Engine Build Advice for 78 GS1000 Roadracer

[first timer]

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

 

[Guest]

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

 

[Guest]

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.

 

[cbxchris]

I would rather have a head done right on a serdi taking full advantage of your stock valves with some good blending at the seat area. For your application a full port job is a waste. Personally I would get the straight cut gear and a falicon billet hub. If you want heat to not be a issue larger sleeves will help that with the kit you intend to use. Under cutting the tranny is a good idea as others have recommended. I would probably spring for case and cylinder studs/nuts. In your application I am not sure I would spend a great deal of money in cams and titanium retainers with buckets. Your engine with the head work,kit and carbs would pull like a tractor out of the corners. Cams and lighter valve train naturally would increase high rpm HP but trust me for every thing you add up top on the head you lose a certain amount of dependability. I had a GS1000 in 78 and made it a 1055 with turbo.....I found every weakness that engine had to offer.

 

[rcp]

What has 81-100-81 carb spacing?

What has 81-100-81 carb spacing?

Sudco is so far unable to tell me what application uses 81-100-81 spacing on VM33s - they're going to check with the tech in the back and call me back.

The impediments to changing the spacing are the throttle shaft (which can be drilled and tapped if need be), the racking rails (which are easily drilled), and 2 or 3 o-ringed-pipe or tube connections between each pair. The pipes are the real sticking point, as they'd require machining (or a very lucky hardware or auto parts store find) to duplicate.

Anyone got a set of VM33 (good or bad) or parts?
I'm going to check the CVs on my GS1000G streetbike to see if any bits will fit.

- Richard

 

[rcp]

I got a note from another vintage racer from my club that carb spacing for HONDA CB750F, 900F, 1100F is 80-100-80. That must be what these are for.

 

[rcp]

I've got a swap arranged to get a set of GS-spacing VM33s (which should be clean and intact) for the Honda VM33s, and I've got backup set coming from ebay. So I should be covered for carbs. I'll take my time cleaning up the other set, and then pass them on if I don't need them.

I discovered a couple of broken bits in the clutch last night. A broken fibre plate,and a broken spring:

Haven't found the rest of the pieces of the plate yet, but imagine they're in the sump.

- Richard

 

[rcp]

Shopping List

Shopping List

Still have to find, or more likely, will order new from APE, Web/Megacycle:
- reinforced clutch, or reinforced clutch plate kit
- hardened clutch hub nut
- manual cam chain tensioner
- push-pull throttle
- heavy duty cylinder studs
- 54mm pod air filters
- 14mm T.D.C. tool and degree wheel
- not-too-lumpy cams (maybe just an intake cam).

Anyone got any of these parts lying around?

- Richard

 

[first timer]

I would save a few bucks and keep the oem studs. I am running oem, just bought some new ones. They were good enough for Pops. The HD studs are bigger in dia and I don't like the idea of reducing oil flow to the head.

 

[cbxchris]

I would save a few bucks and keep the oem studs. I am running oem, just bought some new ones. They were good enough for Pops. The HD studs are bigger in dia and I don't like the idea of reducing oil flow to the head.

Easily eliminated by drilling the cylinders and using GSXR o-rings to seal the head. Cylinder and head gasket must be properly bored to use the o-rings. Did it for years on a pro mod and never leaked a drop. I also used studs bigger than APE.(Elmer Trett made them especially for nitro/turbo applications.) No oil gear either.

 

[rcp]

What's the word on engine coatings for best engine heat transfer? Is Kalguard (aka KG, aka Gun-Kote) still the best stuff?

Would you mate that with ceramic treatment of headers or more Kalguard?

I can't figure out if the ceramic coating of headers insulates, and thus more heat stays in the exhaust gas and goes out the tailpipe, or if it's something else?

Better to get the hot gasses out the tailpipe, or from the headers into the breeze? (Into the breeze, I suppose, present your cylinder head with hotter air).

 

[first timer]

i am going to kal gaurd https://www.kgcoatings.com/index.php?_a=viewProd&productId=20 the engine and headers.

it was good enough for Pops, gives about a 15% cooling according the a old bike magazine artical.

 

[rapidray]

Richard, ceramic coatings on the header help keep the heat in the PIPE which keeps other parts around it cooler & helps get the heat out of the motor. As for coatings INSIDE the motor, the only thing I would do is have the piston skirts dry film lubricant coated. Ray.