Engine Build Advice for 78 GS1000 Roadracer

[trippivot]

the helical gear is A-OK up to 150 horsepower. and 11,500 rpm .MAXIMUM.

you are not going to need the full blown crank job. just a welded low mileage unit is fine.

back cut 2 and 3 gear is well worth the time.

shim under is good for hi cam lift and hi rpm. suzuki BUCKETS NEEDED
kawasaki retainers and springs do interchange. KEEPERS are suzuki too.
not necessary until .425 lift . other work is also needed to do this.

get a 73.5mm piston kit

mill your head .090 or so. run 110 fuel. re work the piston valve pockets due to the milling changes exact location of valve at full lift.

get a manual camchain adjuster- (learn to set it right)

get the suspension set up right. proper race sag/ ride height ( 3% better suspension effy. is the same as 10% more engine power.)

Gear ratio is very important!! Red line maximum at the end of the longest straight or the finish line in a specific gear.

lighten the hell out of the bike. remove any non essential anything.

[rcp]

it's only money .... here's your glass the koolaid tastes great.....
[...]
You should be able to use your stock boots just ground out to fit the 33's. Your tuner should be porting and grinding the boots to match the head when doing his work.

I'm not sipping the koolaid - no,no,nope. :-)

The stock boots don't look to me like they'd work - they're only ~45mm O.D. and the carb spigot diameter is 40mm (42mm at leading lip). I think I've found the right ones (part # 002-053 at Sudco). I've got PM off to Renobruce to confirm, as he's got the same carbs and head for his Beat project. I'm going to call Sudco & APE to ask as well.

the helical gear is A-OK up to 150 horsepower. and 11,500 rpm .MAXIMUM.

you are not going to need the full blown crank job. just a welded low mileage unit is fine.

Which is why you're going to sell me yours, right? :-) Right?

- Richard

[rcp]

back cut 2 and 3 gear is well worth the time.

shim under is good for hi cam lift and hi rpm. suzuki BUCKETS NEEDED
kawasaki retainers and springs do interchange. KEEPERS are suzuki too.
not necessary until .425 lift . other work is also needed to do this.

get a 73.5mm piston kit

mill your head .090 or so. run 110 fuel. re work the piston valve pockets due to the milling changes exact location of valve at full lift.

get a manual camchain adjuster- (learn to set it right)

get the suspension set up right. proper race sag/ ride height ( 3% better suspension effy. is the same as 10% more engine power.)

Gear ratio is very important!! Red line maximum at the end of the longest straight or the finish line in a specific gear.

lighten the hell out of the bike. remove any non essential anything.

I hear you both on the Kawi retainers. No luck there.

It's certainly light now!:


The previous owner removed a lot of weight, including all the charging system and starter. He's cut out most of the sprocket cover, and he got a low-clearance, lighter left-side engine cover welded up out of the original:


I've got a local vintage roadracer (builder of this bike, and previous owner two owners ago) asking his drag racing buddy if he's got any used H.D. valve springs. The roadracer has successfully used four of those paired with a stock (big HD, small stock on intake/big stock, small HD on exhaust) in the past with stock and mild cams.

- Richard

[first timer]

post up what you find out about the boots, I may end up going 33's if my 29's are to small.

[renobruce]

post up what you find out about the boots, I may end up going 33's if my 29's are to small.

Here's what looks to be a nice set on ebay right now. With pods!

http://cgi.ebay.com/ebaymotors/ws/eB...%3AIT&viewitem=

[first timer]

thanks, I give them a try hopefully not to many folks bidding against me.

[renobruce]

thanks, I give them a try hopefully not to many folks bidding against me.

Not sure why, but the 33's go for alot less money than the 29's. Maybe if you get these, you can sell you 29's for big bucks!! Then have more money for other goodies for your build.

[first timer]

Thats my plan, for the time being I would like to have both sets to see what works better and get the bike on a dyno to compare the diff as well. Should be a fun little experiment...only if i ever get it back together......

[rcp]

post up what you find out about the boots, I may end up going 33's if my 29's are to small.

Here's what I found out about the boots:
VM33s have a 40mm carb spigot diameter (O.D. of the part that fits into the boot), with a 42mm lip at the end of it. They fit into GS1000G stock boots, which are 40mm I.D., with a 38mm lip.

So, if you're looking for a set, I think you want Sudco Part # 002-053: 60mm bolt spacing, 40 mm carb spigot diameter, @$22.84 each. I found it more cost effective to buy a GS1000G head and get the bigger ports too.

- Richard

[fast pom]

I know its prob to late as you are in to your build but Craig Smith also has his rebuilt {pussy] engine up for sale pussy because its only 135bhp i think he wants 10.000 nzd about 5.000 us for it bargin. he can be contacted through the OSS site , but you may have to wait for a reply as he works offshore.

[GSexpress]

Just a little cost cutter here. I have taken the rubber off of a set of carb manifolds which leaves just the meatal plate with the O ring groove. I welded a short section of round tubing to the carb side and used fuel hose of the right diameter and 2 hose clamps to mount the carbs. You will need to have a support bracket for taking the wiegt of the carbs off of the hoses and you'll need to make the hoses long enough to keep the carbs from touching the mounting tubes(vibration isolation). The big benifit of doing this is you can dial in more touge on the low end by lengthening the tubes as room allows and dyno runs dictate.

[GSexpress]

Oh, I forgot.... You'll need to incert a smaller dia. piece of tubing to match th iner dia. of the carbs and fit snugly against the mounting tubes to maintain smooth airflow if you move the carbs back more than 10mm from the mounting ring welded to the plate. Make sure everything is fuel compatible and strong enough not to cave under heat and vacuum.

[BadBillyB]

thanks, I give them a try hopefully not to many folks bidding against me.

Dont forget, the Suz and Kaw 33's use dfferent slides and air correction jets. May be difficult to tune with the wrong (Kaw) slides....Maybe seller can ID them for you.......Billy

[rcp]

Bugger! My VM33s have the wrong cylinder spacing. They're 81-100-81mm instead of 77-93-77. Not sure how that is, as they're off a KZ1100, and I though those had the same port spacing as the GSes.

There's a fair amount that would need to be swapped to correct the spacing (throttle shaft, racking rails, 2-3 o-ringed pipe or tubing connections per joint), so I don't know if replacement parts are an option - I may need a replacement set.

- Richard

[renobruce]

Dont forget, the Suz and Kaw 33's use dfferent slides and air correction jets. May be difficult to tune with the wrong (Kaw) slides....Maybe seller can ID them for you.......Billy

True. The Kawis have a richer throttle valve and air jet. But with his ported head, he should be able to dial them in.