Just a quick question?

When I ride on the on flat ground I hear a knocking noise in the cylinder, is this normal with all bikes or just some bikes. My bike is a 2001 Montesa.

Gavin

Is it just on flat ground? It's probably pinking but without more info we'll struggle to help. It's usually easy to check pinking by giving it some sharp bursts of power. Pinking usually shows up just as you let off as a sharp knock.

Yeah its only flat gound. I thought there might be a problem but people it happens to all bikes on thw road (trials).

Gavin

I've never heard of a bike that knocks of flat ground and is fine without more investigation. As I said it could just be a little pinking and that would be OK as long as its not to bad. Pinking does create forces on the top end that will eventually damage it if left unchecked.

I would suggest you get someone in the know locally to listen to it and advise you.

As bigfoot says, if it is pinking (my 99 mont did this too), it will knock just as you shut off from a blast of throttle. I found that using better fuel helped (optimax or good old 4 star, if you can get it.)

As bigfoot says, if it is pinking (my 99 mont did this too), it will knock just as you shut off from a blast of throttle. I found that using better fuel helped (optimax  or good old 4 star, if you can get it.)

my montesa does the same (2002) model and i use optimax all the time mixed @80:1 just wondering if anyones tryed any of the octane boosters that are available

I'm using optimax with STP octane booster in my 300 Fantic(which also knocks when it's hot).This combination definitely reduces the detonation.

I got the STP from halfords(it comes in an orange bottle).It also seems to work well enough with Super plus unleaded.

Bear in mind my bike would have been designed to run on 98 octane leaded petrol so you modern petrol heads should get equally good results.

Cheers,

I'm using optimax with STP octane booster in my 300 Fantic(which also knocks when it's hot).This combination definitely reduces the detonation.

I got the STP from halfords(it comes in an orange bottle).It also seems to work well enough with Super plus unleaded.

Bear in mind my bike would have been designed to run on 98 octane leaded petrol so you modern petrol heads should get equally good results.

Cheers,

what is the ratio that you use ie 1.5%,2% also do i need to add xtra oil to keep the 80:1 mix correct

I'm using optimax with STP octane booster in my 300 Fantic(which also knocks when it's hot).This combination definitely reduces the detonation.

I got the STP from halfords(it comes in an orange bottle).It also seems to work well enough with Super plus unleaded.

Bear in mind my bike would have been designed to run on 98 octane leaded petrol so you modern petrol heads should get equally good results.

Cheers,

Don't listen to Spencey, he knows **** ALL !!

I've always felt that the Monty knocking is definitely octane related, others reckon its jetting - the only cures I have found are either 4 star (99.7 RON) or elf GPM-2T (100 RON). As the elf fuel is very expensive, dig out a localish 4 star pump.

You can find your nearest 4-star via:

http://www.leadedpetrol.co.uk/list.htm