Crf won't kick start


34 replies to this topic
  • Tiffanii24

Posted April 28, 2013 - 09:09 PM

#1

Alright well I got a 2005 crf250r. I've got a new crank in it, a new head with valves, piston, rings,cylinder. All that. Have the valves shimmed perfect. Timing chain is right on spec. Spark plug is good. And the carb is good. But it still will not kick start. Only push start and it has no power whatsoever like it should. Any help would be wonderful

  • Fistfullofthrotl718

Posted April 29, 2013 - 04:31 AM

#2

After you get it running what is your idle like? Smoke?

A couple things I can think of is weak spark, faulty plug, carb slide plate in wrong, bad carb float needle, ring in upside down (where applicable), if your stator is adjustable check you are not to far advance or retarded. or simply wrong or poor jetting.

Not to insult your intelligence but I have read time and time again people saying they have checked and rechecked certain components and everything was where it should be. Just to revisit things to find out something was in fact, misassembled. The simplest answer is usually the correct one.

  • Eddie8v

Posted April 29, 2013 - 05:06 AM

#3

My bet is that your cam timing is off a tooth or two...

  • Krazy98Z28

Posted April 29, 2013 - 10:15 AM

#4

Put fresh gas in it, not something sitting in a can for awhile

  • Tiffanii24

Posted May 01, 2013 - 04:07 PM

#5

After you get it running what is your idle like? Smoke?

A couple things I can think of is weak spark, faulty plug, carb slide plate in wrong, bad carb float needle, ring in upside down (where applicable), if your stator is adjustable check you are not to far advance or retarded. or simply wrong or poor jetting.

Not to insult your intelligence but I have read time and time again people saying they have checked and rechecked certain components and everything was where it should be. Just to revisit things to find out something was in fact, misassembled. The simplest answer is usually the correct one.

We have tried absolutely every bit of that. It idles a bit when we push start it . No smoke. Well I posted that we had changed the cylinder but we haven't done that yet. That's the only thing we can thing of that's left


Put fresh gas in it, not something sitting in a can for awhile


We have brand new gas in it as well

  • Tiffanii24

Posted May 01, 2013 - 04:08 PM

#6

My bet is that your cam timing is off a tooth or two...


Not that either. Timing is right on.

  • Eddie8v

Posted May 01, 2013 - 04:19 PM

#7

I give it a 20% chance that your timing is off...

  • keepitroostin116

Posted May 02, 2013 - 04:43 AM

#8

My 06 did the same thing after a rebuild. had me stumped so after about a week of trying to figure it out i took it to local honda shop and my timing was off 1 tooth.

  • Cuttzy

Posted May 04, 2013 - 11:43 AM

#9

hello im new on here ive got a crf 250r 2008 and im having trouble kick starting it, it will bump start easy.
i have just fitted titanium exhaust and inlet valves stage 2 hot cam and a high compression piston, the bike runs wicked when it started has been on the dyno and set up pushing 38bhp on the rear wheel and has full pro carbon exhaust but when i kick it, it will only back fire every 6/7 kicks anyone know anything i can do?? pilot jet settings? it has really stumped me :(

  • Tiffanii24

Posted May 08, 2013 - 10:14 PM

#10

Well. I reckon we are going to put the new cylinder on it tonight sometime. Crossing my fingers that it works. It's gotta be something in the top end. It doesn't have any compression like it should. We did a compression test and it was leakinh air out the exhaust then we adjusted the timing chain & it stopped. The cylinder on it looks fine but it could be a hairline crack we can't see.

  • Tiffanii24

Posted May 16, 2013 - 10:52 PM

#11

Alright so we put the new cylinder on and did a compression test on the intake valves and they are both leaking extremely bad. like its insane how much air is coming out them. So tomorrow we are putting new kibblewhite intakes in and probably exhaust valves too. Hoping its not the valve seats. Thanks for all the help

  • Fistfullofthrotl718

Posted May 17, 2013 - 03:21 AM

#12

You didn't have the seats cut? Did you at least have them lapped?

  • Tiffanii24

Posted May 19, 2013 - 08:19 AM

#13

Yeah we lapped the valves. None of em are leaking whatsoever. But we just looked at the flywheel and as we were trying to remove the bolt that holds it in, we hear a hissing sound like air. And it bubbles in the oil at the bottom right side of the case. It still has no compression. What could it be? Is it supposed to do that? Need help asap
We also changed the cam last night too

Edited by Tiffanii24, May 19, 2013 - 08:21 AM.


  • Fistfullofthrotl718

Posted May 20, 2013 - 05:12 AM

#14

Hiss is normal. You just pulling some air through the oil line until the syph begins. What size piston and valves did you get fot the bike? Is the cylinder a stock bore? Did you put the ring in upside down? And what were your reading on a compression and leak down tests?

  • Tiffanii24

Posted July 01, 2013 - 11:53 AM

#15

I took the bike to a local shop the other day because we just gave up on it. They at first said all It was was just needing reshimmed. He said they reshimmed it and used the smallest shim in his kit on a brand new valve. He told me it wasn't worth fixing because he says my 06 head and cylinder won't work on my 05 motor. Anybody know if that's true? But anyways. We got it back home, roll started it and now it's running worse. It feels like its being held back. Like the brakes are locked up. But they aren't. It's like the transmission is going bad in this new motor. When I had it maxed out in 5th gear it was going the speed it would in like 2nd-3rd. Also if the crank case seal is messed up or something, couldn't that cause it to not start? Thanks

Edited by Tiffanii24, July 01, 2013 - 01:49 PM.


  • Kawabuggy

Posted July 02, 2013 - 04:22 PM

#16

I think since you seem to be having problems with the valves sealing, that you should start with a fresh head, that has had the seats cut properly, new valve guides, new valve guide seals, and new valves that have been cut to match the new valve seats. Then, use new head gakset, & cylinder base gasket, and shim the valves. Set your timing CORRECTLY. Lot's of people posting about bikes not starting and it turns out the timing was off even though they swore it was right..... It was not right.

That's where I would start. You have too many variables working against you and you need to start eliminating them. The shop told you that they are using the smallest shim available and still not able to get the valve in spec. You should NEVER just throw new valves in an old head with old valve seats, and old valve guides. Even if you lap them, that is the WRONG way as you have figured out. Start with a fresh head, & correct valve timing, and see where you go from there. I just shelled out $670 for a brand new head for my '04.. I feel your pain but you need to do it right and get it over with. Otherwise, you will be chasing your tail and throwing money away on other things that are not the root cause of your problem.

  • Fistfullofthrotl718

Posted July 02, 2013 - 05:32 PM

#17

So, re reading this post I found some things that just don't mix. First, in your original post you said you had the bike shimmed perfectly. Yet now a shop had to reshim? Why? If your using the smallest shims on a brand new head you bought the wrong valves. There are valves that they make that have +1mm. I think you bought those by mistake. Get ur self a caliper and measure the valves. Then tell me what you've got. I just did my whole bike over to OEM specs. My intakes and exhaust are in the 2.40+\- range. 2nd. You said you just bought titanium valves. Then lapped them. You just wasted your money. You can't lap titanium. And if you did, that's probably why you had the bike shimmed perfect, then 20 minutes later you need the smallest shim in the case. All this no compression bs can all be from this. Valves are not closing allowing for leakage.

  • Tiffanii24

Posted July 02, 2013 - 08:08 PM

#18

Yeah we have already went through 2 heads on it. We bought all brand new stock valves just to see if they would work. The shop told us the timing was right on and they said the reason they used such a small shim was because it was the wrong valves. Which isn't right because we ordered those valves through that shop for that exact bike. He said its just the intakes. The kibblewhite intake valves we had in the head at first didnt work. One was bent, so we used 2 exhaust kibblewhites and 2 stock intake valves. One of The intakes is what he used the smallest shim on. I think since we have already put so much money into it that were just going to part out everything we have to make our money back and get a newer one.

  • Tiffanii24

Posted July 02, 2013 - 08:14 PM

#19

So, re reading this post I found some things that just don't mix. First, in your original post you said you had the bike shimmed perfectly. Yet now a shop had to reshim? Why? If your using the smallest shims on a brand new head you bought the wrong valves. There are valves that they make that have +1mm. I think you bought those by mistake. Get ur self a caliper and measure the valves. Then tell me what you've got. I just did my whole bike over to OEM specs. My intakes and exhaust are in the 2.40+\- range. 2nd. You said you just bought titanium valves. Then lapped them. You just wasted your money. You can't lap titanium. And if you did, that's probably why you had the bike shimmed perfect, then 20 minutes later you need the smallest shim in the case. All this no compression bs can all be from this. Valves are not closing allowing for leakage.


Well obviously their reshimming of that one valve didn't work either. They claimed at first that that is all it needed. They did that and said it didn't work. But said it has all it's compression back now. I ordered the valves for that bike through them. We bought stock valves and installed the intake ones. The exhaust are still kibblewhites. But still the guy at the shop says the 06 head will not work on my 05 motor no matter what. I've heard of other people doing it and it worked for them. And I still don't get why it feels like the brakes are Locked up.

  • Fistfullofthrotl718

Posted July 03, 2013 - 05:44 AM

#20

The "drag" could be a worn clutch, heavily notched basket, worn clutch springs ect ect. If your cam chain is to tight can also have that effect. If its banging through all the gears I probably wouldn't worry to much about it just yet. Unless your totally beat the hell out of it, most trans are pretty hardy. In 20 years I have never had a trans problem, and I used to be pretty hard on a bike. I'm not 100% certain as I have never tried it, but I believe the 06 head will work. If the 07 works on all previous years then that tells me they would all have to be the same (less porting). This info was gathered from the FAQ section of this forum.





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