Bike wont start

[Dolby67]

My bike wont start. here is what happened.

1. Bike was dirt - oily - took it to the power wash to clean it up
2. Rode the bike home - no issues
3. The tach cable hole in the block was covered with a piece of metal and some JB weld. I have an OE tach cable, so I removed the cover and replace the OE cable
4. Went to check that it was working correctly, and I could not get it to kick over
5. I have gas ( carb rebuilt- but rechecked anyway )
6. I have good spark ( new plugs but rechecked anyway )
7. I have yet yo check compression, but it seems okay.
8. Place starter fluid in the cyclinder, replaced the spark plug and still nothing
9. Shot starter fluid into Carb and when i cranked it , it spit OUT the starter fluid rather then suck it in

I will have more information once i get a compression check. --- but does anyone have any idea ?

[WTF304]

Did you check to see if she had spark ? .... pull the plug, put the wire on the plug and crank it ...

[scottly]

My guess is that the power wash forced water into your fuel tank and/or float bowl. After sitting, while you were installing the tach cable, the water settled to the bottom. Drain the float bowl into a container and look for water. If you see any, turn the petcock to reserve, which draws fuel from the bottom of the tank, and look for any more water coming out of the bowl drain tube. If you have the stock vacuum operated petcock, you will need to disconnect the small hose connecting the petcock to the side of the carb, and apply suction to the port on the petcock to allow fuel to flow to the carb, otherwise you will have to crank the motor over with the starter forever before the float bowl refills.

[Dolby67]

I checked the carb...clean it ---- and put it back on
I also check the spark plug....i am getting a spark.

[WTF304]

Good strong spark ? ... should be nice and blue. Only other thing is timing. .. or valve lash you said she was blowing out the back of the carb .... also when's the last time you checked the balance shaft tension on that chain ... all that rotating mass that's not in sync makes it hard to start to

[scottly]

Did you prime the float bowl after you had the carb apart? Like I said before, it takes forever to spin the motor with the starter to provide vacuum long enough for the bowl to re-fill, as it only sucks 1/4 of the time.
If all you did was power wash the bike and install the tach cable, the compression, timing (which is not adjustable), valve lash and balance shaft wouldn't be affected.

[WTF304]

Yes it isn't adjustable. ... but slack in it could cause it to skip which could explain the blow back through the carb. And i don't know if you have ever started one of these bikes and there was a massive amount of slack in the balance shaft chain ... but they don't run well and with the crankshaft trying to turn and then tug on the balancers it's like if your dog went to chase something and then you yank on his chain and stop him in it's tracks lol best way i could describe it. Which i guess could also explain blow back through the carb if it had enough force to turn the engine backwards on intake stroke ... it's not compressing the air\fuel charge with the intake valves open and once it compresses and the weights rolling to a sudden stop and roll backwards. ... it's possible no ? ...

[scottly]

The ignition is triggered off the crankshaft, so no slack. The blow-back through the carb was related to the extremely volatile ether starting fluid and the wasted spark ignition.  

[Dolby67]

The blow back happens even if the starter fluid isn't sprayed it - it blows air out the carb .
Waiting on compression check.

Could I have a bent valve ?

[triguyracer]

You can pull the spark plug out then remove the valve covers and spin the motor over and look if you can actully see if a valve is sticking while the motor turns over, bent valve maybe ?, but by your  symptoms that you describe it sounds unlikely if the bike was running and all you did was stop it and wash it

[triguyracer]

To much valve clearance if it is quit large can also indicate a bent valve when you have the motor at top dead center on the compression stroke,showing that a valve has not seated all the way,compression check is the easy way if you have comp gauge   

[WTF304]

Compression check is going to show wether it has good or bad compression, determining if it's a bent valve ... not exactly. Low compression could be worn rings, a hole in the piston, a bent valve or could possibly be a gasket leak at the head or base and/or incorrect valve clearance. ... I'd do like he says though. Put it on TDC but check valve clearance first before doing a compression check so you know if test results show good then it shouldn't be a valve issue. And it's a 4 valve head so if one is bent it was way too tight but should be bent in pairs .... only other thing would be to pull the carb and exhaust off and do a visual inspection so you can see and get a better idea before going and fixing something that might not be the problem or broken.

[triguyracer]

If you are having blowback thru the carb it is either cause the the valve is bent and not closeing  or just have a bad valve or you have the valve clearance to tight not letting the valve close completely,make sure they are a tdc on the compression stroke when you check and not on tdc on the exuast stroke

[pault]

This is where a leak down test is called for.  It will tell you where the leak is, not just that you have one.

Paul