SLED POWER 101

[minibajaman]

Odybuggy, what is the reason you are looking for a new engine? *Reliability? *Power? *Original engine blown up beyond repair? *As bugpac mentioned a stock 350 has plenty of power for the minimal suspension that they have. *A Polaris 500 4 stroke makes about the same hp as the 350 but more torque and will be much more reliable. *I have seen someone online do that conversion before. *I don't know how much power that 440 makes, but probably quite a bit more than a stock 350 and most likely too much for the stock suspension. *They are both good choices but it really depends what improvement you are looking for in the odyssey.

[odybuggy]

Mostly reliablity. *I am tried of rebuilding the engine every season. *I am leaning toward the polaris for the fact I can also get away without having premix fuel, have beter fuel economy and still get a way more reliable motor. *

I also feel like the 440 would be to much motor but thought if I did need to go that direction I could tune it down a little and get a little less power and even better reliablity.

If you can find the 500 convertion I would love to get the link to take a look at it.

Thanks again for the comments and any more info that anyone has would be greatly appreciated.

[LiveWire]

I go years between rebuilds on my FL350 and have it significantly modified.

[odybuggy]

I have had the worst luck with mine. *There is one in my group that has 12 yrs on the same rebuild and use it alot all winter long so I know they will last awhile. *Mine has been rebuilt twice in 3 years and developed an air leak that I have not chased down yet at the end of this season. *Just a bit flustrated. *It maybe something simple to fix and away we go. *I am just looking into alterneate routes that I maybe able to go.

[LiveWire]

I have been advising people lately that I an doing top ends for to replace the crank seals if they are original or of unknown age. That is even if they do not feel they are leaking. They are hard and may leak when running. You can replace them without splitting the cases by driving screws into them and yanking from the outside. I used to assemble, leak test then reseal any gaskets that failed with sealant. That is too time consuming as it seems at least one gasket always leaks. I now use anaerobic gasket maker on case, base and reed gaskets. It does not harden until after assembled so it will not add thickness. The excess does not harden so it can be wiped off or washed off later. The excess on the inside will get flushed out. I think there are more reliability issues related to age than the basic design of the engine. If you swap in a used 4 stroke, it may not be that long before it needs work and you may be back in the same boat. Swapping an engine in is a lot of work. There will be many details to work out. I think it will be far less work to figure out your original engines issues. The guys here are building custom buggies so they have no original engine. They are forced to address the details of making one work.

So what is the cause of the rebuilds being needed? What piston to wall clearance was used? Was the exhaust port bridge relieved? Cooling/lube holes drilled in piston? Is the jetting correct? Using stock air box with foam filter?

[LiveWire]

Oh and the one with 12 years is probably about to break a piston skirt off on the intake side and trash the case halves.

[odybuggy]

There you go using common sense on me, the more I think about the second rebuild was a burned piston because it leaned out on a long ½ throttle ride and I do not know what the reason for the *first rebuild was. *It was done right before I bought it. (He had the receipts and I went down and talked to the dealership that did the rebuild.) *The second rebuild was just developed the leak was done by a shop here in town that has been do it for a long time and has a great rep. *I do not know for sure what he did I just trusted him on that one. *It had run great all season until the last time out. * Then it started leaning out witch has to be caused be some type of seal / gasket leak. *

The jetting was a bit rich (the plug was dark brown and a little wet) and I am running an open air box with the double uni foam filter. *

I would like to stay with the stock motor just for the fact that it is 20 yrs old and there are not that many around. *So I am going make a leak down tester this weekend and fix what I have and go from there. *Thanks LiveWire. *

Oh by the way the 12 years old motor is probably going to die soon He is afraid at this point to touch it after all these years. *The motor is the last one that Ct racing had left from the old stadium lites racing and has a water cooled jug and head. *Anyway thanks again I may be after your insight very soon I will do as much of the work as possible my self this time.

[LiveWire]

Removing the air box lid will require jetting up. Often people miss the needle which would probably need to be raised one clip position (middle is stock) The stock slow jet is so excessively large that the plug often looks black/wet *from idle, but the engine leans out at higher throttle positions. If the machine stumbles off idle then 'cleans out' I would drop the slow jet to a 45 from the stock 52. Even with a reputable shop, they are often not familiar with the FL350. A big bore air cooled engine with the cylinder behind a seat. I bore them to .005" piston to wall clearance. The Honda spec is .004 and I allow a little more with the Wisecos. The Wiseco box currently lists .004, but used to only have a rule of thumb type spec sheet that came out to .003. They would practically seize the first time out at .003. Many shops will still use that rule of thumb. The bad ones bore to the same tolerance as the small piston engines they normally bore. The Wiseco sheet lists to drill the holes, but many people and shops don't. The same is true with relieving the exhaust bridge.

The water jacketed cylinders require the same prep. I have a customer here that is for sale. He toasted it and I had a freshly bored and ported cylinder that he swapped on with one of my heads to make the next race. He decided there no point going back to the other one.

[tinman]

How old are the reeds? you might try flipping those.

[LiveWire]

If they are the stock metal reeds, I would just replace. A waded up metal reed will not fit between the crank and the cases. The cases lose.