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Discussion Starter · #1 ·
Ever since I put this ported and polished 00 summit 700 motor in my 00 MXZ 700 I can't get it to run at peak RPM which is rated at 8000 +or- 100. It is currently running at 7000 RPM and pulls ok but is rated to be best at 8000 RPM in the book. My clickers on the primary are at 6 already and I'm not sure what to do next.....

I NEED ADVICE FROM SOMEONE THAT HAS HAD THIS PROBLEM..... OR REALLY KNOWS THERE S#@T!

The motor has been ported, my main jets in the carbs are at 300 from 280 and I also raised the needles one notch. I have an aftermarket silencer, and tried stock but doesn't help.

THANKS DOOERS


I finally got my sled to shift correctly after cleaning up and adjusting the spring in my secondary clutch.
 

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Kuss22 said:
Ever since I put this ported and polished 00 summit 700 motor in my 00 MXZ 700 I can't get it to run at peak RPM which is rated at 8000 +or- 100. It is currently running at 7000 RPM and pulls ok but is rated to be best at 8000 RPM in the book. My clickers on the primary are at 6 already and I'm not sure what to do next.....

I NEED ADVICE FROM SOMEONE THAT HAS HAD THIS PROBLEM..... OR REALLY KNOWS THERE S#@T!

The motor has been ported, my main jets in the carbs are at 300 from 280 and I also raised the needles one notch. I have an aftermarket silencer, and tried stock but doesn't help.

THANKS DOOERS


I finally got my sled to shift correctly after cleaning up and adjusting the spring in my secondary clutch.
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Is you belt shifting all the way out in the secondary? If so you dont have enough pressure on your helix. You said you messed with the secondary clutch spring, did you put it back in the correct location?
 

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Discussion Starter · #3 ·
[snapback]714448[/snapback]​
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Is you belt shifting all the way out in the secondary? If so you dont have enough pressure on your helix. You said you messed with the secondary clutch spring, did you put it back in the correct location?
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How do I go about checking if its shifting all the way out? Can I check it on a stand?

Yes it should be back in the correct spot... I had a dealer do it..... How can I be completely sure though.....??
 

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I had almost the same type of problem with my sled (tra adj didn't make a dif/same with my spring rate on both springs and I even changed the helix), it would pull great out of the hole at 8000 and then drop to 7200....turned out I was missing a bushing in my clutch....If your outer clutch shieve has any small twisting movement you might have worn and or missing bushings in the outer clutch...hope this helps

My clutch had full shift out on the stand, but wasn't getting full shift out when the clutch had a full load with track on the ground

the outer clutch face angle will contantly change with the change in torque and rpm due to the load on the clutch face
 

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To check if your shifting all the way out you mark your primary with a sharpie marker. Draw a line from the shaft all the way up the shieve. I always mark the inner shieve. You ned to run it on the ground it wont work on th stand. What do you have your secondary pretension set at? How old is your primary sping? It sounds like a cluching issues. Is your secondary hot after a long pull? Where is your belt sitting in the secondary? Need more info.
 

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I think you need to start here:
How did the sled run before the work was done?
What else did you change?

I would start back at stock. Run it just ported if possible. Get the sled back to where it was when it was running good. My .02 cents.
 

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My FIII 700 is having the same problem, takin off, the rpms are at 8000 but then they drops back down to 7000 and just stay there. I put a new clutch kit in (EPI) in December. I have also noticed that the belt and clutch are very hot after a ride. I know it is a clutching issue, BUt i can't see it being the springs, they are new. What could be the problem.....Thanks.
 

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When you mod a engine with porting or pipes you can change the power band and the torque band most times raising both bands to a higher level . This will make your stock clutching obelete. your tack is telling you that you have to much weight in your clutch there fore you are shifting up before the engine can handle the load and is pulling the engine to low . You may allso need a shallower helex angle to clamp your belt harder.and stop it from gearing up to fast .
 

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Discussion Starter · #13 ·
Well I took it out again this past weekend and same thing.....

From a dead stop when I give her it will climb up half way to 6-6500rpm with a bog and then around 30mph kick up to 7000 rpm and it then starts to pull pretty good.

I can tell it needs the additional 800-1000rpm to get to peak power, but I have no idea what to change to get it there.. Like I said my clickers are allready at 6.

If I change my primary spring will this make a huge difference?? If so what should I go with? The same stock spring , a heavier one, or a softer one? I would like to get the clickeres down to 3 in the stock position!

I don't see how the jetting and or carb changes I made would cause this to happen. Is that even possible??

MORE HELP PLEASE!! Thanx to those who have gave me some where to start.

I will be testing the shift out this week since the sled is now back at home!
 

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Discussion Starter · #14 ·
mudweiser said:
I think you need to start here:
How did the sled run before the work was done?
What else did you change?

I would start back at stock. Run it just ported if possible. Get the sled back to where it was when it was running good. My .02 cents.
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I forgot that this was an issue from the start before I even touched the carbs!!


So going back to stock will have the same problem....
 
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