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1998 Thundercat RestoMod

19K views 108 replies 21 participants last post by  WickedWango 
#1 · (Edited)
So I have been swiping ideas from ya'll for awhile now so figured it was time to pay it forward. RestoMod project is a '98 T-cat, 121" that I picked up last year. Below are some pictures when I brought it home.

Intention is to break her down to the chassis, and build it back with the AGLT mod and 136" skid. I know it's been done over and over but I have myself have never done it.

Follow along and enjoy
 

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#70 ·
Checked the ring gap on all three cylinders. Two point method 90 degrees apart on the top and bottom of the cylinders for a total of four measurements. Below are the results. Arctic Cat specs are 0.008" to 0.033" so I think we are good to go.

CylinderTop GapBottom Gap
Mag0.019”0.019”
Center0.020”0.020”
PTO0.019”0.019”
 

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#71 ·
Completed a quick mock up of my handlebar set up. I decided to go with a pivoting riser setup instead of the steering post mod to give me some adjustability. Also not sure if I will stick with the stock Cat bars or not. I am using a 1.5 inch universal pivot adapter and a 2 in riser.
 

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#73 ·
Worked on the cylinders today. Red scotch brite with some light machine oil. Each cylinder required approximately 5 minutes of work. The machine oil is not really for lubrication but to hold the schmutz in suspensions. Most of the "glaze" is not embedded metal but embedded combustion byproducts and oil. The pad really just lifts this out and as you can see the original cross hatching was brought back to life.
Zero material was removed from the cylinder and should provide a nice surface for the new rings. Below are some before and afters. Note how incredibly thin the Nikasil coating is adjacent to the ports.
 

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#74 ·
In keeping with the purple theme, finished powder coating the heads. Cylinder are painted with aluminum engine enamel and covered in clear. A little detailing left to clean up some gasket surface.
 

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#75 ·
Very cool!
 
#76 ·
All the external engine parts have been prepped. Recoil and stator cover powder coated to match. Color is "translucent grape". Amazing what you can accomplish with a $99 dollar powder coating system.
Weisco piston kit is here and just waiting on rebuilt crank. The crank is the single most expensive part of this particular build. It is essentially a new crank, new bearings and rods. The approximate cost in universal currency is a "buttload".
I really don't know how much actual riding I'll ever do and I could have purchased a decent used late model sled for what I have tied up in this but I have enjoyed the process and I hope you are all enjoying following along watching a fool and his money part ways. Cheers.
 

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#78 ·
This will be the first time I am running Wiseco pistons in a sled. However, if you will indulge my non snowmobile segue, I have run their pistons successfully in my street/strip car. I am running a set of 11.1:1 forged in 5.4L dual overhead cam engine I put together four years ago. It's in a naturally aspirated 2002 Mustang GT. The car runs consistently in the low 11's. I have beat on those pistons for a long time and sometimes maybe on the bit to lean side and they have never given me any hint trouble. This is just my personal experience, I have been very pleased with them. I know they are not sled pics but here is the engine in the car.
 

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#79 ·
Completed the rebuild of the balance shaft. It was a bit tricky. Huge thanks to Big *****, Zrt1200 and Tcat446 for there outstanding information in the sticky. Not much I can add above and beyond what's in there.
 

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#80 ·
Completed the rebuild of the balance shaft. It was a bit tricky. Huge thanks to Big *, Zrt1200 and Tcat446 for there outstanding information in the sticky. Not much I can add above and beyond what's in there.
It would be a good idea but not imperative to put it on V blocks and check to see how much run out you have. I hit mine with a dead blow hammer on the high spots and got run out to 1/2 thou. Thanks Al for the tip.
 
#82 ·
What brand wrist pin bearings do you plan on using? Reason I ask is I had terrible luck using the Wiseco wrist pin bearings and the Arctic Cat bearing caps. Needless to say they do not mesh and resulted in wrist pin bearing failure in under 200 miles, twice, before I figured out what was going on. So I recommend using the OEM bearing and OEM bearing caps.
 
#84 · (Edited)
That is exactly what I had planned to do, so definitely appreciate the heads up. What was the nature of your bearing failure. The stock Cat bearing is 22mm x 27mm x 23.7mm. One catalog list the 1000cc Thundercat Wiseco bearing P/N B1074 as 22mm x 27mm x 22.8mm which would seem to be to short. The correct Wiseco bearing are P/N B1091. The Thundercat and all your sleds listed in your signature share the same bearing, I wonder if this could have been part of your issue. Thanks for the info.
 
#86 ·
Finished up the top end. Installed the stator, reeds and necessary accessories.
 

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#90 ·
Yes this is a fantastic build!! Great job and thanks for the pics and updates!
 
#92 ·
Not sure if I want to pull the pin on this grenade but I am curios about crankcase sealants. I know this has been discussed before from a preference perspective but I am more interested in a chemical perspective. Both Cat and Polaris recommend RTV silicone sealant for their case reed motors.

Cat part number 0636-069 "High Temperature Silicone Sealant seals exhaust flanges, gaskets and non-gasket surfaces. This sealant is recommended for sealing the crankcase halves of all Suzuki liquid cooled engines."

Polaris recommends 3-Bond 1215 RTV silicone sealant P/N 2871557 "Curing time and film thickness are critical for proper bearing clearance."

So there are three basic types of sealants:
  • RTV silicone
  • Anerobics (dimethacrylate ester) same as threadlocker
  • Motobond, Yamabond..etc (synthetic rubber)
Curios as to why both manufacturers would recommend silicone in this application since silicone is not fuel resistant. Also with RTV, even a thin layer there will be some squeeze out. This can be cleaned up in the rod and crank throw areas but what about the inaccessible areas like the counterbalance shaft. And lastly, is Suzuki using it for bearing clarance also?
Interested in your thoughts.
 

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#93 ·
I have used anaerobic sealant. I am no slather ass when it comes to doing engine rebuilds and I can tell ya first hand I have had leaks with anaerobic sealant. So,...in my opinion, I will never use it again for that. Maybe an aluminum oil pan on a vehicle but not a sled engine. I know that one thing guys will consider is using different things like three bond 1184, 1194, Yamabond ect... ect...thing is you have to beat it with a hammer and then some to separate them. I think Yamabond is more user friendly though, not quite sure.
In my research and asking people that do it professionally they recommend good old Cat case sealant. Its black, goes on great, and so far is holding up as expected. Cases come off with ease. A slight tap and they come apart. No leaks either. I won't use anything else personally. Lots of RTV won't hold up to gasoline and/or some kinds of oil as well. Your call though. this is what I use, got it from Country Cat.

Arctic Cat High-Temp Black Silicone Sealant - Exhaust, Intake, & Top End Gaskets 0636-069 Replaces: 0109-768, 0132-105, 0134-971, 3000-211, Arctic Cat $20.55 Arctic Cat High-Temp Black Silicone Sealant - Exhaust, Intake, & Top End Gaskets 0636-069 Replaces: 0109-768, 0132-105, 0134-971, 3000-211, Arctic Cat Country Cat
 

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#95 ·
Been awhile since the last update. Thrashing do get this done before the season really kicks off. Finished installing pretty much everything under the hood. Wrapped the pipes, installed carbs, air box etc. Installed the clutches with the original Tcat specs to establish a solid baseline. Now onto painting the hood and finishing the tunnel extension. More to come.
 

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#97 ·
Been 20 days since my last update. Kitty is alive an purring. Fabbed up a tunnel extension. Painted the hood and added some decals. Down to trimming it out and polishing her up. Anxious for the maiden voyage.
 

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#100 ·
Well, I think it's finally done. After 9 months the end result is below. Hope you have enjoyed following along. Here is a list of what has been done for those that are interested.
  • New crank, rods and Wiesco pistons.
  • Rebuilt counterbalance
  • Clutches rebuilt to factory specs
  • New CA Pro RZ Skis and Ski Loops
  • AGLT front end conversion
  • 121" to 136" conversion
  • DIY tunnel extension with Crossfire rack bolted on.
  • Skinz rear flap (to narrow, will be replaced with OEM Cat)
  • Thundercat front and rear arms
  • New Ripsaw II 1.25 in track
  • Wahl Bros Anti-Ratcheting Drivers
  • Wahl Bros anti-stab kit
  • Rebuilt Skid front and rear Fox shocks
  • All new skid hardware, bushings, wheels, torsion springs...etc
  • New belly pan
  • Hood, chassis and tunnel repainted
  • Custom seat cover
  • 13" Blacked out windshield
  • Rebuilt caliper, chain case, new bearing all around.
  • REbuilt choke and trottle cables
  • Added rectified and regualted 12V DC source for GPS, Cellphone...etc
  • Carbs rebuilt and synced
 

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