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Odyssey FL250 / Re: 1981 FL250 Won't Start When Warm
« Last post by Marty on February 04, 2021, 06:16:42 PM »
No, It should still start at 119. I've seen them running between 150 - 100 psi. (100 being pretty low).  You can always put a little 2 stroke oil in the plug hole before screwing on your compression tester. If you see an increase in psi readings it's because the oil is helping to seal the rings.
On to your warmed up starting problem....... This one's tough cause they usually start easiest when their warm? If you hadn't said you are getting spark when hot I would look towards the electrical/plug side. One thing you could try is to get a new 2 dollar spark plug, gap it and swap in the new plug after it's warmed up. This would rule out a slightly fouled spark plug since you said it's getting too much fuel (running rich) and it's cheap to try.  If it is getting too much fuel only after the engine is heated up, I can't figure out why the carburetor is supplying more fuel only after being run? I would think if your floats are improperly set or your valve seat is not working you'd have these issues cold as well. When it is running do you have any fuel coming out of your carb overflow hoses? There is very little fuel pressure being built up just by spinning the motor with the recoil starter so why flooding then? Just to be sure this is a stock fl250 gas tank/pump and not gravity fed - correct?
Odyssey FL250 / Re: 1981 FL250 Won't Start When Warm
« Last post by JiveTurkeyJim on February 04, 2021, 12:41:46 PM »
The manual says spec compression is 129. I see what you're saying though. Maybe 125 PSI is still enough to make it start, but 119 isn't enough. I just wouldn't think that would be enough to make a difference.

If it is getting too much fuel, any ideas why it would only do that when warm?
Odyssey FL250 / Re: 1981 FL250 Won't Start When Warm
« Last post by LiveWire on February 02, 2021, 04:15:30 PM »
It is not just the 6 psi. I don't know what a 250 is supposed to have, but a 350 is 138. 125 would be low enough on a 350 to cause problems. The 6psi is more the straw that broke the camels back.

If it seems like it has too much fuel, that may just be because it is not igniting it.
Odyssey FL250 / Re: 1981 FL250 Won't Start When Warm
« Last post by JiveTurkeyJim on February 02, 2021, 12:01:10 PM »
Thanks for the replies, guys. LiveWire, I replaced the fuel pump, so I don't think that should be an issue. As far as the compression goes, I tested it both warm and cold. When it was cold, I had about 125 PSI. When it was warm I had about 119 PSI, and it held the compression fine. Is that enough of a drop to make a difference?

Marty, it has good spark when warmed up and cold. The plug was dry when I pulled it out after running. I tried your trick to make sure the carb bowl was full and still nothing.

I forgot to mention that when I initially try to start it after shutting it down, it fires for just a second. Then it just dies and won't fire at all until it cools down. I have also noticed that it will start fine once I drain the carburetor and pull it again. But that may be just because it has enough time to cool down while I drain it.

I'm starting to lean towards the compression being just low enough when it gets hot. I wouldn't think 6 PSI would make that much of a difference, though.
Odyssey FL350R / EGT Work in progress
« Last post by LiveWire on February 01, 2021, 01:52:14 PM »
Working on an EGT. It will be powered off the ignition and cut the engine if the temp hits 1300.
Odyssey FL250 / Re: Tuning up a new FL250 Ody rebuild
« Last post by LiveWire on February 01, 2021, 11:28:03 AM »
Your problem with the regulator (check tee) has been experienced by many. They are missing the spring and ball. This is why I do not use them at all. I have heard it was just a bad batch and that they were good again after that. Maybe they still pop up though. I use a regular tee and run the return line to the top of the cage and back down. That height sets the fuel pressure.
Odyssey FL250 / Re: 1981 FL250 Won't Start When Warm
« Last post by Marty on January 31, 2021, 01:23:53 PM »
Hi JiveTurkeyJim, I would start by pulling the spark plug after you've been riding. It shouldn't be wet since it's just been running. Next ground the spark plug to the fins to make sure you're getting spark. I wouldn't have thought about fuel leaking back in through the impulse line. To test this I would shut off the fuel from the gas tank. Then pull the line going to the carb and fill with 32:1 to make sure you're carb fuel bowl is full. At this point you should have a warmed up motor with clean spark plug, fuel only coming from carburetor bowl and as long as the carb is allowing air to pulled in (should since it ran perfectly before you shut it down) it should start.
Odyssey FL250 / Re: Tuning up a new FL250 Ody rebuild
« Last post by Marty on January 31, 2021, 12:59:52 PM »
Ok so....  Rechecked points/timing etc. and all looked good. Went down and picked up yet another BR7es spark plug and what do you know I got spark! With the back end jacked up I ran this at all rpm's for about 2 weeks. Two pulls to start with choke on and one once warmed up. Also, after LiveWire mentioned the lean bog I was having at WOT I went back through the fuel system. Blew air through the fuel tank lines to make sure they were clear. Retested the fuel output on fuel pump. And finally disconnected the fuel tee to check. This was a brand new OEM Honda fuel Tee removed from an unopened package. Guess what!!! The Tee is completely open??? You can blow on any part of the tee and there is absolutely NO resistance. Sucks! Luckily I'm a bit of a pack rat and after some searching located the original 1979 Tee. This at least has some resistance when blowing in towards the check valve where as the new Tee has zero. Hoping the replaced tee might let me go to full throttle without the bog I warmed it up good for about five minutes and went for a ride. Well it did ok to about 1/2 throttle but quickly seemed like it might stall. I tried unsuccessfully to bring it up to full speed a few times but then it did stall and wouldn't restart. This time I went right to the spark plug - No spark:(   Pulled the spark plug and it really doesn't look that bad. Pretty clean overall, a bit of brown around the white resistor but not terrible. Geez, I once ran a chainsaw which died on me and when I pulled the spark plug it looked like black carbon was growing out of it (blocked muffler screen was the culprit). Anyway, I took a brass brush and parts cleaner to all the non working spark plugs and now all have spark. So I guess I'll have to pull the rebuilt carburetor. Since it's already been rebuilt, float set to manual specs. I'm hoping I can find something obviously wrong with it. Until I can figure out why its fouling out the plugs I can't do any other testing. Oh well, It's 27 degrees and snowing at the moment so looks like it will have to wait for warmer weather. Thanks, Marty
Odyssey FL350R / Re: New intake sneak peak
« Last post by LiveWire on January 24, 2021, 10:13:38 AM »
The one pictured is for a 39mm Keihin PWK. It is blended to the air guide of a set of V-Force 3 reeds. The boot on the billet intake was actually for a 38mm Mikuni. It would stretch to fit. The rib was not in the right spot, but close enough with the soft boot. This boot is closer to the hardness of the stock boot which is where I noticed the poor fit and modified.

I can make one as a stock replacement. If I made of to fit a stock carb, I could make the same way or more like the stock boot. I have thought about making an air guide for the stock reed cage that also matches up. Then it would be a matter of mix and matching the right parts. I could also make for the 32/34 Mikuni carbs commonly used as a stock replacement.
Odyssey FL350R / New intake sneak peak
« Last post by LiveWire on January 24, 2021, 07:51:48 AM »
The billet intakes I was making were a great success. By integrating the boot and flange back into one, I can get even better blending. The blend starts right after the carb rather than after the bolt on boot. The boots will be urethane. Rather than being inside the flange like the stock intake, the plate will clamp the urethane preventing the need for a gasket. The stock style setup can separate as well.
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