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  #11  
Old 10-11-2016
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Nutty Nutty is offline
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Quote:
Originally Posted by Sideshow View Post
That's actually a decompression lever...... but I take it back anyway.

It's seems that years head doesn't have the hole to put the manual decompression thingamigig.
It doesn't SS, that's true. The WR's de-comp system is centrifugal in nature and operates as the exhaust cam spins. There's no possible way that the stock de-comp system can be manually actuated (that's why there's no casting/hole for it ).

If the exhaust cam is in the wrong place the motor comes up to TDC compression before the de-comp actuator gets a chance to throw out, the starter then doesn't have the balls to get the motor over TDC....Then...you rock the bike in gear whilst on a 45 degree angle on the face of a shitty hill-climb. (hoping that the float level is OK...)

And they reckon KTM 300s have a shitty starter design

How do BluLu and I know all this stuff?...we tested lots of cures, researched it, worked out a fix for YMA and sent them the results. (That was the deal for a free new starter motor)
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  #12  
Old 10-11-2016
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Quote:
Originally Posted by Sideshow View Post
That's actually a decompression lever...... but I take it back anyway.
It's seems that years head doesn't have the hole to put the manual decompression thingamigig.
Yeah I wondered wat the clutch thing was about. U drinkin gin celebratin trump nation nutty?

Edit: didn't see there was a page 2.
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  #13  
Old 10-11-2016
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Quote:
Originally Posted by Nutty View Post
There's no possible way that the stock de-comp system can be manually actuated (that's why there's no casting/hole for it ).
I know... it worked the rh ex bucket. The casting at least was still there up until 2007.
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  #14  
Old 10-11-2016
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Originally Posted by Sideshow View Post
I know... it worked the rh ex bucket. The casting at least was still there up until 2007.
Not quite, the '07 build bikes which were made in late 2006 deleted that casting (which was there because the 426s NEEDED decomp to even kick over). The last heads with a de-comp flange (5TJ-11101-00-00) were cast in 2005.

In the early days of the WR450, Yamaha offered a kit (5TA-W1228-00-00) to fit the 426s manual de-comp to the 450 and lots of kits were sold.

Australian delivered 450s have always had auto-decomp, never a lever. This was necessitated because they went from a FCR to a FCR-MX carb which had remote hot-start and required bar space formerly occupied by the de-comp system.

Old mates bike, being an '09, has the flange-less head (5TJ-11101-10-00), the decomp casting was long-gone by '09.
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  #15  
Old 10-11-2016
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Quote:
Originally Posted by Nutty View Post
If it never worked from day dot how come I've done 16,000 km on mine and not had an issue till now . Add to that the advertisement that I just read for the Hot cams stage 1 exhaust cam that says it uses the genuine Yamaha decomp set up ........... dunno who is right , the seller of the cam or Nutty , but I am not gunna spend the best part of $300 to find out either .
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  #16  
Old 10-11-2016
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Originally Posted by Oldfatbeerman View Post

Add to that, the advertisement that I just read for the Hot cams stage 1 exhaust cam that says it uses the genuine Yamaha decomp set up ...........

dunno who is right , the seller of the cam or Nutty.
Both.

There's nothing wrong with the OEM de-comp mechanism, it's just in the wrong place, too close to TDC compression.

When the mechanism gets a bit tired, the operating arm doesn't get time to contact the shim bucket before the motor builds compression. Shitty/overly-hot oils make the issue worse. Hotcams use the OEM arm in an earlier valve timing postion. Simples.


Quote:
Originally Posted by Oldfatbeerman View Post
If it never worked from day dot how come I've done 16,000 km on mine and not had an issue till now
Luck, good servicing and/or doing a load of open country and not much starting.

My 450 leading a ride down home would start 50-60 times per ride.

All good, you have the data to fix it for good if you so desire.
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  #17  
Old 10-11-2016
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Having had a think about this issue for a while now , my bike just may have had the Hot Cams cams in it from almost new , I bought it with 2 K kms on it in 2011 from a dealer that tried to talk me into a different bike (Blue WR) but I wanted this White one , it has always been a fast bike for a WR and when I put a large diameter header and muffler on it ( special order from Barrett Exhausts ) , it positively stomped on every other WR 450 I have ever ridden with . That would explain why I have never had starting issues until the spring / knob or whatever the issue is now started not playing nicely . Might pay me to pull the Cams out and Mike them to check . Or I might just buy an exhaust cam from hot cams and stick it in and forget about it till something else breaks .
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  #18  
Old 10-11-2016
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Quote:
Originally Posted by Oldfatbeerman View Post
If it never worked from day dot how come I've done 16,000 km on mine and not had an issue till now . Add to that the advertisement that I just read for the Hot cams stage 1 exhaust cam that says it uses the genuine Yamaha decomp set up ........... dunno who is right , the seller of the cam or Nutty , but I am not gunna spend the best part of $300 to find out either .
I can assure you they are NOT identical, despite any claims, the difference is small, but meaningful ....

as for the power delivery, just the exhaust cam alone, it's better, smoother....
that's all i'll say

I would guess @ 16,000 km, you might have other issues, don't know

but good luck getting it right again ...

have you pulled the rocker cover off, and inspected the decomp ?
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  #19  
Old 10-11-2016
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Originally Posted by Oldfatbeerman View Post
Having had a think about this issue for a while now , my bike just may have had the Hot Cams cams in it from almost new . Might pay me to pull the Cams out and Mike them to check ..
i can tell you an easy way to tell the difference

on the mechanism is a small round pin, about 3 or 4mm in diameter

if it is cut at 90 degrees, it's a stocker

if it has a nice domed end, it's the Hotcam

check it

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  #20  
Old 10-11-2016
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Quote:
Originally Posted by Blulu View Post
i can tell you an easy way to tell the difference

on the mechanism is a small round pin, about 3 or 4mm in diameter

if it is cut at 90 degrees, it's a stocker

if it has a nice domed end, it's the Hotcam

check it

Good memory Lu!

Gee we put some time (and beers) into solving that issue.

Remember the first time we put the Hotcam, tweaked carb, megabomb and shorty FMF combo together? Thing was unrideable if not on the tar...

Great days...
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