Engine Work and then something's off.....

URG!!!!!

The neighbors kid's CRF110 wouldn't run, so I took a look at it. Pulled the plug and it smelled horribly of gas.....time for new rings.

So I order up a new piston .25 over stock, new rings, new valves, guides, springs, etc.

Get it all pulled apart take the cylinder and piston and head over to the machine shop. Have them bore it out for the new piston, and then replace all the stuff in the head and adjust to factory spec.

Got it back yesterday and put it all back together today.....start it up and I've got a slight tinging noise.

Can't pin point where exactly it's coming from but damn it, I'm pissed.

 

Valves out of adjustment, easy check. When they're out on those engines (in my experience) they make that sort of noise.

 

Did you forget to put the 3rd and 4th strokes back in?

 

Tell them you added a Chevy cam for performance. Everyone knows they tick slightly.

 

I’d check to make sure the Carrillo rods got installed properly

 

everyone knows the old 3/4 race cam mod... or 19mm on japanese bikes! I did that on an old RZ500... ran like it came out of a skunk works factory in Bologna.

 

Saw something on those 110s about priming the timing chain with oil near the shifter. That’s all I know.

 

I wouldn't think so.....the head has all new valves, guides, valve springs installed by the machine shop. Before I left when picking them up, he adjusted the valves to factory spec per the service manual.



Doing some YouTube research, it is apparently easy to misunderstand the TDC notch on the flywheel and even though you're looking at the T and the Notch, you're not really TDC, so I'm going to pull the valve cover tomorrow morning and pray that's it.

 

I'm curious how you reasoned a gas-smellin' spark plug warranted the parts and labor you prescribed.

 

Fuckin’ ... Harsev builds!

 

Above all else, nice of you to step up and break the engine for the kid

~sent from mobile

 

Op,
After you get the bike running, Id highly suggest that you have one of the resident crayon map makers on this here beeb draw you a map to each member who offered some Bullshyt response in this thread and go all John Wick III on their azzes.

When you tryna fix shyt

 

Really... It's a honda 4 stroke play bike, change the plugs and filter and it would have ran for another 20 years more than likely

 

Well it was the 3rd fouled plug in a short time.

Bike wouldn't start or if it did start, it would die upon any throttle. And then wouldn't restart.

It was smoking from the tail pipe when it did run.....faintly, but there was blue smoke.

Alot of those are signs of failing rings in my opinion.

Didn't want to pull the cylinder to replace rings and then discover the cylinder was scorched and have to order more parts so chose to go up 1 size on piston just to be sure and planned to machine the cylinder from the start.

All the valve parts were like 40 bucks, so said fuck it....it's already going to be apart, no harm in replacing while I'm in there.

Maybe my diagnosis was wrong:

It had spark.

It had fuel.

It had both a cleaned and new plug with no change in running status.

Carb was adjusted.

Card was pulled and cleaned.

Where else should I have looked???

 

Trebuchet.

 

Never heard of that. Cams tick?

Lol

 

I'll take a crack...

Assuming, as you said, you had spark. Also, that the fluid in the gas tank is in fact pure/clean/fresh gas and not gas sitting on top of condensed water vapor that has accumulated since the last time the bike was running AND some rodents hadn't decided to build a nest in the airbox and/or the exhaust.

Gas in the oil from a malfunctioning float needle... (Don't feel bad, this one gets the best of up-and-coming techs. It's not the sticking valve, it's the contaminated oil).
The overflowing floatbowl drains as much down the throat of the intake as it might down an overflow hose but, instead of the fuel going to the ground, it goes past the intake valve, past the rings and into the crankcase. This effectively creates an overly rich condition as the crankcase pressures upon start-up blow the fuel vapors back past the rings into the combustion chamber. It also raises the level of oil in the case, creating oil burning symptoms. No amount of carb adjusting will fix the issue.
- Smack/tap the floatbowl with the handle of a screwdriver and change the oil. Fixed. Fresh fuel can clean deposits that may have caused the needle malfunction. If it happens again, you know where to look and it's not a big deal...maybe needs a new float needle assembly.

Compression check...
Better yet, a leak down test. Either one will indicate a leak, but a leak down will indicate where (intake valve, exhaust valve, rings).
- Further investigation required to diagnose the issue but at least you know where to look...or not look. Coulda just been the valves needed adjusting.

Valve lash inspection...
Pretty easy. If they're too tight, maybe not enough compression to support combustion. If they're too loose, maybe not enough fuel/air to support combustion.
- Adjust as necessary. This a good time to look at cam timing and the camchain tension/wear...could be an issue with timing, camchain tensioner, guide/slider and/or camchain wear.

I have lingering questions...
- Did the machine shop cut/lap the valve seats after installing the new guides? We can assume it would've been part of the job but...I didn't see it mentioned. Kinda points to the "tinging" if the valves and seats aren't concentric.
- The other cause of tinging would be valve-to-piston contact...a result of erroneous cam timing due to operator error or parts wear. It would have to be fairly sever tho'...you can skip a tooth on most engine's stock timing and not have a problem other than a loss of power.
- The only other "ting" I can think of would be piston slap. If you didn't measure the piston yourself prior to the work, you'll have to pull the cylinder to do so. You want measurements from the cylinder and piston to come from one source - you or someone you trust. Otherwise, it's just pulling the head...not a bad idea if you suspect any of the above questions.

Correct online diagnosis is time-consumingly difficult. I hope you find the cause of your concern so your neighbor can have faith in your ability. The fresh top-end can only help if the kid loops it day one with an OMG reaction to his whiskey throttle.

 

wow that post is bigger than the service manual...lol

 

I know. And Broome usually doesnt go that in depth into bike truoble shooting and maintenance. He must have learned from being around livengood for so long.

Who knew he had it in him.

 

After some google searches I found the needle issue on my kids crf 70. I did the “usual” checks as far as compression, leak down, valve check/ adjustment. Had me stumped for a while as I cleaned the carb in the US cleaner, then followed up with a good hand cleaning with proper tools. Turned out the seat where the needle seals (not sure if that is the correct name or not) had a small nick in it you could only really see if you looked under magnification. I didn’t bother trying to fix it and just threw all the jets that were in that carb in a new one and called it a day. I’m very much an over - maintaining type of person and damn oil was smelling like gas more than I’d have liked and it had me stumped. Glad I didn’t rebuild the motor