More Ponys Please

[madjack57754]

A cheap (free) hp increase is cam timing . Advance the exhaust cam 2 degrees by slotting the sprocket will show a nice increase in bottom end torque that you can feel in the seat of pants meter. There should be a description somewhere in the site on how to do this.

[first timer]

Would you consider 29 or 33 to be the better size carb for an 8 valve unmodified motor primarily ridden on the street? Sounds like the 33s might choke a stock motor, but are they better choice once the engine has been modified with an overbore kit, pods, aftermarket ignition etc etc.?

i am running 29mm's on my currenty stock 79 1000, this motor has the smaller ports then the 80's one so i am not sure how the 29's will work on a 80's head or if they will fit. i can't compare before and after cause the bike came with the 29's when i got it. if you are looking to get 29's that will be atleast 400 bucks, you should just call sudco and see what kind of carbs they can set up for you, should be around the same cost as a used set of 29's.

here is some info i got from 80's gs1000 racer

"
The clutch is probably the weakest link in the motor, cam chain (tensioner) is next.
The rivets and backing plate wear and become loose, no doubt you have noticed the rattle at idle. They all do it to some degree. Last time I checked, falicon would still kit these with a new backing plate, larger rivets and heavier springs. I actually had the backing plate fail and one of the springs fall out of the bike I'm parting out. The oil pump (gears) subsequently failed, completely destroying the bottom end and scorching the cam journals of a beautifully ported (by Yoshmura in 1980) cylinder head. Amazing the thing didn't seize and spit me off. This topic is covered in the article I am including, not in much detail, but will serve to reinforce what I am telling you. Any pumped motor needs the clutch done. Failure is catastrophic.
When you do the top end, be sure to clean up not just the ports but the combustion chambers. They are sharp edged from the factory and that promotes detonation. Make sure they are blended into a nice hemi shape. You can do it yourself. This will lower the compression slightly and that is a good thing for pump gas. I also went to great lengths to clean out all the crap and casting flash between the cylinder bores to promote airflow. Use a rattail file or a dremel. It makes a huge difference in the summertime.
The 29 smoothbores are the only decent thing to run for the street for the 78/79 bikes with the small port head. 33 smoothbores are crappy with the big port 80/81 heads, the CV's work better properly set up. Maybe someone has figured out a later model flatslide setup, I dunno. Oh, and the cam degreeing as described in the article I'm including will also yield excellent results. All that and the pipe is probably good for >25 hp gain. "

"How many miles on your bike?
Has it been abused? I put ~80k miles on a 1980 ET model, slightly ported with stock pistons and degreed cams (and pipe). A too long bolt in the clutch cover (top front, be careful) was the only thing that undid it. I had done the topend and the porting at 40k miles. The 1980 big port head with the CV's is a better runner for the street. My race bike was a '79 with a yosh cylinder head, 1085 kit, keihin 31 smoothbores (originally for a honda CR750 and run on the early yosh bikes) and stage 3 cams. It was a monster. Welded crank a must for that setup.
I have another guy very interested in the crank. No decision forthcoming at present.
Falicon still does the clutches. The weakest link and the most destructive upon failure.
Oil pump gears and cooler also critical and I have these as well."

from robinjo

"Using the later head with the 29's is not logical, the ports are matched to 34 mm carbs (yes I know the butterfly decreases the actual flow rate), it would match pretty good with VM33's or RS34's but it's pretty big, the original Yoshi bike only used 31 mm carbs. "

so there is some carb info to chewy on, but like i said it may just be easier to go new from sudco

-ryan