake boots arr made out of radiator hose pieces that are all rotting away.

The air filters are Chinese Cheepies that have a lip on the inside blocking air from the ports on the intake side of the carb. I can’t imagine the bike ever ran with them installed.

The fuel tank had 1/4 tank of a fuel/water mixture inside. It’s heavily corroded on the inside, like growing stalagmites kinda corroded…

 

[Tonkaman]

Good news! She runs!

I changed the oil, turned the engine over by hand. Since everything rotated smoothly I decided to try rotating the engine with the starter. I hooked up a new battery, drilled out the ignition lock cylinder, and made a start button out of a screwdriver lol 😆.

It turned over very smooth, so I did a compression check. Each cylinder had good numbers! I put new spark plugs in, squirted some starting fluid into the intake and SHE RUNS!


I rebuilt the carbs with all the old parts since OEM parts are all backordered. I’ll reinstall them with the rotted radiator boots, and rig up a temporary fuel source. If I can get it to stay running, I’ll go ahead and invest more time and money to this ghetto bike 😎

 

[bryson]

Depending on diameter I may have some fuel filler hose that could replace your intake boots...

 

[Tonkaman]

Depending on diameter I may have some fuel filler hose that could replace your intake boots...

That would be cool! The carbs are 1&5/8”, what size is your hose?

 

[Gravy]

I've had good luck with the eBay knockoff carbs. Those carbs you have right now might need more work than it's worth.

Here's a bobber I built in 2018
It's a 749 Yamaha Virago

 

[jeeper]

Maybe I will join you 🤔

86 Intruder V-twin 700
https://classifieds.ksl.com/listing/67811152

 

[Tonkaman]

Maybe I will join you 🤔

86 Intruder V-twin 700
https://classifieds.ksl.com/listing/67811152

Definitely 👍

 

[bryson]

That would be cool! The carbs are 1&5/8”, what size is your hose?

Sorry, I didn't see this until this AM. I'll check when I get home today. I'll text you the answer to your very personal question.

 

[Gravy]

Updates?

 

[jeeper]

Updates?

I had totally forgotten about this one!

 

[Tonkaman]

This hasn’t changed one bit. In fact, the carb parts are still spread out across my bench. Hopefully I’ll make progress before spring rolls around

 

[Gravy]

Do I need to come over and help kick you into gear? 😅

 

[Tonkaman]

Do I need to come over and help kick you into gear? 😅

No thanks. I’m not in any hurry.

I haven’t bought any parts and I really hate being out in the shop during winter