Head off

General discussion about Street two-stroke Suzuki motorcycles.

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Coyote
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Head off

Post by Coyote »

Well I expected to see scoring ans smeared on ring material. To my surprise, it looks just like the day I put it together. Everything is smooth and slick. Maybe I should have left well enough alone. I mean this thing really sounded like it was self destructing.The mechanical noise was nearly unbearable. You could easily hear it over the exhausts. So I took a few pictures of what I found. Hard to get any good angles with the motor in the frame. Note the total lack of chamfers on the ports. There will be some text with the third (last) picture. I do have to pull the exhausts to get the jugs off.

Image

Image

I didn't really notice this till I was reviewing the pics. Look at the dark band at the top of the left and right cylinders. I wonder what that is? Also there was evidence of a leaking head gasket on the left. I'm going to look the head over very well to see why it started to leak. Remember that was the fried cylinder to start with.

Image
I was born with nothing and still have most of it left.

.
1978 GS1000C
1976 GT550 ongoing money pit.
Vintageman
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Re: Head off

Post by Vintageman »

What can be seen looks nice!

What is that brown stuff right above where the top ring stops at tdc?

Too nice to be the noise (rings catching ports). But maybe.

Did you every verify clearance?
Current registered, inspected, and running well 2 stroke motorcycles
74 GT250 (T350 upgrade),
76 GT250 (T350 upgrade),
71 T350,
70 T350,
74 GT380,
75 T500,
73 GT550,
75 GT750,
72 Yamaha DS7 (R5 upgrade),
77 Yamaha RD400 (Daytona Cyls),
73 Kawasaki H1 500
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Coyote
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Re: Head off

Post by Coyote »

Never did check the clearance. I will do so when the jugs are off. If you're thinking piston slap, that is not the noise. Piston slap has a very distinct sound and that's not it. The book says the chamfers are to prevent rapid ring wear AND reduce noise.. I think that's all it is. My last 550 had the same noise, but not nearly as loud. If I ever find the video I posted on you tube you can hear it.
I was born with nothing and still have most of it left.

.
1978 GS1000C
1976 GT550 ongoing money pit.
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Coyote
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Re: Head off

Post by Coyote »

Ah yes. here it is. you can hear the noise when I get around the left side.
http://www.youtube.com/watch?v=yYt4tVdkyiM" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
I was born with nothing and still have most of it left.

.
1978 GS1000C
1976 GT550 ongoing money pit.
yeadon_m
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Re: Head off

Post by yeadon_m »

Coyote,
My 550B (before it self destructed) made a similar metallic-y noise on the left side to yours.
By contrast, the right side was swishy quiet, just like all the cyls on my 380B.
Any theories?
Mine is that ports were poorly chamfered and also that clearance was inadequate, but I'm really far from sure.
Cheers,
Mike
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Re: Head off

Post by Vintageman »

I could not hear anything wrong.

So some of us of are loosing hearing and can't see well
Current registered, inspected, and running well 2 stroke motorcycles
74 GT250 (T350 upgrade),
76 GT250 (T350 upgrade),
71 T350,
70 T350,
74 GT380,
75 T500,
73 GT550,
75 GT750,
72 Yamaha DS7 (R5 upgrade),
77 Yamaha RD400 (Daytona Cyls),
73 Kawasaki H1 500
parksie
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Re: Head off

Post by parksie »

Vintageman DITTO
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Re: Head off

Post by rngdng »

A leaking head gasket can make a serious noise.


Lane
If you stroke it more than twice; you're playing with it.

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Vintageman
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Re: Head off

Post by Vintageman »

Coyote,

Actually you are doing the perfect thing. You should run the engine for a time and then tear it down and check the piston for high spots and smooth. Since you have to pull jugs to add port chamfers you might as well check and adjust the pistons for "fitting in” to liners. That alone can quiet things down al ot. Since you have almost no scratch marks about the ports (at least the ones that were shown) I think you caught that in time and maybe not causing noise you here.

Just visually (so a guess only) you clearance does not look loose at least for not much gap looking a top of pistons when they are the skinniest. Once you get the jugs off you can see all the cylinders better and the piston marks can tell a lot.

In the video it sounded OK to me. I hope you did not misread for I was accusing myself of being both getting deaf and blind.

Looks nice! Check it, give things the needed tweaks and enjoy it
Current registered, inspected, and running well 2 stroke motorcycles
74 GT250 (T350 upgrade),
76 GT250 (T350 upgrade),
71 T350,
70 T350,
74 GT380,
75 T500,
73 GT550,
75 GT750,
72 Yamaha DS7 (R5 upgrade),
77 Yamaha RD400 (Daytona Cyls),
73 Kawasaki H1 500
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Coyote
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Re: Head off

Post by Coyote »

I give up. I'm about ready to put it back together and forget it. Ruined my exhaust set up so I could get at the front cylinder base nuts. NO WAY!. Four of the six are impossible with the motor in the frame. I can get a wrench on them, but either the frame or the exhaust port prevents me from turning them. No movement at all. Frustrated beyond belief. $#*+!@**!:-!
I was born with nothing and still have most of it left.

.
1978 GS1000C
1976 GT550 ongoing money pit.
Vintageman
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Posts: 1485
Joined: Tue May 18, 2010 5:38 pm
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Suzuki 2-Strokes: Suz, Yam, Honda, Kaw.
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Re: Head off

Post by Vintageman »

I think I understand and have taken cyls off a gt550 a few times (some with engine in frame) and about to do it again in frame.

Yes, first walk away from it. I think if you sacrifice a longer/shorter wrench, grind the heck out of it to make it skinny to fit better in tight places, it helps

I am sure you'll figure it out If you rest well you may even pull the engine back out with speed. I don't think you need to though.
Current registered, inspected, and running well 2 stroke motorcycles
74 GT250 (T350 upgrade),
76 GT250 (T350 upgrade),
71 T350,
70 T350,
74 GT380,
75 T500,
73 GT550,
75 GT750,
72 Yamaha DS7 (R5 upgrade),
77 Yamaha RD400 (Daytona Cyls),
73 Kawasaki H1 500
yeadon_m
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Re: Head off

Post by yeadon_m »

You can definitely get the cylinders off and on with motor in frame. It does require lots of patience as you discovered, no room to swing a wrench more than a few degrees. I use a 14mm ring ratchet spanner whose head pivots also. Its just doable. The front centre few are complete b*****s to do.
It also helps to have a pair of fine, long-nose pliers or even forceps to drop the washers over the stud first, and then a short training in gynaecology to get the nuts started :-)
Mike
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Re: Head off

Post by Craig380 »

The other method is to use two different makes of 14mm spanner. They will usually have different offsets so you can get a few degrees turn with one, then swap spanners, get a few more degrees, swap again and so on.

It's a huge PITA but it is do-able. I got a 14mm 'obstruction spanner' off eBay for this specific job, which was a big help. I think you guys know them as a 'starter wrench'. It cost pennies because it's cheaply-made, but it's ideal for this one job.

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1976 GT380 - wounded by me, and sold on
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Re: Head off

Post by Coyote »

That wrench looks like the ticket. I wonder where to get one? Both ends 14mm with different dog leg angle?
I was born with nothing and still have most of it left.

.
1978 GS1000C
1976 GT550 ongoing money pit.
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Cliff
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Re: Head off

Post by Cliff »

Those nuts in the front will come off, but they are a bitch! I use a couple of wrenches, from different brands, and there is just enough difference in the way they are made that it works!
Here's a link to a quick video of my bike put away after riding two up on the highway for the weekend!
https://www.youtube.com/watch?v=NtzS2M9Clco" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
Cliff!
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