Valve adjustment on pit bike

[my67xr]

Yeah i saw you were US based, the measurement's i gave you were in Inches/Thou, hence the " after the .003" and .004", and not mm's.
We use metric and imperial measurement here too, just depends on what feeler gauges you have.

I guess if you run the clearance's that large, it'll be quite a while before you need to adjust them again.
It could lose a bit of power too, cause the valves wont open as much, but that's up to you.

To adjust the mixture properly you need to warm the bike up, then raise the idle speed up a little.
then turn the mixture screw in or out 1/2 turn at a time, while listening to the engine run.
You want it running at the fastest/smoothest rpms.
so if you turn it in, and the revs drop, turn it back out and listen for the revs to rise.
Keep turning it out till the revs drop again, then turn it back in 1/2 turn, that'll be very close to the sweet spot/setting.
When you are happy with how smooth/high the revs are, then you can drop the idle speed back down to normal.

Then take the bike for a ride and try it out.
It may need some very slight tweaking form there.



With the adjusting your mixture screw, you could buy one of these and screw it into your carby to replace the mixture screw
Makes it very easy to adjust without having to remove the carby

Any auto parts store will sell filter oil,
Maxima Fab 1 Spray-On Air Filter Oil 13oz - Pit Bike Engine Parts - Lubes Oils Chemicals - W-78-9928 - TBolt USA, LLC
Uni Filter Foam air filter Oil Spray - Pit Bike Engine Parts - Lubes Oils Chemicals - W-82-1000 - TBolt USA, LLC

It will change the way your bike runs and you'll need to retune it.
It will be running pretty lean at the moment and could burn your valves out if you don't do something about it asap.

Running your bike with no oil on the filter will damage your engine,
it will get dirt/dust through it and make it blow smoke, wearing out the rings, bore and piston etc

 

[Nicknackzz13]

okay ths some good info.. im guessing i should keep the valves around the .003=0.08mm for intake & for exhaust .004=0.10mm i believe is a good setting which youve told me already? so would this work (im going from my feeler gauges i pictured for you earlier... let me know?


and yeah i built a make shift carby tuner from some old fuel line with a flathead drillbit in the top of it with a tie strapped to it so it wont move when turned, havent tested it out yet but im going too...

to make mysef clear and make sure ive understood this clearly

to tune the carb perfectly ill need to turn the idle right in so the idle is really high? and then twist the mixture screw until it goes away, or just turn it up a little bit, and turn the mixture screw until it sounds like its idling perfecty with a fast idle but low revs, correct?

 

[my67xr]

try reading it again, i have just clarified the tuning part of the post a bit more
And yes, your feeler gauges will be fine, they have both the measurements, imperial and metric

 

[Nicknackzz13]

I adjusted them to .003 inlet & .004 for exhaust, but itll start a bit weird (on choke again but its cold) and itll be a lil rattling but not as bad as before but when i rev it still , kinda high revving to warm her up and get her going, it will bog a bit at the top end..

would pistons or rings have busted?? im uploading a video of my bike started to show everyone the problem

hope my bike aint busted!!!!

 

[my67xr]

Well the top end bog would be caused by not having the Air Filter oiled.
When you run a foam filter without oil, it lets too much air through the carby, this makes the engine run lean and will cause it to bog.
It probably wasn't quite as noticable before because the valves weren't adjusted properly.
With it being harder to start cold etc, would be the Pilot jet, i advised you to fit a bigger one a #20

Once you have oiled the air filter, and fitted the bigger Pilot jet it will need retuning, (adjusting the mixture screw )

 

[Nicknackzz13]

Well the top end bog would be caused by not having the Air Filter oiled.
When you run a foam filter without oil, it lets too much air through the carby, this makes the engine run lean and will cause it to bog.
It probably wasn't quite as noticable before because the valves weren't adjusted properly.
With it being harder to start cold etc, would be the Pilot jet, i advised you to fit a bigger one a #20

Once you have oiled the air filter, and fitted the bigger Pilot jet it will need retuning, (adjusting the mixture screw )

Yeah i understand what youre saying dude, onl thing with the whole jets and carbs is i dont know where to find the right size jet and all that cause im unsure of what i type in, ive tried googling 20 jet and well that doesnt work lol (im stupid) >_<...

is it normal for the bike to sound a little rattle then?

here is the video of my bike start up and rattling. high revving noises for you to have a listen to finally!

(my bike never ran liek this until i started messing with valves

https://www.youtube.com/watch?v=5ZAcy-K3RIU

 

[Nicknackzz13]

ooh and hey if i were to buy air filter oil, what type does everyone suggest i go for? could i go for any in a car autozone store? or auto place? or would i need a bike/pit bike type for it?

 

[Nicknackzz13]

Also someone on miniriders said, the mikuni vm22/26 needs to be tuned to around 2.5 turns out from in?


my mikuni came as a VM26..is that a 22?? hell i dont even know these damn carbs lol

 

[Nicknackzz13]

ooh and by the way my jets in the carb.. i know one is 20, it says 20 on it i think or 21.. (unsure)

i just remembered this lol as the other day i took the crb off for a clean.. cnt get a foam air filter or filter oil for the bike yet if i have to order them online, (wonder if any filter oil is fine? Walmart etc) or does it have to be specially for pit bikes/ motorcycles in general (of course) lol

 

[my67xr]

ooh and hey if i were to buy air filter oil, what type does everyone suggest i go for? could i go for any in a car autozone store? or auto place? or would i need a bike/pit bike type for it?

See post #21

If you want a link to Walmart then get either the Uni Filter foam oil, the BelRay foam oil or the PJ1 Foam filter oil, or get the cheapest you can find, it's up to you
foam air filter oil - Walmart.com
If you get the spray on oil, spray the filter 9off the carby) and give it a good squeeze through, dab any thick sections with a piece of paper towel to remove any excess.


Yes it's normal for the engine to rattle a little, the factory do up the valves too tight, that's why they are quiet when you get them
Also when your engine warms up the clearances get smaller too, so with them set tight once it's warm the valves don't shut properly, and will damage your engine if you don't adjust them.
It will also make the bike run weird and harder to start.


If your bike already has a #20 Pilot jet then leave it there, just tune it properly to suit you bike (after you have oiled the filter)


Your bike has a Mikuni 22/26mm carby, it isn't genuine Mikuni, it's a china copy
Most of them are pretty good. they are called 22mm carbys, or 26mm carbys or 22/26mm carbys
The width across the bore of the carby is 22mm, and the height is 26mm.
They use a foam filter to suit a 38mm neck on the carby.
Uni Filter UP-4152ST Uni Dual Stage Pod Filter Straight 1 1/2in x 3 1/2in x 4 - Walmart.com
The angled filters can be turned to move it away from obstructions on the frame or your legs etc
Uni Filter UP-4152AST Uni Dual Stage Pod Filter 15 Degree Angle 1 1/2in x 3 1/2in x 4in - Walmart.com

 

[Nicknackzz13]

would this be any good for the air filter?

damnit wish i ordered some from tbolt when i ordered my valve covers!! >_<

Bully Dog Air Filter Cleaning Kit 229000: Shop the best Air Filter Oils/Cleaners at Advance Auto Parts


(just wanna give everyone here a big thanks for the help and info and sticking with me on this!)

 

[my67xr]

Do you have a motorcycle shop near by ?
They'd have a few different filter oils, for cleaning Turpentine is cheap and good because it doesn't affect the foam filters.

 

[Nicknackzz13]

See post #21

If you want a link to Walmart then get either the Uni Filter foam oil, the BelRay foam oil or the PJ1 Foam filter oil, or get the cheapest you can find, it's up to you
foam air filter oil - Walmart.com
If you get the spray on oil, spray the filter 9off the carby) and give it a good squeeze through, dab any thick sections with a piece of paper towel to remove any excess.


Yes it's normal for the engine to rattle a little, the factory do up the valves too tight, that's why they are quiet when you get them
Also when your engine warms up the clearances get smaller too, so with them set tight once it's warm the valves don't shut properly, and will damage your engine if you don't adjust them.
It will also make the bike run weird and harder to start.


If your bike already has a #20 Pilot jet then leave it there, just tune it properly to suit you bike (after you have oiled the filter)


Your bike has a Mikuni 22/26mm carby, it isn't genuine Mikuni, it's a china copy
Most of them are pretty good. they are called 22mm carbys, or 26mm carbys or 22/26mm carbys
The width across the bore of the carby is 22mm, and the height is 26mm.
They use a foam filter to suit a 38mm neck on the carby.
Uni Filter UP-4152ST Uni Dual Stage Pod Filter Straight 1 1/2in x 3 1/2in x 4 - Walmart.com
The angled filters can be turned to move it away from obstructions on the frame or your legs etc
Uni Filter UP-4152AST Uni Dual Stage Pod Filter 15 Degree Angle 1 1/2in x 3 1/2in x 4in - Walmart.com

Ahh oka yeah, No sorry man, the air filter im using is not foam, sorry i got that confused when you were saying which i had, i have one of those steal performance ones i guess.. you can see it n my video here https://www.youtube.com/watch?v=5ZAcy-K3RIU thats a video of my bike that i took the other day of the noises etc, i had the valves at .003 inlet & .004 exhaust in this video and it sounds a bit better, carb needs tuned yes, and im assuming ill have to adjust the valves to .002 inlet .004 for exhaust cause it bogs a bit at high revs, ill have to keep a look out for the oil i have the links you linked me saved, and yeah walmart has everything but most of it is either delivered to you or not in stores and gotta order it, we have loads of auto parts stores around here where im sure i could at least get some sort of good filter cleaner oil, when i tune the carby, is 1.5 turns out from in a good baseline? only trouble i have is getting something up in under to where the fuel screw is so i can tune it and twist it, , cause i gotta turn the idle up a bit right? warm the bike up, then twist and turn until the idle lowers but its sped up a bit more not slow idle.. is what im taking from all this.. so i think i understand that

https://www.youtube.com/watch?v=5ZAcy-K3RIU check out the video man and let me know whatcha hear and think of it..

 

[gottagetacheaperhobby]

Turf the filter and buy a uni filter. Start your tuning then. Does sound rattlier than any of my engines, but it could be a combination of the phones mic and the rather low idle speed on your engine (imo)

 

[my67xr]

Dont go adjusting the valves any tighter, that wont fix the lean bog.
Oiling the air filter and a tune should help that out.

You could get a Carby spinner, that would help you tune it, you can mount the carby out to the side so you can get at the mixture screw easily.
Just unbolt your manifold from the head, and then bolt the spinner onto the head,
then the manifold can be bolted onto the spinner so the carby will be hanging out to the side of the bike on the spinner
12 Way Carb Kit I - Pit Bike Engine Parts - CARB KITS & CABLES - TRC-0130 - TBolt USA, LLC
Or get the remote mixture screw from TBolt that i posted the link to above

this is a carby spinner-

 

[Nicknackzz13]

Dont go adjusting the valves any tighter, that wont fix the lean bog.
Oiling the air filter and a tune should help that out.

You could get a Carby spinner, that would help you tune it, you can mount the carby out to the side so you can get at the mixture screw easily.
Just unbolt your manifold from the head, and then bolt the spinner onto the head,
then the manifold can be bolted onto the spinner so the carby will be hanging out to the side of the bike on the spinner
12 Way Carb Kit I - Pit Bike Engine Parts - CARB KITS & CABLES - TRC-0130 - TBolt USA, LLC
Or get the remote mixture screw from TBolt that i posted the link to above

this is a carby spinner-

Now that12way carby thing is a very good piece of metal to have been invented haha,

Well guys today i was free to work away on the bike so i did, i tightend the inlet to a .002 and the exhaust to a .004 and there is no rattling, no bog and it vroooommss like it did before but, it sounds more powerful??? so i guess i finally got it right? for some reason she doesnt wanna sit on any valve setting other than .002 inlet (.004 for exhaust) so ive done that and ive left it at that, the bike starts fine and runs fine but i havent got a chance to ride it yet (raining all day and night tonight) plus our track is off limits due to overflow of water/mud etc...

since we can use that 12way thing for the carby, is there by any chance a way i could turn the manifold around pointing out towards the front wheel and connect it all, start the bike, heat up and tune the carb that way? once tune,i could take the manifold off and just turn it back to hiding under the tank... would this be okay to do? i have a long enough fuel line to do so and ive been thinking of doing that today but i wanted input before i go messing something up... whatcha all think?? good idea? bad idea? may i mess something up by doing this or would it be okay, from what i know, i think it would be fine just not ride'able lol... if anyone doesnt understand what i mean by all this...

the carb sits on the manifold pointing a little crooked out the rear end of the tank under it.. (normally)

what if i moved the manifold & carb around backwards and install it that way so i can get to the mixture with no worries..

good or bad?

 

[Nicknackzz13]

ooh and i made sure on the sizes of my jets..

took me awhile to find the tiny numbers on them but i found them,i think these are correct..

Main Jet: 95
Pilot Jet: 15

thats the numbers i could see on the jets, (not exactly positive on the pilot jets number because i could barely see it and i just came up with 15 but its probably around that range lol)

i thought mine were the 20's but i guess not or i cant see lol


i guess theyll do for the time being, ive bought so much stuff for my bike that i cant get much more for awhile lol

so if all is well im going to try this manifold thingy but i have a question, i got the tools to make new screw threads.. one side of my manifold/engine inlet hole for the carb/manifold is sorta shredded but i got it in there some way, if i do this manifold moving thing so i can tune the carb easier by getting into the mixture screw, if i cant get the damn screw back in, i could possibly make a new thread in there? i got the tools to do it, the drill bits and a hand held turner to turn the screw by hand to make new threads.. only thing im worried about is making it a bit bigger but it will have to be a tiny bit bigger but small enough for the holes to connect (sorry if not making myself clear

 

[my67xr]

Ok, your Main jet is good for a 125, the Pilot is a bit small as i've said before.
If you fit a #20 it will make your bike run a lot better, and be easier to start etc


You mentioned above about turning your intake manifold around 180°, have you tried it ? it might work ?
The only problem i can see is it may change the float/fuel bowl angle a bit , it might flood or run rich?



How did you damage the thread in the head for the intake manifold ?
Try not to over tighten any bolts on the engine, it is only cheap cast alloy and will strip the threads out easy enough
The thread size in the head for the inlet manifold is M6 x 1mm pitch

There are a couple of options to fix the thread, one is to buy a longer bolt/s, if your current bolt only goes into the head say 6 or 8mm, the actual hole is about 20-25mm deep.
So you could try another bolt about 10-15mm longer than what the engine came with.
Clean and bit's of alloy out the thread before you tray another longer bolt, use a vacuum etc, but don't drop bits into the inlet port, tape it up

You might be able to drill it a bit deeper and then tap the thread down to the bottom of that, you can only go 8mm deeper though
You'll need a bottom tap which is not tapered and the threads go all the way to the bottom of the tap.
like the bottom one here- Westward 5TWA3 M6 High Speed Steel 1"L Hand Tap Set 3 pcs. - Walmart.com

Make sure that you tape up the inlet port of the head too, so you don't get swarf down into the engine.



The other way you could go is to fit a Helicoil thread into the head.
You buy them in a kit, they come with a drill bit to suit, a tap, and a tool to wind the new thread in, but they are kind of expensive if you are just fixing 1 thread.
Amazon.com: Helicoil 5546-6 M6 x 1 Metric Coarse Thread Repair Kit: Automotive
You could ask your local mechanic how much he'd supply and fit one for ? i reckon it'd be under $20


Are these the Valve/Rocker covers you bought ?
TB Billet Red Tappet covers Z50 CRF50 XR50 CT70 & Pit bikes - TB Parts - CHINESE ENGINES - TBW0672 - TBolt USA, LLC

 

[Nicknackzz13]

Ok, your Main jet is good for a 125, the Pilot is a bit small as i've said before.
If you fit a #20 it will make your bike run a lot better, and be easier to start etc


You mentioned above about turning your intake manifold around 180°, have you tried it ? it might work ?
The only problem i can see is it may change the float/fuel bowl angle a bit , it might flood or run rich?



How did you damage the thread in the head for the intake manifold ?
Try not to over tighten any bolts on the engine, it is only cheap cast alloy and will strip the threads out easy enough
The thread size in the head for the inlet manifold is M6 x 1mm pitch

There are a couple of options to fix the thread, one is to buy a longer bolt/s, if your current bolt only goes into the head say 6 or 8mm, the actual hole is about 20-25mm deep.
So you could try another bolt about 10-15mm longer than what the engine came with.
Clean and bit's of alloy out the thread before you tray another longer bolt, use a vacuum etc, but don't drop bits into the inlet port, tape it up

You might be able to drill it a bit deeper and then tap the thread down to the bottom of that, you can only go 8mm deeper though
You'll need a bottom tap which is not tapered and the threads go all the way to the bottom of the tap.
like the bottom one here- Westward 5TWA3 M6 High Speed Steel 1"L Hand Tap Set 3 pcs. - Walmart.com

Make sure that you tape up the inlet port of the head too, so you don't get swarf down into the engine.



The other way you could go is to fit a Helicoil thread into the head.
You buy them in a kit, they come with a drill bit to suit, a tap, and a tool to wind the new thread in, but they are kind of expensive if you are just fixing 1 thread.
Amazon.com: Helicoil 5546-6 M6 x 1 Metric Coarse Thread Repair Kit: Automotive
You could ask your local mechanic how much he'd supply and fit one for ? i reckon it'd be under $20


Are these the Valve/Rocker covers you bought ?
TB Billet Red Tappet covers Z50 CRF50 XR50 CT70 & Pit bikes - TB Parts - CHINESE ENGINES - TBW0672 - TBolt USA, LLC

im not sure if it would flood or do anything to the bowl in the carb but it seems like a good idea just to tune the engine in, and im not sure how i fu@ked the threads up to be honest man, because a few days ago i had it off the manifold i mean and i was cleaning everything checking etc etc, and i just bolted it back on with the bolts that were already in there and then it just didnt wanna turn no more and its a big screw like a inch.2 long at least lol


yeah i got all the thread fixing things here in grandather in laws garage, i got the drillbits, and the thread maker bits and other weird **** lol, im gonna test the drillbits on something else to make sure i do it properly then move on to the bike

and yes dude, that is the valves covers i ordered, i ordered the last pair and they were here yesterday but the mail person wouldnt leave them (THEY ALWAYS DID BEFORE!) so there being redelivered today hopfully.. is something wrong with them?

 

[Nicknackzz13]

Well fellas i fixed her today, shes running fine and starts fine now, carb is on a 1.5 turns out from in and i havent tuned it n yet but its fine for now, cause what i wanted to do was get the bike working good agin and start with no weird noises so i fixed it all, and i also took the weird air filter off that was hooked up into the engine i forget the name of it?

but i hooked a big (modified nosal) up to the engine part and threw on a new air filter that came with the cabr the time i bought it..

heres some pics of what i took off



and this is what i put on



and the engine hose where the air filter thing went too



now all thats left is to tune it in and sometime in the future get bigger jets.

another question, whats the best way if you aint got a chain breaker, to break a chain and add a link into a chain thats a link short ?

ive tried hammering it but to no avail unless i just keep trying!! a big heavy duty race gold chain! replacing the standard.