GS1000 cylinder head improvements

[Anonymous]

Having got the bike to run as factory intended after a ten? year lay up, I began to improve its performance in every way, open cheque book. I am certain that the power of a motor is generated in the head. I have fitted new valves/springs - standard - & recut the seats. Slight cleaning of the ports, to take out the machining marks.
What are the best power gains for a street bike that anyone has gained? Especially in the cylinder head.
I am aiming for full range power, with torque from low revs. I keep running out of road for real high speed stuff, am concerned enough to retain my licence, so am looking for mods that will help with low/mid-range power.
Where should I post the bike's development history, lest anyone is interested. Last dyno reading was 93 HP at the back wheel, three years and much money ago. I am aiming for 100+ HP, naturally aspirated through CV carbs & stock airbox (K & N already in there).

[Anonymous]

When it's eventually posted - waiting for info on where and how now - check out the Yoshimura artile. The specs on this bike lay claim to 133 hp in 1979 with a top speed of over 169 mph. This all with a 10.33/132 quarter.

[Anonymous]

IN THE OLDEN DAYS, I USED TO COLLECT PHOTOS FOR THE GANG AND PUT THEM ON A PAGE AND THEN POST THE URL. THAT IS NO LONGER NECESSARY BECAUSAE JB HAS STARTED A WEBSITE WHERE WE ALL CAN EASILYPOST PHOTOS OF WHATEVER WE WANT. http://groups.msn.com/SuzukiGSGarage...pgmarket=en-us

NO THE CAPS DON'T MEAN I AM YELLING--IM JUST REVAMPING A WEB PAGE OF MINE AND I ALWAYS TRY TO USE CAPS SO US OLDER GOATS CAN SEE THE WORDS

[saaz]

If you are really after low and mid range power, the first things to do are as you have done with the head, plus a big bore wiseco kit or similar. This adds torque through the range, but mostly down low

The next step is porting the head (street rather thanrace) with some stree cams. I did this to mine in the early 80s (78 GS1000) which I still have running now as my only bike. Power down low is better than standard, but it just builds from 3000rpm, then really goes above 6500rpm. The head work was good for around 15% of the power increase (the bloke who did it was very good with race bike experience).

It sounds like what would do you is the big bore kit. Someone I knew did that alone, making the bike very nice to ride on the street. Mine just keeps on going!!

[Anonymous]

cylinder head improvements

Thanks for the info so far, confession time; mods so far include:
1. Dyna S & coils, Taylor leads. (Original coil breaking down on 2&3 under pressure when warm, so got junked & whole new system installed as described).
2. Full careful carb clean & rejet.
3. K & N replacement air filter, retaining air box.
4. 1085 bore kit.
5. Predator 4 into 1 stainless system. (Superb!)
6. Crank (100K old) & rods (new) balanced with new mains fitted. Rotor lightened & balanced. Chris Applebee, Essex. Excellent work, probably not worthwhile for regular street bike.
7. All non-stress steel bolts swaped for alloy.
8. All non essential weight junked. Smaller indicators fitted.
9. 18" stainless spoked alloy front wheel built. Same weight as OE.
10. Stainless guard.
11. Harrison brakes & EBC (drilled) discs.
12. Bandit master cylinder for front brake.
13. 7" after market chrome headlight.

[Clone]

When I had my beetle everyone was "porting and polishing" the heads to get more performance. This involved grinding out the excess metal from the passages and to get a more direct flow and then polishing the passages so they were perfectly smooth. Do people do this on motorcycle heads? What is the power gain percentage wise?

That is some list of modifications. What was your weight difference after all of it?

[saaz]

You can gain power from porting, but you can also stuff the head up unless you know what you are doing! Just opening the ports out does nothing if you loose flow velocity. Sometime a mirror polish is not as good as slightly rougher. Best to leave heads to an expert, preferrably with a flow bench and experince with that model. Cleaning up casting marks etc should be ok, but not a high horsepower mod.