Carby and Valve issues

[kungfuzing]

 
I have had my bike into the local Honda Franchisee, and had nothing but trouble with them.
I went to have the valves replaced on the front left cylinder after I miss-timed the valves when replacing a waterpump gasket.
After spending $1500 for that job, they returned the bike not running. The left cyclinder bank had 50psi compression. I suggested that the valves were not timmed correctly.
Took it back, to get bad fuel as an excuse, so I flushed the tank and the carbs and new fuel put in.
Again the bike would not run.  Took it back to the Honda Franchisee.
They had the bike for 3 days they claimed they did 10 hours work on it, made all sorts of claims that the issue was NOT their fault.
They made a claim that I had over filled the oil, and that was causing the lack of compression. According to their paperwork they drained 3.5 litres out of the bike to get it to the propper level. (Not bad since I filled from empty and only had a 4l bottle of oil.)
They played with the timing again (which they deny was wrong in any way.) but the bike runs now.

The issue is that it idles at 3500RPM and the throttle wheel on the carby wont touch the stop. not even with the adjuster screw all the way in.
It also seems that the carb for the front left cylinder does not seem to be drawing air at all.
Whay could they have done to cause this?

Also the compression on the front left cylinder is still at 50psi.

After spending $2500 with the Honda Franchisee, and having Consumer Affairs onto them, I have nothing I can do about what they charged me, and have the bike back worse than when it went in.
With the list of faults the Head Mechanic could not solve on my bike, these are the two that I could not solve and rectify in under an hour.

[Brock]

The valve seats could be damaged, you would need to remove the left head to check that. Check your oil level in the sigt glass to make sure the level is correct.

They may have screwed the vaccum adjust out/in to get more fuel into front left carby, it will be difficult to do a carb ballance until the compression is fixed. You may even have a cracked piston if it hit the valves..

[Greencan]

Oh Dear!  ...where to begin.

For a start and not knowing how you managed to drain fuel from both the carburetors and the tank, I'd begin by looking at both the throttle cables and the throttle manifold to establish there isnt any physical obstruction or routing that is preventing the return to idle. A clue here is to note (if you remember), the markings on the twist grip at idle, or mark with a small piece of electrical tape where the grip is at idle stop. If you cannot find fault here, then look to see that the throttle manifold is correctly assembled and rigged (if its been apart), and consider possible incorrect seating of cable ends or damage of the mechanism within the twist grip of either the open or return cables.

That's a start.

As for your low compression on the damage effected cylinders, consider the likelihood that when the piston has made contact enough to bend valves, these forces are also great enough to bruise piston crowns sufficiently to narrow the top piston compression ring groove and grab the ring. The two compression piston rings in these engines are only about 1mm thick, so the piston grooves that accommodates the pair of them has only a few thou clearance and the top ring groove isnt all that far below the crown. Therefore, it doesn't take much force to damage a piston.
 
Next, after sorting out the throttle, I would undertake a wet-compression test on both cylinders on the left bank. Use no more than 15-20ml of new engine oil for this per cylinder. I suggest testing both as it will give you a reference of the uneffected cylinder if you think it wasnt struck by a valve. Bearing in mind however, that as both pistons are on the same plain, its hard to imagine it too wasn't struck 360* latter.

Just a thought and good luck...

The can :-)

PS: I must have been channeling the originator of this thread when I repeatedly wrote throatle, instead of throttle;-)

[kungfuzing]

Thanks guys,
I will have a go with the carbies this weekend, when I have time.
I may be sending it into a mechanic to do the compression issue by the sounds.
Hopefully I can get it to run, and keep the bike.

[StinkyPete]

I have a decent compression tester if that is of any use to you, and am at Blackwood.   

[Greencan]

Just one thing that Brock alluded to...in reference to low compression...

The valve seats could be damaged, you would need to remove the left head to check that.

...that is worth consideration (you may have already be aware), assure yourself that the first repairer when replacing valves, did so in pairs. That is if an exhaust valve was noticeably bent, then best practice would be to replace both valves. Same would apply to the inlet valves and have them both re-seated.

I have expanded a little more of the possibility of having a compression ring grab...

http://ozstoc.com/index.php?topic=11507.0

...as the OEM service repair manual (I think in section eight), makes mention of this as a consequence if a belt were to fail, that results in loss of crank-to-cam synchronisation and subsequent damage(s).

If comes to the worst, send me an email as I have 2 short engines and 2 cylinder heads (could build one complete engine from the 2), one from Californian 1100, the other from a UK 1100 and both bikes had relatively low mileage before they were dismantled. (bit of a plug ;-)

I am down sizing, so I will probably be listing these and some other components shortly.

Again, good luck with it ...

Cheers, the can :-)