2018 Montesa 4rt no start

[Cookiemonster]

Thanks, wont worry as you both say but next time I change the coolant I’ll try the ice stuff

[The_Drew]

3 hours ago, Cookiemonster said:

Thanks, wont worry as you both say but next time I change the coolant I’ll try the ice stuff

I wouldn't waste the time & Money on Engine Ice unless the bike is actually overheating.   Nothing wrong with the fan being on.

If you do switch to a Propylene Glycol coolant(such as engine ice); you will need to thoroughly flush the entire cooling system first.

[jonnyc21]

6 hours ago, The_Drew said:

I wouldn't waste the time & Money on Engine Ice unless the bike is actually overheating.   Nothing wrong with the fan being on.

If you do switch to a Propylene Glycol coolant(such as engine ice); you will need to thoroughly flush the entire cooling system first.

True, he would need a full flush if switching to engine ice. 

As for not needed, I agree it isn't needed, but I prefer having my fan run less myself and just switched it to ice because it was time to flush the system anyway and so took the opportunity to do so at the same time.  Working well for me and I will keep using it myself. 

[lineaway]

On 4/3/2023 at 5:21 AM, Cookiemonster said:

Bikes starting as it should now on 2nd kick or sometimes 1st

Tacho reads ~ 1,450 rpm on start up then steadily creeps up to ~ 1,900 rpm before fan kicks in then drops to a steady 1,850 rpm

is that how it works for anyone else?

i know 4 strokes run hot & 4rt run at a high rpm but the fan is on almost constantly 

read before this is quite normal is this something I should be looking at?

thanks

 Mine starts about 1750 and I let it idle till I see several over 2000. It pops over 2100 with the fan on. I do this every time I restart. Mainly after I walk a section. My bike ran like crap Sunday at the start of the event. I turned around before I got on the loop, parked it. Reset the ECU and did my usual start up. Got to section one and took my only point of the day. It ran perfect after that.

[Cookiemonster]

Thanks lineaway 

ill see how I get on with the current set up & leave it if it continues to be reliable or up the rpm slightly if not

all part of getting to know the bike but still feels a little odd after 15 months of ownership without having to change anything

[lineaway]

I bought my bike in July of 2021. I never had a problem till May of 2022 when it stalled in a section and ran like crap on the loop.It was a very hot day though. It was not till about October I finally put the tach on. Usually runs great 99.9% of the time. I just love it at my age. Solid as a rock.

[Cookiemonster]

Done about 8 hours practice over the last 2 Sunday’s & the bikes running great 

generally riding for about an hour then leaving for about 20 minutes before riding again & bike starts 1st kick with perhaps the last ride of the day when I have to do the reset thing to get it started

this similar to what others experience?

then drive home for say 30 minutes & it starts 1st time before I clean it

thanks

 

[jonnyc21]

How often I have to do the reset varies on a few things but I usually have to do it at least once per ride.  Most commonly because I stalled it and it didn't like that. 

If it gets any worse maybe give it an extra 50-100 RPM increase to see if that helps?  All bikes have there individual quirks so that may or may not help but might be worth a try if it is bothering you. 

[Cookiemonster]

Thanks

[82911sc]

Spark plug cap ?

 

[lemur]

I don't even need to read the thread to know that if a 4RT gets hard to start or outright fails for no obvious reason, it needs a valve adjustment.  Not a check or inspection, but a very careful and accurate reset of the valve clearances. 

 

[lemur]

Montesa having fuel injection and no battery makes it imperative that the engine completes one+ rotation at idle speed for it to start running.  That's all you really need to do to start it, get the engine spinning and producing enough electricity to make things work.  

Step one do not touch the throttle when you kick it, that messes up the fuel injection.

Don't jab at the kickstarter like a 2-stroke, kick it like you are trying to spin the engine up to idle speed only, nice steady speed.  It's going to want to be in neutral too.  If the engine is parked in 10 below freezing temperatures the oil will be too thick to allow it to spin up fast enough, they are that sensitive to anything that will resist the crank spinning freely. 

Here's the critical part - there is a decompressor on the camshaft that needs to do its thing on that first kick over, or the crank won't spin over fast enough to catch that vital second engine cycle which equals a running engine.  That decompressor is super tiny to say the least and is very dependant on the valve clearance setting being on spec or it will never activate.

I've had 5 Montesa 4RT's since 2005 and owned 3 of them all at the same time, when one failed to start I swapped everything assembly imaginable from one machine to the other with no joy.   I finally adjusted the valve clearance even though the compression readings were not terrible and bang, first kick starting engine from then on and ever after.  All 5 my  Montesa 4RT's have required the same service after several years of operation. For that matter every Honda engine I've ever owned has needed a valve clearance adjustment after several years operation, generators & lawn equipment included.

Difficult to adjust the valve clearances without dropping the engine from the frame on the 4RT at least slightly but the screw adjusters make it possible to set the clearances very accurately, way better than bucket and shims.  The square screw head is the same size as a Robertson (red) screw, you can improvise a tool to hold the valve adjuster in place while you tighten the lock nut, by simply putting a Robertson screw into the end of a short wood stick, you don't need to buy a special tool.

Have a micrometer handy so you can check the size and 'feel' of your feeler gauges when the clearance is correct and your results will be much better.

 

Edited July 3, 2023 by lemur
typo

[lineaway]

Usually I start with the easiest things when finding a solution to a new occurance on any non starting machinery. Not jumping into something  towards the end of possibilities. 

 As i typed this my sons kick starter stuck to his foot peg. I handed him a grinder and fixed in 30 seconds.

[lemur]

fwiw 4RT came with 2 different length kickstart levers over the years, the one pictured above is the longer one that comes on a 300RR

I found the long actually don't jam up as badly or wear out your right boot like the shorter one does.  Little easier to kick.

[lineaway]

Trouble with the short one, it's like a knife blade. Had one make a friend an extra drain. Halfway between his anus and scrotum. New Year, first trials first section. What bad luck!