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RC Valves on my 93 MC21


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nsr250racer

 
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RC Valves on my 93 MC21

Thu Nov 02, 2006 4:13 pm » Post: #1 » Download Post

Hello All! I have a problem, I ran my mc21 3 weeks ago in a club race and noticed in the first few laps that my bike wasn't making power like it was the day before. Engine temp was 70c , and rpm needle would not climb past 8k rpms (was really odd, knowing that the bike has alot of healthy overrev to 13k rpms, however I was still making my way through the majority of Sv650's (Lightweight GP class) I finally finished the race riding through the problem in 4th place(edged out by a Hyosung 650r - very disapointed hehehe) Today I started prepping the bike for this weekends races and noticed a couple of oddities. The exhaust (where they connect to the manifolds) has this white powdery substance that wipes off easily(don't know what this is) and the battery is completely dead (noticed on morning of last race day that off/on switch was on, which probably drained my battery) Could the problem be that the RC valves were not fully opening/operating as should be??? because of dead battery ??? I appreciate all of your expertise in this dept!!!


Randy
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300_mike

 
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Thu Nov 02, 2006 5:13 pm » Post: #2 » Download Post

Randy,


TPS?

Something about the white wire being connected to the RC valve. May not be the problem but worth a check if you have a multimeter.
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Andy
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Thu Nov 02, 2006 6:02 pm » Post: #3 » Download Post

The MC21 thrives on a well charged battery. If yours was discharged (or even low on charge) it can play havoc with the performance of the NSR's electrical system even with the motor spinning over at high RPM.
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jeff350lc
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Thu Nov 02, 2006 7:50 pm » Post: #4 » Download Post

Yep! battery for the RC valve problem, and as a guess for the white powder, check for water leaks it could be anti freeze stain.
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Andy
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Thu Nov 02, 2006 7:54 pm » Post: #5 » Download Post

Did you de-grease the motor at all recently? The white powder could be oxidisation of the alloy. Mine looks a right state at the moment as it has to live outside. Sad
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StephenRC45
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Thu Nov 02, 2006 8:04 pm » Post: #6 » Download Post

Now you know how mines looks after my own bike had to live out side while yours was in my garage Rolling Eyes Very Happy
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nsr250racer

 
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Battery is dead

Thu Nov 02, 2006 9:56 pm » Post: #7 » Download Post

Hi all! Thank You for all the posts, I did confirm that the battery was completely dead, which relates to the power valves not opening up and allowing for full performance. With regard to the powdery substance, all I can think of, is I used a product called Space Age Exhaust sealant, kinda like a real soft rubbery gasket that you kneed onto the flange which gets sealed in when inserting exhaust onto exhaust manifold flange (to give a good seal). It obviously got real hot and appears to have melted/disintegrated and discolored into the white chalky substance. Hmmm, don't know if I will use this product(sold here in the states) I will get the battery recharged and make sure from now on to disconnect and keep a trickle charger on it! I'll post up the end of the weekend to let you all know how the bike and I do this weekend.

Randy
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Dave Ett
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Thu Nov 02, 2006 10:17 pm » Post: #8 » Download Post

Good luck!
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Fri Nov 03, 2006 9:24 am » Post: #9 » Download Post

Check your regulator. A discharged battery should be charged while sitting on a running machine but if it isn't charged, the symptoms are exactly as you describe them:
The lower the voltage on the battery gets, the lower your rpms will be, as the bike uses more current at higher rpms (more ignitions pr minute).

After a rebuild I forgot to connect the regulator and my max. rpms would go lower and lower as the battery became discharged.

If yours stayed at 8000rpms, then maybe its charging a little, but not enough.
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Matt@TYGA
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Mon Nov 06, 2006 2:14 am » Post: #10 » Download Post

No one has congratulated you on finishing 4th on a bit making less power than a twist and bop shopping scooter!
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