Starter locked??

[ORION '95 Speedster]

Possibly. I would clean all the particles out of the crank, and roll it over by hand. Do the bearings make noise? You would need to pull the motor, and flush the crank with gas or something to clean it out. There is a very good chance that the crank is still OK.

 

[ORION '95 Speedster]

You will need to find out what caused the failure, or it may happen again. It obviously ran too hot. A plugged fuel filter, vacuum leak, plugged carbs, malfunctioning oil injection system, or maybe a plugged cooling system caused a lean condition, which increased the engine temperature. If it blew up from running lean, replacing the engine block will not remedy the problem. It will run lean again and blow up. You can get a "temp gun" on eBay for about $10. It shoots a laser beam at the engine and tells you the temperature instantly. After installing the motor, run the engine in the water for a while, and keep checking the top end temperature every few minutes. The temperatures on each cylinder should be similar between the two different engines. If one cylinder begins to overheat, shut it down right away.

 

[cncsignman]

Thanks for the advise. I've never rebuilt an engine before. Is there a good how to vid or a step by step manual out there? I'm not scared to get dirty but need to know the best way to pull engine, rebuild and install.

 

[cncsignman]

I have a shop manual

 

[ORION '95 Speedster]

The shop manual should have the step by step procedures. If you have never rebuilt a motor before, this is a good one to start on. MUCH simpler than a 4 stroke motor. Removing the engine is very strait forward, just pull the motor mounts, drive shaft, wires, hoses etc. For assembly, make sure you follow the manual precisely. Torquing the head bolts in a certain pattern and to the correct LBS is very important. Make sure you measure the clearances and everything on the cylinder/piston. Put oil on all the contact points before assembly. Etc.

 

[cncsignman]

Any special tools needed besides an engine alignment tool?

 

[ORION '95 Speedster]

You will need a torque wrench for sure. A piston ring compressor might be useful, but definitely not required (I never use mine). You will need a gasket kit of course, and probably some gasket maker. Permatex® the Right Stuff® 1 Minute Gasket™ is the best gasket maker I have found by far.

Rebuilding the top end of a two stroke is very easy. All you do is connect the new piston to the rod (via the wrist pin), and slide the cylinders back on. You can probably just hone the old cylinder and pick up some new pistons.

When you break in the new top end, it should be done properly in order to get good performance and life expectancy out of the motor. Basically what you do is pre-mix your first tank of fuel in addition to the standard oil injection. Don't run the motor at a constant RPM for the first tank of fuel. Vary the throttle as much as possible in a slow consistent motion. No quick accelerations. Keep the RPM's at 75% or less. Warm it up before putting any load on the engine. A compression check after the first time out on the water will give you a good idea how well it went together. Keep checking the temps with the temp gun.

Total rebuild cost should be under $500 including parts, gaskets, etc. Without searching for the best price, I spotted a complete top end kit on eBay for $175 with free shipping. Comes with pistons, wrist pins, gaskets, etc.

 

[cncsignman]

I'm also looking at a new sleeve as one is cracked

I've seen used jugs with sleeve for 65.00. Mine are standard bore. Should a used rebored work? Just wondering if SBT would be easier at this point. I'll check the bottom end before I go that route though. It's been a PITA to get the motor out. Have all but the oil lines to disconnect. I did find out I'm gonna need to pinch them off first. I made a hell of a mess!!

 

[cncsignman]

Well I got the engine out yesterday. After looking in the bottom case, I've decided to replace with an SBT engine. Got it all stripped down and ready for core