first copy
**Note: the pics that were originaly set in this thread were removed durring migration to the new format. PM me if you need any as I can email them)
I am starting up a "Do-it-yourself". This is due to the amount of information requests I have been getting after the completion of mine. I want to help anyone that I can, so I need the help of others that have been down this road like I have so I do not miss anything when I put all this info together. So please reply with helpful tips for me!
This direction I went is from a proven recipe, as time goes by and more exploration is done by myself and others, I will add to this.
BTW, there are a ton of "little things" that will come up. Nothing major just pesky things. PM me if you like.
This is my perspective on what I have found on building a big watercraft based triple from the ground up. I wanted as much "bolt together" with the least amount of fancy fabrication. Since completion I have found cheaper sources for some of the parts, PM if you like.
With this type of motor package, you can get more (Naturally Aspirated) HP per dollar than having anyone build one for you, plus ported and stock cyl's can make 230HP or higher depending on the setup. Keep in mind, this DIY paper is geared towards the budget minded person like me. There are many, many decisions during this process but I will be going with the less expensive route without compromising on integrity of the motor or HP!
Having the privilege of working closely on this project with Doug Ruth, porter and R&D for Union Bay for over 6 years. This project has given me an opportunity to tap a large amount of info that I normally would have taken me years to discover on my own. Along with several other owner of these motors and builders I tried to take the best that each had to offer.
By taking the crank case from a triple 1050/1200 Polaris watercraft you can run snowmobile crank parts, cyl's and so on. It is just like adding a 3rd cyl to a 800 or 700.
The 1050 is based from 3 rods, bearings and cyl's from a 700. This is the 68mm stroke motor. You can use big bore 770 stuff to make an 1140cc.
The 1050 is the least expensive route to go.
The 1200 is a 70mm stroke based motor. It is made up of the rods, bearings and cyl's from a 800.
Crank case
Any 1050/1200 Polaris watercraft crank case will work for this job. All you need is the two case halves. If you get a complete motor to rob it from, hang on to the domes, water covers, reed cages w/stuffers and water rail. You may want to use them later for your motor.
If you go with a 1200 you will need to have the case fly cut out to accept the 800 (or 85mm) cyl's . If you are building a 1050, this will not have to be done to the case.
You can use a twin recoil/mag housing. Is a bolt on deal. However, you may need to work the inside of it where the stator plate goes depending on what type of ign system you decided to go with. Union Bay Racing has a billet mag housing that will allow you to use several styles of ign stators and incorporates the use of a v-belt driven water pump found on older Fuji motors from Polaris. Very reliable and inexpensive water pump. Note: the shock tower on mag (right) side may or may not need to be notched if the domestic twin mag/recoil housing is used in conjunction with a 12.5" Center to Center belt (same as any Gen 2 twin ###1065 Pol p/n).
The front of the top case has the provisions cast into it the same as the twin for a water rail. Having this milled flat and two holes taped with the water passage in the center of them will allow a bolt on style water rail. If you still have the water rail from the top of the motor, this can be used as a template. It can also be used for this application. All of the billet water rails that I have seen are basically identical as far as bolt pattern. I have seen home made rails that use a 0-ring just like what comes on the twin. This works if you chamfer the passage for the O-ring.
If you decide to use the UBR mag housing, there are a few things to discuss on the use of it.
Mock up, mock up. You can never mock this thing up too much. To make sure everything fits perfectly. You will have to make sure the hole in center of stator plate will be big enough for the crank. Make sure you get the water pump pulley from UBR when you purchase the housing. Starter cup, depending on what type of flywheel and or ign system you use, you will need to make sure the starter cup will contact the pawl.
One thing to look at when selecting a case is to make sure the crank bearings have not worn into the case. Feel the edges for "knifing" and make sure the bearing surface is smooth. It is OK to see the places where bearings have been living, just not feel impressions in the aluminum. This will ensure you have a good "bite" on the bearings when the case is mated with the crank.
One last thing before assembly, you must chamfer oil hole on the PTO side with a small carbide. The object is to make it give oil to the sides of the bearings as the bearing with the snap ring covers up the factory oiling hole. The mag side is done in this fashion from the factory. Bottom line, make the PTO end oil hole look like the mag end oil hole.
Crank
There are several different ways to go about this.
One is to purchase a new crank that is built for this purpose. Many shops out there can supply them, I can supply anyone a new OEM crank.
Another way is to send two twin cranks to a shop like SLP in Idaho to have them rebuilt into your application. From some of the experts on these I have been told that the 70mm cranks do not need to be welded but the smaller 68mm ones do when buying new. Something about the "glue" on them is just as good as welding. I did not have my 70mm crank welded.
The PTO end should have a wide bearing (5207-ILT) and a narrow bearing (6207NX18). The narrow bearing being closest to the end should be of the type that incorporates a crank locating snap ring on it.
There is another snap ring (crank locator) that goes on the mag end. It sits in the case and not on a bearing. This is ring is needed if a twin housing is used and is used with a watercraft crank as well.
On the UBR style, a pto seal is used (Being a metal seal coated in rubber) and the little square nubbies cut off flush with a razor blade.
Ignition
Several different direction to go on ignition. There are many that have not been tried or are being tried as I type this. The two most common ones used to this point that I am aware of are 1984-1989 Indy 650 (I am told that the old Polaris Centurian is the same) and XCR/Ultra ignitions.
Pros/cons of these two systems:
-650: Pros. Easy to find, lots of aftermarket support, low cost.
Cons: 120 watt lighting coil, timing curve is conservative in low RPMs.
-Ultra: Pros. 280 Watt lighting coil, better low end timing curve.
Cons. Expensive, harder to find, aftermarket support is sparse.
I went with the 650. I got a complete system for under 100 bucks on ebay from a '89 650. As far as the timing curve goes, once you find the peak torque on these motors, set 16* BTDC at that RPM. I didn't use a dyno, I just set mine at 16* @ 8000 RPM. This is a good base line setup. These motors make so much torque on the bottom (even without VES jugs) that the little extra timing and lighting coil power was not worth the cost to me. I am able to run my hot grips on high and a PIAA head light, LED tail light with power to spare. Hot Grips pull 15 watts, the headlight pulls 65 watts. I did use a Autometer brand temp gauge set up with a rectifier from Radio Shack ($3) but it pulled way to much power to run the rectifier. So I went with a dummy light instead. A XCR/Ultra alternator would do it with power to spare.
The flywheel for either system will have to be re-tapered to match the crank taper. I do all flywheel tapering in-house for $75.
There are some folks out there that use the twin recoil housing and water pump with the twin stator. I don't know which flywheel and CDI they are using, but I think this route has some real advantages if you consider using a stock mag housing. I say this because the stock twin mag housing needs to be machined slightly to make the stators from the triples fit. If I were to go this route I would be curious on where the flywheel would need to be in relation to the stator, how deep do you cut the taper? Not rocket science, but would have to be addressed. These little things (among the hidden ones, air gap on a triple flywheel for example) along with using the proven V-belt pump is why I went with a UBR mag housing. It is as "bolt on" as you can get.
You can use a twin stator in a twin mag/recoil housing with an XCR re-tappered flywheel.
Regulators
Part number of old 650 ignition should be 4060071.
And if you are using the new 650 / RXL ignition the part number is 4060092.
Pistons:
In one word, ELKO. You cannot beat the stock Polaris piston. It is well worth one's while to buck up and spring for the stock ones. This can be a subject of great debate, but this is my recommendation. As far as the new coated pistons go, unless you have issues with sticking pistons, the older non-coated will work fine. Plus they are much, much cheaper as a kit (rings, pin and piston).
Cylinders:
Stock, valved or non-valved. Doesn't mater, however, I would highly recommend the newer valved jugs. Better design all-around.
I had Doug Ruth do his "race port" on my brand new non-VES jugs.
Always check your port timing. What you should be shooting for, believe it or not, is as close to Polaris twin as possible.
