trouble starting when hot

bikeman · 07-25-2019, 11:30 AM

Hawk 250 is running great. I have stock everything, including carb, but with two needle shims and a 110 main jet. I kick start it cold at half choke, and runs fine with no choke.

If I stall the bike when HOT or shut it down, I have not been able to get it restarted by kicking until the bike has almost completely cooled down. This takes 30 mins to an hour. My battery is currently dead/wont charge so kick starting is the only option. Realize that it takes only one kick to start from cool.

I have considered throttle positions, and have tried no throttle, full throttle, half throttle, just cracked throttle but nothing works. I have considered vaporlock, and have ensured no pressure differential from tank to carb by removing gas cap. I shortened the fuel hose from tank to carb to make a straighter path for fuel. Nothing works. I do notice that the tank outlet is almost level with the inlet on the carb. But still a downward path from fuel. Gravity should be at work here.

Could the A/F mix be off? I am currently running 1.25 turns out from seated at 0ft elevation. Again, the bike starts EASILY cold,cool, or warm. There is no rich exhaust odor or NOx lean odor from the tailpipe.

Upon manipulation of the throttle, I will achieve a "popping" noise on an attempted kickstart. I know the spark plug is firing, thats been tested. It must be a fuel/air delivery problem.

Anyone have experience with this, besides generic 4 stroke motorcycle advice? I know how to kickstart a bike. (Just maybe not THIS bike) I have had dirtbikes before but none have been as difficult as this one to start hot. Advice, questions, concerns, Bueller?

Thanks in advance.

**JerryHawk250** · 07-25-2019, 11:37 AM

Have you adjusted the valves yet? Valve come set tight form the factory so once it's up to operating temperature the valve don't completely seat because of lack of clearance. Lower compression will make it hard to start. Once it cools down the valve will seal back up thus making it easier to start.

bikeman · 07-25-2019, 11:40 AM

I have not, I should have mentioned, I plan to tackle that very soon. Any other ideas?

**JerryHawk250** · 07-25-2019, 11:43 AM

Quote:

Originally Posted by bikeman

I have not, I should have mentioned, I plan to tackle that very soon. Any other ideas?

That will more than likely be the problem. I wouldn't wait too long to adjust them. Could cause a burnt valve. You can use the Valve adjustment tutorial for the TT250. It's not necessary to pull the tank. There plenty enough room to do it without pulling the tank.
https://www.cscmotorcycles.com/check...lve-adjustment

bikeman · 07-25-2019, 11:48 AM

Quote:

Originally Posted by JerryHawk250

That will more than likely be the problem. I wouldn't wait too long to adjust them. Could cause a burnt valve. You can use the Valve adjustment tutorial for the TT250. It's not necessary to pull the tank. There plenty enough room to do it without pulling the tank.
https://www.cscmotorcycles.com/check...lve-adjustment

Great, I'll make it my next job. Thank you.

**JerryHawk250** · 07-25-2019, 12:01 PM

Quote:

Originally Posted by bikeman

Great, I'll make it my next job. Thank you.

You will be surprised how much better it will run.

OneLeggedRider · 07-25-2019, 12:31 PM

Jerry hit the nail right on the head. When hot your valves aren't closing completely. My KZ 650 did the same. Started fine and ran like a raped ape, but if you shut it off it wouldn't start for 45 minutes. It was a shim under bucket inline 4 cyl, so I measured and recorded each clearance and using a bench grinder and a micrometer I ground each shim to the size it needed to be. The bike was even faster after that and started easily hot or cold.

bikeman · 08-27-2019, 08:56 PM

it was the valves

running better than ever now

wedooit · 08-27-2019, 09:16 PM

The masters have spoken well. Congrats on your find!

OneLeggedRider · 08-28-2019, 03:08 AM

There's a running joke on the fb groups about Frank (me) and his 'slappin booth', the premise being that I travel the country and set up my booth at the local events and meetings for China riders. Have them form a line like a kissing booth and question each about valve adjustment. "Oh you thought you could run it without adjusting the valves first?" *SLAP!* "And you were told to adjust them first and chose to ignore it? Here's another fresh one for ya" *SLAP!* And it would be well worth the $5 to get some sense knocked into ya..

But all jokes aside it's amazing how many owners are clueless about the importance of valve adjustment. And then you always get some idiot that chimes in about how he's ridden his bike for a year without adjusting them and it runs fine. I would gladly waive the $5 fee to enlighten that individual. MtnManPoe says I'd need to get some bag balm for my hand and invest in some good slappin gloves.

NzBrakelathes · 08-28-2019, 06:06 AM

Quote:

Originally Posted by OneLeggedRider

There's a running joke on the fb groups about Frank (me) and his 'slappin booth', the premise being that I travel the country and set up my booth at the local events and meetings for China riders. Have them form a line like a kissing booth and question each about valve adjustment. "Oh you thought you could run it without adjusting the valves first?" *SLAP!* "And you were told to adjust them first and chose to ignore it? Here's another fresh one for ya" *SLAP!* And it would be well worth the $5 to get some sense knocked into ya..

But all jokes aside it's amazing how many owners are clueless about the importance of valve adjustment. And then you always get some idiot that chimes in about how he's ridden his bike for a year without adjusting them and it runs fine. I would gladly waive the $5 fee to enlighten that individual. MtnManPoe says I'd need to get some bag balm for my hand and invest in some good slappin gloves.

That why I choose to have a fee kits that relate to first tune and valve oil change tool kit etc
Those 2 things solve pretty much every new bike issues n gives the gear needed (can’t fix stupid or can’t sell common sense) but you get my drift....

bogieboy · 08-28-2019, 09:08 AM

Quote:

Originally Posted by OneLeggedRider

There's a running joke on the fb groups about Frank (me) and his 'slappin booth', the premise being that I travel the country and set up my booth at the local events and meetings for China riders. Have them form a line like a kissing booth and question each about valve adjustment. "Oh you thought you could run it without adjusting the valves first?" *SLAP!* "And you were told to adjust them first and chose to ignore it? Here's another fresh one for ya" *SLAP!* And it would be well worth the $5 to get some sense knocked into ya..

But all jokes aside it's amazing how many owners are clueless about the importance of valve adjustment. And then you always get some idiot that chimes in about how he's ridden his bike for a year without adjusting them and it runs fine. I would gladly waive the $5 fee to enlighten that individual. MtnManPoe says I'd need to get some bag balm for my hand and invest in some good slappin gloves.

culcune · 08-28-2019, 09:59 AM

Quote:

Originally Posted by OneLeggedRider

But all jokes aside it's amazing how many owners are clueless about the importance of valve adjustment. And then you always get some idiot that chimes in about how he's ridden his bike for a year without adjusting them and it runs fine.

I resembled that quote

Had (still have without wheels because I sold them) a 2013 TMEC 200 dual sport. Never adjusted the valves., and she always started. Commuted for 2 years, year round (southwest Arizona) 33 miles a day round trip. BUT...my TMEC was definitely the exception and not the rule! "Your results may vary" I could about use that slap right about now!

wedooit · 08-28-2019, 11:28 AM

Ya I needed a slap as well. A few years ago, had a 650 4 wheeler backfiring thru the carb. One would think my experience would dictate to adjust the valves. Nope. Let it set in disgust, then tore all the plastics off, thought would be carburetion. (oh by the way, this was the mrs 4 wheeler) SLAP! Anyways cleaned the carb, let it set for a few more months in disgust. SLAP. Then one day, a lightening strike from the heavens came down, an epiphany of sorts,SLAP, then I adjusted the valves. Tappy tappy, runs great!

Now getting back to the SLAP....from onelegged? He seems to be a big dude, and has big hands. Therefore, when one sees the SLAP coming, one should duck, it might hurt. So therefore the fear of onelegged coming after a person....the fear alone would be intimidating! LOL Dan might even show up, he has big hands as well!!! okok guys, I will adjust the valves!!!!

OneLeggedRider · 08-28-2019, 11:58 AM

Sadly I fear the line would be so long at some of the events me and Dan would have to work in shifts and have some pretty little thing in cutoffs there to massage our hands after.

07-25-2019, 11:30 AM	#1
bikeman Join Date: Apr 2019 Posts: 26	trouble starting when hot Hawk 250 is running great. I have stock everything, including carb, but with two needle shims and a 110 main jet. I kick start it cold at half choke, and runs fine with no choke. If I stall the bike when HOT or shut it down, I have not been able to get it restarted by kicking until the bike has almost completely cooled down. This takes 30 mins to an hour. My battery is currently dead/wont charge so kick starting is the only option. Realize that it takes only one kick to start from cool. I have considered throttle positions, and have tried no throttle, full throttle, half throttle, just cracked throttle but nothing works. I have considered vaporlock, and have ensured no pressure differential from tank to carb by removing gas cap. I shortened the fuel hose from tank to carb to make a straighter path for fuel. Nothing works. I do notice that the tank outlet is almost level with the inlet on the carb. But still a downward path from fuel. Gravity should be at work here. Could the A/F mix be off? I am currently running 1.25 turns out from seated at 0ft elevation. Again, the bike starts EASILY cold,cool, or warm. There is no rich exhaust odor or NOx lean odor from the tailpipe. Upon manipulation of the throttle, I will achieve a "popping" noise on an attempted kickstart. I know the spark plug is firing, thats been tested. It must be a fuel/air delivery problem. Anyone have experience with this, besides generic 4 stroke motorcycle advice? I know how to kickstart a bike. (Just maybe not THIS bike) I have had dirtbikes before but none have been as difficult as this one to start hot. Advice, questions, concerns, Bueller? Thanks in advance.
	0

07-25-2019, 11:37 AM	#2
JerryHawk250 Moderator Join Date: Oct 2016 Location: Houma, La. Posts: 11,562	Have you adjusted the valves yet? Valve come set tight form the factory so once it's up to operating temperature the valve don't completely seat because of lack of clearance. Lower compression will make it hard to start. Once it cools down the valve will seal back up thus making it easier to start. __________________ 2023 Lifan Lycan 250 Chopper 2023 Venom Evader 2022 Lifan KPX250 2020 Kawasaki Vulcan S 2004 Honda ST 1300 2016 Black Hawk 250 (sold) Keihin PE30 carb,125 main,38 slow.Pod filter,ported & decked head 10:1 CR,Direct Ignition Coil,15/40Sprockets,NGK DPR8EIX-9,De-Cat,Dual Oil Cooler,Digital Cluster 2016 Cazador180 XL 2014 Coolster150 JerryHawk250.com My YouTube Channel
	4

08-27-2019, 09:16 PM	#9
wedooit Join Date: Jun 2018 Location: Pocatello, Idaho Posts: 794	The masters have spoken well. Congrats on your find! __________________ A family that works together, plays together, shoots and trains together, and sleds together, stays together. Second amendment! SkiDoo sleds, NOW 2 TTR225, and a BMS250. A couple of quotes (we are not farmers) "I don't get off the farm much" "Am too old school" I call the china bikes "the china syndrome".
	2

08-28-2019, 11:28 AM	#14
wedooit Join Date: Jun 2018 Location: Pocatello, Idaho Posts: 794	Ya I needed a slap as well. A few years ago, had a 650 4 wheeler backfiring thru the carb. One would think my experience would dictate to adjust the valves. Nope. Let it set in disgust, then tore all the plastics off, thought would be carburetion. (oh by the way, this was the mrs 4 wheeler) SLAP! Anyways cleaned the carb, let it set for a few more months in disgust. SLAP. Then one day, a lightening strike from the heavens came down, an epiphany of sorts,SLAP, then I adjusted the valves. Tappy tappy, runs great! Now getting back to the SLAP....from onelegged? He seems to be a big dude, and has big hands. Therefore, when one sees the SLAP coming, one should duck, it might hurt. So therefore the fear of onelegged coming after a person....the fear alone would be intimidating! LOL Dan might even show up, he has big hands as well!!! okok guys, I will adjust the valves!!!! __________________ A family that works together, plays together, shoots and trains together, and sleds together, stays together. Second amendment! SkiDoo sleds, NOW 2 TTR225, and a BMS250. A couple of quotes (we are not farmers) "I don't get off the farm much" "Am too old school" I call the china bikes "the china syndrome".
	3

07-25-2019, 11:40 AM	#3
bikeman Join Date: Apr 2019 Posts: 26	I have not, I should have mentioned, I plan to tackle that very soon. Any other ideas?
	0

07-25-2019, 12:31 PM	#7
OneLeggedRider Join Date: Nov 2018 Location: Stockport, Oh. Posts: 1,442	Jerry hit the nail right on the head. When hot your valves aren't closing completely. My KZ 650 did the same. Started fine and ran like a raped ape, but if you shut it off it wouldn't start for 45 minutes. It was a shim under bucket inline 4 cyl, so I measured and recorded each clearance and using a bench grinder and a micrometer I ground each shim to the size it needed to be. The bike was even faster after that and started easily hot or cold.
	1

08-27-2019, 08:56 PM	#8
bikeman Join Date: Apr 2019 Posts: 26	it was the valves running better than ever now
	3

08-28-2019, 03:08 AM	#10
OneLeggedRider Join Date: Nov 2018 Location: Stockport, Oh. Posts: 1,442	There's a running joke on the fb groups about Frank (me) and his 'slappin booth', the premise being that I travel the country and set up my booth at the local events and meetings for China riders. Have them form a line like a kissing booth and question each about valve adjustment. "Oh you thought you could run it without adjusting the valves first?" SLAP! "And you were told to adjust them first and chose to ignore it? Here's another fresh one for ya" SLAP! And it would be well worth the $5 to get some sense knocked into ya.. But all jokes aside it's amazing how many owners are clueless about the importance of valve adjustment. And then you always get some idiot that chimes in about how he's ridden his bike for a year without adjusting them and it runs fine. I would gladly waive the $5 fee to enlighten that individual. MtnManPoe says I'd need to get some bag balm for my hand and invest in some good slappin gloves.
	3

08-28-2019, 11:58 AM	#15
OneLeggedRider Join Date: Nov 2018 Location: Stockport, Oh. Posts: 1,442	Sadly I fear the line would be so long at some of the events me and Dan would have to work in shifts and have some pretty little thing in cutoffs there to massage our hands after.
	2