Author Topic: FL350 piston modifications  (Read 5110 times)

Rich Paulson

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FL350 piston modifications
« on: July 25, 2009, 07:21:51 PM »
Once again I am re-building the top end on my 350. The original configuration had a modified skirt on the intake side that was cut away on the bottom matching the intake opening.
Is this suggested for more power AND longevity or is the piston better left alone.
Also, with a water cooled Rand head and banshee radiator will .004 be enough clearance.
Just looking for best practice on my Ody

Adnoh

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FL350 piston modifications
« Reply #1 on: July 26, 2009, 09:33:05 AM »
Do you some pics for viewing.

hoodlum

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Re: FL350 piston modifications
« Reply #2 on: July 26, 2009, 10:17:40 AM »
Quote from: "Rich Paulson"
Once again I am re-building the top end on my 350. The original configuration had a modified skirt on the intake side that was cut away on the bottom matching the intake opening.
Is this suggested for more power AND longevity or is the piston better left alone.
Also, with a water cooled Rand head and banshee radiator will .004 be enough clearance.
Just looking for best practice on my Ody

Is the engine modified as far as porting,a pipe and air intake mods?If not you would probably not feel much difference in a piston that is notched and one that isn't...Probably wouldn't tell much difference if it was modded...Just be sure to relieve the exhaust bridge and drill those cooling holes in the piston...
As for clearance,I usually run .005 on my pilot, and actually, the last engine I just rebuilt ran for over 2 years with.010 clearance without problems, so don't be afraid to go a little bit larger than .004....It's better than siezing...
Hoodlum

Rich Paulson

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FL350 piston modifications
« Reply #3 on: July 26, 2009, 12:19:48 PM »
Thanks for the fast response!
OK here's the list of stuff on my 350
DG pipe, 38 mm Mikuni, 80 MM Wiseco, billet manifold, G-force 3 reeds, K&N air cleaner, gravity fed 5 gallon tank, (correct needle and seat in the mikuni).
I have worked on the passages to the transfer ports to match the original cylinder that came with the 350. You can view the pics at http://picasaweb.google.com/richpaulsonster/1985OdysseyPics?feat=directlink. Would have uploaded to this site but I think there are restrictions on this site for the free g-mail account I have.
Thanks again
Rich[/url]

Adnoh

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FL350 piston modifications
« Reply #4 on: July 27, 2009, 02:51:38 PM »
May want to smooth out those port chamfers. Those will cause you some issues later.

Rich Paulson

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FL350 piston modifications
« Reply #5 on: July 27, 2009, 07:13:58 PM »
They do look rough, will have to get a lighter grit stone to smooth them out. I will also bring the cylinder back to get the .005 clearance. Will take pics on completion.
Thanks for the advice!
Rich

Rich Paulson

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New parts on the Odyssey
« Reply #6 on: February 19, 2011, 03:27:06 PM »
Just wanted to give all a follow-up on what eventually happened to this Odyssey. Turns out the water pump that I put on this motor had a DISTROYED implellor. Did not matter how i jetted the Mikuni as it overheated and melted pistons. I have a few ash trays since my last post.
The net result of what I've done now  is:
1. Added a Spal PWM fan controller and made it control the water pump speed
2. Added a relay controlled by the Spal to turn the electric fan on and off a needed, based on engine temp.
3. Added my own custom air cleaner (Uni foam element) set-up that has a 3" aluminum tube. I found an outfit that makes the transitional rubber transition fitting from the air cleaner tube to the carb. I also found on-line the best clamps to keep every thing tight, instead of the usual worm drive clamps
4. Re-jetted to a 480 main, 60 pilot and have the needle set in the middle groove. What is interesting is that this motor now has 8-10
5. Did some basic restorations, new starter, new water pump (Ford intercooler pump) all new cables, new battery (AGM), took the driven clutch apart and replaced the little shoes/lubricated, replaced the axle bearings
6. I was just letting the overhead tank gravity feed to the carb before but opted to add in the stock pump. At first it over-fed the carb with pressure so I added the bypass line to the filler neck. Randy from Odyssey Salvage has said at long full blast runs the carb will run out of fuel and you will melt the piston if you do not run the pump.
I have taken it up and down the street, really seems to run strong. I will be doing plug chops on my next outing to refine the settings as needed.

I have added sime photos at https://picasaweb.google.com/richpaulsonster/1985OdysseyPics# to show the new air cleaner set-up.
All for now
Rich

LiveWire

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FL350 piston modifications
« Reply #7 on: May 17, 2011, 12:50:32 PM »
I cut an arc on the intake side of the piston on mine. It improves intake flow, so power. It also reduces the piston catching the bottom edge of the intake port. If even after a fresh bore, you hold the cylinder intake side down with the piston in it and slide it across the port, you can feel the bottom edge catch. On a used piston, you can see at least wear marks where the edge of the port touches the piston. On a very worn engine, you can see cracks forming in the piston.