jboomer

~SPONSOR~
Jan 5, 2002
1,420
1
I'm hating my 450 (I don't really "hate" it!)

Well, I just started my bike lastnight, in order to answer a question in another thread...no problem, took about 3 or 4 kicks. Loaded my bike this morning, went to the local riding area to do some trail riding, and the bike won't start. I kicked for 2 hours, got a couple pops, but thats all. These things suck in the cold wx when the engine is cold. I've tried everything.....fuel screw adjustment, couple quick twists of the throttle, tilting the bike, everything. Nothing works consistently. I've gone through this several times and have tried a different technique every time. Im guessing (if not tight valves) the engine is loaded (flooded)..how, I have no idea. I've followed the manuals recommended technique to clean the cylinder out, by holding the throttle open and giving it 10 slow kicks (i usually do it with 50). But, I still smell gas, I still think it's flooded, and it probably wont start until I kick it at least 1000 more times (im serious). Is there a better way to unflood the engine?
Anyway, this is my current dilema: I'm 300' above sea level, about 45 degrees today, fresh gas, plug is firing, stock everything, clean filter. It doesnt matter. So, I'm anticipating the dreaded valve problem. But, I dont have a tool to remove the Crankshaft Hole Cap. Is there any other way to ensure you're bike is at top dead center? I'm ready to either figure this out or go back to the 2smoke.
Best bike in the world when it runs, but who wants a bike that only runs sometimes?
 
Last edited:

jboomer

~SPONSOR~
Jan 5, 2002
1,420
1
I tried the feeler gauges with the lobes in pretty much every position, they would only insert with the lobes facing to the rear (corresponds to the picture too) and I could get the "in spec" feeler gauge in for every valve (exhaust and intake). I'm guessing the largest "in spec" gauge will only fit if the piston is at TDC....which is what I've got, so I assume my valves are in spec, yes?
 

jboomer

~SPONSOR~
Jan 5, 2002
1,420
1
Well, I measured the right exhaust valve at .014 (the left is perfect)...recommended is .011 +/- .001.
And...using the manual's formula (Right Exhaust Valve Clearance plus .014 = decompressor clearance) my decompressor clearance should be .028, but it's only .023

Could this be my problem?
 

Ol'89r

LIFETIME SPONSOR
Jan 27, 2000
6,961
45
jboomer said:
I still smell gas, I still think it's flooded,

Is there a better way to unflood the engine?

plug is firing,QUOTE]

boomer.

Did you by any chance leave the petcock on overnight or while you were transporting the bike? Did you notice any gas dribbiling out of the carb overflow tubes when you got to the riding area? While bouncing down the road in the back of a truck, the carb float can bounce off of the needle and seat and allow raw gas to get into the engine. Always be sure to turn your petcock off.

Sometimes a sparkplug can be fouled with gas and still throw a spark when outside of the engine laying on the head. When you install it in the engine it may not spark while under compression. Try a new plug. Also, leave the plug out overnight to let the gas in the cylinder evaporate.

Does your oil smell like gas?? If so, change it. It could be diluted.

Doesn't sound like valves could be the problem as long as you have clearance.

Also, you can check TDC by carefully placing a screwdriver down the sparkplug hole and feeling the top of the piston. If you can't get the inspection cap off, place the bike on a stand and put it in gear. Rock the back wheel back and forth while feeling the top of the piston. You will be able to feel TDC close enough to check the valves.

Just my $ .02 :thumb:
 
Last edited:

George S.

Member
Jul 2, 2002
9
0
Did you try bump starting? In every situation where I absolutely could not get the bike to start, cold weather included, bump starting in 2nd gear has always worked.
 

jboomer

~SPONSOR~
Jan 5, 2002
1,420
1
Like I mentioned, this is a recurring problem, not a one time deal. The plug's good and yes, I always turn my fuel off before transporting and when storing. But, an idea occurred to me...it only seems to happen when I transport the bike a long distance. I wonder if A. maybe the bike bouncing around in the back of the p/u is allowing the fuel already in the bowl to splash into the cylinder and/or B. when I load/unload if I'm not twisting the throttle a tad (it's kind of an odd angle, ya know?).
I've gotten the bike started since my post, so I know everything is in working order. It has got to be something to do with it flooding. I left it to sit for probably 8 hours (after kicking for 2 hours and not having any luck) and when I went back to try and start it it fired first or second kick. It has to be something to do with transporting it. I'm going to start it and let it run for a few seconds with the petcock off before taking it out to the riding area tomorrow. Just to see if it helps any.
 

Jon K.

~SPONSOR~
Mar 26, 2001
1,354
4
I always turn off the fuel and let my 250f run out of fuel before putting it up. Then, when I need to crank it, I am assured of the freshest fuel possible in the carb.

Might be worth a try.
 

tnrider

Sponsoring Member
Jun 8, 2003
576
0
I have experienced the same problem (not as bad though) on my 03' crf450 - took about 15-min of kicking to get it to start. It sat for about 4-weeks in temps low as 20's. I do turn off the fuel and let the engine run for a short while but not until runs out of fuel. I think the crf450 will overheat if let run out of fuel??? just my guess as if it runs much at all without moving, it starts pumping out radiator fluid.
 

Jon K.

~SPONSOR~
Mar 26, 2001
1,354
4
tnrider said:
I think the crf450 will overheat if let run out of fuel??? just my guess as if it runs much at all without moving, it starts pumping out radiator fluid.

Yeah, my Yami did get a bit hot, and would lose a bit of coolant. It got to where I would turn the fuel off before I got to the truck, and would use most of the fuel out of the carb before I would stop.

I didn't always remember to do this, but didn't let the loss of a little coolant bother me much.

On the up side; it always started good when I did this!
 

jboomer

~SPONSOR~
Jan 5, 2002
1,420
1
Well, had it running day before yesterday. Adjusted the fuel screw and idled it up a tad. It's about 42 degrees here today, the bike has been sitting in the shed since...haven't touched it since I pushed the kill switch and turned the fuel off. Wanted to go riding today, but kicked 543 times (still in the shed) got two good backfires and a dozen or so "bubabahs" and that's it. I tried twisting the throttle 8 times about half way through, didn't help. Even tried going back to the original fuel screw setting and idle setting. Still no joy. Pretty tired now!
 

truespode

Moderator / Wheelie King
Jun 30, 1999
7,978
249
Have you re-routed your hot start? I was greasing everything on my bike the other day and doing a lot of maintenance and when I put the front end back together I made the mistake of getting the hot start routed wrong. This caused it to bind and when I went to start it I couldn't. It took a ton of kicks.

Finally I saw the routing of the hot start (I have a Dr. D) and noticed it was different so I routed it carefully to avoid binding and have not had a problem since.

Ivan
 

jboomer

~SPONSOR~
Jan 5, 2002
1,420
1
Nope, the only thing I've done to the hotstart is to loosen the cable a tad to ensure it wasn't being held open a bit. I just pulled the carb apart to check for dirt, cleaned the filter, loosened the throttle cable a tad, gas is good, getting plenty of spark (plug was wet when I pulled it out), and not even getting a pop.
 

GREENBEAN

Member
Jan 8, 2000
179
0
Maybe the Cold air and wind from trailering on a long trip really cools down the motor internally which makes it difficult to start for some reason. What works for me is if I have kicked a considerable amount say 20 kicks or if I smell gas. I will turn the gas valve off and continue with my starting procedure that usually does it after a few kicks and the extra gas gets cleaned out of the carb.. I had a fouled plug and this was the only way to get it to start it took me like 30-40 minutes of kicking and trying other things... Another time after 20 minutes of kicking I took the plug out and scraped it with a knife then heated it with a Hot Blue flame type butane lighter inserted it quickly and it started literally first kick. After not riding for a while say 2weeks I have a difficult time starting my bike it rarely takes less than 20-30 kicks to get her going. So far my procedure is I must prime the throttle a few times (2-4) to even get a sputter to happen and I must repeat that procedure of at least one blip with the choke on per every 2-3 kicks. Then I will get it to light up. I am getting better it only took 10-15 kicks last time after a week of not riding. Someone suggested to raise the idle 1/4 to 1/2 turn to start while cold then back it off after around 10-20 minutes That also seemed to make a big difference in starting since the throttle is kept closed to start. I think these are real sensitive COLD BLOODED bikes...
 

Spine_Thrust

Member
Oct 3, 2003
149
0
I would try turning out the air screw a 1/2 turn and turning out the idle screw about 2 turns. It may be that if your plug is wet then you are giving it too much gas with the idle screw adjustment. Back it off and see what happens.
 

jboomer

~SPONSOR~
Jan 5, 2002
1,420
1
I posted this back on the 18th on another site, this topic didn't go very far here so I just kinda let it die:

Well, got the starting fluid this morning, squirted a burst into the intake and started kicking...nothing. Pulled the plug out (it was damp) squirted a burst into the cylinder, put the plug back in, kicked 4 times and it started...it ran at VERY high idle for about 1 1/2 seconds, then popped twice and died. Refused to start again, so I repeated the above (damp plug again), kicked 4 times and it started again with the same results. Tried the above procedure again 3 times without getting it to start. So, I squirted another burst into the intake and one into the cylinder, put the gas tank back on, kicked 10 tiimes and it fired and stayed running. I readjusted the idle screw, it seems to idle the best at 4 1/2 turns out. Got it back together and have ridden it around the yard for the last 10 minutes or so.

I guess I'm going to make starting fluid a new addition to my tool box. If it refuses to start for me at the track, but I can shoot starting fluid into the intake and it'll run, I'll be OK with that. It's a tradeoff I know, but one that I can live with. As long as I don't have to leave the track with a clean bike, I'll be happy!

And then this one after someone questioned my acceptance of having to use starting fluid EVERY time I start it:

I'm pretty sure the whole starting issue (especially to the extent I have taken it) is because somehow, somewhere I'm flooding it. Be it when I'm loading the bike into the back of my truck and unloading it (maybe twisting the throttle a tad because I'm at such a weird angle) or even a slight twist whilst kicking the crap out of it. If I needed the starting fluid EVERY time I attempted to start the bike, then yes something is DEFINITELY wrong and I would be wrong not to search it out. But, if it occurs every once in a while because of something I had done, then the starting fluid seems an acceptable fix.
I'm coming off a KX250 and a WR250 (2 stroke) previous to it. With those bikes, it was acceptable and sometimes necessary to give the throttle a quarter turn when kicking it. I don't think I'm doing it now with this bike, but old habits are sometimes hard to break!
 

DougRoost

~SPONSOR~
May 3, 2001
720
0
I assume you've checked your float height setting? This sounds like a classic case of a carb float out of spec.
 

jboomer

~SPONSOR~
Jan 5, 2002
1,420
1
Actually no, I haven't checked my float height. Ever since I got the bike I've noticed when landing HARD off a jump (coming up super short) the bike bogs and nearly tosses me over the bars...someone had mentioned that it seemed as if my float height may be off. But, it happens so seldom (thankfully!) that I've never taken the time to check it. I've asked for instructions on how to do it, but couldn't make heads nor tails of what they were trying to say! I've got one of those trick little fuel screws on the way, so when I get it, I'll probably go ahead and try the float height. Any one willing to break down the procedure for me?
 

Danman

LIFETIME SPONSOR
Nov 7, 2000
2,211
3
My carb might be slightly different, but the pocedure should be similer. Take the carb off the bike. Remove the Bowl. Turn carb upside down. Measure from the top of the floats (at the center) to the bottom of the carb body (remeber is upside down so it will be under the float top). It should Be within the specs. If not there should be a tab on the floats that actualtes the needle vavle. you can bend that tab to adjust the height in either direction. Does it puke gas at all?

I hope you get it cleared up as I have seen the thread on TT.

Its got to flustrating to have a nice bike and cant get it to start reliably. I definatly think there is something amiss in your carb.
 

KXaggerator

~SPONSOR~
Feb 4, 2001
252
0
I think Doug might be correct about the float height. If not I have a friend that had an YZ426F that he had a hard time starting and would foul plugs. I always was able to start the bike cold with no problem, so I watched him and he was unconsciously twisting the throttle when he was kicking the bike over causing the pumper carb to flood his bike.

In fact sometimes I ride with a group in which there is a guy I grew up with who is so annoying that I never pass up the opportunity to give his bike a few twists of the throttle when nobody is watching to see him freak out when he tries to start his 450. I know it is wrong, but I will have to go through a 12-step program to stop doing it. :aj:
 

rmcmichael

Member
Jun 27, 2002
47
0
I've got the '03 CRF450R and I'll pass on the two things
that I absolutely *swear* by to keep it starting on the
first or second kick.

1) After I'm done riding, I take a 17 mm socket and remove
the float bowl plug on the bottom of the carb. Now the carb
is *empty*. (If you haven't turned off the gas petcock yet,
you'll notice that right away, so do it.)

2) When you're ready to start, turn on the gas petcock,
open the choke, and DO NOT TOUCH the throttle. Keep
your hand on another part of the handlebar.

The only time I've ever had trouble with my bike was when
I left it too long with fuel in the carb. Had to take it apart
and clean it good.

One other tip. I put the ZipTy fuel screw on my carb so I
can adjust it with my fingers. I start out rich and go
leaner until it doesn't cough or backfire when I roll off
into corners. That seems to be about perfect.
 

arrow101

Member
Feb 23, 2004
26
0
i hope you get it sorted the float level does sound kinda suspect if it bogs off big landings and when in the back of the ute.
Im only new to this so i posted and draged it open again :) I hope the new interest finda a solution for you.
Im not a fan of startign fluids as the morots tend to become dependent on them for some reason. I just hope you can suss it out and get back to enjoying biking
 
Top Bottom