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2005 M7 Low RPM

R
Nov 10, 2014
6
0
1
I bought an M7 last year rode it a few times and realized that I was not getting the RPM’s. It was running at max 7400, mostly 7200. it has the correct weights in, the exhaust valves are clean. it has good compression. Where do I start looking next? The secondary clutch?
 

boondocker97

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Oct 30, 2008
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Billings MT
Check the secondary clutch rollers and see if they are worn. Also check how worn the large bushing is on the moveable sheave. Once these get enough slop in them they can bind. An old belt will loose RPM compared to a newer one too. If it has been on there for a couple of seasons you might be due for a new one.
 
A

arctic2009

Well-known member
Nov 19, 2009
1,864
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Minnesota
I bought an M7 last year rode it a few times and realized that I was not getting the RPM’s. It was running at max 7400, mostly 7200. it has the correct weights in, the exhaust valves are clean. it has good compression. Where do I start looking next? The secondary clutch?

How many miles? Have you checked for a broken spring? what springs are you running? have you checked for torn motor mounts? Stuck roller in the primary?
 
R
Nov 10, 2014
6
0
1
not sure off hand what the miles are. It not a ton i do know that less than 2500? I am running a yellow spring on the primary clutch and a yellow spring on the secondary. Springs are good.

Thanks for the help.
 
A

arctic2009

Well-known member
Nov 19, 2009
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Minnesota
not sure off hand what the miles are. It not a ton i do know that less than 2500? I am running a yellow spring on the primary clutch and a yellow spring on the secondary. Springs are good.

Thanks for the help.


Yellow spring in the driven? What rate is it? I would try swapping a different driven clutch and see if you can reach rpms. First, check the motor mounts. You may need a flashlight to see if they are torn.
 
R
Nov 10, 2014
6
0
1
I looked at the motor mounts and they seem to be in good shape. The spring is the one from the factor , so I am not sure of the tension. The belt has about a 1/4 inch play in it from side to side on the primary clutch,so I am guessing that it needs to be changed. The sled has 195.8 hours, it has 385.0 miles on it. Does that mean it has 3850 miles? I was talking to a guy and he said put liquid graphite on the clutch bearings is that a good idea?

Once again I really appreciate the help
 
A

arctic2009

Well-known member
Nov 19, 2009
1,864
670
113
Minnesota
I looked at the motor mounts and they seem to be in good shape. The spring is the one from the factor , so I am not sure of the tension. The belt has about a 1/4 inch play in it from side to side on the primary clutch,so I am guessing that it needs to be changed. The sled has 195.8 hours, it has 385.0 miles on it. Does that mean it has 3850 miles? I was talking to a guy and he said put liquid graphite on the clutch bearings is that a good idea?

Once again I really appreciate the help


195 hours is waaaay over 385.0 miles. Average miles an hour should be around 12-15. so 15x195=2925 miles. My guess is the wire is broken going to the speedo sensor in the diamond drive, therefore only logging hours and not miles. At that many miles Id guess your driven is shot.. swap for a known well working driven clutch and go from there. Make sure your deflection is about an 1/8" above the sheave on the driven.
 
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diggerdown

Well-known member
Apr 25, 2004
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Deer Park Wi.
Your primary spring has to be two colors or it is not a cat spring. It should be yellow/white if it is yellow/ green your R's will be down some. A orange driven clutch spring should be in the secondary. I would guess someone has put after market springs in the clutches and they are not matched up for pressures or need replacing.
 

vinpie1

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Feb 19, 2009
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Gunnison, Co
I'd put a flashlight behind the mag side motor mount. You really need to look close and check for light coming through. I did all new mounts on both my m7's last year and both sleds need new mag side mounts. I was really surprised. One was even a solid rubber type. It actually failed first. If you do need to replace them, use 60 duro mounts that were standard in 2006 m7's. They last the longest. Our 2005's use 45 duro (softer) mounts.
 
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diggerdown

Well-known member
Apr 25, 2004
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Deer Park Wi.
Between the throttle bodies and engine, when you take the throttle body off you can look in the rubber boots and see the valves but you need to unbolt and take them out to really see if the tips are chipped or cracked. They usually are more noticeable on the low end of rpm but will effect the entire range.
 

JoeySlushr

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Dec 6, 2007
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LeCenter, MN
if you can find somebody with a bore scope, its easy to send the camera thru the throttle bodies to check them out
 
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