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Crf250l spark question

By furball751,
in CRF250L/Rally & CRF300L/Rally

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Not here

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I talked to NGK about the life of the plug and sent pic's to them all they said was how's the gap look :/

I was still getting good spark I replaced it with the same one and kept the old on as a back up until I can find more info on the avg life of these plugs.

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Horneteer

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Does anyone know if the coil fire's only on the compression stroke or if it also fire's on the exhaust stroke also? So a single or dual fire?

I think it's single fire as I have my tach set to 0.5 pulses per revolution (1 spark for 2 revolutions) with the sensor on the plug wire. The tach reads correct at idle (1450 rpm give or take a bit), if the PPR were wrong the readings would be half or double what the engine was doing.

As per the Honda manuals (owners and workshop), the plug should be checked at 16000 miles and replaced at 32000 miles. The gap can be checked but not adjusted, renew the plug if it's out of spec. Gap should be 0.8-0.9mm, if a 1.0mm wire type gauge fits through the gap or the centre electrode is rounded and has lost its projecting tip then it's time for a new plug.

 

http://www.hondampe.com.au/docs/owning_a_honda/owners_manuals/motorcycles/62KZZ00_CRF250L13_OM.pdf

Edited by Horneteer
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gnath9

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I have a cheap tach on my bike right now but I'm not sure it reads right. It is right at idle 1450rpm or so but when I'm going 60mph it reads 3100rpm or so but it sounds like is running at a higher rpm then that. It is new and all stock. What do you all get for rpm at hwy speed?

 

My guess is that all stock with 14/40 sprockets at 60 mph would be about 6000 rpms .... I'm sure somebody will correct me if I am wrong ...  :doh:

 

My guess may have been correct as this is from CRF'sOnlys web site ..... it shows 6096 rpm's at 60 mph 

 

http://crfsonly.com/howto/gearing/motorcycle-gearing-calculator.php

 

Looks like my bike with 13/44's is at 6922 rpm's at 60 mph and 8653 rpm's at 75 mph 

 

Edited by gnath9
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Horneteer

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My guess is that all stock with 14/40 sprockets at 60 mph would be about 6000 rpms .... I'm sure somebody will correct me if I am wrong ...  :doh:

 

My guess may have been correct as this is from CRF'sOnlys web site ..... it shows 6096 rpm's at 60 mph 

 

http://crfsonly.com/howto/gearing/motorcycle-gearing-calculator.php

 

Looks like my bike with 13/44's is at 6922 rpm's at 60 mph and 8653 rpm's at 75 mph 

 

For stock 14/40 you are correct, I'm getting slightly lower rpms than mph,  something like 6200 rpm for 64mph.

 

The TTO tach wraps around the plug wire, and has a button on the back of the unit to set the PPR, sensitivity and refresh rate

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USMCVietVet

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The tach I have is one that wraps around the spark plug wire and doesn't have any way too change its settings. it is cheep as they come I will have to just wait for the new one

 

The works tach is 40 bucks at TT and wraps around the spark plug wire --works fine shows max rpm's when shut off and shows hours used also-- ? ?

Edited by USMCVietVet
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UtahPaul

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In lieu of a tach I made the following chart when I first got the bike. These figures are for stock gearing (14/40) and tires. From the owners manual, page 27, the recommended up shift speeds are 12, 19, 25, 31 and 37 mph. These may be appropriate, on flat or downhill roads, if you are trying to squeeze every last mile out of fuel, but with ZERO fun factor. As you can see, max rpms are around 4200. As I recall from some dyno graphs posted here and elsewhere, the bike produces it's best torque between 5000 and 8000 rpm. Keeping life simple during breakin I shifted more or less @ 20, 30, 40, 50 and 60mph thus keeping rpms on the reasonable side of decent torque range. Yesterday, I went for a 140 mile round trip ride which included going up over a summit on I-80, sorta steep, well over 7000 feet, and the bike was maxed out at an indicated 58 mph in fourth gear. Hope this helps!

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gnath9

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Okay .... I really love all you guys ... I really do but, 

 

all this is just RPM talk is just silly to me .... when the bike loses power or acceleration you shift up ... when it dogs or loses power you shift down ... this applies to all bikes weather it is a 2 stroke or 4 stroke or a dirt bike or a street bike .... it even applies to a Harley Davidson .... ?

 

The newer bikes including our beloved CRF250L have a built in rev limiter and until you are constantly bouncing off of that we really have no concerns with RPM's ... I for one look forward to that problem and is exactly what I am in search of ....  ?

 I personally will not be happy until I can bounce off the rev limiter in 6th gear ....  :goofy:

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gnath9

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Gary to hit the rev limiter in 6th you would need either a 75 tooth rear sproket OR a 5 miles straight road and a big set of cajonies???

 

I understand your disbelief .... I think 13/48's will put me there as I am running 13/44's now I can still hit over 75 MPH ... I honestly did not think that would be possible and I can also tell you that is also wound up high and tight ....  ?  ... maybe 9,000 RPM"s .....  

 

This bike is kind of shocking to me as all modded up with the 305 and 13/44's etc ..... and it still goes over 75 MPH ....  ?  Datz crazy man ..... ?

 

I am almost willing to bet that when I get 13/48's on there .... it will still do 75 MPH but I will be closer to 10,000 RPM's and we all know that we would not want to hold there for any length of time down the highway ....  :banghead:

 

it may take a 13/51 combo to bounce off the limiter in 6th  ....  :excuseme:

Edited by gnath9
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