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Unburnt Fuel?


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Having removed my exhaust for other reasons I've noticed the pipe on cyl# 2 on the exhaust is quite clean as is the cylinder head port (see attached pic). This to me would indicate unburnt fuel escaping through the exhaust and washing the tract. It's a Pi engine which runs absolutely fine once up to temperature.

Any informed ideas?

Richard.

Exhaust 1.jpg

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Richard,

It may well be it is running very lean.

I suggest to check spark plug(s) and injector first.

Waldi

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Ello Richard, that could be a few things

1, that cyl is running lean,   culprit  could be worn spindal on TB, and an injector no injecting enough

2, may also be a HG  going,   loosing water,!!

3, too bigg a valve gap,

4, an air leak int TB gsket

 

 

wots yer CR like, down on one,!!

 

M

Edited by GT6M
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See attached pic, plugs 1 - 6 viewed from left to right. I'm no expert, but I reckon they look alright, 1 & 6 maybe a little darker.

Engine fully rebuilt 2000 miles ago, throttle bodies also reconditioned, injectors changed 500 miles ago, valve clearances as per Newman Cams spec. A compression test I carried out as a matter of curiosity after the 1000 mile run-in, all cylinder were quite equal, somewhere around 180psi as I recall.

It'll be some weeks before the engine will run again.

Thoughts and opinions on the plugs please......

Plugs.jpg

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6 minutes ago, Mike C said:

It's so clean it looks like water. Are you losing  any coolant?

No, doesn't seem to be losing any coolant, no tell tale signs in the expansion bottle and no excessive pressure in the cooling system. I might whip the cyl head off at the weekend and have closer look.

Richard.

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7 hours ago, Mike C said:

Or at least do a compression check to see if there's anything odd about No 2.

Yeah, might just do that. However, the starter motor (WOSP) was failing maybe one in 20 attempts, so I dropped that off for a health check yesterday. I've never been happy with the oil pressure (new pump) since rebuild, it's around 20psi at hot idle, I have a replacement from Chris Witor to fit. There's quite a loud ticking noise at idle which could be a blown exhaust, something wrong with the valve train or just my ears playing tricks on me. I have quite a bit to do over the next few weekends so might just as well remove the head.

Richard.

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