How can I believe Tim and Savage? Taking Measurements

Incidentally, here is the bolt from the head that goes in the bottom hole surrounding the timing chain cavity. The grey stuff is rubbery RTV type sealant. This is a weak spot- clean off the RTV well, hit it with acetate solvent, add some blue (medium) Permatex locking liquid (Or medium loctite) and reinstall.
















Savage taking measurement.

Protrusion / height of alignment sleeve above head flange surface.

This is the depth that MUST be in the rocker arm assembly, or the pin is too long!









The height of the sleeve above the mating surface of the bolt hole flange is 0.3695"

This means the rocker arm assembly counter bore MUST be 0.3695" or greater in depth.










This is the measurement on the UN modified sleeve, overall length.











This is the depth of the counter bore in the rocker arm assembly. WAY TOO SHALLOW!

THE PIN IS TOO LONG!

File or grind the sleeve down to a final measurement of around 0.465". Remember to put a slight taper on the outside of the pin. This may help center the counter bore of the rocker arm exactly where it should be.

How can I believe Tim and Savage? Cylinder Head Close Inspection!

These pictures were taken from 10x to 30x magnification, through a microscope. Initially, I was trying to identify what small black dots were on the face of the head. I discovered a load of pits and voids across the face of the head, in the combustion dome by the valves, etc. Most were not of a troublesome size or location. However, it should be noted that it is extremely risky to take a head like this, and re-flycut it to remove material in a warped-head condition. This is because you could potentially open up a big void- it's like trying to cut away at the opening of a cave. You could make matters far worse.

The surface roughness and flatness of the surface were very good on this head, in my opinion. Again, the flatness was within 0.0005" across the entire head surface, which is kind of surprising considering everything I expected to see.

20X magnification
Coolant passage opening, edge. The discoloration is burnt coolant and carbon. Note the fracture-looking pits. Further- and of great importance- note how the sealing feature of the gasket dug into the head.

In most areas of the head, this mark looks like a rope. In this area, and along the leaking side of the head, the mark looks like a continuous groove. This is a result of the movement of the head gasket when running. The rope or cross-hatched pattern of the mark is caused by the high and low spots of the tooling that cut the head. The flycutter cuts a series of circles across the head, these circles are alternating high and low spots in the aluminum, very small indeed. As the head gasket moved, shifted, and vibrated; the tool marks were worn down so far that they are no longer visible in the problem, or leaking, areas of the head. This is important to know when you inspect your head, as it will point out very readily where the gasket was actually loose.


30x magnification

Further pitting and apparent fracturing at the coolant passage opening edge.

Note again the depth of the head gasket seat groove in the head aluminum. It is not only continuous in this photo, but it is also significantly deeper.

Again, the discoloration is burnt coolant and carbon- not black gook from the head gasket coating.



Roughly 15x

This is a further view of the bottom of the timing chain side coolant hole. Tool marks are not visible in the head gasket sealing groove, caused by vibration and shifting of the gasket.











10x
And still further away.














30x magnification


This image shows a void under 30x magnification. Again- this could be a real problem for some heads- causing leak paths, potential starts for fractures, and could make flycutting for warpage a dangerous and risky operation.

How can I believe Tim and Savage? Cylinder Head!

2006 QLink Pegasus 150cc Cylinder Head

This is the condition of the head prior to cleaning:

The red identifies the remaining RTV / Sealant on the problem side of the head.

The orange shows that there are no leaks going into the timing chain cavity. This is important, as if a particular bike did not seal well, coolant could be forced from the coolant passage into the timing chain cavity. This could mean coolant (and lack of lubrication) flowing into the timing chain, and upper end of the motor to the rockers, valve stems, and camshaft.

The yellow in the following image shows the actual leak path between the combustion chamber and the coolant passage. Again- the black residue found here is a combination of burnt antifreeze and carbon deposits. This is a huge image that will show, in an upcoming post, how the aluminum began to suffer fatigue as a result of the hot, high pressure gas, flowing over the sharp edge of the coolant passage opening.

The green circle shows where you should look if you click on the image and view it full size. The blue highlight did not do well in the photo, but if you look at the larger version, you'll clearly see when comparing it to the first image- there is a load of RTV in this hole.

Following a good cleaning, this cylinder head was placed atop a granite inspection table. Using standoffs that are within 0.0002" in height, the entire surface of the head was inspected for warping. This head measured ONLY 0.0005" different from corner to corner! Incredible! No head warping, and it had a few hundred Km put on it (gingerly) since the gasket first lost its seal!

How can I believe Tim and Savage? Head Gasket!

2006 QLink Pegasus 150cc
Head Gasket Analysis

Note that pictures are labelled directly with what they are showing. There are two sides to this gasket, and both are in this post.

Take special note to the shiny area surrounding the leak path into the coolant passage. This is the passage closest to the timing chain cavity. Also notice the stringy appearance of the black coating as it comes off of the gasket. The single reason why this coating came off like this, is due to high-pressure, hot exhaust gas, continually passing over the gasket. It literally cooked the coating off.

Now, understand that the coating will come off in other areas due to combustion, but all of this coating should have been expelled via the exhaust valve and exhaust pipe; NOT via the coolant.

This black coating is what I found at the very beginning of the ordeal, when I was flushing out the coolant!!!!!!!!!!!

How can I believe Tim and Savage? Cylinder!

...huh? Proof? OH!

Here's the proof.

Here is the bare cylinder. Sorry for the poor pic. In the images that follow, you'll see evidence of RTV/sealant that was applied only to the left hand side of the cylinder face. You will also see the leak path, which is very visible here, from the cylinder to the coolant passage / coolant jacket.

The blue area shown here is where RTV / sealant remained on the face of the cylinder housing. The areas where it is not visible are due to bad photography, or that they have stuck to the gasket upon removal. The sealant is a rubbery, RTV-like film. It is thin in most spots, grayish in color, and had to be carefully scraped from the cylinder during repair.

The following image shows a pink area that represents the very visible leak path shown in the first picture. Though there is a lot of black colored residue on the cylinder in this example, most of the black residue is from the gasket coating. However, in the area denoted below, this darker color was carbon deposit- completely different in composition than anything else surrounding the cylinder and water jacket, except where the gasket is normally not sealed. In this area it is identical.

Please read the posts that follow for more examples.

What caused the problem in the first place?

1. CFMoto applied an RTV or Sealant on the cylinder and head in an attempt to remedy a known head leak:
1. The RTV was applied only from the centerline of the cylinder, to the left side of the head and cylinder housing. This means it wasn't a "for good measure" fix, it was intended to fix a specific problem, or for a specific purpose.
2. The RTV is on the same side of the cylinder that the leak occurred.
3. The RTV is on the same side of the cylinder as the inherent assembly flaw or engineering flaw.
   
4. The RTV applied to the head-cylinder-gasket junctions was counterproductive. It caused more problems than solving them.
1. The RTV was put on sloppily, and oozed into the lower timing chain head bolt cavity.
2. This RTV prevented the proper torque being applied to the lower left head bolt, and allowed torque to relax in use.
3. This may be an individual scooter's issue, or could be commonplace. In any case, this did not solve the problem, and in my case it made it worse.
2. The Stock "acorn nuts" have adequate clearance for the cylinder studs, due to copper colored spacers atop the rocker arm assembly. However, the internal friction between the nuts, the spacers, and the studs is such that prevailing torque precluded a proper final torque value, on the order of 30% of the required torque value.
   
3. The Cylinder bolts are weak. Because of the above condition with the stock hardware, the internal friction adds shear stress (twist) to these weak studs. Under torque called out in the CFMoto Echarm service manual, the bolts torque forward something on the order of 90 degrees with the stock "acorn nut" hardware. This means that when torque is applied and released, the tool will move 90 degrees forward when tightening, but will relax back 90 degrees when the wrench is released. It is possible that some units- even beyond the 2006- could experience gasket leaks due to studs stretching over time. But only time will tell.
4. The left hand alignment sleeve is 0.064" too long. The protrusion of this pin above the surface of the head is something like 0.370". The cavity left in the rocker arm assembly is only 0.306". This means that the head gasket will NEVER become fully compressed. There is a slight lead angle on the sleeve, that may enter into the counter bores a little bit more, but regardless- this is the major reason why the head gasket leaks.

The long sleeve(s) caused the problem. The RTV made it squeak through inspection, but amplified the final problem. The weak studs and incorrect hardware make the entire affair impossible to correctly torque. All together, these three things MUST be remedied in order to properly address the cylinder head leak. Look forward to the next posts for a detailed process and procedure on how to do this.

What really happened here?

Here is my interpretation of the entire situation, from CFMoto manufacturing, to the owner(s) "Voiding their warranties" by continuing to ride the bikes... according to QLink.

SPECIAL NOTE: LEFT = LEFT WHILE FACING THE VALVE COVER OF THE ENGINE. (Like sitting on the seat backwards.)

1. CFMoto was aware that there was a problem with the sealing of the head gasket in [certain] 2006, 150cc, water-cooled engines. These engines were destined for QLink, perhaps for the ECharm, but I have no evidence to support the latter.
2. CFMoto attempted to fix the problem by adding a small amount of RTV or sealant to the left side of the cylinder, and left side of the head.
   
3. CFMoto may have performed a QA (Quality Assurance) test on the engine prior to shipping, and it is feasible to assume that- if they did- the engine passed a seal test. I believe this could have happened simply because so many scooters were test ridden, and ridden following the sale, prior to mechanical failure and the coolant leak occurring.
4. CFMoto failed, for some time, to properly identify three key problems that were the root causes for the cylinder head gasket failure.
   
5. QLink may- or may not have- been aware of the conditions above.
6. The customer test drove the scooter, bought it, used it, and it eventually failed.
7. Some customers sought advice from their dealer.
   
8. Word has it that many dealers attempted some minor troubleshooting and repair. To my knowledge, not one single dealer fixed the issue after it occurred.
   
9. Some dealers advised their customer to keep riding the scooter, saying it would simply continue to run hot.
10. It is my impression that these dealers had no clue what they were doing, OR, that they wanted absolved of all responsibility in the matter. They probably assumed that the engine would eventually fail, and that QLink would either fix it, or their warranty would be voided. In either case, the dealer couldn't lose, unless the customer took them to small claims court and won. It may be that QLink was not aware that this was happening, and saw, only, a customer with hundreds of miles on their scooter following declaration of a problem.

Some of what is above is speculation on my part, but the following post shows facts.