oz thumper

At last somebody is talking about something other than the bloody colour!! I must live in a different world, when new models were coming out we used to look what was lighter, more powerful, better handling and all the innovations that we thought would save a couple of marks during a trial. Now we have no discussion on the latest cam profile, just the colour of the RIMS ! Its all bloody great rocks here anyway that rip paint and anodising off them, why would you want to paint them? Is looking good a modern substitute for being able to ride ???

I don't normally reply to a topic that I don't have personal experience of, however offer the following thoughts. My 05 always ran rich and would foul plugs regularly, after checking all readings we eventually swapped all components systematically with a mates bike (Painfull process). In my case nothing changed until we swapped the throttle body and then the bike was completely different. I obtained a new throttle body and that bike has been fine ever since. I reckon in this case though I think you have two different things going on running rich should not give significant backfiring on the over run, in fact it is normally a sign of a weak mixture or an air leak. On carburreted bikes at the shop backfiring through the exhaust on the over run was always traced either to an air leak in the exhaust or a burnt exhaust valve (as others have noted). Now the bit I am not sure of is with an injected motor is it possible for a faulty injector to dribble rather than cut off clean after injection (this is common with diesel motors) I would guess a small amount of fuel getting into the cylinder could produce ignition when the exhaust valve was open? Personally would still see the most likely cause of backfiring to be an airleak and probably at the barrel to pipe joint, have you cleaned out that area and put new seal in?? Good luck

In an aluminium case you will not need to drill out the stripped hole, should tap out directly as the helicoil tap is not much larger than the root diameter of the old thread. If you clean up the drain plug and check it will screw into the helicoil before it is fitted you have the right size. However the cost of the helicoil kit, including tap and insert tool will be dearer than getting somebody to do it for you provided they have that size available. Good luck

I agree it would require hundereds of hours of running before wear became an issue, i.e electrode erosion. My plugs were simply very sooty and presumably shorting out on the insulator.

Like many others I have had a number of plugs fail. You know the usual missing and banging,stalling and refusing to rev out. I had tried ringing its neck down the road, contact cleaner etc without ever getting a plug to run ok once it had failed. In the shed the other night looking at a pile of seven failed plugs I thought I would try the oxy acetylene torch on one. Used a small gas welding nozzle with a very oxygen rich flame and concentrating on the central electrode and insulator (very carefully). The insulator wound up white and clean in a few seconds, thread clean up an in the bike and found it runs perfectly. Did all of the others the same and tested each one with the same result. Now have a box of spare plugs!

Why didnt i think of that LOL Nice one cheers Jaybee Because if you could undo them with a screwdriver you wouldn't have stuffed the hex head in the first place. At least socket headed bolts are easy to center the drill when drilling out the stud.

I guess anything is possible however I would suggest mostly likely is a fouled plug. If they guy gave it a bit of an handfull before it was warmed up, mine typically behaves as you have described when the plug dies. Try a new one first before you investigate further.

Doesn't sound correct to me, when I checked my valves from new it was on the T mark and the clearances were correct. The T mark is TDC and this would be normal position for most motors to check valves and both of my bikes have been set at the book clearance when on the T mark and have always run top notch (whereas the Utah bulletin says bike will run badly if at all!!). Reckon it would be worth asking Sandifords for clarification. What has happened to the ferret flasher?? he always had all the tech answers. I have also always set my oil level as in the manual with the dip stick unscewed and never had any oil dramas at all since 05.

The manual says without screwing in the dipstick, but I recall that ferret flasher suggested that the full mark when screwed in was what he used. In regard to breather venting to atmosphere, I reckon there is a big problem with this in allowing contamination into the crankcase. Crankcase pressure is not positive all the time and the idea of terminating the breather in the airbox on the engine side is that only filtered air is drawn back into the motor. Some other motors use a pcv valve to prevent back flow into the motor others use a breather filter most does as Montesa does in venting to the filtered side of the airbox. If you think about it the airbox has a small (if the filter is clean!) negative pressure on the engine side and therefore probably breathes slightly better than to atmosphere. If you do choose to vent to atmosphere don't forget to plug the entry into the airbox otherwise you will draw crap into the motor at both ends!

Hi Mike, I told you it wouldn't work properly on your TLR !

They originally advertised that 500 would be produced for that year. I have #156 from memory that arrived December 05

Remember earlier post where I had the same problem after dropping the bike. The issue in my case was the throttle cable had pulled back in the rubber sleeve and was holding the throttle well open. This shuts down the whole system, no spark and no injection either. When I finally noticed it, pushed the cable back in and it started first kick as usual. Other thing to be aware of is, if the cable adjuster is screwed to far in on the throttle body it can jam on the throttle quadrant and hold the butterly open with the same result. There was a Montesa alert on this specifying how far out the cable adjuster must be set. Hope this helps

I have had a few plugs die of the last couple of years and they cannot be resurected by cleaning. Just about every time has been after starting when I have not warmed the motor thouroughly and given it a big squirt over a step or similar. occasionally a full bore blast down a track will clear it, but sometimes it just fluffs and bangs and will not clear. Never had a plug fail when warm or during a trial.

What rear sprocket are you running? most people find the standard sprocket a bit high geared, 43 or 44t seem to be the usual fittment. Secondly technique does make a diffence, with the engine braking available from the motor the bike slows more rapidly than a 2T, I have found that stalling can occur if you snap shut after a step or similar.It takes a little time to get used to rolling off the throttle later and a bit more gently. I run my bike at a measured 1650rpm and don't have any problem, generally if it is starting all right when hot, then tickover is fast enough. We have two riders over in the West who have changed from 315 Monts to 4RT and have had no problems at all adapting. Good luck

HI Guys, I have managed to avoid breaking one but reckon the main problem is the way the main alloy lever sticks outside the clutch cover, so even though the end pivots you still hit the end of the lever. Do any of the aftermarket ones tuck in behind the clutch cover? Not only would it be less vulnerable but would suit my size 8 boots!!

Some of the machines over here have completed two very full seasons of trials and practice without any issues at all with the EFI. Despite the concerns EFI is really very commonplace and has been operating reliably on a variety of petrol motors for some years now. In time there will almost certainly be some failures however the smooth trouble free and programmable power available in between time is worth every dollar.

To answer the original question, Ferret Flasher is spot on. We have a couple of early 05 models that have been campaigned for two very full seasons (generally a lot hotter and dustier than Europe)with no issues.They have required no top end rebuild and compression and leak down tests inicate that they are well within specification. There is no detectable change in engine noise or perfomance compared to a couple of new machines in the club. Nobody over here has shared the negative experiences of the alcoholic. Without entering into the best bike debate, all owners over West are extremely happy with the 4RT and without exception have all enjoyed improved results since aquiring them. Good luck

Sounds most like restricted fuel flow, hence rise in revs as it leans off before stopping. Two main options, no air flow into the tank or restriction if fuel flow from tank. Former, take off the tank filler cap and see if that cures the probelem. If it doesn't then must be fuel restriction. All the usual checks, fuel tap restriction,fuel pipe damage or blocked,needle valve into carb and finally check breather into carb float bowl. Good luck

Impressive, but she is riding one of those fourstrokes, not one of those real bikes that you all keep writing about!!!

It alters the ECU map according to the notes delivered with my bike. I understand to do with the requirements to be road legal in some countries

First check after six meetings found one tight exhaust tappet, all have remained constant since then.(About 30 trials) They can be difficult to check if you do not have a slim set of gauges or those with an angled tip.

Thanks for the info guys, can you confirm its 75 SAE,that is really heavy compared to the recommended HTX 740 (that is about the same at auto transmission oil). Doesn't the heavier oil cause more clutch drag?

Might be a few kilo's lighter and all blinged up, but if you have your feet down as in the photo, whats the point!

Maybe save someone some embarasment. Having had fourstrokes for a good number of years and two 4RT's I still got caught out today after dropping the bike in a section. Bike fell amongst the rocks and was revving fairly high when I hit the kill button. Picked up the bike as many times before and but for the first time ever it didn't fire up. Pushed out of the section and kicked until I was stuffed, fetched new plug still no go, found I had no spark so disconnected kill switch and all usual things but no go. Got home checked all wiring etc including diagnostic tool, but no change. Finally found (after a tip off from our friendly importer. Tarp) the throttle cable had pulled out of the twist grip housing and slid up the rubber ferrule and was holding the throttle about half open. Pushed it back into place and Bingo! I was aware that heaps of throttle was a disaster for starting but didn't realise it killed the ignition and injection circuit when to far open. Cheap repair but wish I had found it at the trial !!!

Thanks for warning, not something I would have been looking for when working on the bike.