GT750 won't idle on left cylinder.

[busa1300]

I can give up my idea of turning this into an end table, .....
....and let it be used for what is was designed for.

[Striker1423]

Well, if worst comes to worst, I could get the exhaust to seal using the goop shit in the hole method I did last time. Teazer, if you do have a set, I'd be willing to pay you for it and the shipping to get it over to Bill Bune. But, you might have to call them and let then know. I don't believe they've started on any of my work yet. So, that's going for us for now lol.

Busa, I appreciate the look, the problem is the cylinders are slightly different from the early to later models.

[Striker1423]

Crank and top end are back from BBE. I think a few good weekends and the bike will be together. So, times that by the sporadic working hours I get for this project... spring's cutting it close!

[m in sc]

 

[IR8D8R]

 For exhaust port repair consider an epoxy like Coltronics Durabond 7025, or maybe Devcon F. You'll need to get the pitting very clean for it to adhere properly. The Durabond 7025 is supposed to be good for 1000 degrees F. You'd use like body filler then grind or sand smooth. Might want to grind out the pits to good metal if you can.

Devcon F doesn't have the same temp resistance but it will fill pits and sand out invisible in aluminum. Temp resistance is only 250F. I've fixed oil pan and valve cover casting flaws and "PO pry damage" to gasketed surfaces with it. It is not affected by oil. When it fully cures it is much harder than pure aluminum. 

Devcon F is expensive but a 1lb can lasts for many years.

IR8D8R

[teazer]

Devcon F is ideal for repairing crankcases on TZ or RD motors when a rod punches a hole in the bottom end to let all the big end rollers out. 

And no sign of it going soft or leaking years later. It's a great product but not for exhaust ports. I went through my stock but didn't find a stock L or MAB set of barrels.

I would try JB Weld 37901  High Temp which is also rated to 1000F and is cheap. They claim it is good for exhaust manifold repairs.

[m in sc]

or find someone that's wiling to weld it up. 

[Striker1423]

Might take you up on that Mark. At this point, I'm just breaking shit left and right. With another screw extraction in the mix, I can't actually make progress. I'm just happy the Yamaha isn't like this. Shitzuki isn't a term I used to throw around, but with this bike it's growing on me.

[Striker1423]

Finally to a point where general lower-end assembly can begin. I keep repeating...Triples are sweet. Triples are sweet...

[sav0r]

Hang in there. It will be worth it.

The GT750 is a convoluted mess of a motor, but they sure are sweet when they work.

[Striker1423]

Ok, many moons and updates later... The GT750 is in process of reassembly! Second set of crankcases (three total now) showed up off Ebay. Cleaned and in good shape. Crank and second top end are back and aside from cleaning the top end good, the lower crankcases are basically ready to go together.

The transmission, crank, and new water-pump is in, all the little bits are in as well. Just need to glue the cases together, then focus on the top end.

[Striker1423]

She runs! But she also leaks coolant all over. Fixed all the external leaks (drain plug and upper head stud), but unfortunately she's also leaking from the new cometic gasket. I just lined it up and bolted it down, I did not coat the gasket in any kind of sealant, so I think the plan will be to drain down the coolant below the head a bit, remove the gasket, clean and dry it, then permatex copper spray it before reinstalling. The gasket is $100, so it would suck to eat the cost and have to go with the Athena spare.

[m in sc]

was the head checked for straightness? im sure it was but...

[Striker1423]

Would you believe me if I said no? 

First thing I'm checking now though. It didn't leak before the rebuild so I figured I'd get lucky.

[2steve]

...Triples are sweet. Triples are sweet...

Yes. Yes, they are!