Metal Tapping Sound from Engine - Page 6

detours · 04-27-2016, 11:23 PM

Wow, what a story! That's awesome that CSC took care of you!

I'm curious, did Gerry say why he recommended 20w-50 oil? The normal viscosity is 10w-40.

jbfla · 04-27-2016, 11:36 PM

Quote:

Originally Posted by detours

Wow, what a story! That's awesome that CSC took care of you!

I'm curious, did Gerry say why he recommended 20w-50 oil? The normal viscosity is 10w-40.

He did...best I can remember was something about "film strength", but I'm not certain.

I don't know if the recommendation is because I'm in hot Florida.

I thought 20w50 was for air cooled engines, but I will follow his recommendation.

jb

SpudRider · 04-27-2016, 11:45 PM

Quote:

Originally Posted by jbfla

He did...best I can remember was something about "film strength", but I'm not certain.

I don't know if the recommendation is because I'm in hot Florida.

I thought 20w50 was for air cooled engines, but I will follow his recommendation.

jb

I think you are correct. Gerry probably recommended the 20W/50 motor oil because you are in sunny, warm Florida.

SpudRider · 04-27-2016, 11:47 PM

Quote:

Originally Posted by detours

Wow, what a story! That's awesome that CSC took care of you! ...

X2; I'm glad your problem is fixed, and I think it's great that CSC treated you so well.

Jay In Milpitas · 04-28-2016, 12:05 AM

JB asked if a 250 really needs a decompressor.

By reducing the effort needed to start the engine, the parts that are used to start it can be designed to be lighter or don't need to be bulky (in the case of kick starters) or use less energy (electric starters).

It's all part of the game of saving ounces.

SpudRider · 04-28-2016, 12:10 AM

Quote:

Originally Posted by jbfla

...I'm still pondering these questions:

How much did the decompression mechanism contribute to the damage?...

The decompression mechanism did not make any contribution to the damage. In fact, it alerted you to the damage before the damage worsened, and allowed you to fix the problem before you were stranded somewhere with engine failure.

Quote:

Originally Posted by jbfla

...Does a 250 cc, electric start engine, even need a decompression mechanism?...

Perhaps a 250cc engine doesn't need a decompression mechanism, but it is certainly a nice feature to have. It can't hurt anything, and it facilitates starting the engine.

My Honda CRF250X has a similar decompression mechanism. It is a good design, and it works well.

Quote:

Originally Posted by jbfla

...The prescription by head mechanic Gerry Edwards was to:

Check / adjust valves at 500 miles.

Check adjust valves again at 2500 miles, and every 2500 thereafter, or sooner if start / idle problems...

Based upon my experience, I think the original inspection interval of 2,500 miles should be observed by everyone, whether they have had engine problems, or not.

I check my valve clearances every 2,500 miles, and I will continue to do so, until I see the valve lash stabilize. I have ridden my bike over 14,000 miles, and the valve lash has not yet stablized.

I also recommend setting the valve lash to 0.08 mm for all four valves. This setting doesn't adversely affect engine performance, and provides a little more safety margin between valve lash inspections.

Haggis · 04-28-2016, 06:24 AM

You saying that the roller on the rocker arm wore away the cam at the base ?
Poor surface hardening treatment would be my first thought.
Your explanation seems to be that the cam was so worn that the rocker arm roller was making contact with the decompresser finger and causing the bob weight to rattle about and make your noise.
No clearance would have affected your starting and running and any wear would normally take place at the tip of the cam.
I still think it was a poor quality part that was your problem, ask Honda, they know about cam problems.

jbfla · 04-28-2016, 09:01 AM

Quote:

Originally Posted by Haggis

You saying that the roller on the rocker arm wore away the cam at the base ?
Poor surface hardening treatment would be my first thought.
Your explanation seems to be that the cam was so worn that the rocker arm roller was making contact with the decompresser finger and causing the bob weight to rattle about and make your noise.
No clearance would have affected your starting and running and any wear would normally take place at the tip of the cam.
I still think it was a poor quality part that was your problem, ask Honda, they know about cam problems.

Thanks for the input, Haggis.

Gerry said the surface of the cam lobe was worn away all the way around the lobe, and that he had never seen that condition before.

I am not fully satisfied with the explanation of the cause of the problem.

That is why I wanted the worn cam returned, or a least a photo of the damage.

But I am overjoyed that the bike is fixed, and I'm back on the road again.

jb

pyoungbl · 04-28-2016, 10:40 AM

FWIW, lots of European high performance auto manufacturers (BMW M series, for one) spec out 10W60 full synthetic for their water cooled engines. Guzzi does the same for their newer air/oil cooled ones.

Weldangrind · 04-28-2016, 11:17 AM

I'm not an expert, I'm only guessing.

If the clearance tightened up to 0.0, the hydrodynamic barrier that occurs with oil would likely be burned off very quickly, after which excessive friction would occur. It seems reasonable that a hardened surface would not survive long under those conditions.

Inroads · 04-28-2016, 12:01 PM

Gerry would know if there was zero clearance and he would have no other reason than report that since they ended up paying for it anyway.

Weld and Grinds assesement seems plausible
Along with a burnt valve.

jbfla · 04-28-2016, 12:23 PM

Quote:

Originally Posted by Weldangrind

I'm not an expert, I'm only guessing.

If the clearance tightened up to 0.0, the hydrodynamic barrier that occurs with oil would likely be burned off very quickly, after which excessive friction would occur. It seems reasonable that a hardened surface would not survive long under those conditions.

Quote:

Originally Posted by Inroads

Gerry would know if there was zero clearance and he would have no other reason than report that since they ended up paying for it anyway.

Weld and Grinds assessment seems plausible
Along with a burnt valve.

Inroads and Weld, thanks for your insight.

Perhaps I am looking for something that is not there.

It is still puzzling to me that there were no symptoms or warning of zero valve clearance.

The only clue was the metal tapping, after the damage was done.

At least if any other RX3 riders should hear that tapping noise, they will know what they are in for.

jb

2LZ · 04-28-2016, 12:27 PM

This kind of service and support makes me feel all the better about buying the TT250 from CSC. Awesome........ Glad you're back on the rod and I think W&G nailed the explanation.

SpudRider · 04-28-2016, 01:44 PM

Quote:

Originally Posted by Weldangrind

I'm not an expert, I'm only guessing.

If the clearance tightened up to 0.0, the hydrodynamic barrier that occurs with oil would likely be burned off very quickly, after which excessive friction would occur. It seems reasonable that a hardened surface would not survive long under those conditions.

Quote:

Originally Posted by Inroads

Gerry would know if there was zero clearance and he would have no other reason than report that since they ended up paying for it anyway.

Weld and Grinds assesement seems plausible
Along with a burnt valve.

Quote:

Originally Posted by 2LZ

This kind of service and support makes me feel all the better about buying the TT250 from CSC. Awesome........ Glad you're back on the rod and I think W&G nailed the explanation.

X4; I agree with the others.

Lee R · 04-28-2016, 06:32 PM

Thanks for posting an update!

I certainly will be checking the valves and adjusting to .008mm for added assurance every 2500 miles.

I'm glad CSC helped take care of it! They are doing a good job taking uncertainty out of purchasing a bike from China sight unseen.

Maybe if we don't hear "happy tappy" valves it's a good idea to do that adjustment early!

04-27-2016, 11:23 PM	#76
detours Join Date: Sep 2014 Location: Arvada, CO Posts: 1,004	Wow, what a story! That's awesome that CSC took care of you! I'm curious, did Gerry say why he recommended 20w-50 oil? The normal viscosity is 10w-40. __________________ Red 5 standing by! 2015 CSC red RX3 with 19" front wheel, Shinko 804/805, skid plate, tall seat, 13T/45T sprockets, progressive shock, Winyoochanok windshield, GENSSI LED headlight, SW-Motech tankbag, Shorai Lithium battery 2014 Ural Patrol
	0

04-28-2016, 12:05 AM	#80
Jay In Milpitas Join Date: Jul 2015 Location: Milpitas, CA. USA Posts: 775	Decompressed JB asked if a 250 really needs a decompressor. By reducing the effort needed to start the engine, the parts that are used to start it can be designed to be lighter or don't need to be bulky (in the case of kick starters) or use less energy (electric starters). It's all part of the game of saving ounces.
	0

04-28-2016, 11:17 AM	#85
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	I'm not an expert, I'm only guessing. If the clearance tightened up to 0.0, the hydrodynamic barrier that occurs with oil would likely be burned off very quickly, after which excessive friction would occur. It seems reasonable that a hardened surface would not survive long under those conditions. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
	2

04-28-2016, 12:27 PM	#88
2LZ Join Date: Mar 2010 Location: Volcano, Ca Posts: 7,095	This kind of service and support makes me feel all the better about buying the TT250 from CSC. Awesome........ Glad you're back on the rod and I think W&G nailed the explanation. __________________ "Light a fire for a man, and you heat him for a day. Light a man on fire, and you heat him for the rest of his life." 2007 Suzuki DRZ400S (SM convert) 2009 Q Link XP 200 1967 BSA B25 250cc Starfire 2022 Royal Enfield Interceptor 650 2023 Royal Enfield Scram 411 1948 Royal Enfield Model G 350
	2

04-28-2016, 06:24 AM	#82
Haggis Join Date: Mar 2016 Location: Scotland Posts: 21	You saying that the roller on the rocker arm wore away the cam at the base ? Poor surface hardening treatment would be my first thought. Your explanation seems to be that the cam was so worn that the rocker arm roller was making contact with the decompresser finger and causing the bob weight to rattle about and make your noise. No clearance would have affected your starting and running and any wear would normally take place at the tip of the cam. I still think it was a poor quality part that was your problem, ask Honda, they know about cam problems.
	0

04-28-2016, 10:40 AM	#84
pyoungbl Join Date: Feb 2016 Location: Portsmouth, Virginia, USA Posts: 632	FWIW, lots of European high performance auto manufacturers (BMW M series, for one) spec out 10W60 full synthetic for their water cooled engines. Guzzi does the same for their newer air/oil cooled ones.
	1

04-28-2016, 12:01 PM	#86
Inroads Join Date: May 2015 Location: Wimberley Texas Posts: 193	Gerry would know if there was zero clearance and he would have no other reason than report that since they ended up paying for it anyway. Weld and Grinds assesement seems plausible Along with a burnt valve.
	1

04-28-2016, 06:32 PM	#90
Lee R Join Date: Aug 2015 Location: Upstate NY Posts: 343	Thanks for posting an update! I certainly will be checking the valves and adjusting to .008mm for added assurance every 2500 miles. I'm glad CSC helped take care of it! They are doing a good job taking uncertainty out of purchasing a bike from China sight unseen. Maybe if we don't hear "happy tappy" valves it's a good idea to do that adjustment early!
	2