Hard to E-start or Kick Start, no decompression?

Hi, I've just re-built a 04 WRF 450 by fitting a 03 YZF head complete on it, new piston etc...

I fitted the WRF exhaust cam to keep the WRF specs, as the Intake camshaft is identical on YZF/WRF.

When it starts, it runs fine but it is very hard to kick, as if the auto decompressor wasn't doing its job. Also the E-Start has trouble to go past the TDC and compression.

I've checked the auto decompressor and it appears to work fine (protrudes when low revs, retracts at hi revs)

Does anyone has any idea?



Are you sure you have it timed properly? If you mistime the WR cam it will cause this problem. 1 tooth off can cause it, and the bike may run fine once it starts but starting can be a bear. Double check the timing marks. Hope this helps.


Thanks Josh!

Looks like I was one notch off... I may be because the intake shaft is from YZF and the exhaust is from WRF, anyway it runs MUCH better now with a timing featuring 13 pins btw the marks (instead of 14)...

Just a bit tedious to E-start still, it rotates much quicker but doesn't fire well...

The kickstart is a charm though...

Any idea why the E-start doen't fire it up?

I'll have the battery topped up, just in case it's a electrical prob...

I don't personally have e-start, but I seem to remember that they all had a little trouble due to an undersized starter motor. I don't know if there is anything you can do about it or not. You could ask Indy_WR450 to know for sure. Hope this helps.


Do you know the compression ratio with the changes you made?

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