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WR426 Hot cams now won't throttle

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Hi All,

This is first time I have ever used a forum, thought I would give it a try to see if anyone else has come across this. I know it's becoming quite an old bike now the 426 range, but I never had the opportunity to own one until now. I had some issues starting it (as everyone who doesn't weigh more than 14 stone) so I brought a Hotcam from the USA. Fitted it no probs, until it came to running it up. Now it will not throttle up. I'm tempted to throw the old cam back in it to see what it does. It's great at starting now throttle it a couple of time and then kick, but open the throttle slowly or fast and it wont rev past about 3000 rpm (estimated).

 

I'm a BMW bike mechanic, So I'm pretty clued up on this. I have checked the valve timing twice, and the carb just incase it is because I left it for 6 months, valve clearances are all spot on and re-shimmed but still feels odd, like the ignition trimming is retarded. Throttle it and it makes that horrible induction roar could also be lean mixture or air leak. Obviously I have checked all of these, except putting the old can back in it (which is probably a good option) But I just don't want to. I like being 9 stone and able to kick a 426!

Any help would be amazing please guys!

Thanks in advance  

Edited by Jamie Hewett
Poor spellings

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There is a mark to the left of TDC, that is the various firing markings the second line is for TDC that you line up through the sight plug. When in this position the marks line up with the top of the head. Exhaust DOT to the left and the inlet dot to the right. Pretty sure that's spot on.

Edited by Jamie Hewett

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On 14.6.2017 at 11:21 PM, Jamie Hewett said:

It's great at starting now throttle it a couple of time and then kick, but open the throttle slowly or fast and it wont rev past about 3000 rpm (estimated).
 

a ) cam lobes waay off (wrong TDC mark or cam mark position/alignment incorrect during install), although it would be amazing that it'll idle nicely then.

b ) half dead CDI. Especially the perfect start, smooth idle and limited rpms sound very familiar. Been there seen that twice, check out that thread:

 

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