TDR_50

Hey Gotmils, I am not on here often but the T-Rex cylinder can be ported to be a very competitive motor. The most important thing is that is has more torque and a wider powerband. With the proper gearing and exhaust that motor will accelerate harder than a motor that produces more peak HP with a narrower powerband. Again tuning and chassis setup is paramount. In 300 foot dirt drags I prefer a motor with more torque and acceleration. I use a tall gear and run all 5 gears. I, TDR now have all the remaining T-Rex parts and have extensive background on porting and setup. I will be going thru all the remaining cylinders making improvements, changes and offer them early next year.

TDR has 18 and 19 tooth sprockets in stock.

I would be glad to do a complete post so it could be pinned. It will be a few day as I am busy, but i will start a new post with all the information combined. Thanks Guys.

Different web manufacturers have slightly different center web dimensions. The crankshaft does need to fit in the cases, preferably as centered as possible. The crank will always be driven to the mag side as well by the forces on the right side of the crankshaft. Here is my analogy of budget cranks. The crankshaft is the heart of your engine. It also has intense pressure loads on all the components. This being said, if you needed a pacemaker for your heart, would you buy a Chinese one, Taiwan made, Japanese, USA made or Swiss made. You get what you paid for. Yes in today’s technology and business world things are getting cheaper by the day. Many companies do this by eliminating all the middlemen and then finally by going with cheaper manufacturing companies and materials. Bottom line. If you are a rider that shifts at the correct RPM, and recreational ride at lower RPM's the budget crank will work for you. If you are an abusive rider you will not fare well. We hear stories of multiple cranks failures and instantly see the blame being posted back to the crank builder. If you have multiple failures that are the same something is being missed. Crank builder?? Mechanic?? rider input ???? Over-Rev and abuse is the number one cause of crank failure. JC Whitney and Manufacturers supply appear that they may be the same supplier. WSM is different as they use o-rings and not locator pins. Just do a search on banshee crankshafts and you will see how many different people are selling them. How many they sell?? I would always suggest buying from a company that builds the crankshafts in-house. At least you have a better chance of getting a better one. We are all still human, and defective parts happen. crustydeamon. Yes that is a bad picture. I'll see if I can get a better one. Grab a crankshaft yourself and check it out. stroking: if you had e-mailed the picture direct to me I would have explained it and send you all the pictures and info direct to you. Simple communication should have been used here. I have contacts in Indy car racing, Nascar, SCCA, NHRA, and have access to all the high-tech technology being used today. I take great pride in my quality control and upholding my company name. I have hundreds of pages of crankshaft design and balancing articles, as well as access to design programs. Most of it is engineering data and concepts. I have spent the last 40 years in designing and building 2 stroke motors, porting design, expansion chamber design, crankshaft rebuilding, etc. As a few of you may know I am slowly going into the firearms industry as well. My time is valuable and I do not spend much time on forums unless necessary. My time is better spent, testing, researching and checking all the facts. I would be glad to post all the articles and data but there are hundreds of pages to go thru. You can also do searches on Rocking couple, crankshaft design, crankshaft balance, twin cylinder crankshaft balance, twin cylinder crankshaft design, etc.

Also for reference the stock factory Yamaha crankshaft has 3 mm clearence on thicker outside web and 5mm clearence on the inner web. The webs are slightly misaligned as well. If you look at all the crankshafts in the previous post you will see that the rod in not centered between the webs.

Factory specs do not apply here because the webs are not machined to the same exact dimensions.

OK Guys , I have compiled a world of information for all of you. It will be posted in a new Post titled Crankshafts Design . Following are 7 pictures and they have the sorce listed. You all know who the companies that are listed. These are all different manufacturers. Look at the pictures and see for yourself. All the webs are not lined up. All have larger flywheel and PTO or clutch side webs than the centers do. This is done by the engineers at the factory. The fact that the webs do not line up has nothing to do with the trueness or balance of the crankshafts. There is nothing wrong with any of these crankshafts. I will cover the topics of design , Rocking couple, torsional twist, static balance, dynamic balance, and more in the new post.

Seal was in backwards but it is designed to seal in either direction . The pre-mix oil is gathered from the rundown in the transfer area and in the trough on the crancases , then collects and runs into the hole above the bearing. Also as the atomized fuel/air/oil mixture moves thru the crancase area it collects on the bearing surfaces . You can see that it is extremely important to lube all the crankshaft bearings when installing a new crankshaft as there is no real collection of oil at that point. If the seal was leaking it would have sucked up all the transmission oil and looked like the mosquito truck going down the road.

Hey Guys . I am not on the forums very much as I am always busy. I have seen thousands of crank failures over the years. Every different type of failure has a specific sign as to what happened. If you have multiple failures and the same type of failed parts something is being missed. In diagnosing a crankshaft failure I look at the evidence, (what has failed), and work backwards to find the problem. I started rebuilding crankshafts in 1973 and to this day have rebuilt, (my company & workers) close to 50,000 crankshafts. All 2 strokes and a very small amount of 4 strokes. Right crank bearing outer race failure: The cases are matched sets and CAN NOT BE MIXED . They are line bored from the factory. If you mix cases you will have bearing failure. Bearing clearance is by spec clearance scale. If the crankcase area where the bearing ride is out of round by even a few 10,000 of an inch it will put pressure on the outer race and this pressure will create friction in the ball or roller area. This friction will create heat that will further close the clearance resulting in catastrophic bearing failure shown in some of the previous pictures. Once a bearing fails or spins in the race the crankcase race is generally out of spec and cases are now trashed. Crank separation. Crank web separation has a few different causes. First, pin to web clearance is critical. The interference fit or press fit needs to be within spec. If it is excessive or too tight the web will crack and the material will roll and distort. This results in never being able to true correctly. If it is too loose it will separate. It is up to the crankshaft assembler to be aware of the amount of pressure being applied on assembly. Once a crankshaft has been assembled with the correct pressure and it separates there as other reasons for that failure. Over-rev: Over-reving is another reason for crank separation. An engine makes horsepower at a specific RPM peak and looses horsepower beyond that. A CPI exhaust has a power peak at 9800 rpm. We have installed data acquisition on many motors. Ones that are prone to crankshaft failure are ones that are continually over-revved. Over-revving creates a harmonic vibration that shows up in different ways. One is crank separation, Crankcase bearing surface chattering marks, flywheel separation, lower rod bearing cage failure. Over-revving cases a large percent of the failures followed by improper installation or not being aware of any crankcase imperfections. Also keep in mind you are revving the engine at the start and dropping the clutch. The tires try to stop the engine or crankshaft rotation on the right side while the heavy flywheel is still moving on the left side. Crankshaft twist applies here. Also press fit also applies in this case. The looser the press fit the faster the crank will twist. This twisting creates pressure again on the bearing race and creates heat and eventually failure. There are 2 different lower rod bearing cage styles used in most of the Banshee cranks. The more expensive cranks use the better bearing. Again over-revving will cause the lower cage to break apart and the small pieces will be evident in the top of the pistons. The small pieces will contact the rollers and make them skid causing lower rod meltdown. Out of balance flywheel and welding of the flywheel onto the crank web. If a flywheel is pried on to remove it the flywheel shell will be out of alignment with the inner solid support. The only way to remove a flywheel is to use the correct puller that pulls directly in the center. Any prying or tapping on the outer shell will cause damage. This misalignment will again cause a vibration and make the crankshaft separate and chatter. Misaligned flywheel key: When installing a flywheel key you must make sure it is seated correctly or the flywheel will be off-center and cause the same separation and vibration. Offset keyways are especially prone to this. I do prefer a good adjustable timing plate. OIL: Outboard motor oil is not a high-performance oil. Not that you have taken your 33 horsepower from the factory Banshee motor and are producing more that 100 hp the same oil does not sufficiently lubricate the critical parts. Especially if you are using alcohol. Alcohol is a solvent. Solvents dissolve and wash down oil from the moving parts. Special oils are required for alcohol engines. If this oil is not used the crankshaft moving parts will fail quickly. Lack of lubrication is evident when the disassembled parts are inspected for excessive wear or general meltdown of the lower rod parts. And I can keep going. The crankshaft leads a very hard life and needs proper assembly and proper oil to run a long time. Even if installed perfect with all new parts, over-revving and rider mis-use will destroy it in only a few runs. Just because a crankshaft fails it is not necessarily the crankshafts fault. All 3 components combined, proper build, proper oil, and proper rider input, will result in a long running motor. If this is not your case carefully read the above.

I made the reeds for FMF for years and have them in stock. TDR 800-321-6354

Delta 3's are the best bet.

I have a CR 500 motor complete with ignition cdi and coil, New Pro Design Head, Extra blank dome, Wiseco piston, Bore, rebuilt crank, Ported for full drag race, custom manifold , Delta reed cage, Hinson clutch. extra gaskets, extra o-rings, and much more. This is a new rebuilt motor. Never been fired up. A customer never paid for the bill. It was to be installed in a 3 wheeler. The bill to build this was $2400.00. First $ 2,000.00 takes it. CALL Tony AT 800-321-6354 !!! or e-mail me at www.bansheesuperstore.com

I have a CR 500 motor complete with ignition cdi and coil, New Pro Design Head, Extra blank dome, Wiseco piston, Bore, rebuilt crank, Ported for full drag race, custom manifold , Delta reed cage, Hinson clutch. extra gaskets, extra o-rings, and much more. This is a new rebuilt motor. Never been fired up. A customer never paid for the bill. It was to be installed in a 3 wheeler. The bill to build this was $2400.00. First $ 2,000.00 takes it. CALL Tony AT 800-321-6354