Early-Mid 70s Enduro 250 bogging down.


Konoc

Member
Sep 7, 2008
6
0
Hello all, I started a thread already and am now unable to find it..

I have the bike in the title. Idles great, when in neutral and rev'd it'll hit 6k-ish and bog down. I let off, the rev's fall, and it catches itself and stays running. Under load you can only twist ~1/4 throttle before it sputters, hittin a max of like 20mph. You can shift up and keep going, but again, no more than ~1/4 throttle or else it sputters like mad.

Carb has been totally gone through and is clean and working great, oil pump working fine, tank and pepcock were taken off/apart and cleaned, everything looks good. New plug, new air filter, new plug wire.

Fairly mechanically inclined, but at a loss here..

I've visited these boards many times before, have just now registered to recruit some help.

Thanks in advance for any and all help guys, hope to hear some good news. lol

r.

Edit: Cleaned all the gunk and grime off of the gvw tag, manufacture date is 3/75, so I believe it is a 1976 model.
 
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Konoc

Member
Sep 7, 2008
6
0
Anyone? Excited to get this thing ridable, would appreciate any input.

Could the coil possible be failing at the higher rpm's??
Timing off?
r.
 

2strokerfun

Member
May 19, 2006
1,500
1
I'd bet it's in your carb. Did you pull the main jet out and look through it to make sure its perfectly clean?? And make sure choke is really off.
I'm sure you cleaned the air filter. Sometimes if you put too much oil on them, they can act a little like this but usually clears up as oil gets drier.
 

Konoc

Member
Sep 7, 2008
6
0
Compression is real good. When I picked it up the guy said it wasn't running last year, and he hadn't touched it this year. Was indoors, so no rodents and such had made a home of it. First thing I did when I got it home was give it a kick(no electric start), it for sure had good compression. Timing seems to be good.
And like I said above, after all the cleaning and checking, it starts up and idles perfectly fine.
I did pull everything apart on the carb and clean, but just in case I ordered a jetting kit from a track shop here in town, hopin that is it.

I'll let you guys know.

Thank you for the help/advice everyone, really appreciate it.

r.
 

zoommx

~SPONSOR~
Apr 23, 2001
282
0
Possibly sounds like a fuel delivery problem. Make sure fuel flows freely into the bowl and shuts good when needle valve closes.
 

midlifemoto

Member
Oct 4, 2007
53
0
check float level too...sounds like it's starving for fuel...bowl may not be filling up enough...either get the specs or as a baseline make sure the float prongs are perpendicular to the bowl base gasket...if the carb specs are close to OEM then it's possible it could be electrical...does it backfire at all under power? if so, maybe a bad stator or coil or ignition box...when you take the mag cover off does the mag bolt wiggle at all, even the slightest? if so, bad crank bearing and no amount of jetting or continued troubleshooting will help....I'd check that the very first thing...

don't ask me how I know to check all these bad things :-) everyone of these things I've had go wrong
 

Konoc

Member
Sep 7, 2008
6
0
k, carb cleaned out again with new jet in. Problem persisted. Bought a gasket kit, took motor out, head off, and WOW was there alot of carbon and gunk buildup! Cleaned everything out and reassembled. Started easy, and RUNS GREAT!!! :)

Thank you all for your help, this project drove me absolutely nuts. lol Gonna clean her real good and get some pics up for ya.

Thanks again all!

r.
 

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