I hate my 450

jboomer

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#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?
 
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jboomer

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#2
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

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#3
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?
 
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#4
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:
 
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#5
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

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#7
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.

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#8
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

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#9
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.

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#10
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

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#11
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

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#12
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
 
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#13
my bike has never taken over 4 kicks to start.always starts, under 20 degrees you have to adjust, but thats normal on any bike
 

jboomer

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#14
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.
 
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#15
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...