2018 CRF250R, Problems with starting engine, will not start.

Robbcrazy
Hey guys, looking for some insight on my 2018 250r, I started it up this morning and it ran without any issues, I turned it off and then tried to turn on again but nothing except some pops and 1 backfire, I tried this several times but nothing worked, I thought it was flooded so I pulled the plug let it dry out and made sure I had spark, both were good.

I made sure all connections were solid however after several hours of diagnosis I am at a lost, some insight regarding this would be great.

Bike is completely stock, no rebuilds and only 30 hours.


This Is what I have done so far:

Fuel Injector is working as it should

Fuel Pump is working,

I have spark,

Air filter is clean and not over oiled

Bike does not want to fire at all, will crank rapidly and battery is fully charged and does not drop below 11v while cranking.

I have tried to spray quickstart down the intake however nothing happens,

I have compression.

I have disconnected the kill switch to see if it would start however nothing changes, still cranks and has spark. MIL does not indicate anything and boots like normal.

Could valves be the issue? It ran fine a few hours prior to this happening.



Any insight regarding this would be helpful.
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watson90
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CA
watson90 4/21/2022 2:28pm
4/21/2022 2:28pm
Check the valves it’s pretty easy on these bikes. And it might seem odd but try cranking it with an exhaust plug in the right muffler
Robbcrazy 4/21/2022 5:58pm
4/21/2022 5:58pm
watson90 wrote:
Check the valves it’s pretty easy on these bikes. And it might seem odd but try cranking it with an exhaust plug in the right muffler
I tried it with the plug in the right exhaust and it pops now when I try to crank it over. I believe the valves have to be checked. What do you think?

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watson90
Profile picture for user watson90
Posts
166
Joined
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Location
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watson90 4/21/2022 6:01pm
4/21/2022 6:01pm
watson90 wrote:
Check the valves it’s pretty easy on these bikes. And it might seem odd but try cranking it with an exhaust plug in the right muffler
Robbcrazy wrote:
I tried it with the plug in the right exhaust and it pops now when I try to crank it over. I believe the valves have...
I tried it with the plug in the right exhaust and it pops now when I try to crank it over. I believe the valves have to be checked. What do you think?
I would definitely check them, takes 20 minutes to have a look. I check mine on my 2019 every 15hrs. I’m at 92hrs and they have not moved since new
Robbcrazy 4/21/2022 6:44pm
4/21/2022 6:44pm
watson90 wrote:
Check the valves it’s pretty easy on these bikes. And it might seem odd but try cranking it with an exhaust plug in the right muffler
Robbcrazy wrote:
I tried it with the plug in the right exhaust and it pops now when I try to crank it over. I believe the valves have...
I tried it with the plug in the right exhaust and it pops now when I try to crank it over. I believe the valves have to be checked. What do you think?
watson90 wrote:
I would definitely check them, takes 20 minutes to have a look. I check mine on my 2019 every 15hrs. I’m at 92hrs and they have...
I would definitely check them, takes 20 minutes to have a look. I check mine on my 2019 every 15hrs. I’m at 92hrs and they have not moved since new
Sounds good, I've ordered a set of feeler gauges and plan on checking it over the weekend. If I have to shim it what size is it? 9.48mm?
watson90
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Posts
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Joined
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Location
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watson90 4/21/2022 7:30pm
4/21/2022 7:30pm
Robbcrazy wrote:
I tried it with the plug in the right exhaust and it pops now when I try to crank it over. I believe the valves have...
I tried it with the plug in the right exhaust and it pops now when I try to crank it over. I believe the valves have to be checked. What do you think?
watson90 wrote:
I would definitely check them, takes 20 minutes to have a look. I check mine on my 2019 every 15hrs. I’m at 92hrs and they have...
I would definitely check them, takes 20 minutes to have a look. I check mine on my 2019 every 15hrs. I’m at 92hrs and they have not moved since new
Robbcrazy wrote:
Sounds good, I've ordered a set of feeler gauges and plan on checking it over the weekend. If I have to shim it what size is...
Sounds good, I've ordered a set of feeler gauges and plan on checking it over the weekend. If I have to shim it what size is it? 9.48mm?
You’ll have to check spec first and what shim is in there. Check out this video, explains it better then i can.
https://youtu.be/wxfwJfioLEQ
BrettBosley 7/9/2024 10:19am
7/9/2024 10:19am
watson90 wrote:
I would definitely check them, takes 20 minutes to have a look. I check mine on my 2019 every 15hrs. I’m at 92hrs and they have...
I would definitely check them, takes 20 minutes to have a look. I check mine on my 2019 every 15hrs. I’m at 92hrs and they have not moved since new
Robbcrazy wrote:
Sounds good, I've ordered a set of feeler gauges and plan on checking it over the weekend. If I have to shim it what size is...
Sounds good, I've ordered a set of feeler gauges and plan on checking it over the weekend. If I have to shim it what size is it? 9.48mm?
watson90 wrote:
You’ll have to check spec first and what shim is in there. Check out this video, explains it better then i can. https://youtu.be/wxfwJfioLEQ
You’ll have to check spec first and what shim is in there. Check out this video, explains it better then i can.
https://youtu.be/wxfwJfioLEQ

Did it end up being the valves needing shimmed? Mine is acting the same exact way and I've replaced every part you've listed as well. Went through the same process you have and so I'm going to check the clearances tonight and make sure it hasn't jumped timing as well. 

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