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rodmac

4Rt Wont Start !

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2007 4rt has beeb sitting since september, i went to view to buy and it wouldnt start, was started by the owner the night before by bump starting it. It will not start off the kickstart. Took plug out and it is sparking with good spark, and the plug was wet. The bike has not been started since is was parked up in september and was working as it should when parked up............any ideas what could be wrong or what to try . Cheers

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4RT's are designed to start with no throttle. This is because of the way the fuel injection works. The first kick is used to energize the system, then usually they start on the second kick. Check that the throttle cable is not pulled out at all. I had a problem once when my throttle cable had been pulled out from the twist throttle and the bike simply would not start. It was only out about 56 mm and looked fine until I popped the cap off the Domino throttle and could see that the cable was not fully seated.

There is a reset procedure for the injection. If my memory is correct: hold the throttle wide open. kick the starter through 2 times. Close the throttle and kick to start.

When it does start, DO NOT TOUCH the throttle until the radiator fan to turns on.

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Did you 'reset' the throttle? Is the first thing that springs to mind.

One or two slow kicks with the throttle wide open, than start it as normal with the throttle closed...

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4RT's are designed to start with no throttle. This is because of the way the fuel injection works. The first kick is used to energize the system, then usually they start on the second kick. Check that the throttle cable is not pulled out at all. I had a problem once when my throttle cable had been pulled out from the twist throttle and the bike simply would not start. It was only out about 56 mm and looked fine until I popped the cap off the Domino throttle and could see that the cable was not fully seated.

There is a reset procedure for the injection. If my memory is correct: hold the throttle wide open. kick the starter through 2 times. Close the throttle and kick to start.

When it does start, DO NOT TOUCH the throttle until the radiator fan to turns on.

Why not? I think there's something wrong with your bike if you have to wait so long to touch the throttle.

As the manual says: gently warm the engine up by blipping the throttle. Nothing wrong with that.

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Yep tried resetting throttle, but no joy, fresh petrol was used aswell, the throttle sounded like it was returning fully but never looked to see if cable was pulled at all

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Check the throttle cable is seated correctly as mentioned above. Also it will be a pig to start if the idle is set too low. Get it bump started again and make sure it has a steady tickover.

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Have you heard it run or are you taking the vendors word for it that it starts if you bump it.Check the valve clearances and clean the connector plugs on the injection and ignition systems, a tiny bit of water or corrosion in these can cause problems. Have you tried a brand new plug

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If the idle is set too low it will be very difficult to start . A new plug and turning the idle stop screw anti clockwise by half a turn (or so) to increase the idle may help.

/Carl

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DO NOT TOUCH the throttle until the radiator fan to turns on.

Why not? I think there's something wrong with your bike if you have to wait so long to touch the throttle.

As the manual says: gently warm the engine up by blipping the throttle. Nothing wrong with that.

Dang, I just typed up a detailed reply, clicked “Post” and it disappeared! I guess that’s a 5! Can I get a re-ride? LOL

Let me give you a little more background. I bought my 2005 4RT last year. After riding many bikes, cars, trucks and tractors for decades, I am accustomed to giving the throttle a little blip once the engine fires. A few extra RPM’s seem to help the engine wake up. So, that is what I did with the 4RT. Mind you not massive throttle just a little blip.

After some outings, the bike was getting harder to start and was running poorly. I changed the plug, gas and cleaned the air filter with no improvement. It got to the point of being almost unrideable for trials.

So, I read back on this forum about starting problems and found others recommending the “Don’t touch the throttle” technique. I started using that and the bike responded well and now runs perfectly. No changes to anything except my starting technique.

I do not fully understand why this works, I just know it does. Sort of like I know that if I lean my head inside on a turn I will dab. If I keep my head out, I will not.

I suspect the running has to do with calibration of the fuel injection (FI). Remember the 4RT has no battery to help the FI remember any calibration. The ’05 does not have a mappable throttle body so I think it calibrates at start up and holds that setting. What I suspect is, the FI must have a basic setting that will start the bike. Then it must check for rich / lean operation and adjust its own calibration. If the throttle is open at all, it creates a super lean condition that the FI then adjusts for. Then, once the engine warms up, it runs super rich.

So now, I simply unload the bike, fire it up and let it idle while I put my gear on. Then I shut it off, fill the fuel, restart and have a great day of falling down! LOL.

I use this “no throttle” technique whether the engine is hot or cold. In fact. to help me break that old habit of cracking the throttle, I do not even hold the right side grip when I kick it over. I happen to use bark busters (I don’t mean to start that debate here) and now simply put my right hand on the bark buster to avoid any temptation to give her a blip. Once the engine is warm for the day, I do not need to wait before riding off. She runs perfect all day.

I know it is a different engine but I recently bought a new 4 stroke string trimmer. The instructions also say “Do not touch the throttle when starting” “Allow the engine to warm up at idle for 1 to 2 minutes before accelerating.” When I follow this, it runs perfectly. When I try to rush the warm up, it runs poorly, popping and skipping and not speeding up cleanly. I think this is probably the result of requiring super lean running to meet emission control laws.

FYI I ride between 300 and 3000 feet (about 100 to 1000 meters) elevation: Temps from below freezing to 90 degrees F (about 30 degrees C, I think).

I love my 4RT. 2 kicks and she is idling. Meanwhile other riders are fiddling with chokes, hot starts and using up their energy kicking and kicking.

Cheers all! :beer:

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Thanks... :beer:

I understand and respect that your experience has led to that starting procedure.

But my '08 4RT runs fine, even when you blip the throttle while warming up.

I expect from a high tech fuel injection system that it runs without any tricks applied, given the fact that everything else is in working order (no clogged fuel or air filters, a good ignition spark, good compression etc.)

Just out of interest, have you ever checked/cleaned your fuel filters?

Edited by guys

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I once had a problem with a Honda Montesa 4RT 2005 that would not start.

This bike has not been started for a couples of months and have been stored in a cold and humid environment. After i had followed the basic test procedure for fault finding on this bike and found nothing wrong with the bike - i then decided to take a closer look on some of the electrical connectors.

The first connector i disconnected was for the charging rectifier and what i saw was not something i like to see on electrical connector pins. Three of the connector pins had some corrosion on them. I was well aware that it could be the problem i was trying to solve.

The next i did was to clean the connector pins with some cleanning spray and then smear some di-electric grease on them and then plug the connector on again.

To my big surprise - the bike started on first kick. With that experience on my mind i always remember to smear all my connectors with di-electric grease.

It is worth checking !!!

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Thanks... :beer:

I understand and respect that your experience has led to that starting procedure.

But my '08 4RT runs fine, even when you blip the throttle while warming up.

I expect from a high tech fuel injection system that it runs without any tricks applied, given the fact that everything else is in working order (no clogged fuel or air filters, a good ignition spark, good compression etc.)

Just out of interest, have you ever checked/cleaned your fuel filters?

I know there were changes to the FI between my '05 and your '08. And I think that once the engine is partially warm I could probably blip the throttle with no bad effects but I don't know if that means I should wait 5 seconds, 10 seconds, one minute, etc. So I simply follow what worked for other people and let it warm up on idle while I get my boots and protective gear on, check the tire pressures and such, and it runs perfectly.

I have not ever checked the fuel filters. I have no problems with fuel flow at full throttle but I take your advice and will check and clean or replace the fuel filters when I am back on the same side of the world as my bike. Currently on travel for work.

Edited by thats_a_five
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My thinking was that if it was electrical there wouldnt be a spark, but took the plug out and it was a good spark and plug was wet so again my thinking was fuel was getting through. So leads me to think that timing is the issue ......... It has to be said though i am a disaster with spanners and definetly not gifted with mechanical expertise

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