Jump to content
Sign in to follow this  

'04 RMZ250 wont start need suggestions

Recommended Posts

I put an fmf titanium powercore slip on on my bike last summer. The dealer who i bought the muffler from said that i would not have to change the jetting with only a slip on. So i took ths pipe home put it on and ran it and it ran good for like ten minutes and then i put it away for the nite and came back out tomorow and it started and i let it idle for like 5 minutes. I came out 10 minutes later to go riding and it wouldnt start. I thought it was flooded so i took the carbeurator out and properly installed the correct size jet. It still wouldnt start so i took it to a machine shop in town where i was told that all my clearances were good and that the cylinder and the piston were fine. I took it to the dealer a few weeks after and they told me i needed a new top end which i think is load of shit because the guy at the machine shop (who's been building motors for years) said that it would just be a waste of money to put a new top end in and that everything was correct. I recently put the motor back together and double checked everything before putting it back together, timing and all. It still wont fire even when i put fuel in the cylinder. It is getting spark but it just wont fire. I heard from someone i know that it might be the fuel/air mixture screw, could this be the problem.

If you have any advice, please let me know, i would greatly appreciate it.

Share this post


Link to post
Share on other sites

Um....did the "machine shop" guy disassemble and inspect your top end? Did he check your valve clearances? How did he know the clearance specs? It is fairly involved to actually disassemble the engine to the point where you can measure the piston and cylinder to determine if they are within spec or not. Checking the valves, while quite easy, still requires some disassembly and the specifications to check against.

How does it feel when you kick it? Does it kick over very easily? My money is on tight valves, at a minimum. Especially if it started when it was cold, then would not start after it warmed up. Do you know how to check your valves? If so, do it. If not, get a service manual or do a search on here to learn how. I would bet a dollar to a donut that one or more of your valves is tight.

Let us know what you find out! Don't be one of those posters that never comes back and lets us know what the problem was! :confused:

Share this post


Link to post
Share on other sites

I gave him my manual and he measured everything and i put it all back together yesterday night. I took the carb. apart and leaned it out a little bit and i redid the timing today and it is backfiring and shit when i go to kick it but it still sounds like it wants to turn over but doesn't. Tomorow im gonna check to see if there is enough compression building up. I'll keep you posted.

Share this post


Link to post
Share on other sites

I just noticed...you're in CT, and you mentioned backfiring. Is the bike kept outside? Is it really, really cold (less than 40 degrees F or so)? Maybe it's just that it's so cold and your jetting is off that it's difficult to start. I know both my son's RMZ and my old YZF were killers to get started in the cold. I always cheated by keeping them in a heated garage before trying to start.

Share this post


Link to post
Share on other sites

It sits in my climate controlled basement, so it's not cold. Anyway,I bought a compression gauge at an auto parts store and it didn't fit properly in the hole but i also saw that there is a little hole on the right side of the head down towards the bottom. Every time we go to start it air blows out of it so I am wondering if anything is supposed to fit down there. That might be y i dont have enough compression. It might just be in my best interest to resleeve it and throw a new piston in it. I might just take it to the dealer and have them fix it becuase im sick of having a broken bike. I welcome any suggestions though.

Share this post


Link to post
Share on other sites
It sits in my climate controlled basement, so it's not cold. Anyway,I bought a compression gauge at an auto parts store and it didn't fit properly in the hole but i also saw that there is a little hole on the right side of the head down towards the bottom. Every time we go to start it air blows out of it so I am wondering if anything is supposed to fit down there. That might be y i dont have enough compression. It might just be in my best interest to resleeve it and throw a new piston in it. I might just take it to the dealer and have them fix it becuase im sick of having a broken bike. I welcome any suggestions though.

Sounds like you found your problem to me. I just ordered a new head and was looking at the parts diagram on line and there is a part called out as "Plug" and I think it goes in the area you reference. I'm not sure what it is, what it's function is or why it would come out (probably some kind of "weak link" release?). It may be a simple fix.

Share this post


Link to post
Share on other sites
Sounds like you found your problem to me. I just ordered a new head and was looking at the parts diagram on line and there is a part called out as "Plug" and I think it goes in the area you reference. I'm not sure what it is, what it's function is or why it would come out (probably some kind of "weak link" release?). It may be a simple fix.

The purpose of this plug was to install and aftermarket decompression switch...which I have never heard of anyone actually buying :confused: The plug missing is very likely your problem so replace that and you will probably be in luck.

Share this post


Link to post
Share on other sites

Hey How did you make out getting the bike to run? I'am having the same trouble with mine...

Share this post


Link to post
Share on other sites

It still won't start. I'm either going to put a new top end in it or just bring it to the dealer, but it still sounds like it wants to fire.

Share this post


Link to post
Share on other sites

the 04s had faulty ignitions, try to borrow one to test it.

Share this post


Link to post
Share on other sites
the 04s had faulty ignitions, try to borrow one to test it.

The ignitions were recalled. It should have been changed by the dealer by now.

Soo....what's the final diagnosis/cure? Let us know.

Share this post


Link to post
Share on other sites

not all got the recall if they were sold on, also the connector that goes into the unit goes bad as well, a fix is to cable tie around the box to hold the connector into the unit tighter.

Share this post


Link to post
Share on other sites

Before you spend more money, do a simple dio. Check to see if you have spark, and fuel to the engine. I read all of the threads and I didnt see where you checked the spark plug.

Share this post


Link to post
Share on other sites

I have spark, I've checked multiple times and i'm getting fuel, I bought a compression tester and it didnt thread into the sparkplug hole properly so i havent been able to tell if im getting enough compression. I'm just going to bring it to the dealer anyway. I'll keep you posted on what they say.

Share this post


Link to post
Share on other sites

No I didn't repalce the plug that was missing, I am going to try and take an accurate compression test. It feels like it still doesn't have enough compression. I am going to check and if so put in a new sleeve and piston. Has anyone heard highly of the athena or cylinder works bore kits?

Share this post


Link to post
Share on other sites
No I didn't repalce the plug that was missing, I am going to try and take an accurate compression test. It feels like it still doesn't have enough compression. I am going to check and if so put in a new sleeve and piston. Has anyone heard highly of the athena or cylinder works bore kits?

Dude. ***? You have identified a problem (the missing plug). If not THE problem, it is at least A problem. Fix it and see if it solves the problem!

Share this post


Link to post
Share on other sites

Yea a hole keeping compression from building definitely isnt going to let your bike start, that sounds like a pretty obvious one to me...

Share this post


Link to post
Share on other sites

No doubt bro I assumed since you were checking other things you replaced the plug, but you never mentioned it again so I figured I would ask. As you've heard a couple times you have got to get a plug in there. It may "feel" like you have enough compression, but just a bit of blow buy will be enough to not get the bike running. Once you get the plug there is a bolt with a washer that keeps that plug in place ensure you get that also.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×