Valve clearances problem

[The Artist]

2 thing people.

1. Does anyone know the valve clearances for a suzuki gs 125 1983 kickstart only model.

EDIT: Found these on the internet, do they sound about right?
0.08mm and 0.13mm

2. How do I do the clearances when I take the rocker covers off and the rocker arms are at such and angle, I can't get a feeler guage in the gap flat, I would have to bend them.

Yes the engine is in the correct position but I don't see how to do it.

Thanks to all who help

[stinkwheel]

[The Artist]

So there is no knack to it, I just have to get bent ones

[stinkwheel]

You can bend normal ones too, but if you keep bending and straightening them, they will snap.

They sell angled ones in Halfords and most other auto parts suppliers.

I've had some engines where they were so tight to get in, I had to snap a piece off the end of the feeler guages and use that.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Kickstart]

[Damon]

[Kickstart]

Hi

Good question, but that is what is listed, and for other bikes using virtually the same engine. And the same for newer manuals for newer versions of that engine.

Maybe the exhaust valve is well cooled. Maybe the inlet valve is longer. Both would affect the comparative clearances.

Although suspect more likely they are not that worried either way.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[The Artist]

I know the principles of valves and have done valve timing diagrams and set them on big diesels but these are a PITA.

My feel guages won't bend without snapping, I even tried the thinnest ones in a combo but still won't work.

I believe exhaust clearance is bigger because it opens before the end of the power stroke, all the way up the exhaust stroke and can overlap with the inlet valve opening aswell.

[Kickstart]

Hi

Quite normal for there to be some overlap between exhaust and inlet valve.

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[stinkwheel]

As a gebneral rule with those small, simple aircooled japanese singles. As long as there is a gap of some sort, even a very tiny one, you are usually ok. It's when there is no gap at all you run into problems.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Damon]

[Kickstart]

Hi

Exhaust clearance shouldn't really be affected by needing to get more gas out (most bike seem to have more intake volume than exhaust, ie the 5 valve Yamahas had 3 inlet and 2 exhaust valves).

Think that the normal reason the exhaust valve clearance is greater is that the hot exhaust gases heat up the exhaust valve more, and as it is heated the valve gets longer. The wider clearance allows it to still close when it is longer.

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[TUG]

[Damon]

[Kickstart]

Hi

Think the amount of flow of the inlets vs the exhausts is a design issue which isn't fully settled. Some take the view that who cares about the exhaust, it will find its own way out. From memory rule of thumb is something like 2/3 the flow on the exhaust as the inlet (but that is from memory, and a rough figure anyway).

Might be that your mentor misunderstood the question (ie, mixed themselves up with more flow and more heat). A wider clearance would mean the valves are open for less time and so reduce flow (ie, the cam would have to turn a few more degrees to take up the slack before opening the valve).

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Damon]

[.....]

I've had success with Motion Pro feeler gauges in the past when faced with very resticted access. They're really quite small and will fit into the smallest areas with ease.

I picked the ones I needed up from eBay for not much money.