Recommendations, boring, ballancing

[Mekanix]

Thanks again Graham.

[Mekanix]

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?

[Mekanix]

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

[Mekanix]

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.

[Mekanix]

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

[scottychop]

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

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

[Mekanix]

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.

[Mekanix]

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

[Graham]

Looks like all you need now is some machine work. Machine the GR sleeves bottom for a height of 102.35. And bore the GS block (barrel) to 83.99 or 83.98 to fit the GR sleeves. GR sleeves and GS block equals same deck height.

[Mekanix]

Yup, I did some pricing around today and wow its getting expensive.

One shop wanted $80 an hour for 4 hours + They were really hesitant as well.

Another independent shop said its in my best interest to have it done by a shop that does allot of this type of work and wouldn't take it on for less than $500

And the place that will most likely do the work will be this gentleman:

http://www.ural.ca/

Haven't been quoted a price (wasn't in the shop today) but He claims " in a Russian accent" that he will beat anyone's price

I'll find out Monday.



I made a calculator in excel and at 78mm bore, every 1 mm of gasket increase is 4.8cc's. This got me thinking. I have some 2024 T3 aluminum in various thicknesses, I'll make some base spacers out of that stuff If the Compression ratio needs to be adjusted

Check this out GR on the left Stock 400 on the right ( cell phone pic, sorry)

[Mekanix]

Dropped parts off yesterday, Waiting for news.

Pistons should be in tomorrow.

Starting to make gasket shims out of aluminum. 1mm and 0.5mm.

I'll post updates and pics as things develop.

[Mekanix]

Customs... Feel the burn

All I have to say is WoW

Pistons were shipped through UPS by JE pistons and then I find out there is a brokerage fee of 107.28.


Where did this come from ??



I called UPS to find out if they were going to ship it to my door or to the local post office and then the Rep mensioned

"Just so your not surprised, There is a $107.28 brokerage fee"

I wouldn't have any possible way to know unless I would have called !!!

"Surprised" Ya, A bit!


It breaks down to

Cost of pistons $307.20

Cost to clear shipping 62.00 plus the cost of taxes in NS 15 % of 307.20

which is $107.28.

I called JE and they have never herd of this "customs" thing. Maybe they can help me out a bit, maybe not.


Its not the first time I've ordered from the states but it is the first time with a big courier like UPS (JE's only choice i guess) USPS and Canada post has never cost me duty in the past.


Oh well

Chalk it up to experience I guess...


End of rant

pistons are here, that's at least enough to make me smile

[gearhead13]

All I have to say is WoW

Pistons were shipped through UPS by JE pistons and then I find out there is a brokerage fee of 107.28.


Where did this come from ??



I called UPS to find out if they were going to ship it to my door or to the local post office and then the Rep mensioned

"Just so your not surprised, There is a $107.28 brokerage fee"

I wouldn't have any possible way to know unless I would have called !!!

"Surprised" Ya, A bit!


It breaks down to

Cost of pistons $307.20

Cost to clear shipping 62.00 plus the cost of taxes in NS 15 % of 307.20

which is $107.28.

I called JE and they have never herd of this "customs" thing. Maybe they can help me out a bit, maybe not.


Its not the first time I've ordered from the states but it is the first time with a big courier like UPS (JE's only choice i guess) USPS and Canada post has never cost me duty in the past.


Oh well

Chalk it up to experience I guess...


End of rant

pistons are here, that's at least enough to make me smile

I NEVER have anything shipped UPS or FEDEX from the us, unless I feel like getting screwed. I have paid $2-300 in brokerage fees at times. My $500 piston kit ended up costing me $800
If they dont ship USPS, I dont buy