04 RM 144 rebuild questions

dlewy946
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33
Joined
7/14/2013
Location
Reading, MI US
10/10/2014 2:45am Edited Date/Time 10/11/2014 1:04pm
I bought the bike back in 07 the previous owners took good care of it maintence wise, I'm just having trouble putting any more faith into it, I've went through multiple cranks crank bearings and rod bearings. We always throw a new piston in the bike as well depending on the piston head. It's a great bike I just don't know what's going on with it. Starting the 5th rebuild tonight.

Always run a wiseco top and bottom end kit
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Paw Paw 271
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3640
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4/3/2013
Location
Benton, LA US
10/10/2014 5:07am
What fuel mix are you running?

Paw Paw
10/10/2014 8:25am
Thats your problem drop it down to 32:1 or even lower depending on how fast you are.
dlewy946
Posts
33
Joined
7/14/2013
Location
Reading, MI US
10/10/2014 9:50am
What about jetting? The way I have it now it runs great clears out and never loads up but on the rich side

The Shop

Spagina767
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912
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8/27/2013
Location
Fredericksburg, VA US
10/10/2014 12:43pm
dlewy946 wrote:
I bought the bike back in 07 the previous owners took good care of it maintence wise, I'm just having trouble putting any more faith into...
I bought the bike back in 07 the previous owners took good care of it maintence wise, I'm just having trouble putting any more faith into it, I've went through multiple cranks crank bearings and rod bearings. We always throw a new piston in the bike as well depending on the piston head. It's a great bike I just don't know what's going on with it. Starting the 5th rebuild tonight.

Always run a wiseco top and bottom end kit
Get a Pro-X crank next time.
Matt Fisher
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4/1/2008
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Visalia, CA US
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1084th
10/10/2014 12:55pm
If you're running a Wiseco crank, that could well be the source of your problems. They are pretty well regarded as crap. OEM is good stuff, as is the Pro-X mentioned. Make sure the bearings are from either US or Japan, no "Made in China" bearings allowed.

It could also be something like the way it's being installed, cases that were incorrectly machined, a off-balance flywheel, or any number of odd issues. I would disagree that 40:1 is the issue, particularly when it's the crank going out, not the piston. Roller bearings actually don't need very much lubrication and the flash point of virtually any oil you're using isn't going to be an issue for the crank (though it can be for the piston).
dlewy946
Posts
33
Joined
7/14/2013
Location
Reading, MI US
10/10/2014 4:10pm
Pro-x is affiliated with wiseco, wiseco cranks are actually pro x I've talked to one of the big guys on the west coast about it. As far as bearings goes the wiseco provided ones were made in Japan. Also I managed to take the cylinder off and the case had a significant amount of oil.
Matt Fisher
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3947
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Location
Visalia, CA US
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1084th
10/10/2014 5:49pm
dlewy946 wrote:
Pro-x is affiliated with wiseco, wiseco cranks are actually pro x I've talked to one of the big guys on the west coast about it. As...
Pro-x is affiliated with wiseco, wiseco cranks are actually pro x I've talked to one of the big guys on the west coast about it. As far as bearings goes the wiseco provided ones were made in Japan. Also I managed to take the cylinder off and the case had a significant amount of oil.
Interesting. It was my understanding that they were under the same company wide umbrella, but were very different products. The Wiseco pistons are forged, while the Pro-X ones are cast. Wiseco cranks come from China, Pro-X from Japan. Maybe the person you talked to was "stretching" the connection between products due to the common owner, I dunno.

I have seen where the Wiseco cranks have earned a bad rep, while the Pro-X ones have the opposite. Given your struggles, it might be time to try a different manufacture for the next rebuild. Seems more logical than going for rebuild #6.
dlewy946
Posts
33
Joined
7/14/2013
Location
Reading, MI US
10/10/2014 6:08pm
I ended up getting a free top and bottom from wiseco so were going to wing it one last time replacing a few minor things here and there. If it happens again I'm just going to end up going to Eric gorr or just switching back to a stock jug and oem everything. Thanks for the feed back everyone.
Jakes Dad
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1865
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6/22/2009
Location
Brooksville, FL US
10/11/2014 1:04pm
A squish band width of 50% of bore and .030 to .040 max gap. Run at least 95 octane and Motul 800 at 32 to 1. Haven't had an engine failure in over a year with this combo.

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