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DT175 start up after rebuild


Par62003
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Well I' m scared, the rebuild is finished after holing the piston last year, whilst its been off the road I've redone the paint work, painted the frame and loads of other little jobs, but I can't avoid it no longer I'm going to have to try and start it sooner or later !

A couple of things have me concerned though, how do I get oil from the oil tank to the carb, I.e. how do I bleed the pump ? I've got clear lines so I can see if oil is making its way up but at the moment theyre bone dry and there's no way I'm going to start it with no oil getting in there, would running premix for the first start up be OK ?

I know these bikes are CDI but how do I know the timing is right before start up ? I've put the stator back on in the position it came off with the lines lining up, is that it ?

I'm so so scared of holing another piston that I need to get these things right, thanks for any help, cheers.

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B8es is the correct plug, right?

What oil is recommend for the gearbox.

I have a Haynes manual but is more geared toward the earlier points bikes ?

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No problem, taking out the bleed screw on the pump and let gravity pull the oil through to prime the pump.

The engine would be ok to start with the assembly oil. Then prime with the engine running. Different people use either, both work.

As to ignition, the lines you mention. Are they marks you made during dissasembly. If so you will be fine.

Dts are holing pistons because of modern fuel. The ethanol in the fuel releases oxygen during combustion, (among other negatives) that leans out the mixture. I sufferd the same failure.

The safest method for now is stay 1000 rpm under the red line unless its a short blip. I dont know of any other method of allowing for it as yet. Save for using ethanol free fuel.

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No problem, taking out the bleed screw on the pump and let gravity pull the oil through to prime the pump.

The engine would be ok to start with the assembly oil. Then prime with the engine running. Different people use either, both work.

As to ignition, the lines you mention. Are they marks you made during dissasembly. If so you will be fine.

Dts are holing pistons because of modern fuel. The ethanol in the fuel releases oxygen during combustion, (among other negatives) that leans out the mixture. I sufferd the same failure.

The safest method for now is stay 1000 rpm under the red line unless its a short blip. I dont know of any other method of allowing for it as yet. Save for using ethanol free fuel.

Thanks for your help, oil ? Spark plug?
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Motorcycle engine oil will be fine in the gearbox?? Yes that plug works as well as any other with a resisted plug (4k) cap. On a new motor you might want a couple of spares. Test them on something first if you can or use the plug that was last in the bike.

Too often I have been looking for problems because of a dud new plug.

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I've got four newish b8es plugs and non of them work ! Tried them in other bikes and nothing ? Are they just poorly made these days ?

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Probably copy"s,,, canna see 4 failing tho.. :eusa_think: did you fire it up then,,,shudda pre-mixed a little fuel . i hold the pump wide open by pulling the pump cable [ while on idle] till i see oil up to carb...

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No, not fired it up yet. Going to get a new plug tomorrow and fill with gearbox oil (hopefully no leaks), and add a bit of 2 stroke oil into the petrol to ease my mind a little, then give it a kick ! Still not sure how to set the timing tho' ??!

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Do you have a manual ? setting are there, to set correctly , you need a strobe light . and run at 4000 rpm, to see marks line up.

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Did you not set it when you built the engine up. It is set staticly then checked with the strobe.

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Tried to start it, no luck, occasional small backfire and tiny tiny fire up for about 1 second but that's it. Got a spark, got compression, blocked carb?

I have an inline clear fuel filter fitted and strangely despite fuel flowing freely from the tap, when I connect the pipe no fuel flows down into the filter until I disconnect the other end from the carb ?

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It wont if the valve in the carb is shut, did you set the float heigh, if you did how and what to?

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Overflow isn't blocked because when I leave it on the side stand with the fuel tap on, petrol pours out ?

As an update, a mate and I have just bump started it down the road ! After about 30 yards it coughed spluttered and started !

Gently blipped the throttle and left it ticking over for 5 mins, turned it off, kicked it again started straight away, yay !

No wait, left it half an hour, tried to start it again, nothing, zilch, damn.

Don't you love these simple 2 strokes ?

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I would say you havent set the carb up right and/or your choke circut is faulty.

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Try and put a tea spoon of fuel right into the cylinder quickly replace the spark plug and see if it starts.

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It definately needs a new plug, it's an old denso that's in there at the moment, I've got 3 b8es plugs and non will spark?

Just been back out and after a dozen or so kicks wahay it started, nice tickover and crisp blips, it's a bugger to start but it does start, phew.

Thanks for the advice.

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