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post #1 of 11 (permalink) Old 07-30-2011, 09:06 PM Thread Starter
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hard start

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Originally Posted by CJMJ View Post
Thanks for the idle speed info. Just got the bike back from the shop and the idle speed is now 1300. They changed the air filters, plugs and put in new fuel with fuel treatment.

Bike runs amazing(just like before), but is still difficult to start when hot. I have to give it some throttle and then it starts up. Never had to do that until 3 weeks ago.
The second paragraph is exactly what my bike is doing yesterday and today. It's 100 degree weather here now. This issue is brand new to my bike. I'll follow the advice from the thread the above quote came from.
  • Look at plugs, although they were new 3000 miles ago.
  • Look at and clean the air filters,
  • make sure idle is proper--1300,
  • check the small hose on my fuel pres reg. for fuel leak
  • Damn, i did just fill my gas tank right before this started, guess I better dump the remaining 2 gallons...
I'm pretty weak in this area, did I miss something?

I will consult the manual now, but I started searching our forum first. Three of you had the right diagnostics for CJMJ. To me, that's more valuable than any mechanic for hire!

John, 2000 RC51 #000100


Last edited by jondog9; 07-30-2011 at 09:09 PM. Reason: too many words :)
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post #2 of 11 (permalink) Old 07-30-2011, 09:21 PM
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What did the plugs look like? What was the insulator tip color?
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post #3 of 11 (permalink) Old 07-30-2011, 09:43 PM Thread Starter
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Its too late tonite to look. I'm doin this in the morning.
I once saw a chart of sparkplug diagnostics that I think you posted? I lost some of my favorites when my computer crashed recently, do you still have that? It would really help tommorow. Thanks SubSailor.

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post #4 of 11 (permalink) Old 07-30-2011, 09:51 PM
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How new is your battery and what type of gas are you running?

My last RC did this to me because the heat from the bike and being over 100 deg just killed the battery. (I remember it quite vividly because it happened at Mid-Ohio, lucky me for the hills in that area for a bump start)



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post #5 of 11 (permalink) Old 07-30-2011, 09:53 PM
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Here's what mine looked like a ways back in '08. This is with 16K miles on them using a Jardine 2-1 full exhaust with PCIIIr.


Here's what the last set looked like in '09.
This is after a remap for my Akrapovic full exhaust with PCIIIr.
I'll be remapping again for my PCIIIUSB, and will try to tweak the air/fuel ratio a bit better.
These are still considered normal plug colors, although slightly on the richer side than the other ones, which are perfectly tan.
A light gray to tan is normal.

Last edited by SubSailor; 08-02-2011 at 10:57 PM.
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post #6 of 11 (permalink) Old 07-31-2011, 10:11 PM Thread Starter
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Nice close-up SubSailor, I couldn't get quite that close. But mine look pretty thrashed compared to yours. I remember pulling them out and looking early on in my project. I thought they looked ok at the time and put them back in. I could have been wrong cause I really don't know how to read plugs. Aside from the obvious clean or dirty. What do these plugs tell you? too rich? (Yosh pipes, yosh map from PC, and PCIIIr)

I think I found the problem with my stall/hard start. Fuel pressure reg. Makes sense to me cause it acted like it was flooded on the hard starts. If I would slowly roll the throttle open it would catch and start. Gas was leaking into the small line, apparently draining into the front throttle body? At idle thats already to low (1000-1100).

Is the small line on the FPR a vacuum, or a way to evacuate gas to the throttlebody in the event of leakage?

Airfilters are at the end of their life too. I'll replace those as well.

Thanks to recent posts about testing the fpr, I knew just how to do that. A big thanks to the regulars on this forum for all the great tips and information. Make's things go much faster.

Pictures: FPR, front cyl. sparkplug, rear cyl. sparkplug
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post #7 of 11 (permalink) Old 08-02-2011, 02:26 PM
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They look a little rich to me. Not too bad though. Ideally they should be a medium to light tan color like the ones subsailor has.
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post #8 of 11 (permalink) Old 08-02-2011, 11:04 PM
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Quote:
Originally Posted by jondog9 View Post
Nice close-up SubSailor, I couldn't get quite that close. But mine look pretty thrashed compared to yours. I remember pulling them out and looking early on in my project. I thought they looked ok at the time and put them back in. I could have been wrong cause I really don't know how to read plugs. Aside from the obvious clean or dirty. What do these plugs tell you? too rich? (Yosh pipes, yosh map from PC, and PCIIIr)

I think I found the problem with my stall/hard start. Fuel pressure reg. Makes sense to me cause it acted like it was flooded on the hard starts. If I would slowly roll the throttle open it would catch and start. Gas was leaking into the small line, apparently draining into the front throttle body? At idle thats already to low (1000-1100).

Is the small line on the FPR a vacuum, or a way to evacuate gas to the throttlebody in the event of leakage?

Airfilters are at the end of their life too. I'll replace those as well.

Thanks to recent posts about testing the fpr, I knew just how to do that. A big thanks to the regulars on this forum for all the great tips and information. Make's things go much faster.

Pictures: FPR, front cyl. sparkplug, rear cyl. sparkplug
The line on the FPR is a vacuum line.
Each throttle body has a vacuum fitting and hose that joins at a T-fitting at the rear throttle body. The other end of the T-fitting joins the FPR.

The photo your plugs were a bit hard to discern due to the size.
At first it looked like your plugs were dark and shiny, indicating possible flooding or oil problems.
If the plug was dark and sooty, then it would be running too rich.

But since your FPR was bad, it was probably dumping fuel into the airbox and wetting the plugs.
Now that the FPR has been replaced, it will be interesting to see what they look like a bit farther down the road.

Last edited by SubSailor; 08-02-2011 at 11:09 PM.
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post #9 of 11 (permalink) Old 08-02-2011, 11:10 PM
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Quote:
Originally Posted by jondog9 View Post
Nice close-up SubSailor, I couldn't get quite that close. But mine look pretty thrashed compared to yours. I remember pulling them out and looking early on in my project. I thought they looked ok at the time and put them back in. I could have been wrong cause I really don't know how to read plugs. Aside from the obvious clean or dirty. What do these plugs tell you? too rich? (Yosh pipes, yosh map from PC, and PCIIIr)

I think I found the problem with my stall/hard start. Fuel pressure reg. Makes sense to me cause it acted like it was flooded on the hard starts. If I would slowly roll the throttle open it would catch and start. Gas was leaking into the small line, apparently draining into the front throttle body? At idle thats already to low (1000-1100).

Is the small line on the FPR a vacuum, or a way to evacuate gas to the throttlebody in the event of leakage?

Airfilters are at the end of their life too. I'll replace those as well.

Thanks to recent posts about testing the fpr, I knew just how to do that. A big thanks to the regulars on this forum for all the great tips and information. Make's things go much faster.

Pictures: FPR, front cyl. sparkplug, rear cyl. sparkplug
Damn Jon...you got the "drip"...sorry to hear it.



The very first schoolbook that was written had God all over it. --Dave Mustaine
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post #10 of 11 (permalink) Old 08-02-2011, 11:36 PM Thread Starter
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Quote:
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Damn Jon...you got the "drip"...sorry to hear it.
Yea, but it doesnt burn. That's good, right?
Your rash clear up?

John, 2000 RC51 #000100

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