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Discussion Starter #1
07 grizz 450 here.
Took it to HMT last week. It ran great nearly all day. A few miles from camp, it lost speed. Like a limiter kicked in. We had an easy ride that day. No major mud/water. We were cruising up the road when it happened.

It now tops out at 20-22 MPH. The engine rpm seems normal for the speed. Its NOT revving high. I've had that happen when the primary is packed with mud.

It starts and runs fine. Gets up to 20 MPH no problem, but won't rev up any more, won't go any faster.

I pulled the clutch cover. In park, it seems everything is working normal. Rev the engine and I watched the belt ride the sheaves like all is fine. Take it for a ride and the belt never makes it to the outer edge of the primary.

Not sure if this is a clutch, or belt, or ignition issue.

I'm running a CDI from AMR Racing.

Everything else is stock.



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Sounds like there is a restriction of gas or air to the engine.
Also a weak plug or valves out of adjustment can reduce power out-put.
 

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Discussion Starter #3
I'll check those things. It has maybe 15 hrs on it since I changed the plug and adjusted the valves.

All fluids were changed and air filter was cleaned and oiled before heading to HMT. Only rode it one day before it acted up.




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Is the reverse light flashing?
When it hits 20 MPH, does the engine start spuddering?
 

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Check throttle cable?
 

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Discussion Starter #6
Is the reverse light flashing?
When it hits 20 MPH, does the engine start spuddering?
Check throttle cable?
No reverse light flashing.
No sputtering. Just tops out and holds steady.

Didn't check throttle. My thumb feels like it's going thru the normal range. Maybe someone is pranking me and screwed the limiter in on the housing.

It feels like a clutch issue but, the RPMS aren't going up.

I will check your suggestions. Thanks

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Discussion Starter #7
Ok, had some other issues in the garage to clear up and finally got some room to check out the grizz.

Spark is good. Throttle good. Plenty of fuel making it to the carb.

Opened clutch again. Noticed the belt and sheaves have a very light film of grease on them. Basically everything under the cover is coated lightly.

I cleaned/greased the cvt about 2 years ago (don't see many miles). I used ultramatic and polyurea as recommended in JBS videos. It did go thru some DEEP water on its previous outing this spring but, ran fine afterwards.

I cleaned all the hard parts in kerosene last night. I cleaned the grease off the belt with some purple power, then rinsed, then cleaned with dish liquid and rinsed again. Seems like new.

I'll try and get back together for a test run soon.

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Probably leaking around wet clutch housing seal.
 

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Probably leaking around wet clutch housing seal.
X2.
Remove the primary inner sheave and see if the shaft seal is leaking oil.
Also pull the secondary clutch and see if that shaft seal is leaking oil.
 
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Discussion Starter #10
Never considered that. I've got both sheaves removed for cleaning. Everything in there needed wiped down.

Should I start the engine to check the primary seal? I can't see that helping much in checking the secondary eh?

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Never considered that. I've got both sheaves removed for cleaning. Everything in there needed wiped down.

Should I start the engine to check the primary seal? I can't see that helping much in checking the secondary eh?

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You can start the engine if you like. You may need a little rpm higher than idle to engage the wet clutch and turn the shaft. Just be easy with it as the engine will want to rev quickly. The only weight you'll have at that point is the flywheel on the other side of the crank.

And yes that won't help with checking the secondary...lol
 

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Never considered that. I've got both sheaves removed for cleaning. Everything in there needed wiped down.

Should I start the engine to check the primary seal? I can't see that helping much in checking the secondary eh?

Sent from my SM-G930V using Tapatalk[/QUOTEū]

You can start the engine if you like. You may need a little rpm higher than idle to engage the wet clutch and turn the shaft. Just be easy with it as the engine will want to rev quickly. The only weight you'll have at that point is the flywheel on the other side of the crank.

And yes that won't help with checking the secondary...lol

CHECK THE TIN GREASE COVER FOR THE PRIMARY THAT IS HELD IN PLACE WITH THE PHILLIPS SCREWS.MAKE SURE THE "O"RING IS IN PLACE AND NOT DAMAGED. CHECK COPPER SEALS ARE ON SCREWS
 

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Discussion Starter #13
Copper washers were good. That O-ring showed some wear but was intact

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Discussion Starter #14
Fixed!

I picked up a socket to tear apart the secondary today. Disassembled, cleaned, greased.

Same with primary.

Put it together, left cover off and did a quick lap. No improvement.

I was bummed! While riding, it seemed like the intake was noisy. I could hear air sucking.

Pulled in garage. Checked filter again. All good.

Pulled fuel tank and found the diaphragm cover laying there!

I cleaned everything up. Put it back together and it runs as well as it ever did.

Thanks to all who offered suggestions.


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Well you don't see that everyday....lol.

Thanks for taking the time to post the fix.
 

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Discussion Starter #16
I installed this carb back in May of 2016. I guess I forgot to torque those screws. I'm surprised it lasted as long as it did!

I was glad to see the diaphragm was still sealed to the top of the carb. It didn't take much cleaning

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