Motorcycles

[Graeme]

I thought that the sidecar motocross video would be tough to top. I was wrong. :o

[Sam]

Hey guys,

Some help needed.

I spent a bit of time trying to get @Giles 's bikes working today with limited success.
They both have the same engine and the bikes are SR500 and an XT500 (i'm sure some of you are familiar)
The SR500 gets close but doesn't quite get going. It sparks and turns over for a a second but cuts out.

I'm not that familiar with these yamaha engines and i spent some time getting to know the mikuni carburettor today and with a bit of tinkering i got it close but no cigar. tried closing off the air more to make the mixture richer which seemed to help. Could it be more than a carb issue? i thought maybe the fuel had lost its potency since it has been in there for a while.

Any tips or advice?

Sam

[Graeme]

I left my BMW standing for six or seven months, and it fired up pretty easily. I don't think that the fuel would go off in that time. I don't think that Giles's bikes have been sitting around that long either.

Could it be something electrical? Do they have batteries?

[4c]

That's a thought. Maybe the battery is out of water. The motorbike I sometimes ride does something similar with sparking and cutting out if the water level in the battery gets low.

[Giles]

They do not need batteries to start.  In fact the SR does not even have a battery….

[Sam]

Yeah its not an electronics issue for either.
I've been told that maybe i have the petcock in the wrong position while starting it. It's supposed to be in the pri position. I'll try that next.

Cheers guys. We're getting there Giles…

[Streetwise Hercules]

I just did a search for MotoGP and didn't get a single hit.

Undeterred, I'm going to assume someone on here watches motorcycle racing.

Fast bikes and a slow talkin' Brad:

[injunjack]

if the bike ran when it was left sitting in the garage, DO NOT change carb settings. There are no little elves that go and
tinker those.

Modern day gas is piss.  It can and will go bad in 3 months or so and leaves powder like stuff in carb bowl. That'll clogg tiny passages in the carb and it won't operate properly.

Take the carb off, take the bowl off, blow all passages and jets with compressed air and preferrably wash it in an ultrasound washer. assemble the carb and you should be fine.

Basically motor(cycle) needs 3 things to run: gas, air, spark.  If all 3 are present, motor should fire up.

Todays piss for gas also destroys rubber parts fast, especially if they have been exposed to gas and the dried.  Check gashoses, they may look OK but are deteriorating inside, also see that manifiold rubber is in good shhape and there is no intake leak (too much air -> no go or lean condition, poor start)

hth

[brentkuz]

You can buy "real" gas. With no corn juice in it. It is pricey but IMO is worth it on older small engines. Since they get good MPG for the most part.

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[Giles]

Where can you get that?

[injunjack]

G, Stateside they nowadays have also proper gas again. Also here you can buy leaded by 5 liter containers, it's called utility motor (engine) gasoline or something like that, Don't know exact translation.  It's meant for lawnmowers etc.  or for longer storage.

[Sam]

Great info @injunjack

I'd had a feeling the carb might be clogged. I just won't catch for itself which suggests to be that you're right about the jets being clogged. It's Giles's bike though and i don't want to mess it up. i'll wait till he's back and we'll mess it up together. Or get a pro in… oh the shame!

SP

[harley dave]

as injunjack said a bike only needs three things gas air and spark .
start with fuel ,is it coming out of the tank ,take the fuel pipe off  the tank end and turn the fuel on ,if it comes out move to the carb end and repeat .
if it is coming out to the carb check the float bowl ,and the the jets .there are normally three main , assuming you have a spark ,to check take the plug out attach the ht lead and rest the plug on the head and kick .you should see a healthy blue spark .
sorry to sound like i am telling you how to suck eggs but it is fairly simple ,other than this it may be your wiring .
in which case contact ferret at ferret wiring .
hope you get it sorted

[harley dave]

allso which part of the country are you in ?

[Giles]

Gosport…

[brentkuz]

@giles - I can only speak for the states. But VP fuel makes non-ethanol gas. Also I would check any place that sells small engine parts etc. Usually I've seen 5gal cans of it.

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[natehate]

like a rocket launching to the moon….? damn iphone

[harley dave]

is it running yet giles ?

[Giles]

Nope, but I've been away and not tried since I returned…...Want to swap clothing for expertise?

[harley dave]

if i get a chance i will pop down ,no clothing offer needed i would do it as a favour for you