Ok here goes.
My buddies wifes fl350 would not stop bogging this weekend out at Dumont dune. Works that's been done. full race porting 38mm mikuni carb boisen reeds eee pipe 82mm wiesco watercooled head running 175psi. It was fine out at johnson valley 3 weeks agon ran all weekend long. Its been a champ all year. We get to Dumont go to do a plug chop and after half throttle bog city. So we richend it up cuz it felt like a lean bog. Went all the way to a 530 and rich as hell it still bogged. So we went the otherway jet by jet all the way down to 410 still the same. Tried 2 other new fuel pumps and even an electric fuel pump still the same. Then we thought electrical. so 1 by one we tried the coil then the CDI (Capacitor Discharge Ignition) with no luck. We spent more time on this thing then we got to ride. So I want to get it figured out. Any help will be great thanks.

Any leaks? Clean the carb? Hows the tank look? Is the choke working right?

I dunno, just some things that come to mind that are simple.

No air leaks( idles great) cleaned carb before reassebly everytime during jetting. choke works.

Clutches working ok?

Yeah they are shifting out fine. Its just wierd that once you hit 3/4 throttle when its warmed up it just boggs but when you back off its fine. When its cold you can run it all the way full. Could it be the rectifier? Or maybe the magnito assembly. Now I thinkg we should of tried a compression check when it was warm....... hmmmmmmmmmmm something else to try.

Have you done another compression check, my guess is that you no longer have 175 lbs compression.

Gary

Yeah we checked it out their while it was cold but not warmed up. So I'm planning to swing by my friends house and try a few new things after work tomarrow. We are gonna throw the carb it from his bike and check the compression after its warm. To me it felt as if it was running out of fuel but after trying 3 different pumps 1 being an electric pump my buddier running on his fl350 we can rule that out. We checked the tank on reserve and in the on position, blew the lines out with the compressior. It sucked because his wife was being a real bitchey about this thing and making It uncomfortable out their. Since I put the Engine together I've got to try and help him out and get it fixed to get him out of the dog house. I just don't get it. Anyways I'll post updates tomarrow with new results

ok, just a stupid question.....I know you use a fuel pump, I am using a gravity fed tank.....

When the fuel filter was getting plugged, it would cause the Engine to bog at 3/4 to full throttle, I guess because at full throttle, the carb bowl was not being kept full, and the filter was plugged and not allowing enough gas thru fast enough...

All the way up to half throttle or so, it was fine, but anymore than that, and it started bogging....just a thought....

My next thought is fuel delivery too. I have had similar problems after hopping up 350s. There may not be enough fuel getting to the carb because its going straight through the Tee fitting and back to the tank instead. clamp or plug that return line then try it again. If that fixes it, you need to put a restriction in the return line(such as a large main jet). I also added a second glass filter between the carb and tee fitting just to ensure I am getting fuel.

Gary

Fouled plug?

Or weak spark?

Bummer hope you get it fixed. I now you changed and gaped plug , cleaned filter, and check main jet and retained for pluging so what plug you running. What was you smoke ring size on plug. since you thought it was a len bog and changed jet is there a main jet retainer in carb with little holes in it that can get pluged and block fuel pressure to main jet on WOT (Wide Open Throttle). Run any fuel additive, they tend to gel up after a couple of weeks and liked to hang out in the bowl causing blockedge at WOT (Wide Open Throttle) and then settled back daown then block again. Comp,ignition, fuel. Also check blow back strenght in behind carb in boot, easy reed check since your running dual stage boyseen.

Good luck, were alll interested. Keep your head up and don't let it get you down helping other is gratfing even when theres a problem. Any issue can be resolved and it sounds like it ran good untill this. Chin up.

Messed with ody tonight. Blew out lines (reserve and "on") through petcock into tank, just to make sure nothing was in the way. Forgot to mention the tank was kreme lined due to rust build up a while back. Plug is a BR9ES, we also tried a BR8ES at dumont, but nothing changed. With the mikuni carb we are not running a T in the fuel line as instructed by Randy Bridgewater at odysseysalvage. Also, i am running a #50 pilot jet, if this is too small would it make the bike starve for fuel through the rev band? Bridgewater, by the way, sold my buddy the carb with NO PILOT JET in the first place. As a result he had to get one from the local shop and biggest they had was a 42.5, and it had no side holes, just a really tiny main hole, and it tended to cut out (this was when the motor (( Internal Combustion Engine ? )) was first built). Since, it has been replaced with the #50. We jetted it tonight with a 470 main, 50 pilot, clip was in middle, sir screw at 1&1/2 and it ripped up and down the street 2 times fine (really fast too), but again when it warmed up, it started cutting out. There is no fuel additive like an octane booster being used either. Checked the windows on the reeds with finger when carb was out, all seemed ok, we did a leak test when we built the motor (( Internal Combustion Engine ? )), no leaks, problem still persists!!!!! Might try throwing carb on from other ody and seeing what happens, it is jetted same but with a 480 main and it hauls A$$!!!!

do another leak down test??? re- torque everything...

That was another idea I had. Also, forgot to mention that we did a compression test last night, cold the motor (( Internal Combustion Engine ? )) had 170psi, after it warmed up and started bogging it dropped to around 120 to 130psi. Is that normal? Do motors drop compression as they warm up, or is the motor (( Internal Combustion Engine ? )) toast?

I am assuming its trying to seize, don't run it until you do some checks, pull the exhaust pipe look in the exhaust port for scuffing on the piston, roll it to BDC and look at the intake side of the cylinder wall for scuffing also.

If you see any scuffing the top end has to come apart again to see whats wrong, maybe too tight of clearances?

This is the owner if the ody (Nick, shoubadaba [Rusty's] friend). I pulled the top end off after trying to look through the intake and exhaust ports, i could tell there was scoring on the cylinder, but it was unclear. i will try to see if i can figure out how to attach pics on this post. Also, the reeds are actually stock metal ones (couldnt recall at the time, thought they were boysen), would that have a big impact on how the bike runs after it warms up?

Hi and welcome to the site.

How about some pics of the piston through the port openings, I see what looks like scuffing on the cylinder walls.

I am a lil surprised Hoser did not mention a lil trick he showed me. See if your camera has a "macro" setting on it. It makes them take MUCH better close ups that are in better focus.

Thanks for the "welcome"
I will see if the camera has a macro setting and will try to post more pics soon. I might just be doing a new top end, I have another cylinder that I can build off of.
Will get pics up soon
Nick

Top end was done, the lower ring siezed into the piston and the piston was really scarred. Put on a new top end, totally different cylinder, 81mm piston cleared at .004 and STILL HAVING SAME PROBLEM!!! I did a propper break in, let it idle 4 times for 15 minutes, letting it completely cool between cycles. Cruized it around for 15 minutes at a time, no more than half throttle for about 7 or 8 cycles, letting it cool. It is still jetted pretty fat as well, #490 main on a 38mm mikuni flat slide carb, puffs out smoke pretty well. The first time we rode it around at about 1/2 to 3/4 throttle, it started cutting out again!!!!!!!! It acts like the spark just cuts out, or maybe fuel. I am suspecting it might be the carb since I have had nothing but problems with that carb, and I bought it brand new!

I am so frustrated with the damn bike, I will probably just sell it and let someone else figure out the problem (inform them of it first of course) and just buy the wife a Revolt.

Oh yeah, to top it all off, same exact trip when the wife's ody cut out, i swapped rides with her, rode hers back to camp and she blew the top end on my ody!!!! Wasn't her fault, I think it was just time, too many hours on motor (( Internal Combustion Engine ? )).

AAAAAAAAAAARRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR

sounds like classic rusty tank syndrome, little specks and flake of rust and dirt getting stirred up at various times either blocking fuel flow or restricting jet

Nope the tanks been kreemed already and the line are free flowing. I think its the carb also.

If the carb was leaning out,or any other fuel delivery section was,then should'nt the piston top,plug,exhaust etc be grey,dry powdery? Not black n shiny as they are?

Nothing about this problem has made any sence. Nickrnr and I have tried everything but put the stock carb back on. Old piston came out severly warped crown was melted down 1/4 inch. but during the plug was black no signs of lean or over heating. Then bogg city after the 4th weekend out with it. Dunno I think its the 1 in a million lemons you just get. Nothing works.