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Tx 240 engine


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put new condensor - used 12v from a nissan car - it looked the same.

I earthed the condenser to the coil and got all my wires going to the coil and soldered the whole bunch together.

I removed the flywheel and disconnected the old condenser isolated it and got all the wires that were connected to it and soldered the whole lot together.

I gapped and cleaned the points 

the old condenser was not bad and this helped the bike marginally. 

I can rule out the ignition now - the bike was supplied with a working ignition and it was. 

my carb is a phbh26PS 

I dont think Eurocarb lists this particular model to get the specs from. 

Standard Jetting for a phbh26 bs

40 Slide
X7 Needle
266AV Atomiser
110 Main jet
50 Idle jet
70 Choke jet
200 Float valve
9010.2 Float – 6.5 grams

My Carb is completely different I think the slide is stamped 110 or 90 or something 

wonder should i just get a working carb off a swm 280. trying to tune a carb that the maker does not list seems like a lot of faffing around. then again fitting an X7 needle might solve the problem

its the needle jet at fault the bike wont rev high but you could lug it about all day 

I am also confused where this main jet is - i thought there was usually 3 jets in a carb pilot jet needle jet and choke jet?

Edited by Kdtx240
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i am actually wrong

my main jet is 88

slide is 50

atomiser is av266 bn264 came originally. original needle is lost 

my carb is off a 240cc so 280 is much bigger and needs more fuel 

float jet is 200 float needle looks good and i put new white "floats" in

the bike could actually be lean bogging and creating a black plug as it never gets cleared out making it look like rich

I am going to go with an X7 needle and 110 main jet check float height and take it from there 

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  • 4 weeks later...

I had a Montesa 349 that I mounted the condenser on the frame under the tank to keep it cooler. On my SWM I used a timing box I made to set points. I have since switched the ignition to electronic (about 3 or 4 years ago). I bought the kit from MotoSWM, works awesome! I switched my carb to a OKO from MidAtlantic trials, that also works awesome! They do make a OKO kit for the 240 Rotax.

Edited by dozerash
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  • 4 weeks later...

Hi all

moved the bike to another shed and the float valve dropped out - had to buy another one of those before anything happened.

fitted the 110 jet slight improvement - adjusted the needle as far as it could go

plan is to fit 120 jet and see if it gets better.

if not then 125 or 130 jet.

I do think it is a fuelling issue that will be fixed by a bigger main jet and have one on order. 

funny I was recommended an electronic ignition  but they are expensive, luckily my points is good and I have a backup stator/ignition.  - I fitted one to a cr250 because I had no other choice- the cdi's die and replacements are rare as hens teeth -  was not impressed with the fit of the pickup to the flywheel despite a lot of tinkering, I cant remember the clearance I got but it was a very small feeler gauge. it did start. I am bringing this bike back home to finish and am quite excited I done all the linkage bushes on this one and it should be very tight and the engine is good. 

good to talk to you all again. 👍


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