Frequently Asked Questions:
Q: How much does the service cost?
A: Services are billed on a per task basis. See our services and pricing tab for a per task labor cost. Each repair task has its own individual price x the number of times the task is performed to a given part. IE: Valve seat cut is $25 per seat (task), thus 4 seats = $100 ($25 x 4). Each cylinder head will need a different number of services performed based on how a given part has worn. This can only be determined after Phase 1 evaluation.
Q: Do I need to take my head apart before I send it to you?
A: For cylinder heads, we only need the head casting, with valves still installed. All other parts and pieces should be removed: Camshafts, rocker arms, rocker box, dowel pins, intake manifolds, tappet adjuster covers and cam chain tensioner parts.
Q: Can I mail it to you first for the evaluation?
A: No, you must purchase our Phase 1 cleaning & inspection service before we can evaluate any of your parts.
Q: What if I have my own new / replacement / used parts (valves / guides )?
A: Only genuine CMC parts are used for any service work we provide; as we can guarantee the quality and consistency of our products. While we respect that you may have rounded up replacement parts for your engine, we are not able to use any parts provided to us. There are a lot of “mystery parts” on the market and have seen many customers burned by what they believed are the correct parts for a rebuild, just to find out something doesn't fit properly or is of questionable quality. Our Phase 1 cleaning & inspections services are used to determine the exact parts needed for a rebuild of any given part.
Q: Do you fix / weld broken cooling fins, gouged surfaces, pitting from corrosion, worn bearing journals?
A: No, our shop is not equipped to tackle any of the above repairs.
Q: What all actually gets done / replaced during the rebuild process? What parts get reused or replaced?
A: On a cylinder head the typical work is to re-cut the valve seats and the head gasket surface lapped. Valve guides are a 50/50, sometimes they are well within service limit and can be put back into use. If out of service limits we will bronze line them. All threads are cleaned with a chaser. Valve springs and hardware will be reused and shimmed.
Q: What if it turns out that my head is not rebuildable?
A: We will be in direct contact with you to discuss alternatives given the exact details of the Phase 1 evaluation. We may be able to source a suitable replacement part for you.
Q: Can I have only some of the quoted processes done and skip the others?
A: Our objective is to do the minimal amount of work necessary to bring your part back into proper working specifications. No more, no less.
Q: Why do I need to pay for the services up front?
A: So there are no surprises for everybody involved.
Q: I live International, will you be willing to offer this service for me?
A: Yes, as long as you are willing to pay the international shipping expenses.
Q: Is there a warranty on the parts and labor?
A: We stand behind our work, however each warranty claim is on a case by case basis. There are many factors that can cause a claim and we need to examine the situation and determine the root. A defective part? An error in machine work? Improper assembly by the engine builder? Freak situation? Alignment of the planets? Regardless, we give you 60 days from the time you receive your part back to be installed on the engine and put into service to make sure everything is working correctly. That means get your engine together and running ASAP!.
Q: I have a bike that is outside of your supported models, will you do machine work for me?
A: No!
Q: What if it turns out my part is in good shape and does not need major service aka things are well within service limits?
A: At times we find that a head is in great shape and still has lots of service life in it without needing any major machine work (you lucky dog). However any used head will need some very minor touch up work before going back in the engine. Typically head gasket surface is leveled and valves + seats may need to be lapped. We will not perform any service work that is not necessary.
Q: Can I reuse / touch up original Honda valves?
A: The short answer is NO. The long answer is the original Honda valves are actually a very soft alloy that has been Stellite coated. Stellite is very hard and wear resistant, but not very thick. Think of an M&M but imagine the shell was as tough as a jawbreaker. A lot of older automotive engines had valves that could have the tips ground square and the face re-ground to be used again. Attempting to do this with the original Honda valves will grind through or weaken the Stellite, which means we are down to the soft alloy core being used as the wear surfaces. Valve failure will be certain, typically in only a short time. A valve failure like this will likely cause catastrophic failure to the engine. This is why we always replace valves when doing a cylinder head rebuild.
Q: Do you replace valve stem seals?
A: Yes, if the engine was originally equipped with them. Not all models use them and some are only used in certain positions.
Q: Can you repair stripped threads / spark plug hole / remove a broken bolt?
A: Most of the time, yes. Broken bolt repairs are quoted on a case by case basis
Q: Do you replace valve seats?
A: At this time we are not replacing the original valve seats in any head. We only machine the seats back to proper shape, surface finish, and interface angles to work with new intake and exhaust valves.
Q: Do you do a 3 angle valve job?
A: Yes, this is a 30 / 45 / 60 degree seat cut.
Q: Do you replace the valve guides
A: Only as needed. Our preferred repair for worn guides is to bore them oversize and install a bronze liner. We only install a new guide if the original is missing, broken or some other reason that will not let us use a bronze sleeve.
Q: Why does CMC restore vs. swap out valve guides?
A: Replacing guides is more labor intensive, more expensive (parts), can cause damage to the head casting during the install or removal process, and often changes the valve to valve seat alignment. When this alignment is off, it necessitates more machining (labor and material removal) to the valve seat to make it concentric with the valve’s new position in the casting. We view it as an outdated process that attempts to fix one problem, while possibly causing more. Our philosophy is to be as minimally invasive when doing a head repair in the prospect it can be machined again at future top end services intervals.
Q: Do you replace valve springs?
A: No. We have found that the valve springs are almost always in good condition to be used again. Same goes for the spring seat, retainers and locks (keepers). We do shim the springs to restore the pre-load values due to spring fatigue and valve seat sink. NOTE: CB450 cylinder heads which use torsion bar valve springs cannot be shimmed.
Q: At what mileage should top end service / inspection work be performed on my engine?
A: Motorcycle mileage is vastly different from automotive mileage; it is about a 5:1 ratio between the two. A modern car with 30,000 miles on the clock is low, but a vintage motorcycle with the same mileage indicates that a bike was ridden a lot. This would be the equivalent of a car with 150,000 miles. These machines require more frequent maintenance due to fast running engine speeds, how hard an engine has to work (smaller the engine, the faster it wears), radical temperature fluctuations (air cooled vs. water cooled) and nature of the metals used to make them back in the day. Based on our experience here are the approximate mileage service intervals where one of these vintage Honda engines would expect to have the “top end” (head and cylinders) taken apart for cleaning & inspection. These mileage intervals also assume that an engine has been well cared for during its service life, which means regular oil changes with proper zinc fortified oil, valve and cam chain adjustments @ 1500 mile intervals and the engine was not abused (aka not run overlay hard for long time periods). Most engines are not perfectly cared for and may need top end service work at mileage intervals lower than these following values. The below values are in miles. Multiply x 1.609 for KM.
- CB175 / CL175 / CB200 = 12,000 - 15,000
- CB350 / CL350 / SL350 = 18,000 - 20,000
- CB360 / CL350 / CJ360 = 18,000 - 20,000
- CB450 / CL450 / CB500T = 25,000 - 30,000
- CB500K / CB550 K & F = 25,000 - 30,000
