Finding 1978 gs750 performance

[yamahafella03]

Hey i got a 1978 GS750 and i'm trying to a site that supplies 4 to 1 headers and any other possible performance parts you can get for this bike. Thanks for all the help.

[makenzie71]

eBay usually has them.

[SqDancerLynn1]

Cheap hop up is to install a 850 top end

[beergood]

When I read the title of your thread I thought you were asking about performance numbers.

I was going to offer that mine can go from 0 to Broken in 4 seconds. And it will do the quarter mile in just under two weeks.

Z1 is a good place for parts like jets, filters, ignition parts and chain conversion info. You can find info and pretty much unanimous praise for them in the vendor thread.

I got my 4-1 in trade from a forum member here. Keep an eye on the parts and bikes for sale section.

As mentioned above, you can often find some good stuff on ebay. Also, there is a lot of overlap in these older UJMs, not just in the Suzuki family, but across manufacturer lines. GS750 and GS850 share at least 90% of their parts. A lot of 1000 parts work, and I rebuilt my carbs with doner parts from an old Kawasaki (don't remember what model).

As long as you aren't afraid of some research and doing your own work/testing there is a lot you can do with a 78 750.

[yamahafella03]

yeah i looked at the Z1 site and on Ebay but neither had Headers for my year of 750. Whts the difference in a 630 chain and a 530 chain? weight? and on my bike i have the stock carbs but i got K&N individual air cleaner pods so i gotta get new jets and i was wondering if 17.5pilot and mid 120 mains would work for that?

[jabberjoe87]

did you call z1 about the headers, cause i have a 77 gs750 and i got my exhaust there

[yamahafella03]

it said they had V&H full exhaust but they no longer carry it

[wazz]

Cheap hop up is to install a 850 top end

Sorry to pitch my own auction, but I have a complete 79 850 top end on ebay right now.

This is the only year 850 to use the same VM26 carbs as the 2 valve 750.

Item # 180327377315

-greg

[Ludeykrus]

^ Do you have to bore the block, or is it a straight swapout?

[wazz]

I can only speak for the 79 850 top end, it is a direct swap for 2 valve 750 engines and uses the same carbs, later 850s used CV carbs and I'm not certain of the fitment.


-greg

[fast pom]

Try Buzz at Dynoman.com that were i got my 750 stuff

[beergood]

yeah i looked at the Z1 site and on Ebay but neither had Headers for my year of 750. Whts the difference in a 630 chain and a 530 chain? weight? and on my bike i have the stock carbs but i got K&N individual air cleaner pods so i gotta get new jets and i was wondering if 17.5pilot and mid 120 mains would work for that?

Weight is the main advantage of the chain swap. I haven't done it yet, but will soon. A friend who has the same bike swapped his last year and he says he notices a difference. You can also change your gearing to match your riding style (city versus highway).

I don't remember the exact size I ended up with for my mains, but it was in the mid 120s. 17.5 is my pilot size. The needle isn't set at the top position, but close. Expect some trial and error here, but these settings work very well for me.

Best advice I can give: Invest in a Dyna ignition. Completely worth it.

[tkent02]

^ Do you have to bore the block, or is it a straight swapout?

Use an 850 cylinder and 850 pistons. There are no differences in heads between the '79 850 head and the '76 - '79 750 heads, they are identical, share a common part number.

[yamahafella03]

beergood "I don't remember the exact size I ended up with for my mains, but it was in the mid 120s. 17.5 is my pilot size. The needle isn't set at the top position, but close. Expect some trial and error here, but these settings work very well for me"

Wat type of riding do you do? I'm a guy that does alot of both town and highway, but i like to be able to let it loose and take off fast wenever i want. Do those Jets and settings you have allow for that?

Where can i buy a dyna ignition and why is it good?

[beergood]

I live in the city, and the bulk of my riding is stop and go city stuff. My bikes previous owner went up a little on the rear sprocket. It gives you a little extra oomph off the line, but you sacrifice a little bit of top end speed. I think it is a fair trade off. The speedos on these bikes aren't renowned for their accuracy, but I think my rig now tops out at about 100mph, which is plenty terrifying on a 30 year old bike that is prone to the occasional breakdown. I don't think I need to be going 110mph.

As for the carb setup, I don't know how comfortable you are with rebuilding them, but you will probably have to do it a few times before you get it exactly were you want it. One nice thing about pod filters is they make it much easier to remove the carb rack than with the stock airbox in place. As for performance, that is something that has been beaten well past death in this forum. My own experience has been a noticeable gain in performance. It will definitely stretch its legs when you grab the throttle.

One recommendation on the carbs: There is a guy listed in the vendor section that sells complete o-ring replacement kits for around 15 bucks. Buy one. I can almost garauntee that you are going to have a couple dry or damaged rings (you might think about replacing the o-rings on the boots as well, and extra $5). I've never had to bother with buying the expensive carb rebuild kits.

A Dyna ignition is a solid state eclectronic replacement for the stock points system. It is nice, because it is a 'set it and forget it' system, and is way more reliable. Around $120 from Z1.