blowit

I certainly don't stir the pot much anymore but most any machine shop of some stature does not regard a "Hass" (Actually Haas), much of a precision machine. They are the Chevy of the machine world. Every one has them but not to be confused with a Porche. However, I CERTAINLY do not see much wrong with your efforts. I could throw a bunch of rocks at setup, tooling, etc, but as you already know, everyone has to learn it if they want to move forward. Break tools, break parts, "try" not to break machines, etc. It looks like you are making the proper efforts to improve yourself.

That is just called proper website layout and advertising, like we care. We polish every head before we send it out. Most any of our heads will look just like that picture. I am certainly not knocking anyone's work but let's not assume certain things. The head in that picture was a customer head that was shipped that same day.......About 500 heads ago......

I am not real sure what is "photoshopped" on our page. We have been machining stock Banshee heads to perfection for over 10 years now and don't recall any unhappy customers. For the record, anyone here can "PM" us as well for head mods. We are not rookies at it. Brandon Mull Engineering

I will note a few things. Anti freeze should really be regarded only as such. Boil over protection mostly comes from the watr pressure by way of the rad cap. What you have to consider inside an engine is localized heat. This just means though your average water temp holds a certain temp, there are hot spots in the engine that will try to boil the water. This would turn to steam and try to escape the system if not condensed. This can be a mode of water loss that you never really see. It just slowly loses water due to local heat. I will also discuss coolants. Ethelyne Glycol does not have the heat absorption ability of straight water. For this reason, we always recommend running the least amount you can get by with from the freeze table. 30% will usually do. Not only does EP reduce freeze temp, it also help as a corrosion additive and lubricates seals and such. When you buy a product such as water wetter, all you are basically getting is lube and additive to maximize the water content. They advertise this as "better cooling" but tht cooling is really only coming from the increased water amount. You must also consider fluid viscocity. ANY real pump designer (not just someone with a CAD program) knows that pump design and fluid viscocity are closely related. the number one design factor for any pump is cavitation. It can destroy pumps as well as cause localized steaming of the water right at the pump. This steam can them move through the system and escape. For anyone that cares, when water turns to steam, it will expand approx """1700 times!""" What does this mean? it means if you have a cap set to blow off at 15psi and steam being created by the pump, you are going to vent water in the way of steam.... A simple CFD model would prove that many billet pumps on the market are prone to this condition. From my reading so far, I kind of wonder if you have been losing water via steaming and level finally got too low. Unless you check it every ride, I would be inclined to add coolant and see what it does. brandon Mull Engineering

Several months ago we had a few, IMO, dishonest buyers from out of country that have all but stopped us from shipping out of country. One suspect knew how to play the game and I found it strange that his address from purchase to later contact was slightly different. I asked about that and he said "that was his mother's address". I knew it did not sound right but we try to take care of our customers so I reluctantly shipped more (FREE) items on us. I then noticed these FREE items just sold on ebay, brand new, still in package. Obviously there is little I can do when they are in Canada but a swift ass whoopin should be in order since it is people like this that hurt the parts availability for our out of country riders. Canada was smooth sailing for us for many years in shipping but it only takes a few bad apples to ruin it for everyone. Anyway, I am just putting a word out for any other dealers or sellers. This buyer is from New Brunswick, Canada. I don't want to see others get burned!! Brandon Mull Engineering

Good God man, I was clicking around and due to the "terminology" all being the same and the same values, I suspect even some of the engine builders on here are using the wrong shit! I even saw where some were "rounding" these values +/- .5cc. That is a hell no and exactly why some stuff "should" work and doesn't. I guess that is the magic of the Inet. Once something is started and passed around, but wrong, it is like Herpes.....Trendy but still ultimately not cool....

Everything looks good minus the piston dome profile. Assumption there is a constant radial profile over the dome, which is incorrect. You will notice playing with your value inputs that any small change in that dome volume has a radical effect on calculated UCCR. Once you have the volume for the piston dome, it will come back into alignment. Great work so far though. Wish more people would take to the books before guessing and hoping........... By the way, where did that calc come from? It looked familiar so I went through some of my old files and there it was. I have no data on it so just curious where that ever came from. Brandon

I would like to see your math on that. I am not calling you out, I just want to help you on the numbers since you seem to have the ambition to do it the right way.

Hey gents. I will try to help on a few points. Compression ratios do have some practical limits but relating them to RPM is NOT quite the right angle. I will try to apply some physics here for consideration. Compressing a gas causes that gas to heat up. The rate at which you compress that gas as well as how much (ratio) is what determines how hot that gas will get. As engine speed increases, the rate of compression goes up thus those gas charges in the head are hotter. This causes acceleration of flame front propagation thus the need to reduce ignition timing to maintain maximum cylinder pressures at the optimal point in the crank rotation. As point of reference, you will notice most igntion curves will increase with rpm to a point, then decline. This is because the rapid compression of the gasses need less of a "head start" to hit the sweet spot of max performance because the charge burn rate is faster. Many people relate ignition advance to power but realize that in a perfect world, starting ANY spark before TDC is counter productive and in a perfect world, we would really like to start that spark at about 5* ATDC. However, it takes time for fuel to burn and build pressure in the cylinder. The faster it will burn, the less timing advance you need. The main issues regarding changes in fuel and compression ratios are that many will require difference curves than what is in the OEM CDI box. With today's digital ignitions, it is certainly possible to get it right. As it pertains to physics, the higher compression ratio you can handle, the faster you will be. However, regarding two strokes, expansion chamber reverse wave technology certainly throws a curve ball in there. Having a little extra room in the head is sometimes a good thing with well matched porting and pipes. I personally am no stranger to heavy hitting compression. I have built several woods bikes for customers pumping up over 250psi of cranking compression. They have years on those engines and never been opened. The key is getting the timing right! When you feel a high compression engine hit the "brick wall" on the top end, that is a sign that you are starting the party too early and asking for engine failure. I cannot stress tuning your timing enough. Many people get too wound up with numbers on timing. +4, +6, +10, etc. Every engine configuration is different and depending on porting, CR, fuel, ambient air, pressure, etc all makes a difference. In short, don't do what your buddy does, do what your particular engine wants. Unfortunately, those magic numbers above are ONLY the mechanical advance which is just a guess that the entire curve will be optimal in every rev range. +8 on the plate might be dead on in the bottom revs and way too much to get good overrev up top. Brandon Mull Engineering

For the sake of simplicity in finding your issues, I would switch to straight water for now. You can save your coolant if you like. One of the things I would be testing if you have any way at all of doing it is the temperature differential or DT across the radiator. Between the inlet and outlet of the rad, you should be seeing significant drop there. If there is no change, the radiator is not exchanging heat into the air. Sometimes an IR gun works well for this if the tanks on a rad or Aluminum. You can shoot very near the inlet and outlet to test the DT. I would also make DAMN sure you don't have something casted wrong or plumbed wrong in a way that would allow air to be trapped in the top end. That will certainly cause these types of issues. You obviously also need to verify that you are moving water. One thing I have seen in years past is a radiator that has a strong oxide layer inside for some reason when new and that layer does not exchange heat near as well as bare Al. I don't know of a good test on that other that we caught it when we applied venting air with a fan and never got a DT across the radiator. Another radiator fixed that.

Before you go through the hassles of checking your bike, I would test that gauge by taking the probe inside and boiling some water in a pot. It should be about 210*. Also a good reference to test your tap water temp too. At 256* with no cap on the radiator, I woulx expect to see some gassing visible in the radiator. Brandon Mull Engineering

You will only be guessing until you fully mic the bores and pistons.

Yes, if ring end gap is excessive, they are worn out. You would be looking for .004" per inch of bore so .010-.012" optimally. It does not appear your piston skirt have suffered but yes, your pistons can overheat even if coolant temp stays nominal. Just remember that exhaust gasses will easily exceed 1000*F so rinsing that heat down the sides of the piston will cause bad things but pistons and bores would indicate that. I would certainly COMPLETELY mic that engine. Bores for square, size, roundness, and taper, as well as the pistons and rings. That should tell most of the story in what is going on. If this engine pumped up identical numbers when new, you know what it should be. If not, you need to measure the exhaust port height on each cylinder from the top deck of the cylinder to see of they are the same height.

Lets take a look at the exhaust side of those pistons. 15lb difference between cylinders is certainly enough to tear down and find out what is wrong. Most likely hung up rings in a piston from overheat. Also need to mark and remove the rings from the pistons, check ring end gap while in bore, and inspect for heavy wear on the exhaust side of them. If they are worn excessively on the exhaust, exhaust gas will start sneaking around the ring and causing this as well as reduce compression induced ring seat thus causing blow by and overheat of the piston. brandon Mull Engineering

I don't see any reason that would not work just fine. If the cover will work with the factory or OEM impeller, it will work with ours as well. Thanks

I talked with someone (possibly this customer) a short while ago. I will mention a few things for any other customers with questions. We manufacture our pumps tighter than all other manufactures to optimize efficiency. It is important to remember that the pump shaft is pushed away from the clutch cover housing by the engine case pushing against the back of the shaft when the cover is installed. If a thicker than OEM clutch cover gasket is used, you could experience minor rubbing. This can be remedied by using a thinner gasket, lightly sanding the leading edges of the impeller, or by shimming the back of the shaft about .005" to gain clearance. Also, if the bearing and seal are replaced and not pressed in all the way, this will also cause issues. Brandon Mull Engineering

Regarding your pump issues, there is usually some drag on the pump due to the shaft seal in contact with the shaft. However, the bearing may have failed as well. If you slowly spin the shaft and feels "catchy" at all, replace the bearing and seal. Regarding the billet pump, since we manufacture the billet gear and pump, I might be biased but IMO, replacement of both the gear and pump is an important upgrade for reliability and protection of todays expensive engine builds. Why yamaha opted for a plastic impeller head is beyond me. They have caused a lot of documented problems over the years. Brandon Mull Engineering

Squish, dome shape, jetting, timing. If you are chopping the plug, you are missing most of the critical data regarding the ground strap and relation to ignition timing. Squish clearance is a good start. I have been telling people for years to ignore the number on that timing plate and focus on how it runs. Due to several factors, they are not all that accurate. A timing light is the only real way to know what you are really getting. Brandon Mull Engineering

Guys, I am involved right now and will work through the issue with him. I am still not quite sure what the "play" is but I believe this is in reference to the axial or push/pull play in the impeller with the pump cover off. They all move a bit in that respect but never the less, we will get it figured out and get him going. I am still not sure what is going on.

I don't think even we knew how many problems there were with the plastic drive gear when we built the billet replacement. It has been quite an issue for some, even newer bikes. If there is just a little to much drag on the pump for whatever reason or a little piece of clutch material gets up there, it will fail. Sounds like you got it all figured out! Brandon Mull Engineering

You mean until they get their ass handed to them by one.

We had considered advertising in a couple quad mags. Price is high and debating the actual exposure due to all the digital media these days. Do you guys still get a subscription and with who?

That's what we want to hear! Thanks for the feedback!

Not being totally familiar with the product, I will say that the hardness of the wear surface is what will determine how it wears. Knowing the hardness of the basket would be good. If it was not heat treated properly, it could be like bubble gum and very ductile. Simply comparing hardness of the plate vs the basket will tell you which will take most of the wear. On the other hand, if the plate is not presenting a uniform flat surface to the basket, that will increase the PSI load or point load on the basket and could damage it. IE if the plates have a ridge or something on the face, that can cause issues. It is VERY common for people to grind on the face of clutch plates thinking it will fix the problems only to find that the problem got worse. The plate is designed precisely clocked so each load face takes some of the load. If you grind on them, you risk getting them uneven and only a few ears take all the load which can shatter the plates and cause rapid basket wear. On a new basket, this will be obvious by not showing uniform wear on each load face on the basket. Things to consider I guess.... Brandon Mull Engineering

Not an HQ member that I am aware of. Not looking to out anyone right now as much as I would love to. Try to keep it professional. Just wanted to let you guys know that if our policies change, you have our reason. We receive a lot of email from foreign customers that they cannot usually get parts and I know why. I very much doubt anyone wants to pay 50 bucks in shipping for a 50 dollar item but it may end up there. At the minimum, we will probably make all foreign customers use paypal only and ship to their verified address. That of course does not prevent "not received" scams.