Keith Sutton's 1972 GT750

Zook-e · Post by **Zook-e** » Sun Mar 29, 2009 7:43 pm

I am slowly rebuilding Keith's bike for him. He already put on Jemco exhaust and 34mm Mikuni Slide Carbs. Currently all has been moved over to a lightly braced 72 frame and braced swingarm. New tapered steering bearings and bronze bushing are insttalled.

Painting on assorted brackets, trees and such are being done before assembly.

The motor is being ported with a base spacer addeed and intakes milled at a 15% angle to aid in the intake and carbs clearing the cases.

Engine cases have been blasted and painted as well as the topend.

These are some of the pics I have so far until I can get the rest out of my camera. Hope you like.

The bike will be at Deal's Gap this year.

tz375 · Post by **tz375** » Wed Apr 08, 2009 10:24 am

Is it time for an updated progress reports yet?

BTW, what thickness spacer do you recommend with your porting?

rngdng · Post by **rngdng** » Wed Apr 08, 2009 10:27 am

What's not to like? It's looking great.

Lane

Zook-e · Post by **Zook-e** » Wed Apr 08, 2009 11:34 am

I should have some progress pics this week. Motor is in. The spacer with both gaskets is 2mm total. What I wanted to raise the transfers. Then raised the exhaust and lowered the intake and cut the pistons. Didn't want to get too close to the transfers.

As for the head and head gasket, they aligned very, very well so I didn't have to pin or dowel the head.

tz375 · Post by **tz375** » Wed Apr 08, 2009 12:35 pm

Sounds good.

Are you using Tom Turners TSR by any chance? I use Bimotion to set targets and then model the port shapes in the Graphical version of Bimota to make sure I'm getting the port time area that I think I'm getting.

A couple of years ago i paid a porting "expert" to analyze a GT750 barrel and run the numbers through TSR to get 100 and 150HP at the crank. His numbers said not to use too much transfer timing and that's what i read in AG Bell and Jennings and Robinson. He did think he could get away with huge tall exhausts and with very low intake floors too, which seemed to fly in the face of conventional wisdom.

MOTA's simulation program is a great piece of software but boy does it need a truck load of data to drive all those calculations. I ran a couple of other people's GT750 port figures through MOTA recently and that was eye opening. Then I jacked up the barrels and moved all or some of the ports and that was even more interesting.

Of course it all assumes I measured things correctly in the first place,and there is no proof that the numbers on the screen will work in the flesh. And in reality, all I'm doing is trying the same things that people with porting tools do and the end result is likely to look just like a barrel from someone who knows what works.

Zook-e · Post by **Zook-e** » Mon Apr 13, 2009 10:57 am

Time for some updates:

Bottom end assembled showing the spacer installed.

Cylinder head cleaned, painted and ported.

Assembled Motor

Underneath of motor in frame.

Engine with 34mm Mikunis in frame.

Mostly complete bike with Candy Lavendar paint. Keith is going with a different paint scheme but I put this on for Deals as the body work he had is nasty. This body work I will sell after he gets his done. It is fresh paint but not perfect.

TLRam1 · Post by **TLRam1** » Mon Apr 13, 2009 12:04 pm

Looking good!

Zook-e · Post by **Zook-e** » Mon Apr 13, 2009 1:09 pm

Got this body work for sale if anyone is interested. Keith is going back to his black for Deals. He already has a T500 in this color.

Have to admit that this did look good for the pic.

Buffalo-guy · Post by **Buffalo-guy** » Mon Apr 13, 2009 5:19 pm

Question.
Do you have the jetting info on those 34mm carbs? Mains, pilots needles,
needle jets, etc. I have a set of those, but the jetting is definitely
questionable. The bike has Tomcat pipes and a very mild street porting
job done by Tomcat when they built the pipes. It presently has re-jetted
32mm carbs that work great for the first 2/3 throttle but has nothing up
top. I don't want to ventilate a piston with this setup, so any assistance
would be appreciated. Thanks and cheers.
Fred

Buffalo-guy · Post by **Buffalo-guy** » Mon Apr 13, 2009 5:32 pm

Zook-e wrote:Got this body work for sale if anyone is interested. Keith is going back to his black for Deals. He already has a T500 in this color.

Have to admit that this did look good for the pic.

Zook.
Nice, nice job on detailing that bike, especially the engine. I look forward to
assembled pics, if you post them. Now that I've buttered you up a bit,
What is a fair number for that body work. I crashed my trusty Gold J bike,
and most of the painted stuff suffered terribly. Ask Uncle Rick, he's seen
it. I could be convinced to ride a pink bike, or should I say MANjenta. This
is a great forum, and I would love to make it to Deals Gap just once to meet
some of these guys in person. Cheers.
Fred

Suzukidave · Post by **Suzukidave** » Mon Apr 13, 2009 7:43 pm

Hummm , maybe i should slide my barrel spacer in the reed motor after all

very nice work Zook

Zook-e · Post by **Zook-e** » Mon Apr 13, 2009 7:50 pm

Thanks for the compliment guys. Tedious work, but the finished product does look nice.

As all of you that do this know. It always looks better to the other person as the one building it sees it everyday so the overall effect is not the same.

Zook-e · Post by **Zook-e** » Mon Apr 13, 2009 7:52 pm

Fred,

I'll get back to you on the jetting after a trial this weekend. Before porting it was a little on the rich side with the jetting that came stock in the carbs. So i hope that it will be close now.

I'll get you the info this weekend.

Eric