Further problems with my Derbi senda.

[TomC]

Ok so i was having problems starting my bike, I got a mate to buy me some spark plugs while he was in town, he brought them back i opened them and installed one and then relised the end, where the wire attaches to was slightly different (although it would fit) it was fatter and wasnt such a tight fit. so i tryed it anyway it started ok, so i went for a drive. But when installing the plug i had managed to knock something off (pictured below) which i am guessing is a sensor of some sort? (i have managed to break the wire off the top ) It was attached just towards the front of the bike to the spark plug on top of the engine. First question, what is it?
I fixed it on again as best i could as and i needed to use my bike again this morning, when i was riding though the engine just died on me. After a while though it started and ran for about 100 metres and died again, seemed like it was just struggling for power and just cut out. could my spark plug be the cause of this? anything else anyone can come up with?

[kasandrich]

Would love to help, but that picture is about as much use as a chocolate tea pot.
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Richard

CBR1000FM

[TomC]

lol point taken, i shall take another

[TomC]

Theres new pic.

[kasandrich]

Sorry I can't identify it positively, but the only thing I can think it could be is a temperature sensor??

How did you manage to break the we off
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Richard

CBR1000FM

[TomC]

yer that is what i thought it would be. Well it looks as though it had been broken off previously and been glued back in place, ive developed quite a shopping list in the past week..

[Keith]

Thats the thermostat I believe, if it fits into the cylinder head, behind the spark plug.

They arent that expensive and you'll be able to get one from Bike Spares if you cant fit that back on.


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Aprilia RSV Mille R Edwards Replica - Aprilia RS250 - Suzuki GSXR600 Supersport Race Bike

[cagiva gezzer]

The new spare plug doesn't fit as you need to remove the nipple from the end of the plug. Use a pair of pliers to remove it.

Its not the thermostat. Its the (i think the term in the badly translated manual is) temperature sender. Not sure about the newer bikes, but on the older ones it was just a red light on the dash. If the newer ones have a temp dial, the needle should be on cold and if you attach the end of the broken wire to a earth, it wil read VERY hot, or the temp light comes on.

As said, it attaches onto the head. Can't remember which end the mounting point is, but its the opposite end to the coolant hose.
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"because one stroke isnt enough and four strokes waste two"

[TomC]

Thanks geezer, so do you think that this could be the cause of it running and then stopping after a short distance?? or could it be the spark plug or something else?
Also, the temperature sensor had a spring underneath it, which fell out when i was riding, i take it this is for the purpose to conduct? in which case it could be replaced with a metal object?

[cagiva gezzer]

The cutting out could be due to the fact that the spark plug cap isn't attached to the spark plug fully. This can be solved by removing the nipple from the end of the spark plug.

As for the temperature sender. Haven't played with a derbi engine for years, so i'm not 100% about the complete details. From what i remember, that connector you have should split into two parts?

Best get on the phone and order a new one. It can't be more than a few $$.
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"because one stroke isnt enough and four strokes waste two"

[TomC]

Thanks cagiva geezer, been really helpful, well i have decided if i can get the money to completely sort the bike out (engine rebuild and all) should be alrite then so i have a nice list of things that need ordering.
Cheers mate

[cagiva gezzer]

Ooo, engine rebuilds!

I like them. The derbi was the first engine i tackled on my own. Easy little engines, seem so cute compared to 125's and 250's.

You've prob worked this out, but you get a lot better deal with ordering parts directly from Derbi Uk (derby area) as they know their stuff and it cuts out the middle man.

(my only advice with derbi engines is - dont press the crank seals back in tooo far (although it applies to most) , as the inner lip has a party with the inner race of the main bearing! )

Good luck, they're fun little bikes, but don't go spending TOOOO much $$$ as you won't get it back and the next person who buys it will just trash it anyway. Plus, save your money for performance pipes for a 125!
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"because one stroke isnt enough and four strokes waste two"

[cagiva gezzer]

This might be useful.
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"because one stroke isnt enough and four strokes waste two"

[TomC]

Thanks that is really useful

[scottc1088]

that is the temp sensor btw
and before you spend all the money on a rebuild, check the rubber hasnt split that attaches the carb to the engine as this has happened to me before
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2000 Derbi Senda R, Malossi 80cc, evolution n.g. full circle race crankshaft,26mm carb,Malossi mhr exhaust,TNT filter,Hebo reedblock + carbon reeds,Alien front light,Kundo 330mm rear shock,13-53
Breaking 2000 senda r

[TomC]

Thanks, not sure if any of one will know this but..
The temperature sensor had a spring inbetween the plastic body and the end of the sensor and the large metal nut that attaches to the engine. What was the purpose of this spring?

[scottc1088]

iv got no idea m8 but id also like to know as i noticed it on mine aswell lol
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2000 Derbi Senda R, Malossi 80cc, evolution n.g. full circle race crankshaft,26mm carb,Malossi mhr exhaust,TNT filter,Hebo reedblock + carbon reeds,Alien front light,Kundo 330mm rear shock,13-53
Breaking 2000 senda r

[TomC]

well i ask because i have happened to loose it , if it is just for the purpose of fitting the end in tightly (which it wouldnt do a very good job anyway) then its no need to worry as i plan on gluing it together anyway, but if it is to conduct, which i cant really see? then it can be replaced with something similar.... hmmm

[scottc1088]

lol, mine isnt connected up cos it melted when i seized my engine
iv only got it in to seal the hole
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2000 Derbi Senda R, Malossi 80cc, evolution n.g. full circle race crankshaft,26mm carb,Malossi mhr exhaust,TNT filter,Hebo reedblock + carbon reeds,Alien front light,Kundo 330mm rear shock,13-53
Breaking 2000 senda r

[TomC]

Well i have managed to rip the wire out of the end and loose the spring

[yambabe]

Hint from He-Who-Knows-About-These-Things:

Go to a scrapyard, look for a Fiat, any Fiat that's fuel injected. Take the plug off the cold-start temperature sensor on the RHS of the engine. Cut the wires off leaving yourself abour 6" of wire to connect to your wiring. (Use crimp connectors). That should go straight on (but take your part just to compare).

Apparently he does this all the time for the ones they sell/fix/service in the shop.
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Sod falling in love, I wanna fall in chocolate.