2013 CRF450R runs great, cold start lags

Suspension712
I have a 2013 CRF450R that I bought with a locked up motor. Tore it completely down and rebuilt it and it runs and rides great. I have been a Yamaha tech for 6 years and haven't played much with Hondas but have seen they have always had cold start issues or people always seem to have issues starting them, however you want to phrase it.

Runs great and will restart hot first kick. Cold start after sitting it takes about 4-5 times kicks through from compression stroke to get it to fire up and stay running. Cold start knob out, idle set at about 2000 rpm (running rpm, not with knob pulled out) 4-5 kicks. What's your thoughts? Fuel pump runs when bench tested, should it make noise when I kick it over the first time? Valves and timing are set and good, checked and rechecked and rechecked. Fuel filter is good. Plug is good. New kill switch. TPS is in spec. I have not replaced the spark plug wire and boot, the yellow boot is partly torn off, looks like someone took pliers to it, not sure how sensitive these bikes are too that insulation boot. Let me know your 2 cents if you have thoughts or if it is not a big deal. Thanks
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jamiechapman418 2/11/2021 5:21pm
2/11/2021 5:21pm
I may be wrong but doesn’t the stator take a few kicks to get enough current to get the fuel pump running?
Suspension712 2/11/2021 5:34pm
2/11/2021 5:34pm
That was my thought...I know a lot of people like to say their bike will start first kick every time and that may be true with older carbed bikes but it seems to me that fuel injection needs a couple good rotations to get the voltage up when cold. I don’t think I am going to worry about it as it reliably starts just takes a couple kicks cold. I know electric start bikes I always bump the button first time to get everything activated and then fire it up second time. Never had an issue, same theory I guess.
walent215
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walent215 2/12/2021 4:56am
2/12/2021 4:56am
You say fuel filter is good.... has it been replaced?
A couple of our Honda’s had similar symptoms and needed the filters replaced.
Suspension712 2/12/2021 9:03am
2/12/2021 9:03am
I have not replaced the fuel filter just cleaned and inspected the fuel pump. It probably wouldn’t hurt to try replacing it, Honda sure is proud of them $$.Fuel filter wasn’t overly contaminated and runs good otherwise so assumption was it wasn’t an issue. I have read other forums that have said filter causes issues just thought it would be all the time not just start up.

I would guess that maybe on startup it doesn’t have that initial ability to get through the filter from contamination so it take a bit longer to start up but one it’s started it’s able to get through. Guessing eventually it will start lagging throughout even during running.

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walent215
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walent215 2/12/2021 11:43am
2/12/2021 11:43am
ours just had a starting issue from what i remember but once started it ran fine....i think the kit with orings , filter etc was like $55.....
Suspension712 2/12/2021 11:58am
2/12/2021 11:58am
Thanks for the insight. I will give it a shot and see what happens. Dealer here wants $72 for the kit. Dealer didn't believe they made a filter kit, I have looked it up before and had to convince him they do because I couldn't remember the number. I will get one coming from RMATV for $60.
Paw Paw 271
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Paw Paw 271 2/12/2021 5:17pm
2/12/2021 5:17pm
A very minor leaking fuel injector will cause this issue and those bikes were known to have leaking injectors right out of the box.

Paw Paw
Suspension712 2/12/2021 6:53pm
2/12/2021 6:53pm
I've been doing some reading and looking into this injector issue, seems it went on for a while and irritated many. When I split the motor there was no sign or smell of fuel in the oil nor is there any now. I have changed the oil once since rebuild (hour run time) and didn't notice anything and the oil now is at the same level as I put in with about an hour run time as well with multiple start ups. Do you recommend anything to check to see if it might have a "minor" leak? Did they ever give a fix for the issue and/or is it resolved?
Paw Paw 271
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Paw Paw 271 2/13/2021 6:43am
2/13/2021 6:43am
You can do an injector cleaning or replace it. The minor leak is a dribble right after the engine is shut off that causes a rich condition on restart. It can do this and still not be enough to get into the oil.

Are you sure the TPS is set correctly? What is the readings at closed throttle and at WOT? Every bike acts differently so each may require a different TPS setting at closed throttle. The factor set it up , in general, to be at .5 volts at closed throttle, but it may need to be set to a different reading in a range of .48 volts to .62 volts.

Paw Paw
Suspension712 2/18/2021 10:41am
2/18/2021 10:41am Edited Date/Time 2/18/2021 11:42am
Paw Paw 271 wrote:
You can do an injector cleaning or replace it. The minor leak is a dribble right after the engine is shut off that causes a rich...
You can do an injector cleaning or replace it. The minor leak is a dribble right after the engine is shut off that causes a rich condition on restart. It can do this and still not be enough to get into the oil.

Are you sure the TPS is set correctly? What is the readings at closed throttle and at WOT? Every bike acts differently so each may require a different TPS setting at closed throttle. The factor set it up , in general, to be at .5 volts at closed throttle, but it may need to be set to a different reading in a range of .48 volts to .62 volts.

Paw Paw
What are you using to determine what is the best reading? Right now I have it set at about .59 v at closed throttle haven't got a WOT reading yet. I have no specific reason for why I adjusted it there, just seemed like that is where it is happiest running.

Edit: It is adjusted to .54 Volts at closed throttle. 0.59 seemed like too much the way that it was running. 0.54 it runs good, good idle. If I go lower it starts running like crud. Still starts every time on the third kick cold. Other than replacing fuel filter I'm not going to play with it too much. Runs great otherwise. Cleaned the injector as well. Thanks for all the input.
Suspension712 2/18/2021 4:13pm
2/18/2021 4:13pm
Just wanted to update. I believe I have it figured out just not sure which step got it solved. I neglected to think that after all the testing I was doing and not riding the bike that I was fouling the plug. Trying different starting techniques, testing TPS, hot starting, cold starting...I wasn't really running the bike and fouled the plug. Cleaned all up and the bike fired first kick even being 30 degrees out and sitting for 5 hours since last kick, normally wouldn't. There was obviously an issue as it was a brand new plug but one of the steps fixed the issue. Appreciate all the input and tips as I break into the Honda world, gives me great info for the next bike.

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