Bypass?

Post your Kettle problems here and cures
Tipper2
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Re: Bypass?

Post by Tipper2 »

Thanks Roger, much appreciated but I know where I am with carbs, just wasn't sure about the cooling system.

One of the floats is rotted and holed so will sort that out tomorrow.
teazer
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Re: Bypass?

Post by teazer »

Tipper2 wrote:Sorted it.

The mild steel fitting at the bottom of the bypass hose where it enters the crankcases was blocked. There's only about a 3mm hole which was blocked solid. Got the engine back together but now got carb problems. Yippee....
3mm? The hole in the lower steel fitting is 9mm and so is the hole in the upper crankcase half. The crankcase lower I just measured is closer to 10mm but not exactly round where the two passages meet.
Tipper2
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Re: Bypass?

Post by Tipper2 »

That's the size of the hole at the end of the fitting but it has a reducer in the middle.
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mark.read3
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Re: Bypass?

Post by mark.read3 »

Tipper2 wrote:That's the size of the hole at the end of the fitting but it has a reducer in the middle.
?????
teazer
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Re: Bypass?

Post by teazer »

Not sure what that's about. I just checked two of the stand pipes and they are wide open inside. No restriction.

Sounds like a 6mm washer fell in there and got lodged in place. I would remove the stand pipe and push that restriction out, unless someone else chimes in and has evidence that at some point those were restricted.
Tipper2
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Re: Bypass?

Post by Tipper2 »

This hasn't been touched since new and there's a restriction manufactured into the bottom hose fitting. I'm a hydraulic technician so quite familiar with pipe connections and it was machined in there, presumably by Mr. Suzuki- it's working OK so not going to worry about it.
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oldjapanesebikes
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Re: Bypass?

Post by oldjapanesebikes »

Tipper2 wrote:The mild steel fitting at the bottom of the bypass hose where it enters the crankcases was blocked. There's only about a 3mm hole which was blocked solid. Got the engine back together .
3mm ? That doesn't sound right at all, and as far as I'm aware the part number for that union (17631-31000) didn't change during the entire production run. It is either a factory defect, or some else has had it apart previously and messed with it. 8-)
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teazer
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Re: Bypass?

Post by teazer »

I agree Ian, I have only built a handful of GT750s and so far I have not seen one with a machined in restriction. Given the sizes of the other parts of the bypass, a restriction doesn't make a lot of sense but I'm not a hydraulics engineer and it's way too long ago that I had to study that stuff.
Tipper2
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Joined: Sun Aug 07, 2016 8:08 pm

Re: Bypass?

Post by Tipper2 »

Zombie thread!

Apologies for the extremely delayed reply but I've only just started working on the kettle again after not having time for the last couple of years.

I've attached a couple of pictures of the lower bypass connector, out of curiosity as much as anything.

The bike's stripped down to the frame and it's a case of sorting out what's to be painted/ plated/ rebuilt or scrapped. I've got a home plating kit which I've had good results with so planning on re-doing a lot of the original parts.

I have to say I'm pretty stunned at the increase in the price of used parts compared with when I last looked two years ago, wish I had a shed full of them...
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RichardsMorphy
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Re: Bypass?

Post by RichardsMorphy »

Drew. '75 GT750M
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