Author Topic: FL350 top end rebuild questions? (Read 3275 times)

Trailbuggy · « **on:** October 03, 2009, 06:48:23 AM »

I picked up an FL350... Always wanted a 350 or a pilot. Finaly got one!

Anyway. I pulled the top end down to see why it sounded like bolts in a blender and found the piston destroyed on the exhaust side.
Seems to be fairly common on these beasts so no big deal.
I measure the cylinder at 78.9 mm and the piston at 78.6mm. Keep in mind these are rough measurements with a pair of digital calipers to see what size it is.
This must be stock bore? are the honda/art pistons still available so I dont have to go to a 80mm weiseco? If so where can i get one? who is reputable and could bore my cylinder and clearance the exhaust bridge? how far down on the piston do the oil holes need to be drilled?

On a good note the engine looks great inside, crank and rod check good pretty much in the middle of tolerance, and it leak tested good

Here are some pics
John

hoodlum · « **Reply #1 on:** October 03, 2009, 09:48:27 AM »

I don't think the art pistons are still available,but I could be wrong...Just call a Honda dealer and ask....Before doing that though,you need to get someone with a bore gauge to measure the bore and make sure it's not tapered....It could be even wider in the middle,or somewhere you couldn't measure with the caliper...It definately siezed though...I wonder how long it had been since it was rebuilt? I can still see crosshatch on the cylinder walls...I think...Actually,it appears to have been sleeved.....I think...Hard to tell by the pics...
Hoodlum

Trailbuggy · « **Reply #2 on:** October 03, 2009, 03:17:57 PM »

It absolutely needs to be bored before a new piston goes in. I was just roughly measuring to see where it was because there are no markings on top of the slug. it looks to have been seized but it ran okay when I took it apart, it was just noisy.

does weed bore cylinders? what about aftershock? I've heard things about aftershock :shock: but no first hand knowledge.
What about odyssey salvage do they do machine work? I want someone that knows the animal to do the work.

I will look at the jug and take some more pics. the way the bolts and nuts looked I was thinking that it had never been apart.

Thank-you for the response I have some questions about this thing for sure. I have built plenty of two strokes but these things seem to be a little different with the heat they generate.

John

Adnoh · « **Reply #3 on:** October 03, 2009, 08:58:56 PM »

Can you pot a pic of the crown of the bad piston. Thanks adnoh.

hoodlum · « **Reply #4 on:** October 03, 2009, 11:28:12 PM »

Quote from: "Trailbuggy"

It absolutely needs to be bored before a new piston goes in. I was just roughly measuring to see where it was because there are no markings on top of the slug. it looks to have been seized but it ran okay when I took it apart, it was just noisy.

does weed bore cylinders? what about aftershock? I've heard things about aftershock :shock: but no first hand knowledge.
What about odyssey salvage do they do machine work? I want someone that knows the animal to do the work.

I will look at the jug and take some more pics. the way the bolts and nuts looked I was thinking that it had never been apart.

Thank-you for the response I have some questions about this thing for sure. I have built plenty of two strokes but these things seem to be a little different with the heat they generate.

John

Yes,it needs to be bored regardless,but having the bore measured will let you know exactly what size piston you will need...It could actually need larger than the next size,depending on the widest part of the bore...
As for repair shops,there are good and bad in all...For example,I had engine work done by both....Odyssey salvage was a nightmare,where on the other hand,I had a cylinder bored by Aftershock, and it ran for 3 years before a lower end failure sent parts up beside my piston and ruined my bore...Steve at Aftershock has been playing with 350's for a long time, and is quite knowledgable with what works best in them...I would give both a call and decide for yourself....
Hoodlum