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kenjolly
07-11-2007, 05:45 AM
I just freshened up Haydens 50 last night and it seems to be way out of toon"carb". I’m I just getting old and forgetful and don’t remember tuning it last time or is something else wrong.

Also the cable I guess hooked to the oil injection if im pre-mixing is their any reason to leave it hooked up.

Thanks, still learning

bulldogfallon
07-11-2007, 06:40 AM
What is the problem with how it is running?

To keep it looking stock you should keep it hooked up (wink wink)

hotquads1
07-11-2007, 07:00 AM
Originally posted by kenjolly
I just freshened up Haydens 50 last night and it seems to be way out of toon"carb". I’m I just getting old and forgetful and don’t remember tuning it last time or is something else wrong.

Also the cable I guess hooked to the oil injection if im pre-mixing is their any reason to leave it hooked up.

Thanks, still learning


you should leave the cable hooked up because it is also your throttle cable and tends to hang open if it does not have the return spring preasure of the oil injector, replacing the cable with a single pull race cable is your other option , but as gary mentioned this would not appear stock.

dirttrack86
07-11-2007, 08:51 AM
DO NOT !!!! , I repeat, DO NOT unhook the cable from the oil pump. It WILL stick wide open sooner or later, usually within 3 to 4 rides. I have the bent bumper, a-arms, shock, and frame to prove it. LOL.:)

camsdad
07-11-2007, 10:41 AM
freshening up shouldnt change jetting.......when you say "out of toon" do you mean rich ,lean,???????? give more info amd we'll try to help.........

kenjolly
07-11-2007, 11:02 AM
after the new rings,piston and everything was in it took a littlt while to start. After That it wouldnt idle and if you hit the gas it just sits there and slowly winds up. I do have it jetted alittle to the rich side.but i have been running the same way all year will good results. HELP

markvette
07-11-2007, 12:39 PM
check compression. you may have broke a ring putting it back together.

Mark

camsdad
07-11-2007, 02:21 PM
i second what markvette said................

kenjolly
07-11-2007, 04:55 PM
Strike 1 138psi i wouldnt have thought of that.

I did run it some more and its better at idle and good once you get the rpm's up like you would on the line. Still has a bad lag from idle up. Im going to clean carb and try that, i may have gotten something in their. keep the ideas coming i would like to try to fix that lagging.

AFROracing
07-12-2007, 12:40 AM
:D
this brings up a funny story of our rebuild..
quad would start after rebuild and act pretty much as you discribed... I notice very little pressure coming from the pipe.

After a very long investigation of the carb, electronics and motor I found that a small furry varmit had made a home in the expansion chamber of the pipe hindering full revs... :mad:

kenjolly
07-12-2007, 06:18 PM
well i cleaned the carb and its running great ,except it still has a bad flat spot froma dead idle. other than that it running gooooood.

i only ended up with 1 extra part after the rebuild, a very small flat brass washer. any ideas where it might go?

camsdad
07-12-2007, 07:56 PM
on the pilot air screw ...maybe??????

wrhracing
07-12-2007, 08:10 PM
So you have 138 psig and a spare washer.....On a DRX 50.....

To me the compression sounds low, you could have put the ring over the ring locating pin and bent the ring on either grove. This would be evident if the cylinder did not s l i d e right over the piston during assy.
Or.. A different thickness of gaskets was used.
Or.. a different dome heigth on the piston . (Other Than Stock).
Or a leaking head gasket . 14.5 ft. pounds of torque on those head nuts?
If the piston had the holes facing the exhaust port it would run poorly also, but generally the problem of low power and jetting would be all over the place.
Or trash is in the pilot jet.
Or Torn intake boot.

I guess the other question is why did you replace the top end?

Just some ideas

kenjolly
07-12-2007, 08:30 PM
The piston went in smoothly.
the piston is from drr and i didnt match it to see if they were the same.
the gaskets also looked the same.
I replaced the top end only because it seemed down on power and we havent done it since Feb.

Should i pull the piston and check it and what should the compression be.

wrhracing
07-13-2007, 04:33 AM
When you ask if you should pull the piston, Or pull the cylinder off. I've done it often trying to locate a noise or to verify everything is okay in there.
If you have ridden the quad and it seems to have much less bottom power than before you did the top end then I would revisit the top end.
You'll be able to see how the cylinder is wearing in , if chamfers on ports are good, if the piston has any 4 corner seize marks from being run to hard too fast , or if it has a lean seize.
If all appears well then look for shiny spots on the piston or cylinder which would indicate, possibly, tighter tolerances.
Lastly check for a piece of old base gasket left behind which could create a small air leak.
If it's all good then bolt her back together with the same care and love as you did before.
Then revisit all maintenance performed while you serviced the top end.
Chain Adjustment to tight when you sit on it.
New rollers installed?
New Belt installed?
Air filter over oiled?

You will probably figure it out and it will not be anything I mention, but getting you to look at one thing may get you to see something else.

The small brass flat washer....maybe from between the idle screw and the idle spring.

jetski_dawg
07-13-2007, 05:19 AM
this might be a dumb question..is the arrow pointing to the exhaust port?

ecmini1
07-13-2007, 05:49 AM
Originally posted by jetski_dawg
this might be a dumb question..is the arrow pointing to the exhaust port?

YEP

kenjolly
07-13-2007, 08:13 AM
I looked at a makuni diagram and i think the washer is off the idle screw.

The piston and rings are find, im thinking its more of a carb problem. maybe the pilot jet clogged or some trash in the hole.

once it get on the main jet it runs fine.

Thanks to everyone for their help, im trying to lern this stuff without having to many extra parts.

I think im going to change my screen name, EXTRA PARTS JOLLY

kenjolly
07-14-2007, 06:20 PM
Well i dont know how or why it was so out of tune, but after drr5 worked on the carb for about 3hrs its running better than ever. we did find the needle setting was to rich and went to a 110 main jet and a good cleaning. it still has just a small bogging issue from idle up but not near as much.

Thanks,drr5 and everyone else

Nichols Atvs
07-14-2007, 07:06 PM
Im going to change my 50 to a 70 next week will see how that goes im going to try the keihin 20 with the new drr intake and take off my mikuni 16 ill keep every one posted . I know im in maine but im running a 125 main and ours is ripping. we just need a little more power to keep up with the 90s. Our track has no rule on CC size so i thought we would go up 20 cc .

drr5
07-15-2007, 06:53 AM
we run a keihin 24 on our 70 national motor with great results

jread14
08-28-2007, 09:12 PM
I am not trying to jack his thread but I am having a very similar issue. I have not replaced the top end yet but I just got the new cylinder and piston and I guess that will be my next thing to try. It was running really good all year and then it starting getting a terrible bog abd sputter when he stabbed the throttle. I guess it first started before his last race when he was practicing at a track that had a somewhat steep hill out of a corner and it really seemed that it was just bogging its way up the hill and then when he would get to the top of the hill it would clear out and fly. Then at his last race on his holeshots or even when he would come out of a sharp corner and has to get off the pipe and get back on it it would just have that bog like it didnt want to go and then take off. The odd thing is that when it does get going it runs like a raped ape. So, being new I just started replacing stuff. I first freshened up the clutch with all new springs and rollers. That seemed to pep it up a little but then the problem is still there. I am running a 125 main which seems to be perfect here in Texas and I have the needle on the lowest clip towards the pointed end possible. When I tried to lean it up it seemed to get worse. So then I checked the compression and i only had 120lbs of compression. I know now that it needs to be replaced which will be done tomorrow evening but what else could it be? Do you think that is what would cause such a poor bottom end? Could it have anything to do with clutch shoes or the clutch bell being glazed and casuing it to slip. Any help to the dumby from Texas would be greatly appreciated. Thanks, JR

bulldogfallon
08-29-2007, 04:36 AM
What carb are you running? Did you mod it?

Have you replaced your plug?



Let's get some more info and see if we can get this fixed for you.


Does it start right away?

airtime821
08-29-2007, 05:05 AM
jr check your carb and see if the float needle is opening up properly. I had this same problem with my 50 i must have bet the tab on the float when i was doing some tuning. everytime a corner was to sharp or the bike was going up a hill the fuel would pull to one side of the carb and cause the choke.

ecmini1
08-29-2007, 09:11 AM
Hopfull this is not the the problem but low compression can cause some issues like this.

jread14
08-29-2007, 10:06 AM
Originally posted by bulldogfallon
What carb are you running? Did you mod it?

Have you replaced your plug?



Let's get some more info and see if we can get this fixed for you.


Does it start right away?

Stock Mikuni carb with no mod to the carb.

I have not replaced the plug but will do when I rebuild it this evening. I just didnt think that would cause this issue, but I am no rocket scientist.

It strats great. Like I said it runs great when you get it going. It just does not want to go out of the hole.

jread14
08-29-2007, 10:08 AM
Originally posted by airtime821
jr check your carb and see if the float needle is opening up properly. I had this same problem with my 50 i must have bet the tab on the float when i was doing some tuning. everytime a corner was to sharp or the bike was going up a hill the fuel would pull to one side of the carb and cause the choke.

That is a good idea but it does it worse on the holeshot. I dont think it has to do with the hills or the corners. I just think that when the engine or clutch is put under a lot of pressure all at once it just does not want to go. :confused: :confused:

jread14
08-29-2007, 10:22 AM
Originally posted by ecmini1
Hopfull this is not the the problem but low compression can cause some issues like this.

I honestly hope this is the problem... That would be a simple fix for me. :D

Steven623
08-29-2007, 10:36 AM
Was the rear clutch torque spring replaced? Sounds like the belt isn't going down on variator? Just a thought?

jread14
08-29-2007, 12:32 PM
Originally posted by Steven623
Was the rear clutch torque spring replaced? Sounds like the belt isn't going down on variator? Just a thought?

Yes it was but it was doing this before I replaced the spring. :confused:

jread14
08-29-2007, 06:02 PM
Ok, I just got home and let him ride it real quick. When it first starts up it runs great and throws dirty everywhere out of the hole. After it warms up is when it starts bogging really bad out of the hole. So, with my limited knowledge that is telling me that a.)when the cylinder gets warm it expands and starts loosing compression or b.) the clutch shoes or something in the clutch is getting hot and causing this poblem. I am on my way out there to tear it down and rebuild it. I will let you know what I find out. Thanks for everyones help. JR

jread14
08-30-2007, 09:10 AM
I put the new cylinder and piston on it and it started up easily. I let it run and varied the throttle for about 5 mins to try and get the rings to set in. Then I took it out an road it a little just getting on it a little and it seemed to have better throttle response. I am 200lbs so I have to be easy on it so I wont know until this evening how well it is or is not running with him on it. I think I need a new compression gauge because now it is only getting up to about 110 with a fresh build and it was 120 before the build. Kinda odd....

jread14
08-30-2007, 08:14 PM
Please help me.... It ran great again at first and then it started running terrible again after it warmed up. It just boggs like crazy coming out of the hole. What else can I do. I have replaced the entire topend. All the springs and rollers in the clutch. Put a fresh plug and K&N on it and it is still doing it. Any thoughts.

Nichols Atvs
08-30-2007, 08:30 PM
I had a wire that keep coming undone at the connection when we hit the throttle real hard not sure but check all the wireing

AFROracing
08-30-2007, 10:29 PM
Check the rubber intake boot for cracks...
this sounds like a jetting issue to me..
but then again your 110psi reading doesn't sound very good.

jread14
08-31-2007, 08:20 AM
Originally posted by AFROracing
Check the rubber intake boot for cracks...
this sounds like a jetting issue to me..
but then again your 110psi reading doesn't sound very good.

If this is Spanky, this is Jason Read that was on the red YFZ #111 last weekend with all the TQRA guys. This is my sons black w/ green lettering DRR 50 that you have seen out there riding before. Which boot are you talking about. There is the main intake boot and then there is another intake boot on the metal tube that goes up to the filter? I replaced this one but did not check the other that is bolted to the motor. I will do that today and see what it looks like. What kind of jetting issue do you think it could be?

tireman43
08-31-2007, 11:33 AM
The intake boot he is talking about is the one behind the carb to the motor.

hotquads1
08-31-2007, 03:43 PM
if the boot is found to be good, spend 20$ for a lighter set of rollers and try it , if that does not do it the carb jetting is suspect . As the engine builds more heat the torque spring loses some tension making bike shift to early ,before best power range, lighter rollers will be a cheap diagnosis.
marc

jread14
08-31-2007, 05:02 PM
Originally posted by hotquads1
if the boot is found to be good, spend 20$ for a lighter set of rollers and try it , if that does not do it the carb jetting is suspect . As the engine builds more heat the torque spring loses some tension making bike shift to early ,before best power range, lighter rollers will be a cheap diagnosis.
marc

The odd thing is Hetrick racing sent me 4 gram rollers and from what I am reading that is heavier than the stock ones. which causes what????

AFROracing
09-01-2007, 12:30 AM
nope this is not Spanky, but I am at the track 99% of the time. I live in the red house across the street...

We run the 90's..
The 1st thing we do from factory is add 4 or 4.5 gram rollers...
lighter rollers make it wind out letting the quad stay on the pipe longer when taking off..

Are you familar doing leak down test on 2strokes?

bulldogfallon
09-01-2007, 01:46 AM
Originally posted by jread14
The odd thing is Hetrick racing sent me 4 gram rollers and from what I am reading that is heavier than the stock ones. which causes what????

I hear the samething from other riders.....Some of the shops are sending out heavier rollers and stiffer torque springs...

Not sure why.....Stock set up is pretty much the best set up


Our previous 2007 DRX50 did the same thing......When it was cold it would take off like a rocket with me on it...After it warmed up it would have a bottom end flat spot/bog....

Our new liquid cooled 50 with the Sunworld(Mikuni Copy) carb doesn't do that at all...

To see if it is the tranny set up you could try a heavier torque spring whch would make sure it was in low gear and not trying to take off in high gear...If that doesn't change anything then I would look at the carb.

I do like lighter roller weights in the 50s....3.2 has worked well for us in the past(with stock torque spring)

hotquads1
09-01-2007, 05:10 AM
Originally posted by jread14
The odd thing is Hetrick racing sent me 4 gram rollers and from what I am reading that is heavier than the stock ones. which causes what????

if you still have the original rollers they should be 3.5 grms , put them back in . .5 grms roller weight has huge affect . What torque spring did you use ?
marc

jread14
09-01-2007, 08:50 AM
Originally posted by hotquads1
if you still have the original rollers they should be 3.5 grms , put them back in . .5 grms roller weight has huge affect . What torque spring did you use ?
marc
It was running the same way with the stock rollers in there as well. However, I do still have the stock rollers but they have some flat spots on them. That is why I replaced them. Hetrick also sent me a white torque spring. I am also using the green clutch springs which is I think the 1000 spring set.

bulldogfallon
09-01-2007, 09:01 AM
What carb?


The white spring is probably the Malossi 1000RPM spring which is stiffer than stock....

Stock DRR stuff works great.IMO

jread14
09-01-2007, 02:28 PM
Originally posted by bulldogfallon
What carb?


The white spring is probably the Malossi 1000RPM spring which is stiffer than stock....

Stock DRR stuff works great.IMO

It has the 07 Mikuni Carb on it. I have heard that the Keihin carb setup really helps these 07's out with the tuning issues.

Eventhough I put the white spring on it, it was doing this before I changed the spring. I still have not taken the boot off which I plan on doing this evening. IF that is not the case what setting have you guys found works the best on the air fuel mixture screw? JR

hotquads1
09-01-2007, 02:52 PM
If you have the mikuni carb then the boot will not need to be checked those didnt have any problems, likewise the mikuni carb had no real issues either. Lets go ahead and dial the carb in , if no jetting has been done then you are very rich , I am sure it is 90+ and humid in texas right now.In this weather I would put a 100 main jet and 1 turn on air screw and a 20 pilot jet , this will perk it up quiet a bit . this will be very close. but I still think the real problem may be in the cvt. (roller vs torque spring combo)
marc

jread14
09-01-2007, 05:04 PM
Originally posted by hotquads1
If you have the mikuni carb then the boot will not need to be checked those didnt have any problems, likewise the mikuni carb had no real issues either. Lets go ahead and dial the carb in , if no jetting has been done then you are very rich , I am sure it is 90+ and humid in texas right now.In this weather I would put a 100 main jet and 1 turn on air screw and a 20 pilot jet , this will perk it up quiet a bit . this will be very close. but I still think the real problem may be in the cvt. (roller vs torque spring combo)
marc

I will try the jetting... I went to the larger jetting (125) because it has a K&N filter and it was way to lean and this is what dialed it in. I will also check the pilot because I am not 100% sure what it has in it. Thanks for your help. I will let you know what I find out. JR

bulldogfallon
09-01-2007, 08:13 PM
I believe the Mikuni has 32 Pilot in it stock...

Our 50 did the same thing...

When it was run cold it would fly out of the gates, but once it was warmed up it had a bog off the line....never figured it out

Could the belt be worn?

We run a 105-110 main jet....with a Uni directly mounted to the carb...


125 seems a bit on the rich side, especially with the hot temperatures....

I ran a 115 on our 06 with race gas....which would lead me to say a 110 should be good if your using 93 octane

bulldogfallon
09-01-2007, 08:18 PM
I think the Sunworlds run great (Mikuni Copy), but the Keihin carbs are very easy to tune....


I would say that is their biggest advantage is their "consistent" performance and tunability.

jread14
09-01-2007, 08:40 PM
Ok, the pilot jet is a 25 the main is a 125 and the air screw was 2 turns out. I turned the air scew in 1 turn and i am not sure that helped that much. I dont have a smaller pilot so I will have to wait until Tuesday to get one. I will also get a 100, 105, 110, and a 115 to try and dial it in. Thanks for all your help. Let me know if you think of anything else. JR

hotquads1
09-02-2007, 03:38 PM
125 main? that has got to be rich . How does the plug look , my guess is black and sooty. Since you have the K&n filter I would put the 105 main, if you cant find a 20 pilot , the 25 pilot will work decent, but you will need about 2 turns out on air screw. do you know where needle clip is ? needs to start in bottom groove. . Now I am thinking the carb is alot of your problems, your going to be real happy when you get this carb jetted ! bike should act lean and bog a little until COMPLETLY( five minutes or so of running) warmed up then it should run crisp and no bogging.
marc

jread14
09-02-2007, 08:40 PM
Originally posted by hotquads1
125 main? that has got to be rich . How does the plug look , my guess is black and sooty. Since you have the K&n filter I would put the 105 main, if you cant find a 20 pilot , the 25 pilot will work decent, but you will need about 2 turns out on air screw. do you know where needle clip is ? needs to start in bottom groove. . Now I am thinking the carb is alot of your problems, your going to be real happy when you get this carb jetted ! bike should act lean and bog a little until COMPLETLY( five minutes or so of running) warmed up then it should run crisp and no bogging.
marc
Yeah I was 2 screws out and the 25 pilot so that may work. I will try and get the main jets on Tuesday and try it out. How many turns out should I be if I get a 20 pilot?

hotquads1
09-03-2007, 08:50 AM
with a 20 pilot start at 1 turn out
marc