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Rookie question: overheating

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Simply: How do you know if the bike is running hot/overheating? Just comparing to other riders bikes, my CRF feels very hot. How do I know if it's overheating?

 

Many thanks

T

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Short of having a computer on-board, or a temp strip on the top of the raid, when it starts to steam and spit<g>

 

Have you re-jetted the bike?   The jetting on these is very lean from the factory (for emissions), which gives you a hot running motor.

 

Jim.

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Thanks guys, I recently leaned it out by adjusting the needle because of a hanging idle issue (whether that does anything to fix hanging idle is probably for another thread). I bought the bike with an airbox mod and it's been bored out to a 300 or something. I assume the jetting, therefore, was not factory.

 

I ride at about 2000m ALT above sea level.

 

I've looked up the hanging idle issue and have messed around a lot, following all sorts of instructions. There seems to be a conflict as to whether or not adjusting the mixture using the needle has any impact on idle. I found that it did. If I go back to a richer mix (the bike pops on decal a lot) will it give the same idle issues, and if so, can anyone suggest a solution?

 

Lastly, the bike seems to guzzle oil, but only smokes when cold. Recently I filled it up to the upper end of the dipstick and after a 3 hr ride it's not right back to the bottom. Have I got piston issues?

 

Thanks for all the help

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On what impacts what, here's a picture:

 

Keihin <a href='https://thumpertalk.com/link/click/4794/' rel='nofollow' data-ipsHover-target='https://thumpertalk.com/index.php?app=autolink&module=links&controller=content&id=4794' data-ipsHover target='_blank' rel='noopener' data-autoLink>FCR Carb</a> Tuning Components.jpg

 

 Generally, a hanging idle is caused by a lean condition as is popping on decel.   So overall it sounds like your lean especially given that your asking about overheating.

 

 First, I would look over the exhaust system carefully for leaks.  If your letting air in anywhere, your going to get popping.  Also if you still have the PAIR valve (emissions, which I doubt from the sounds of it).

 

I'd then check the following:

 

1. Check the slide seal to make sure it's in good shape. 

2. Also check that it is installed correctly (hole down, flat side out).

3. Check the hot start connection.  Make sure the plunger is moving, that the cable is not being pulled, and that the connector is screwed down tight.

4. Check that the rubber boot between the engine and the carb has now leaks.

 

 I'd then move back to jetting.

 

Jim.

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BTW, do you know what your current jetting is?  Might give us an idea if it's in the ball park or not.

 

Jim.

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Yes I agree that the needle has an effect on the low speed circuit. Even main jets have an influence on the low speed circuit.

 

Lean mixtures do cause hanging idle because the slide needs to be higher to maintain idle speed and that high slide position is where three circuits overlap; low speed, needle, and slide cutaway.  Mixture wise a confusing situation. 

 

Jim recently posted a guide on adjusting the idle speed and mixture, as well as determining if the pilot jet is the correct size. 

 

The oil consumption is from failed oil seals, the oil is leaking into the tranny, check the tranny oil level.  Also there is a recent thread on the oil seal issue.

 

on edit: Jim already answered!

Edited by Chuck.
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Thank for all the responses guys, much appreciated.

 

I reckon the bike is too lean so will sort that out and then see what happens to the idle. No idea what jets it's got cos I forgot to check the last time I took the carb apart.

 

I'm also pretty sure the seal between the exhaust & the muffler is not airtight. It's all a bit rusty; any tips on anything I could use to tighten it up (a material which won't bust into flames).

 

Thanks again

T

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Redneck exhaust leak test: get a cheap cigar, and with the bike running on a work stand in a closed garage/shed with no wind chief on the cigar until the immediate area of the bike is swimming in smoke. A flood light will show the smoke moving with the air currents. No movement = no leak.

An OEM gasket is the best fix. Don't break the studs though. :)

Don't forget to take the side panel off and check the mid pipe connections as well.

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Thanks again for all the replies.

 

A quick one: I opened up the top of the carb to remove the needle which is set at 3clips from BOTTOM- remember the bike has airbox mod and I ride at about 2000m above sea level. I still don't know if it's been re-jetted BUT: I turned the throttle stop screw out until it was NOT pushing the throttle at all, re installed the carb etc and set the fuel screw to 2 turns out. Warmed up, the throttle stop is now more than 4 turns IN (i.e. lifting the slide plate) in order to prevent stalling.

 

The question is: is that many turns on the throttle stop normal, or am I still running lean and having to make up the difference using the throttle stop? If so, could this be contributing to the hanging idle?

 

Thank you!!!

T


BTW, I've fixed any potential leakage at the exhaust end...

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It's really not a set number of turns.

 

What you want to do is adjust the fuel screw so that it is correct with the correct slow jet, then raise the idle to 1700 rpms  with however many turns it takes.

 

Jim.

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