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Discussion Starter #1
There has been lots of talk on jetting in this site and I have some questions. I have a 01 ZR800 and want to rejet or drop the needles.

I ride at 1000ft elevation and don't ride at temps below -25C I think 410's are fine for this. Does any one run 410's and not burn up. That is only 2 lower than stock. Should be ok on the theory that you are rich from the factory.

Can you drop the needles one clip or a half clip if you use yamaha clips and spacers? Has anyone done this and not burn up?

The reason I want to drop the needles is it seems to load up when I am not driving the machine hard (riding with the wife and kids) but runs well when I ride with the boys. i have checked everything including the oil pump and all settings are correct.

I know you don't have to push the limits with the 800 because it makes lots of power anyways, but I think some fine tuning is required.

Let me know what your expeirence has been.
 

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I ran 400 mains successfully all last winter in Muskoka (ZR800CCE at 750 ft.) with the shelf and cones removed. The 800 twin has a hot spot in the timing curve at approx. 6500 rpm. You may run into trouble when trail riding if you drop your needles (or add a timing key). Have you re-calibrated your oil pump? They are very oil-rich from the factory and run crisper and much cleaner when you attain a 70/1 fuel-oil ratio and run a quality synthetic oil. ;) Hope this helps. Where do you ride?
 

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Discussion Starter #3
Muskoka 800 I ride in Haliburton 35 and 118 is home. 400's seem a bit lean though. How were your plugs and piston wash? The oil pump is just below factory one line width. I plan on measuring fuel to oil burn this year to get it right. i also am planning on running Blue marble oil.
 

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I ran 410's all of last season in my 02 800. Plug color looked good in temps all the way down to -35 and below while riding northern Ontario. As Muskoka said leaning the needles out will more likely than not spell disaster. The other thing to remember is that the 800 Cat is not a jet prone engine. When jetted a little rich it just doesn't seem to bother performance but yes it will run a little crisper when your closer to its sweet spot. Meaning that theres no need to jet/run them on the edge for good performance as is necessary with many engines.
Rick.
 

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had 2001 and 2002 800 ran 400`s with the needle dropped 1 and had 10 off the heads and a .020 timing key never had problems it g was rode from slow trail to hard lake running to constant 70 down the rail road grade out of hurley . thats with premium
 

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my friend is running 410's here in northern ont....no problems
 

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I ran 410's in the Zr900...........as for the needles I would leave them in stock position because 9 times out of 10 they go down in the mid range.
 

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petestoy,
I've heard from guys with AC 800 twins running 380 mains all winter in the UP of Michigan with no problems??? Mine was just fine at 400's, shelf and cones out. I may fool around with an aftermarket pipe this winter so could be back up to 430 mains.
I also have a couple cases of Blue Marble to try this winter. Hoping for the kind of good results others have experienced. :D
 

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Discussion Starter #9
Thanks guys anything less than 400 worries me so I won't go any lower as far as dropping the needle I think i'll try and watch the plug wash. If i don't like it changing the needles is easy and quick.
 
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