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bike with brand new top end hard to start?

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sometimes it started first kick easily.. sometimes it wouldnt start at all and it was VERY frustrating. very very frustrating. I tried with choke on/off, gas on/off, hot start on/off and nothing. I had a friend help push the bike half way up a hill and I bomb started it and it started very easily with a bomb start... why is that?

also, I used to be able to just keep kicking and kicking, without finding TDC, non stop. but now if I kick fast and hard the kick start (or engine!) seems to lock up or something, and I have to let off the kick start and find TDC again.. I think it MIGHT be my decompression lever? or possible the spark plug. it might just be my technique. I will check the intakes today although I doubt they have moved. SS intakes with less than 2 hours on them?

also, I dont know if this is normal as I cant remember since its been so long since ive ridden.. but the engine sounds quite loud, like a ticking sound when its idiling. I think im just being paranoid, pretty sure nothing wrong as it ran fine all day, but just wondeirng what you guys think. could it be the SS intakes making more noise?

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cam timing

but it starts perfectly sometimes and very hard to start others.. you still think its the timing being 1 tooth off?

I kinda doubt it as I was positive I had the lines lined up PERFECTLY... but its possible that im off 1 tooth :embarrassed:

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Ok I just replaced the top end also and have the same problem. New piston, etc and installed new vlaves. I also installed an Stage 2 hot cam.

I have the same problem as thumper1241. I checked timming and it's spot on. Valves where loose on the exhaust, but on the money on intakes. I shimed the exhaust and I checked everything again last night and all is normal.

It's running great but it's gotten hard to start just like the decomp is not working.

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sometimes it started first kick easily.. sometimes it wouldnt start at all and it was VERY frustrating. very very frustrating. I tried with choke on/off, gas on/off, hot start on/off and nothing. I had a friend help push the bike half way up a hill and I bomb started it and it started very easily with a bomb start... why is that?

also, I used to be able to just keep kicking and kicking, without finding TDC, non stop. but now if I kick fast and hard the kick start (or engine!) seems to lock up or something, and I have to let off the kick start and find TDC again.. I think it MIGHT be my decompression lever? or possible the spark plug. it might just be my technique. I will check the intakes today although I doubt they have moved. SS intakes with less than 2 hours on them?

also, I dont know if this is normal as I cant remember since its been so long since ive ridden.. but the engine sounds quite loud, like a ticking sound when its idiling. I think im just being paranoid, pretty sure nothing wrong as it ran fine all day, but just wondeirng what you guys think. could it be the SS intakes making more noise?

assuming your timing is correct, check your valve and decompressor clearances. Did you bench shim your valves?

I feel like the honda valve train is noisier than most, but that could be because your valves are out of spec. Plus, I've heard that stainless is little noisier than Ti

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my bike is a 2005 with the easy decompressor assembly :lol:

were supposed to go riding today (in 10 mins to be exact) so I have no time to check that stuff!!! :thumbsup:

im going to see if the bike will kickstart and not be a bitch today or else im going to have to be taking my bike apart while everyone else is out riding :ride: worst case scenario is the bike starts, and when I get out there it starts being a bitch again. ill take a tie down in my camelback just in case I need to get towed to the top of a hill for a bombstart.

I didnt bench shim the valves, I did it in the bike.

thanks for the answers guys, ill have more info/specs for you tonight!

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sooo.. just got back from ridng. had to end the day early for me due to EXTREME frustration.

first thing in the morning, half asleep, still in my skate shoes, the bike started first kick easily, rode it for a bit, fell over on a hill, tried to start it and nothing. tried for about 10-15 mins and still nothing, let it sit for 5-10 minutes and it finally started!! seems it doesnt like to start once its warmed up. I didnt want to ruin the other guys' days with my POS CRF that wont start so I packed up and went home very very pissed off.

im going to start taking it apart later today and check my intakes, spark plug, and decompressor.

what should the decompressor arm clearance be on a 2005 crf 450r?

in my clymer manual is says .35mm

in my downloaded online manual, it says .10mm

and somewhere I remember reading that its the exhaust clearance (.30mm approx) + .30mm for a total of .65mm as my decomp arm clearance... so whats the actual gap supposed to be?

edit: heres what I was talking about when you google "2005 crf 450r decompression arm clearnace"

Decompressor clearence:

Right exhaust valve clearence +0.35mm (0.014 in)

ex)

if measured right exhaust valve clearence is 0.28mm (0.011 in) ,decompressor clearence is;

0.28mm (0.011 in) + 0.35mm (0.014 in)=0.63mm (0.025 in)

thanks guys.

Edited by Thumper1241

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use two feelers and put the .011 in the valve, and then measure and adjust the decompressor lash.

Make sure the bottom of the lobe is where you need it when you measure. Its pretty obvious but ya gotta pay attention to it

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use two feelers and put the .011 in the valve, and then measure and adjust the decompressor lash.

Make sure the bottom of the lobe is where you need it when you measure. Its pretty obvious but ya gotta pay attention to it

ok, but what is the proper decompression lash is the tough question? ive seen 3 different answers so far...

also, what do you mean by the bottom of the lobe? dont you measure decomp lash at TDC like everything else?

thanks for the answer, I would really like to get this done tonight but cant start until I know for sure the specs.

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Didnt you just get this back from the shop running? Now different problems or the same. What did the shop fix or say. I'm sticking with my original thought from your previous thread, cam timing.

You might think you got it right, but just a few degrees off is going to make a difference.

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Didnt you just get this back from the shop running? Now different problems or the same. What did the shop fix or say. I'm sticking with my original thought from your previous thread, cam timing.

You might think you got it right, but just a few degrees off is going to make a difference.

nope, I took it back from the shop in a box full of parts. I wasnt going to wait another week, on top of 3 already, plus another 300$ for them to put the engine together when im more than capable of doing it myself.. kinda :thumbsup:

I will check my cam timing when I take it apart, hopefully later tonight if I can get the decomp gap figured out.

I thought if the cam timing was off it wouldnt even run? ill def keep that in mind and post pictures and see what you guys think.

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what year bikes are we talking? 02-06 or 07+?

My bike is an 07. I'm really not sure if you can adjust the decomp or not. Any help would be nice.:thumbsup:

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My bike is an 07. I'm really not sure if you can adjust the decomp or not. Any help would be nice.:thumbsup:

your best bet is to make your own thread about it... get more answers that way.

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Hey Thumper, not sure if you go the answer on the decomp lever. I just did this and the difference in my bike is night and day, so easy to start now.

Yes, get the bike to TDC, which I did by lining up the marks, perfectly. I put it in a high gear and moved the bike because it would not stay at TDC otherwise. After measuring what the TDC was, I put in the .011 feeler gauge and set with the gauge in the entire time. After it was tight, I removed the gauge.

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If your still haveing problems check your stator. I have an 03 and this past summer I had problems starting also like you.Since I have another bike did not really look at problem till this winter. and a few others had the same problem here on TT recently. I could be an intermitent problem. If I held the kill switch while I kicked then let go of it and kicked again it would start,But if I stalled it would not start. It might be worth checking.

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07 you cannot adjust the anything on the decomp. Means your timing is off

.

Again,My timming is not off that I'm sure of. I have the exhaust set at a tight .28 and intake are at .15. It's like the hotcam changed the lift so much that it made the bike hard to start.

I can apply pressure to the kick starter and it will start moving. I then complete the full kick and she starts on the 1st kick. This was my first 07Honda to replace the cam with an Hotcam. I used to be able to kick it alot easier before the rebuild.

I didn't think you could adjust the decomp, But I might try and tighten the spring on the decomp lever making the rpms increase before it starts moving.

Anybody tried this?

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.

Again,My timming is not off that I'm sure of. I have the exhaust set at a tight .28 and intake are at .15. It's like the hotcam changed the lift so much that it made the bike hard to start.

I can apply pressure to the kick starter and it will start moving. I then complete the full kick and she starts on the 1st kick. This was my first 07Honda to replace the cam with an Hotcam. I used to be able to kick it alot easier before the rebuild.

I didn't think you could adjust the decomp, But I might try and tighten the spring on the decomp lever making the rpms increase before it starts moving.

Anybody tried this?

Do the marks line up or not? If they do, then you need to degree the cam

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