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Discussion Starter #1
Can anyone tell me what the correct sparkplug and gap is for a 150cc engine. Also the contact breaker Gap and timing setup.
The bike is running but struggles a bit in 4th gear and is very difficult to restart when hot.
regards Rae:brutale:
 

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Hi Rae.

Points gap for your 150 is 0.4mm

Spark plug is listed as a NGK B7HS with a gap of 0.6-0.7 mm, but please double check for length just to be sure.

Timing is 19-20 degrees BTDC Static with an automatic advance of 18-19 degrees. Therefore a total advance of 37-39 degrees.

These figures are for the standard 150 Sella, which i think yours is.

If you have the GT version then it's 11 degrees static, 25 degrees auto advance, giving a total of 36 degrees.

Check your advance springs as these have been known to give your symptoms.



All the best.

Dorian

ps; Did you get the dating letter OK?
 

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Wow Dorian that's a fantastic response.

Care to repeat the info for a TR 125? Keen to keep The Flying Ant in top form.

Cheers.
 

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Discussion Starter #4
Thank you Dorian

Dorian, thank's for this vital nformation on timing. I must also thank you and the MV owners club for the help in obtaining the information required to sort out this bikes paperwork. It has worked out fine and the bike is now on the road.
regards Rae:f4:
 

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Hi Guys.

No worries Rae, glad to be of help.

Jon, here is the same info for your 'Flying Ant'. You need to keep hold of all those 5.6 HP that the Count put in your engine back in 1955:).

Spark Plug NGK B8HS with a gap of 0.6-0.7mm

Points Gap 0.4mm

Ignition timing 20 degrees BTDC static, with an automatic advance of 18 degrees. Therefore giving a total advance of 38 degrees.

With these old MV's it's a very good idea to rig up some sort of timing disc so you can strobe check the timing/advance. It's not that it needs to be super accurate, but it will give you a good idea as to how the advance is working after all these years.

Have fun.

Dorian.
 

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Discussion Starter #7 (Edited)
rough riding!!!

I have set up the timing and purchased the correct plug. All gaps and settings are now correct and the static timing of 19-20 degrees has done wonders for the starting. It will now start easily when hot. I took it out of a test ride but the bike keeps surgeing so I stripped down the carb but all seemed fine. When the engine is reved up the bike spits and coughs fuel through the carb. I have tried various settings on the fuel /air mix but nothing seems to make a difference. The Carb is a Dell'orto UB22b. The jet sizes fitted are 260b atomiser, 95 main and 40 pilot. The needle is fitted at the middle setting. Any ideas as to what is wrong?

I have also taken a compression reading of 120 psi. The mileage is 5600 km from new, 1964. :banghead:
 

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Discussion Starter #8
Ok I have found out what the problem was.......After stripping the carb again I noticed a very,very small hole inside the main body of the carb in the area that attaches to the barrel. It was so small that I thought it was a speck of dirt. After careful proding with a tiny stiff piece of wire the blockage was clear. I reassembled it and the bike runs and pulls great. This information may help someone in the future.
regards
 

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Well done that man. I had some ideas but you got there before i had a chance to reply.

Bloody big carb for a road 150cc MV though. They are mormaly 18mm or at the max 20mm on the sport.

But if it works, it works, so leave well alone.

Dorian.
 

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Great information Adrian.

In my case I am trying to make my 150rs run. However, I think I need a replacement for the contact breaker.

Does anyone know the answer for the following questions?

- which extractor I need for the DANSI flywheel?
- which contact breaker do I need? any specific model?
- is the Sport model´s firing timing the same one as on the GT model? ( 11 degrees static , with 25 degrees of auto advance)
- it´s the second time i m replacing a contact breaker. any tip?

best regards,
Dong
 
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