Question about 2003 Suzuki RM 250

3 Answers

1980 Rm 250 wont start and backfires

I have a 1980 rm 250.
I have rebult the moter. parts wiseco poiston .40 over
boysen reedvalves and gaskets.
I have to put gass down the sparke plug and it might start
no idel just bogs out no low end.
and it is spitting gas out the air inlet of the carb.
same reson i hade it bored.
It wont run on the stock timing mark eather it need to be all the way retarded to even run.
was told that would fix it.
what would you think i shuld do next?

Posted by on


3 Answers

  • Level 1:

    An expert who has achieved level 1.


    An expert whose answer got voted for 2 times.

  • Contributor
  • 2 Answers

My carb was doing the same thing and i just took it off, took it apart cleaned it out with the air nozle on our compresser and a butter knife to cean out the stuff on the bottom of the bowl, reset the float and it was all good.

Posted on Aug 30, 2009

  • Level 1:

    An expert who has achieved level 1.

  • Contributor
  • 1 Answer

In order to solve this you need to start with the very basics, then keep elminating issues until you find the real cause of your problem. Here is the way that I would attack a problem like this:

1. Check to make sure you have all the correct parts and that they are on the stock settings. This would include checking all the jets and float level in the carb, making sure that the bike has the correct CDI box, correct flywheel and stator, and making sure that the bike has the correct spark coil. Check that your spark plug lead is not damaged, and that your spark plug puts out a consistent, fat, blue spark. Is the air filter clean and properly oiled?

2. Once you are sure that the bike is getting air, spark and gas, check the installation that you did on the top end. Did you make sure the arrow on the piston is pointing towards the exhaust? Did both the cylinder base gasket and the head gasket seat properly? Did you do a leak down test to make sure you are not leaking air around your crankcase seals? Are the reeds on the bottom of the cylinder installed correctly, with the gasket, and the reed stops are the correct distance from the base of the reed block?

3. Now that you are sure the bike has the correct amount of air, spark, fuel, and is not leaking air, it will start and run.

I have a 1980 RM250 and had to go through the same process when I bought the bike 3 years ago. The many owners before me installed all sorts of wrong parts, including the wrong carb, the wrong stator, and the wrong reed cage. After going through all of the above, my bike is now a first class vintage race bike. You can check it out at

Hope this helps you. Take your time and I am sure you can solve this.


Joe Nye
AIM: nye206

Posted on Jun 19, 2009

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 10 achievements.


    An expert that got 5 achievements.


    An expert whose answer got voted for 500 times.

  • Master
  • 1,392 Answers

Sounds like a timing issue then. Recheck your timing to make sure it is correct. It could possibly be a carb issue as you said it will fire up with gas poured in.

Posted on Jun 18, 2009

1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

a 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of.(from cars to computers, handyman, and even drones)
click here to download the app (for users in the US for now) and get all the help you need.

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

2 Answers

(1996 Suzuki rm 250) will 97-98-99-2000 rm parts fit mine like the crank....crank bearings piston rings and gaskets?

Try any of the parts on eBay, it will usually give a list of what model they will fit. Otherwise, a cycle recycle yard will have an interchange book or system.

Apr 13, 2015 | Suzuki Motorcycles

2 Answers

Hi im just wondering what the fuel mixture should be for my 1996 rm 250 ? thanks mark

For a 250, you can get away with a leaner mix like 40:1 but I still race a 250 2-stroke from time to time for fun and I run 32:1. More oil = less friction, less heat, better sealing, etc...

Any idea what it was jetted to run? the difference between 40:1 and 32:1 is fairly minimal and if the bike is jetted fairly well I doubt you will tell a difference. If the plug is black it is too rich.

Sep 12, 2011 | 2003 Suzuki RM 250

1 Answer

RM250 Power Issues

Hello if your motorcycle is blowing a lot of smoke and oil from the exhaust and running poorly,sounds like you have worn crankshaft bearings or the main seal is bad and sucking transmission oil.

Jun 07, 2010 | 2003 Suzuki RM 250

3 Answers

What type motor oil for Suzuki RM 250?

The engine doesn't use oil,the only oil it gets is from the 2 cycle oil mix in the gas,the transmission uses 85\90 transmission oil such as bel-ray or others. I would NOT reccomend running 10\40 in the trans...

Apr 28, 2010 | 2003 Suzuki RM 250

1 Answer

Think i put too much 2 stroke in my rm 250 now it wont start

Drain the fuel and refill it with the correct ratio fuel, it may take a few kicks, but it should start. Cleaning the plugs would not go astray either.

Dec 30, 2009 | 2003 Suzuki RM 250

3 Answers

Bike boggs down no powerband rm 250

i have a 92 rm 250 an i just had it fully rebuilt an it laggs in power band an splutters an feels guttles

Oct 09, 2009 | 2003 Suzuki RM 250

1 Answer

My kx 250 backfires

Two stroke? never heard one backfire while running. But, a leak doesn't make it run better.

Jul 29, 2009 | 2003 Suzuki RM 250

1 Answer

1986 rm 250 water in oil

Its the head gasket ,you will have to replace it.

Jul 21, 2009 | 2005 KTM EXC 125

1 Answer

It wont start and backfires

change your plug and adjust your air screw brass flat head screw nere the air filter boot screw right (in) gently then turn (left) out 3 quarters of a turn try that then go a quarter of a turn at a time out till you find your sweet spot

Jun 23, 2009 | 2003 Suzuki RM 250

1 Answer

Need fuel mixture for 2005 rm 250

my bike runs best 40:1 but you can run it 32;1

Mar 08, 2009 | 2003 Suzuki RM 250

Not finding what you are looking for?
2003 Suzuki RM 250 Logo

686 people viewed this question

Ask a Question

Usually answered in minutes!

Top Suzuki Experts


Level 3 Expert

76846 Answers

Arnie Burke
Arnie Burke

Level 3 Expert

4536 Answers


Level 2 Expert

83 Answers

Are you a Suzuki Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides