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Can't start the engine Evo 96

Hi Glider,

I am back in the UK. Today I had a chance to look into the engine.

What i found is that;

1. The cam looks okay, dot to a dot if you know what i mean.
2. I removed the carburator and it looks like too much air is coming out when crancing - but this is just the imresion.
3. When i removed the gas inlet and had a look into the hole when i was cracking the engine i could see the flash - coming from the spark. The ignition is set up properly, to fire at TDE, So, to me it looks like the inlet valve (actually both of them, on the front and rear cylinder) is not closing properly when it is in TDE. It seems tha it is still open when it should be closed.
Please advice how to regulate the valve.

Let me know if you have any other suggestions.

Thnaks

Adam
 
Not knowing the type of valve mechanism you have there, it could be a push rod adjustment that is needed if you have adjustable push rods. If you find that out, you will then need to know what make they are as they have a different thread pitch per inch for different makers. Also if you adjust them do not rotate the engine after the adjustment to the next adjustment until some time goes by and the lifter bleeds down or you will bend the valve. Usually 30 minutes will be enough to be safe. I only hope that is not why the valves are open now. They may have been adjusted to quickly and bent them already.

You can do a compression test to see if they are closing or not. If you have compression in the right range, they are closing but if you can see the spark, then it becomes obvious that they are not. (not a good sign)

This will give you some input to adjusting the push rods. Look near the bottom and you will see what I refer to about the brand of push rods.

http://www.heavydutycycles.com/adjpushrods.htm
 
Hi Glider,

I took out the push rods and measured the compression with the valves closed, I got some 60 PSI which is less than a half of what it should be.....I sent the bike to the guy I bought the engine from, he is supposed to fix it for free - if it is engine that is wrong...... Hopefully everything will be okay.

Thanks a lot for your help, i will let you know what's the outcome.

Take care

Adam
 
Sounds as if the valves were adjusted then the engine turned to the next valve position adjustment too soon before the lifters could bleed down and bent the valves.

Let us know.
 
Hi Glider,

Just out of curiosity, if the valves are bent; is it just enough to put new valves (all 4? ) or there must be some job done on the head? or Push rods etc?

I am just asking as I am a bit suspicius that the guy will try to charge me for some "other job", trying to prove that I did something wrong either with wires, or what ever else.....
I should know more in a couple of days..will let you know

Thanks

Adam
 
From the way you described it that you could see the spark through the valve seat, it sounds like the valve heads are bent from contacting the piston. When they are replaced they have to be lapped into the valve seat so they seal properly and checked for any further damage that may have occurred. I would check the push rods also to make sure none are bent when the valves contacted the piston. If this guy is local, I would tell him that you want to see the pistons when he opens the motor up.

Wires etc would have no bearing on the results from what you described. The problem seems to be mechanical and was no doubt done when the engine was assembled. You didn't say if you had adjustable push rods or not but being you removed them, I assume they were. If they are there, this is where the damage probably happened when they were adjusted improperly without the bleed down time.

He may end up only changing the intake valves being the larger of the valves as they are the ones that would contact the pistons first.
 
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HI Glider,

Good news, the engine s now working !!!!!!!!!!!!

I was told that it was the push rods that caused the problem. They were the stock ones and for some reason they were too long . They have been replaced with the adjustable ones and the engine is now working. I could finally hear that music after year and a half of bulding this machine.......... you could imagine my smile :)
The only thing is that I do not get the 150 PSI - only some 135, but maybe the engine was too cold when I measured it. BUt even with 135 PSI it seems to be quite powerfull, I had a short ride and it seemed a rocket to me....
The bike is not finished yet, and I also need to do the SVA but now I feel really relieved.

Thanks a lot for your great help

Adam
 
Quite possible the heads were milled a bit causing the PR's to be too long.

In any event, glad it's up and running for you. Enjoy the bike!
 
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