2004 rmz 250 problems

[sniperwolf11]

so i just recently purchased a rmz 250 it needs to be jetted. I ordered a jet kit. i was wondering would this make it harder to start. for the last week it was real easy to start when it was cold, now it is hard to start when cold and easy to start when warm. the only aftermarket part on the bike is a procircuit waterpump. i know im not getting enough fuel im waaiting on the ket kit i pulled my plug and it was burning white it wasent real white like when my yz 250 was burning lean. was just wondering if anybody would have any idea about why starting it cold is so much harder now.

---------- Post added at 12:47 PM ---------- Previous post was at 12:44 PM ----------

also two more questions i have why are there two cables coming off of the throttle on these bikes? and how hard is it to put the jet kit in i know i had no problems screwing around with my older yz250 carb. just because the shop priced me 80 bucks to put the jets in i would rather try myself.

[dodging_roost]

First off the 2 cables one is probably a return like on modern day 4-strokes. Secondly jetting will play a factor in starting a bike, how much of a factor depends how far off it is.

Generally when I get a bike used I take jetting back to stock because I never know what the PO did, they could have some really messed up jetting in there. Also you never know how they were mixing oil, so the long and short is I go with a simple stock jetting and on your bike that appears to be ...172 main 50 pilot air screw I think is about 2.5 turns out and needle is probably 3rd position.

So I would take it back to those specs and then start from there .... Not knowing your elevation that should work O.K. 0 - 1500 feet

Changing jets is easy the throttle will not even get in the way the main is under the bottom of the bowl and the pilot should be next to it usually under a plastic type of block thing hard to explain.

Thanks
scott

[sniperwolf11]

ok thanks for your help. i think the previous owner had stock jettings in it. i dont know if the throttle screw is screwed up. i havent touched it yet i dont really want to until i get my other jet kit so i can do it all at once

[sniperwolf11]

another question i was wondering if maybe its getting harder ot start because ive been driving it lean and maybe it is starting to burn a hole thru the piston??? but then if i jump start it it barely has to turn over and it starts ??

and how bad is it to drive it while its burning lean. the plug wasent super white just a lil white. and what starts happening inside the engine when its burning lean ?? thanks for the help once again guys im new with bikes and just trying to learn

[sniperwolf11]

went out to ride it today for 10 minutes and it was hard to start from cold again this isnt make much sense to me as it was so easy to start before when it was cold. i have read in other threads about valves could this be a valve problem? how hard is it for me to check the valves?? thanks again for the help people

[dodging_roost]

Originally Posted by dodging_roost

First off the 2 cables one is probably a return like on modern day 4-strokes. Secondly jetting will play a factor in starting a bike, how much of a factor depends how far off it is.

Generally when I get a bike used I take jetting back to stock because I never know what the PO did, they could have some really messed up jetting in there. Also you never know how they were mixing oil, so the long and short is I go with a simple stock jetting and on your bike that appears to be ...172 main 50 pilot air screw I think is about 2.5 turns out and needle is probably 3rd position.

So I would take it back to those specs and then start from there .... Not knowing your elevation that should work O.K. 0 - 1500 feet

Changing jets is easy the throttle will not even get in the way the main is under the bottom of the bowl and the pilot should be next to it usually under a plastic type of block thing hard to explain.

Thanks
scott

DUH I looked at an 04 RM NOT RMZ my bad!!! man I got to quit multi-tasking

Thanks
Scott

---------- Post added at 03:25 PM ---------- Previous post was at 03:23 PM ----------

Originally Posted by sniperwolf11

went out to ride it today for 10 minutes and it was hard to start from cold again this isnt make much sense to me as it was so easy to start before when it was cold. i have read in other threads about valves could this be a valve problem? how hard is it for me to check the valves?? thanks again for the help people

It probably is Valves I was initially thinking this was a 2 stroke ... my bad... When a thumper gets hard to start it is almost ALWAYS spec on the valves has closed and you will want to shim them to get back to spec. I also believe you have a manual cam chain tensioner which you will want to check too.

Sorry for the initial mis understanding.

Thanks
scott

[sniperwolf11]

where is the manual can chain tensioner?? and if i have tomorow or friday off i will trying taking the top of the head off too look at the valves do you have any pictures of what there supose to look like if they are good. thanks again

---------- Post added at 02:30 PM ---------- Previous post was at 02:28 PM ----------

and what is cam chain is it the timing chain??

[dodging_roost]

Originally Posted by sniperwolf11

where is the manual can chain tensioner?? and if i have tomorow or friday off i will trying taking the top of the head off too look at the valves do you have any pictures of what there supose to look like if they are good. thanks again

---------- Post added at 02:30 PM ---------- Previous post was at 02:28 PM ----------

and what is cam chain is it the timing chain??

Yes and yes.... cam chain .... timing chain... same.

Woody_393 had a good article on this let me see if I can find it I think he made it sticky.

Yup he did pictures and all.......
How To Check and Adjust Valves

It's on a 450 but exact same concept .... clearances you will want to make sure are the same between bikes though.


Thanks
Scott

[sniperwolf11]

if the valves are off will it still run good when it is running?? and could that be a reason it is running lean?

[dodging_roost]

Originally Posted by sniperwolf11

if the valves are off will it still run good when it is running?? and could that be a reason it is running lean?

depends how far out the valves are.... if they are way out no... if just enough to keep it from firing then yes would still run great just not as strong as it would with the valves closing all the way. The intake valves run out of room basically and start getting held open, so you lose a little compression if they are out and holding a valve open.

The lean running is not usually because of valves, but I would take care of the valves check the float on the carb before you go any further in diagnosing the bike running lean.

Thanks
Scott

[sniperwolf11]

ok im off tomorow im going to take the carb apart. ill check the float is there anything else i should check in the carb while i have it off. if the needle has another notch up it can go should i move it. or if i move it does itneed other jets?? or does it need the fuel air screw to be moved?

[dodging_roost]

Originally Posted by sniperwolf11

ok im off tomorow im going to take the carb apart. ill check the float is there anything else i should check in the carb while i have it off. if the needle has another notch up it can go should i move it. or if i move it does itneed other jets?? or does it need the fuel air screw to be moved?

Jetting is tough nice thing on a 4-stroke your jetting range is VERY broad and if your even close to sea level the stock jetting should be ok.

I would set it back stock if it were mine and go from there. Jetting is more art than science and with a 4-stroke it's more about the sound and popping than checking the plug.

I don't know about Suz but Honda's come with a table for elevation adjustments that has mine pretty close.

Thanks
Scott

[sniperwolf11]

ok my bikes popping alot im very close to the ocean im in nova scotia. the jetting in the bike is stock. maybe i just have a clogged jet or the carbs real dirty tho ill find out today hopefully

[dodging_roost]

When is it popping full open, deceleration, idle??? generally that is a lean signature.

Thanks
Scott

[sniperwolf11]

it is popping during deceleration mostly i tryed taking the bottom bowl off today and one of the screws were stripped to **** tha ti couldnt even get off so im triyng to get some new screws tonight before i take the stripped one off

[dodging_roost]

Originally Posted by sniperwolf11

it is popping during deceleration mostly i tryed taking the bottom bowl off today and one of the screws were stripped to **** tha ti couldnt even get off so im triyng to get some new screws tonight before i take the stripped one off

Deceleration is usually an exhaust leak, I would check that first... all thumpers pop on deceleration mine does and so does everyone else's that I've seen I guess it more depends how much.

Thanks
Scott

[sniperwolf11]

ill check that out but it dosent sounds like i have an exhaust leak but thne again the bikes pretty loud

[sniperwolf11]

wheres the cam chain tensioner bolt? it does sound like you can hear a loose chain in the engine is that bad?

[sniperwolf11]

is it the bolt on the right side of the head ??

---------- Post added at 01:27 PM ---------- Previous post was at 01:16 PM ----------

my buddy said it sounds like its starting to slap. and i looked over the pipe for leaks i cant find any. i was thinking after i ordered the kit i shouldnt have to jet it. with the bike being stock should i

[dodging_roost]

Originally Posted by sniperwolf11

is it the bolt on the right side of the head ??

---------- Post added at 01:27 PM ---------- Previous post was at 01:16 PM ----------

my buddy said it sounds like its starting to slap. and i looked over the pipe for leaks i cant find any. i was thinking after i ordered the kit i shouldnt have to jet it. with the bike being stock should i

Right you shouldn't need to jet it. the cam tensioner should be on the left side where the cam chain is.

slap? what does he mean by that?

thanks
Scott