New member but old bike

[TNWillie]

Greetings and thanks for having me. As my name implies, I'm located in the state of Tennessee and my name is Willie. Some of you may have seen me on other bike related forums. I've attached a pic of my GT750 which I've owned since the late 70's when I bought it as a basket case. Over the years, I've done quite a bit to it both cosmetically and mechanically. Presently, I am in the process of reassembling the top end. I removed the block after 2 of the pistons rusted in place from, and I hate to admit this, being parked too long. While the top end was off, I had the cylinder bores Nicasil plated. I also swapped heads for one that had been welded and new squish bands machined. I made the most of the downtime by greasing the tapered steering head bearings, replacing the fork springs with aftermarket ones and installing emulators. To say that I'm looking forward to getting her running again would be putting it mildly.
Well, that's my story and I'm sticking to it.
Oh, and I guess I should add that I encountered a problem when I tried to replace the bypass hose with a silicone one I had bought from a firm in Australia. It doesn't fit. Now, I'm at a standstill while I try to find out where I can get one that does fit properly.

[teazer]

Welcome Willie from TN. Someone here was looking for a bypass hose recently but I don't remember who or what they ended up using. Maybe someone can jump in.

For sure the nice shiny new hoses are really thick wall and that makes them really hard to fit on any motor and impossible on an early 72 with bolt on intakes.

[TNWillie]

Thanks Teazer. I couldn't agree more about the difficulty in getting the thicker hose threaded through the starter cover. You can imagine my dismay (to put it nicely) when I discovered that I couldn't connect the hose to the underside of the head. I am HOPING that I have come up with a solution though in the form of a 45 degree fitting vs a straight one. I ordered one this evening and will report back with my results.

[Ratbob]

Hi Willie,
I have the same issue, the original bypass hose on my 72 recently crumbled (not bad for 50 years service I guess) and being in Australia I too bought the silicone kit, yep it's too fat for the starter gromet, sent it back.

I'll be watching with interest, good luck, Cheers

[TNWillie]

Hey Ratbob, I just finished connecting the bypass hose with the angled fitting and bolting the head on about 30 minutes ago. It didn't go as smoothly as I'd hoped because I had to tap the hole a little further than it was to allow the fitting to end up pointing where I wanted. All in all, I believe the end result should work well. If you look closely, you'll notice I slipped a piece of clear tubing between the inner edge of the cover and the bypass hose for a little peace of mind. As for the hose, I used 1/2" heater hose from the local auto parts store.

[teazer]

Willie
That's a great solution for the early 72 GT750 bypass hose. And it would also work on later spigot type barrels too.

[TNWillie]

Thank you. Compliments are always welcome. Since that picture was taken, I sliced some fairly thick and stiff clear PVC pipe lengthwise and slid it in between the bypass hose and the edge of the intake manifold spigot like I did with the inner edge of the starter cover.
Now, it's on to improving upon the header pipe to expansion chamber union. I'm leaning towards a sewing a black vinyl sleeve to slide over the union which will be held in place with safety wire. Should look good and be very functional with regard to sealing that union. Pics to follow if there's any interest.

[Alan H]

There's always interest!!

[Ratbob]

Hey Ratbob, I just finished connecting the bypass hose with the angled fitting and bolting the head on about 30 minutes ago. It didn't go as smoothly as I'd hoped because I had to tap the hole a little further than it was to allow the fitting to end up pointing where I wanted. All in all, I believe the end result should work well. If you look closely, you'll notice I slipped a piece of clear tubing between the inner edge of the cover and the bypass hose for a little peace of mind. As for the hose, I used 1/2" heater hose from the local auto parts store.
Hose connected.jpgHose before connecting.jpg

Well done Willie, that's an inventive solution.
I cut out a section of a car heater hose that matched the S bend but it's too fat to fit through the gromet.
Yes I can ditch the gromet but I'm not giving up yet.
Cheers for now, John

[TNWillie]

I finally got around to making sleeves for the header to chamber interface. They came out better than I'd hoped. Fwiw, I used marine grade vinyl on the outside and sewed a layer of thermal barrier on the inside. Between the vinyl and thermal barrier I installed a strip of silicone rubber where the safety wire was going to be holding it tight to the header pipe to offer, I hope, some additional protection against the heat. However, the fit is so tight I am going to try it w/o safety wire 1st.