Vintage Dirt Bike Q & A

i got a running 1975 mr175 for $350 a couple of weeks ago and had some problems with the carb got that fixed and had it running pretty nice but then i ran out of gas and when i put more in it doesnt run right. when i start it it seems to idle ok but when i put in gear and get up to secound and it starts lagging at hi speeds??? i'm 15 and dont know a thing about this kinda stuff so any help is appreciated

thanx

EDIT (april 21) ok so i tried selling it on craigslist but just got a bunch of scams, so its been sitting in the back yard and i've been itching to ride it, but i wana buy a new carb for it... any suggestions as to what i should buy?

Thanks, Jess

I'll ask the obvious question first: did you mix oil with your gas??
If the answer is yes, you may have sucked some crud/gunk from the bottom of the float bowl up into your jets when you ran it out of gas. Take the carb apart and clean it very well, including the jets. Put it back together and try it again.
And it's always good to put in a new sparkplug.

yup i mixed 32/1 hope thats right
the tanks pretty rusty on the inside. i've had the carb apart and had it in carb cleaner but it probly got gunk in it again. i will taki it apart again and clean it.
i put some gas in it today and started it up and was riding around when it all of a sudden reved like really hi i was afraid it was gonna blowup any suggestions on that?

btw thanks for the help mitchie

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-----1975 Honda MR175--------------------------------------1972 Suzuki T500 Titan------------------2003 Honda 250 Rebel

Yamaha XS850
Triumph Bonneville 650

Could be an air leak causing revving, or it could be going lean because of rust clogging jets. Either way, you need to clean the rust out of the tank best you can and maybe put inline filter in ($4 or so). You can clean rust by putting pea gravel in tank with some WD-40 and shaking the heck out of it for a while. Empty, rinse out with gas for final cleaning.
Clean the carb again and pay close attention to the jets. Write down the numbers on the side for future reference. Then, closely check for airleak on carb manifold. Then take off left side engine cover and check seal for airleak. You can try spraying WD-40 on areas when running. If running changes when you hit an area with it, you have an air leak.
If no air leak and carb is clean and jetted properly, might be time to move on to cleaning or replacing points.

well i belive my floats were stickin so fixin that. oh btw hers some pics

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-----1975 Honda MR175--------------------------------------1972 Suzuki T500 Titan------------------2003 Honda 250 Rebel

Yamaha XS850
Triumph Bonneville 650

well I do believe I'm going to sell her, b/c i am working on restoring a 1972 Suzuki T500 Titan and dont have time or money to mess with it anybody wana suggest what i should sell her for?

_________________

-----1975 Honda MR175--------------------------------------1972 Suzuki T500 Titan------------------2003 Honda 250 Rebel

Yamaha XS850
Triumph Bonneville 650

I might be interested...I've got 2 now. One more wouldn't hurt..

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77 MR175, 89 HD Sportster
74 CR125, 00 Kawasaki ZG1000
79 XR185, 56 Cushman Eagle
03 XR650L, 79 Vespa P200E
72 Vespa Super150,
74 HD Z90

name a price

_________________

-----1975 Honda MR175--------------------------------------1972 Suzuki T500 Titan------------------2003 Honda 250 Rebel

Yamaha XS850
Triumph Bonneville 650

PM sent..

_________________
77 MR175, 89 HD Sportster
74 CR125, 00 Kawasaki ZG1000
79 XR185, 56 Cushman Eagle
03 XR650L, 79 Vespa P200E
72 Vespa Super150,
74 HD Z90

hmm aint got none in my inbox

_________________

-----1975 Honda MR175--------------------------------------1972 Suzuki T500 Titan------------------2003 Honda 250 Rebel

Yamaha XS850
Triumph Bonneville 650

Once more...

_________________
77 MR175, 89 HD Sportster
74 CR125, 00 Kawasaki ZG1000
79 XR185, 56 Cushman Eagle
03 XR650L, 79 Vespa P200E
72 Vespa Super150,
74 HD Z90

SOLD!

_________________

-----1975 Honda MR175--------------------------------------1972 Suzuki T500 Titan------------------2003 Honda 250 Rebel

Yamaha XS850
Triumph Bonneville 650

ok so i tried selling it on craigslist but just got a bunch of scams, so its been sitting in the back yard and i've been itching to ride it, but i wana buy a new carb for it... any suggestions as to what i should buy?

Thanks, Jess

_________________

-----1975 Honda MR175--------------------------------------1972 Suzuki T500 Titan------------------2003 Honda 250 Rebel

Yamaha XS850
Triumph Bonneville 650

Jess,

I've gotten the OEM 28mm Keihin carb to run very well from 40 to 90+ degrees, and I estimate my motor's now putting out almost 50% more power than stock using this carb. These units were used on a bunch of different Honda models, and are plentiful on eBay. Is your present carb completely unusable?

There are replacement options available, but quite a bit of work is involved if you want to do it right.

Ray

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'74 CR125M (175cc), '75 MR175, '82 RM250Z, '08 YZ250F, '14 Zero FX electric, '14 Zero MX electric, '18 Alta MXR electric

well i have had this one apart several times and the screws on the bowl are striped, and alot of parts are just to old to be any good, so i thought instead of buying a bunch of new parts i'd just buy a new one. so your saying a new kehin 28 mm will work for it?

Thanks

_________________

-----1975 Honda MR175--------------------------------------1972 Suzuki T500 Titan------------------2003 Honda 250 Rebel

Yamaha XS850
Triumph Bonneville 650