HI, its a bit of shame this is my first post as it could be bad news.... lol. Anyway i fitted a new throttle cable to my 2002 315r, only to find out that when i started it it was too short. The bike instantly went to full revs and must have stayed there for between 2 - 3 minutes before the petrol ran out of the carb. I had the tank on so i couldnt get the spark plug cap off. There were other things i could have done, i know, but i was paniking!! Anyway, nothing went bang and cyclinder gaskets are still intact, just a bit of steam from the coolant reservior under the tank. I put the old throttle cable back on to make sure the bike would still run, which it does thankfully. I took it for a blast up the street and it seems ok but i still have doubts until I can test it on some sections which i know how much power i need to use, if you know what i mean.

The bike isnt normally ridden with full revs, so it was probably a good clean out, the plug looked damn clean anyway!

What i need to know is could this have caused damage i dont know about and what should i look out for? And if this has happened to you please make me feel better and tell me what happened to your engines....

Right, for future reference if you have a 'rev-up', sometimes the kill switch doesn't work if the revs get too high and the carbon in the combustion chamber starts to glow red hot, it effectively takes over and the motor 'diesels'. Best thing to do is to cover the exhaust pipe outlet either with a gloved hand or a piece of cloth (as the gasses get very hot very quickly and can burn the bare skin!) to effectively 'strangle' the motor. Shutting the petrol tap to the off position isn't ideal on a two-stroke as it starves the motor of lubricant being petrol mix.

It is probably the most un-nerving thing to happen to a novice rider a cold 'rev-up' or throttle jam.

When I fit a new throttle cable I carefully check all is OK by taking off the carb rubber boot to the air filter and visibly checking to see that the throttle slide is moving up and down to the bottom of it's stroke and by testing by moving the handle bars from lock to lock and if the slide rises at all, then this indicates snagging or too short a cable!

On the 315R Montesa it is important to route the throttle cable the way it shows in the manual!

Here's a tip, I also check a bike with a normal carb (not a Montesa 4rt with throttle body, as it has a butterfly) before starting, that the slide is returning to the bottom by placing my index finger on the tick-over adjustment screw and flicking the twistgrip, you can usually feel the slide hitting the throttle stop screw!

Also if the motor didn't misfire before stopping, it should be OK, it has not been starved of fuel and it seems to be running OK now. You may just have got away with it, keep checking your coolant level for the next few outings, just as a precaution.

Hope this helps.

Big John

It helps to flip the choke on and it acts as a rev limiter while you scramble to get it shut down...

Cheers John for the long reply, i checked the coolant level as soon as it had cooled down, like a few hours later! Obviously it had lost some coolant in being turned to steam but its still nearly full, i'll keep an eye on it on the next few outings to make sure its not losing any. Fingers crossed the Honda engine has survived.... What damage could an incident like this cause? Seizure? new piston & rings? - any damage deeper into the engine?

Don't worry,did it a few times on my 315 and it never did any harm...just remember to check for the slide ''fot !'' noise like big john said.

Yeah cheers, i'll never ever start my bike before hearing that niose again!

The 315R motor is one tough sob.

When I first got mine that happened a couple times when I wasn't used to routing the throttle cable, many hours later it's still sounding sweet as a nut.

2-3 minutes should not cause it to steam up. it musta been running longer.

make sure the throttle cable is not fouled by the petcock when you install the tank

good luck

ps never put the bike in gear in this situation

Yo jmz my bruthaaaaaa! thought that bike was gonna blow lol some good replys though like the last one ps dont ever put the bike into gear lol straight through the garage door whoop whoop!

HI, its a bit of shame this is my first post as it could be bad news.... lol. Anyway i fitted a new throttle cable to my 2002 315r, only to find out that when i started it it was too short. The bike instantly went to full revs and must have stayed there for between 2 - 3 minutes before the petrol ran out of the carb. I had the tank on so i couldnt get the spark plug cap off. There were other things i could have done, i know, but i was paniking!! Anyway, nothing went bang and cyclinder gaskets are still intact, just a bit of steam from the coolant reservior under the tank. I put the old throttle cable back on to make sure the bike would still run, which it does thankfully. I took it for a blast up the street and it seems ok but i still have doubts until I can test it on some sections which i know how much power i need to use, if you know what i mean.

The bike isnt normally ridden with full revs, so it was probably a good clean out, the plug looked damn clean anyway!

What i need to know is could this have caused damage i dont know about and what should i look out for? And if this has happened to you please make me feel better and tell me what happened to your engines....

I think everybody does this once !

Thanks for all the replies everybody. Anyway, i took it out to my local practice spot and noticed it got mega hot very quickly and the fan was on within about 10 mins of casual riding. Now ive riden the bike all day in the past like this and never even noticed the fan come on. How long does it normally take for the fan to come on? Any explination to why it got so hot so quickly? Coolant level was pretty high so i dont think that has anything to do with it. I'll fill it right up 2moro anyway, any particular coolant or are they all the same?

This might be obvious for most of you, but I will say it anyway. Every single time you fall with the bike, you should always check that the throttle is moving like it should. Ive seen numerous times, riders falling and starting the engine just to realise that the cable has gone of from the rubber cover or handlebar is stuck, causing the motor to rev up like hell. I use handlebar nuts and sometimes when it hits a tree or rock, it tightens up agains throttlebar restricting it to move properly. When you remember this from the beginning, you will remember it for the rest of your life.