Hi there. can anyone help me, my 4rt bogs when you crack the thottle open and it will stall if the throttle is is kept open. but if you back it off 3-4 mm it will rev out as normal. the bike is a 06 repsol. I have tried other maps, but no joy. other than that its a good one. Thanks for any info.

Hi there

I've had a somewhat similar problem with a Honda Montesa 4RT (2005) - but not at such high revs as you describe. Since I had no tachometer on the bike, it's hard to say but I would think the throttle was opened 3/4. When I turned the throttle back to 1/2 opened the engine went back to normal. I went through the electrical on the bike and found nothing abnormal.

My conclusion was that there might be a mechanical fault on the engine and

after it had a new crankshaft - I wondered if it could be the camshaft setting that was incorrect.

To my great surprise, camshaft setting was wrong with a tooth and after the camshaft setting had been set correctly again, it could take a full gas again as normal.

I do not know if it is of any help to you Fatchef.

Greetings

Honda_freak

Edited June 19, 201214 yr by honda_freak

Thanks for the reply. will check the camshaft timing. fingers crossed.

Hi did you find out what was wrong with the 4rt,I have a 05 4rt and when it is gave full throttle won't rev it like back fires,let the throttle off slightly and it will rev ok,I have change spark plug,cleaned the tea bag filter in tank but It has made no difference,yours sounds like it has the same problem,thanks Brian

Hello fellas,

I don't have a 4rt but I've seen a couple of poorly ones which were fixed quite cheaply, firstly the original post, won't rev out quickly?;

Fuel pressure problem= blocked filter in the pump assy'. Twer cleaned up and problem disappeared.

Secondly the pop, misfire post?;

Air leak=the exhaust was loose at the manifold. Twer tightened up and voila...sorted

I hope these fixes are relevant to your situation?

Wayne

Edit, Brian you're right, I think the filter in the pump assy that I'm waffling about is called the 'tea-bag filter' ?

Edited January 30, 201313 yr by ham2

I did all the above on my mates 05 4rt, the tank filter was blocked, and there was a split air pipe, but even with these fixed it was still doing the fault you described, In the end a second hand throttle body sorted it off eBay,