Recommendations, boring, ballancing

[Nessism]

Thanks Nessism I'll do that.

Is it just the 8 valve 1000 1100 that have a 20mm pin? maybe that's what I've been finding.

Only the 1150 has the 20mm pin.

 

[Guest]

Thanks again.

Its not nice enough yet to get my bike out of storage. But it will be soon.

Until then I'll be using a spare case, cylinder, and head for measurement.

Here they are.

The case is 83mm wide and the smallest point per cylinder. I may have to adjust for the new sleeves. No problem there so far.

A few dimensions of the original configuration.

102.36mm sleeve length

67.05mm Inner bore Diameter (mid sleeve)

75.55mm OD (mid sleeve)

83.75mm top ring OD

8.30mm from top of sleeve to outer ring

4.12mm Sidewall (mid sleeve)

98.25mm from stud hole diagonally

7.10mm between top of sleeve recess and edge for timing chain

6.6mm between top of sleeve recess and locating pin

How close can I go to the stud holes?
What size sleeve would be best?


One more thing, On the head, the combustion chamber looks small but suited to its original pistons.

The new piston might be quite larger than the combustion chamber. Not sure where I'm going here, just an observation.

Thanks for reading

 

[gearhead13]

Where are you going to get a head gasket for the wiseco pistons? My 750 required a new (bigger) head gasket. Wiseco 750 overbore pistons are flattop.
Do yourself a favour a just buy a 750 or bigger.

 

[Guest]

Where are you going to get a head gasket for the wiseco pistons?

http://www.cometic.com/custom.aspx Right there.

Wiseco 750 overbore pistons are flattop.

So are mine, this is a GSX400 that I'm working on. Unless your talking about something I don't know about yet. In that case I'm listening.

Do yourself a favour a just buy a 750 or bigger

Now now, I would actually. But I enjoy this. And I have an 80 850g in the works. That's when the real fun will begin.



For now this is a real off the wall thing to do with a little 400. It has some sentimental value to me and It was my first bike. ( I actually did my license on it.)

Most of all its what led me to find the GSR

 

[gearhead13]

http://www.cometic.com/custom.aspx Right there.


So are mine, this is a GSX400 that I'm working on. Unless your talking about something I don't know about yet. In that case I'm listening.

You said something about combustion chamber shape and whether the bigger pistons would fit. If they are flattop there is no problem, except that the cr will be higher than 10.5-1 because of the bigger volume being compressed. Valve pockets should be checked as well.
Just an FYI, but the 750 4 valve sizes are 20mm ex and 23mm intake. I dont know if they are different than the 400. You would only be able to go 1mm over AFAIK.

 

[Guest]

If they are flattop there is no problem

Great, you had me worried for a second

measuring that right now


Ex 20 ( 19.94)
In 23 ( 23.12)

Valves are not something I've looked into yet but I plan to when I get the bottom end finished.
With the head I might go 1mm over on the valves but GregT warned me about going bigger.

If you put bigger valves in the (GSX)400 head be careful, they're known to crack between the exhaust seat inserts and the plug hole.

In my piston search I've found that my deck height is 26mm and the JE/Wiseco will be 27.5mm. which will increase compression even more.

What would happen in a 750 big bore kit though ?

If my 400 is just the middle of a 750 and the big bore kits are designed for the 750, and only require a larger head gasket and boring or resleeving,

Wouldn't it be fair to think that the piston's would have the proper recesses for the valves ?

This is the assumption I'm going on. I don't know yet, still looking.

 

[Graham]

The valves for a GS750E 80-82 and GS750T 82-83 are the same as the 81 GS400L.
As for sleeves the stock 77mm GR650 sleeves would be cheaper and are a closer fit to the GS400 than the 80mm GS1100 sleeves.
Both sleeves should need to be cut shorter. A 3mm overbore (80mm bore) on the GR650 will not leave your cylinder walls too thin.
If you have a deck height issue try a Cometic .043 copper base gasket sand witched between stock base gaskets and/or two Cometic .043 copper head gaskets stacked (copper head gaskets are reusable).

 

[Guest]

Thanks again Graham.

I was thinking boring to 79 and using wiseco gs1100 pistons.
That would make it 554.9cc's, which is enough I think.

What does an 1100 piston look like compared to a 750?
As in; do the valve recesses line up?


I found two possible sleeves

http://cgi.ebay.ca/SUZUKI-GR650-TEM...rcycles_Parts_Accessories&hash=item2c5a1313a4 I believe I can get the sleeves out.

http://cgi.ebay.ca/SUZUKI-GS1100-11...rcycles_Parts_Accessories&hash=item35a921e546


This is my source for pistons so far.
http://gszone.biz/pistons.html

 

[Guest]

Can someone please give me the lateral distance between valve stems on a gsx1100 head.

I'd like to compare that to my 400's spacing.

thanks,

 

[Graham]

Can someone please give me the lateral distance between valve stems on a gsx1100 head.

I'd like to compare that to my 400's spacing.

thanks,

Don?t worry about the valve spacing. It?s the same.

 

[Guest]

Thanks again Graham.

 

[Guest]

Making progress.

Bought Gr650 cylinders on eBay.

Should arrive in a week or so.

Buying pistons from JE. Turns out they only had two left on the shelf and I'm getting them at a discount

They are 78mm, but they have the compression ratio that I want. 10.5:1. the 79mm is 13.5:1 !

Supreme gas around here is 92.

Funny thing is the 80mm is 11:1 but I have to have them manufactured and buy a set of 4.

Contacting cometic for a head gasket.


Would a GR 650 head gasket work?
Edit: (in searching I've found that they are slightly different but still viable with modification)

Thanks

 

[Nessism]

Considering the combustion chamber of your head was designed for a 67mm bore, what do you expect the compression to be with those 10.5 to 1, 80mm pistons?

 

[Guest]

I have no idea,

I'm going to attempt to figure out the math right now.

here's what I know

Stock
67mm bore
56.6mm stroke
Cp ratio 10:1
that makes the combustion chamber 20cc's


New
@ 80mm bore
56.6mm stroke
cp ratio (claimed cp would be 11:1)

Calculated cp is... 14.25:1 without taking into account anything designed into the piston or gaskets.
I'm still learning the calculations but it will be lower.


I don't really have a solid answer.

 

[Graham]

Compression ratio can easily be lowered if you have any pre-ignition issues. For every mm you raise your deck you increase your combustion chamber by 5cc with a 80mm bore. I?d shoot for an 11:1 to 12:1 compression ratio for a bike that still runs city streets. Here?s a little calculator.
http://www.msgulfcoastvwclub.org/TechPages/Tech10.html

 

[Guest]

thanks again,

According to that it would be 10.5:1 @ 80mm just the way it is.
And 10.0:1 @ 78mm

With a deck height of 2mm and a stock 20cc combustion chamber.

 

[Guest]

Update.

Update.

Just a few updates for the project.

Got a GR650 cylinder block and took the sleeves out. Here's some pics

10 minutes at 425

Old sleeve fits into new sleeve

NEW vs OLD

Still waiting for pistons to arrive, Should be a few more days.

Its funny how little cooling surface the 650 has compared to the 400:-k

 

[scottychop]

Its funny how little cooling surface the 650 has compared to the 400:-k

Is that why you're not using the GR barrel? I thought these guys were a direct swap.

 

[Guest]

Is that why you're not using the GR barrel? I thought these guys were a direct swap.

Nope I'm afraid there are differences.

1 you'll need longer studs because the gr is 17.32mm taller.
2 the oil runoff on the base goes in the wrong direction for the GS4xx and 500 base.
3 the crank only has a 56.6mm stroke. Gr requires a 70mm.
4 the base needs machining to so the GR sleeves will fit. They are too big.
5 longer cam chain.


Cam chain oil runoff.

17.32mm height difference.

Also the locating pins are smaller on the GR.

And the timing chain tensioner is different. larger on the GR

All the bolt spacings are identical. I think I'll be ok with a GR head gasket, base gasket definitely.



As far as I've found, Any GS4xx base will accept any 400,425,450,500 cylinder block and can use any head EXCEPT the GR cylinder and head.
I recommend that if you are going to use a 500 cylinder that it should be coupled to a 500 head.

 

[Guest]

Any questions, while i have all the parts right here in front of me ?

I can take measurements of what you see in the pictures.

Stock cylinder barrel height: 81.64mm
Stock cylinder bore OD 74.82mm
Stock cylinder sleeve height 102.35mm

GR barrel height: 99.02mm
GR barrel bore OD 84.03mm
GR sleeve height 127.77m