Honda CM250 Question for Roadghost - Others welcome to chime in | GTAMotorcycle.com

Honda CM250 Question for Roadghost - Others welcome to chime in

mistersouthpaw

Well-known member
So - my girlfriend loves her little bike. It has been somewhat a nightmare though.. after rebuilding the starter clutch twice - once with new springs and rollers another with a new starter motor and starter gear plus the the carb hose with a fuel filter (5 carb cleans later) it ran great.

I now have two issues and since you seemed so knowledgeable about these bikes I figured id send a couple q's your way.

Bike was running dry of oil, oil smelled of gas and was very very thin. I replaced the float needle which appeared to have some ringing around it. I thought perhaps it was sticking open allowing gas into the crankcase causing the oil to burn up. Yet to determine if this resolves the issue. Any thoughts on this?

Second issue was that the rear pulley was warped and fraying the belt. I suppose someone bent the pulley somehow. Due to the belt and pulleys being discontinued, I swapped it for a 520 chain and sprockets. I am wondering if you have a suggestion for wheel spacers? The sprocket nuts hit the axle adjuster and chain is pretty close to the belt guard. I really would like to make the chain work - swapping back to a belt means removing the swingarm, plus they are harder than hell to find and expensive.

I am wondering if I can find the wheel spacers off an 82 which was chain it should properly space the wheel?

Thanks in advance
 
Wait - WTF?

For comparison the
1982 uses COLLOR,RR.PANEL, 42313399000 & COLLAR,WHEEL SIDE 42305KB4000, BOLT,SPRKT,FIXING, 90128382670
1983 uses COLLOR,RR.PANEL 42313399000 & COLLAR,WHEEL SIDE 42305KB4000 BOLT SPRKT FIXING,90128KB4770

whats up with my wheel spacing then? the fiche makes it appear that both 82 and 83 can interchange between chain or sprocket no problem

EDIT: it seems that I need to swap the sprocket nuts with the 82s however, it appears on the fiche of the 82 that the 90128382670 sprocket bolts can be used for the belt pulley or a sprocket. Any input would be great thanks
 
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those wily Japanese ;)


the belt pulley, does it look like stone got between the belt and pulley?
 
lol the pulley looks like someone changed the tire on the ground with a crowbar pulley side down... who knows what happened.
 
honda-cm250c-custom-1982-c-usa-rear-wheel_bighu0165f4c11_046b.gif

missing a big fat washer
make sure your rubber cushion drive parts are good, pretty sure that's what #5 is
 
Is the fuel getting into the motor when it's parked for sure?

Check to make sure your crankcase ventilation is not plugged somehow.
 
I have the washer, it didnt seem to make any difference it just hung loose around the axle. Its currently sitting in my parts bin... The sprocket I am using is a JT not oem and I didnt know wtf to do with the washer. Crank vent hose is cracked and sometimes I see some oil around it and thats what drew my attention to the oil.. I cleaned the crank puke drain in the airbox when I got it. It was pretty noticeable the smell of gasoline in the oil but its possible that I need to replace the vent hose no big deal
 
ill remove the sprocket and reinstall it, something must have gone wrong with the installation after realizing that the spacers are the same for the 82 & 83. I figured the washer was only needed for an oem sprocket oops
 
Sprocket should still sit behind that big cir-clip part #17 does it not?

Belt pulleys are wider the washer is to make up that difference.
 
Pistons on that motor move up and down together on every stroke, that's a Lot of air movement inside the crankcase and around the valve stems, if the motor can't operate with case close to atmospheric pressure it turns into a pump, oil goes where oil should not go, gas goes where gas should not go. The air it's breathing is also suppose to be free of dirt and provide a place for blow-by oil to collect, usually in or part of the air box is where that's all done.
If it is carburetor the bike should in theory be operating rich as all hell. Is it operating rich as all hell?
 
got the wheel fixed yet? :whistle: no pressure or anything
 
Those are all good questions I don't know about using the circlip with a sprocket, the washer isn't as thick as the fiche makes it appear I'll have to look into that more.

I forgot to mention that when it ran dry the valves loosened up like crazy and I had to put them back to spec

Is it running rich? The plugs are looking a little like Trudeau teaching drama class yea
 
It doesn't sound very healthy :|
Do you have the tools to compression test

The cir-clip has to be there, that's what holds the sprocket on the hub. Fits into the groove in the hub.
... it probably floats around just slightly loose in the axial direction behind the cir-clip.
The 4 bolts don't actually hold the sprocket on the hub, they only thread onto the 4 inserts for the rubber cush drive plugs.
 
The hub isn't broken is it? that would explain the missing cir-clip and the smashed up pulley face.

If there is a rough edge where the groove for the cir-clip used to be it's busted.
 
It doesn't sound very healthy :|
Do you have the tools to compression test

yea it definitely wasnt good especially after buying new parts for the damn thing. I would like to see it live another season. Ill keep a very close eye on the oil and ill swap the crank vent hose I think ive got some fuel line that would work

The cir-clip has to be there, that's what holds the sprocket on the hub. Fits into the groove in the hub.
... it probably floats around just slightly loose in the axial direction behind the cir-clip.
The 4 bolts don't actually hold the sprocket on the hub, they only thread onto the 4 inserts for the rubber cush drive plugs.

true hm ill definitely be doing some sprocket reinstall
 
... I forgot to mention that when it ran dry the valves loosened up like crazy and I had to put them back to spec ...
I hope you are ready for some more bad news then, because that means your rocker arms are probably destroyed right where they ride on the cam.
 
Kinda like this but maybe not as bad yet.:
99089d1568305293-cb400t-shitbox-build-daily-driver-lifter2.jpg
 
The bike is for your lady, you need to fix it right or get her a nice new one.
Catastrophic engine failure is not good when you are motoring right along at speed, been there done that.
 

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