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Rebuilding 2002 Suzuki Quad Master 50 2-stroke

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Hey everyone,been dealing with quads since I was a kid,now I have a son who loves my raptor 700 and had gotten him an electric power wheel quad but it didn’t cut it for him.so for his birthday “xmas eve” I picked up a used 2002 quadmaster 50 for 500 bucks. It started and moved but needed work..

got it home drove it for a few feet and it started bogging down and would shut off.

so I stripped quad down to the frame cleaned it up as best I could without removing motor from frame.

replaced top end new head piston rings etc cheap kit off eBay along with carb that will be here today.the filter that was on carb was degraded and soaked with gas. Also new cylinder doesn’t have vacuum line so how do I block that off without getting new petcock valve?

tightened chain.

guy said quad doesn’t take oil as it’s a closed case right then I knew the guy knew nothing about the machine. So I changed oil,was black and thick and just nasty like sludge.

suspension in rear seems good but the fronts are very stiff,any way to adjust these or should I get a new set?

also upon stripping everything down I noticed the exhaust restrictor was gone so without that do I need to update jets in new carb,old carb has original jets??

and also I’m new to cvt tranny so how would I know if it’s bad etc?

sorry for all the questions just want to make this thing safe for my 5 year old knucklehead.

added some photos of my current progress didn’t take any inbetween cleaning everything though 


please any info will be appreciated.

i haven’t rebuilt a quad since 1999 when I had my blaster and my buddies had other 2 strokes I was the mechanic with no knowledge but always seemed to get things right!!

also if you notice the old head looked chipped and damaged and I’m wondering if those chips made it into motor how would I go about finding them?i would think by now they would be chewed up? I did not strain oil that I drained but might do that later when the kids are sleeping and I have time to check it without kiddo seeing!











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That's a good little ATV and it looks like its in good shape. After all your work, your son will have a new quad! It does look like the oil wasn't changed. As far as the front suspension, I don't believe there is a way to adjust the shocks, but not sure.

* I edited your topic title a bit to hopefully get you more responses "Rebuilding 2002 Suzuki Quad Master 50 2-stroke"

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Yeah I got it all back together but just dies with any weight on it on slight uphill grade.and doesn’t have a smooth sound sound to it.

might just rip it all down take out all remaining restrictors,and take spark arrestor out.

I just ordered a new clutch and gasket set and throttle cable also a carb rebuild kit for original carb.

i really don’t know what else to do with this thing to get it running correctly.

also when I take clutch cover off will I need drain oil first?

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Did compression check today I’m getting right about 90psi is this ok for a 50cc.

im assuming nobody actually uses this sight since no one helps.

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Hey  @Jhyman1984 

Nice bike! So that’s a great little engine. 

90 psi is perfect.  I like the way you tore it down. I do the same thing whenever I get my hands on a new bike to fix up. 

So as far as the clutch what made you order a new one. Just to have it fresh ? I don’t think it’s the clutch but if the previous owner beat the crap out of it maybe. 

Does the drag feel like a power loss on the engine side or does the engine rev but no power like a drive train problem? 

The oem rebuild kit for the carb is the best way to go.  Make sure you take your time and refer to the manual for the fuel air mixture screw.  

Quick question. What’s your fuel/oil mixture? How are you mixing and what’s your ratio.  

Its not a complicated engin at all. So it won’t be that difficult to get back up to par. 

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It may be oil injected also so if thats the case I’m curious if there’s too much oil going into the mix. Is there a lot of smoke ? 

Edited by Frank Angerano

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The quad is oil injected no mixing needed,

quad has power with wheels off the ground,once driving it moves but as soon as there’s any sort of incline it completely dies.

i have to replace gaskets for muffler and carb intake area where it connects to the head,so after I strip it all down for the 3rd time I’m gonna remove all restrictors and then go from there.

i ordered new clutch shoes not sure if I need them or not but gonna attempt to take the case apart and see what everything looks like. I don’t really want to mess with the clutch as I’m not sure of what I’m getting myself into.

if none of this stuff works I’m just gonna throw the bike off a cliff and buy a new one when I have the money to do so


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Haha off a cliff??? Nah it’s not that bad. Lots of us get frustrated with this sort of thing so take a deep breath and regroup. 

Based on what you changed and then the carburetor rebuild kit going in if that does not fix then the drag sounds to be in the drive train. You will figure it out.  My guess is it’s the centrifugal clutch.  The springs that allow the clutch to expand aren’t doing so or are opening unevenly and grabbing improperly.  

Its pretty easy to open up the side cover and see what’s going on.  


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Ok so before I go taking the case off,do I need drain oil? No big deal if have to but would prefer to get carb set correctly then run it a bit since the oil has never once been change,and would like to do a good flush,was hoping to have it done by Christmas but all parts won’t be in by then.

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No it should be dry since that clutch works on friction. You def have to change that oil ASAP. Maybe run it a bit after you get it dialed in after the carb and other new parts are in, warm it up a bit and drop the oil and change before thinking about touching the clutch.   Because honestly even after that maybe one more time you should  change it again, that’s a good flush.  

That carb screw air fuel set it at 2-1/4 turns out from a snug position and start it up and see how it goes. If it’s not good go 1-1/2. Try that. If the engine starts up and is some what smooth right away then that’s the set point to start at.  Then a few slight adjustments from that point will dial it in good. Make sure you have the air filter and air box on before you make the adjustment. 

Once you get that engine tuned see how she runs and go from there. 

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I changed oil the day I got the machine that was first thing I did I want to run it with this oil in it for a bit to help flush it out then do another oil change..

im gonna take case off today and take a look at everything without unbolting it so hopefully I can see if it’s good or bad like that.

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Awesome.  When you pull that cover off and get the clutch and belt off you will see the weights and the shoes that grip on the clutch itself. You can take a screwdriver flat head and stick it in between the weights and pry and you should see them expand outward evenly.  There have been some of these cases when opened up have had water inside and a ton of rust.  Hopefully not yours.  

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So with the time I had today after bringing kids to school,I stripped the bike for the 4th time and hopefully last.still need take exhaust and clutch cover off.

but I tried derestricting the elbo to the head I could not get that spacer piece out so I just widened it up with a drill bit gonna have to clean that part good cuz of the shavings.

took carb off and throttle cable and I realized I assembled the carb wrong.the needle was sitting on top of the white plastic piece..I’m an idiot but that’s what I get for having minimal time to tinker with this thing. But I did take out the first jet that piggybacks the other “one part of derestricting”

so I think it’s destricted 

i also tightened down the head more as I don’t have a torque wrench so just got it good n tight with extra tightness haha.

parts coming in by Friday I hope which are 

throttle cable,gasket set,carb rebuild kit for oem carb,a new fuel valve with just on/off/res. And a new cdi box. Also a set of oil seals but hoping I don’t need to get that far.

i will be stumped if none of this works! 

One other question is how could I tell if the oil injection pump is working?

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Wow !! That’s some post. Getting into something like this is a little time consuming and frustrating but rewarding when it works out. If making a mistake like the needle makes you and idiot then I’m an idiot a hundred times lol. It happens !!!! That’s a little extream though. 

Question; why all the removal of the restrictors? I have a feeling that may come back to bite you in the ass and may not allow the bike to run properly just keep in mind.  

As far as the oil injection goes there is a small oil line coming from the pump into the carb? If so you can pull that hose off as well as the spark plug wire and and turn the gas valve off so you don’t flood the head and crank the engine over and you should see the oil pump out of the hose.  

When you tightened the head down did you tighten down in crisscross pattern so it’s all even ? 

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Yes head was tightened in x form until I felt it was tight enough.

for the oil line I’m gonna have to check that again as I don’t think it was connected prior to me buying it,could be the reason why the engine was covered in oil/dirt grime..

i removed the restrictors because some already missing and with all the reading I did they say the quad doesn’t have power to go up any hills in stock form etc and where we live we have hills of all sorts my yard has incline to it etc so I want it to go as best it could.

when I originally purchased the bike muffler bolt and gasket missing etc.

tomorrow I’m taking case off to look at the clutch and see what it looks like hopefully doesn’t need to be swapped out but if it does new shoes will be here day after Xmas hopefully earlier.

i also ordered all stock parts with restrictors today if it runs bad etc so then I can just put them on in where they go,as it’s set for oem it restricts fuel to a very minimal amount etc 



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