Lack of power... (GT380)

[Dbailey]

Hi all... so bike is running after 20 years and I’ve done about 30 miles... runs and idles ok but doesn’t pull and is quite smokey @ higher revs and it bogs down. I’m going to check all the settings, oil pump ignition timing etc. Anyone know where I can get a DTI to check tdc and subsequently set to 3mm btdc? The book states you can get a tool that screws into the plug thread...

Thanks
Dave Bailey

[teazer]

I did a quick search and came up with a few courtesy of Ms. Google.

https://www.ebay.ie/itm/192117934635

https://www.ebay.ie/itm/202186436868

https://www.ebay.com/p/Motorcycle-JMP-I ... 1014869254

https://yambits.co.uk/dial-gauge-igniti ... 24969.html

Or buy a DTI and modify a spark plug to make the holder. I have one like that and one proper set - Central tools - that I use all the time. If the plugs are not vertical, I prefer to set timing with the cylinder head off. Another trick is to use a piston stop and a timing wheel and set the timing in degrees BTDC. Remove all spark plugs and screw in the stop. Rotate the motor until the piston comes to rest against the stop and read the pointed (bent coat hanger wire). Rotate the motor backwards until the piston comes to rest against the stop and take that reading. Adjust timing wheel and/or pointer so it reads the same either side of TDC. And that's how you find TDC with a degree wheel.

Then set timing to 22 degrees or whatever the book says it should be. For the other two pots you can repeat that process, or assume the crank phasing is perfect and just mark the wheel every 120 degrees.

[canaletto5]

Hi all... so bike is running after 20 years and I’ve done about 30 miles... runs and idles ok but doesn’t pull and is quite smokey @ higher revs and it bogs down. I’m going to check all the settings, oil pump ignition timing etc. Anyone know where I can get a DTI to check tdc and subsequently set to 3mm btdc? The book states you can get a tool that screws into the plug thread...

Thanks
Dave Bailey

What is the compression like?

[barney01]

Fresh petrol? Tank and carbs drained first? Carbs will deffo need to be stripped and jets cleaned after 20 years
Also make sure airbox is clear and filter not blocked..

[willowden]

I have fitted accent electronic Ignition, extremely reliable , easy to fit, no need for a dit gauge or worry about slipping points or good or bad sparks. You also receive a 20% discount for being a member of the kettle club. Uwe the guy in Germany that makes them is a top guy , will always help with any issues.

[Dbailey]

Thanks guys for the replies... a quick update...

Carbs have been full cleaned new gaiters etc.. I set the gap for the sliders etc.. the bike starts pretty much first kick.. it just does not rev particularly freely. Compression seems to be reasonable but I have not measured it.

I’ve not had a 380 before.. but you can feel a fair bit of vibration through the foot pegs from about 4 to 5K then it smooths out but it doesn’t pull cleanly.

I’ve checked throttle to oil pump setting and this seems setup ok..

I’m going to check timing and I guess the carbs might need a bit of fine balancing but I have the center pull carbs that are not easy to adjust I believe.

New clean fuel Esso 97 octane.

I think the motor has had a rebuild probably 20 years ago then laid up. Oil was very clean and looks as though the bike hasn’t run much.

It’s got new air filters which have been washed in oil and wrung out.

Still got the original plugs but again they look in good condition.

Just need to keep improving it...

Any advice would be very much appreciated..

Thanks
Dave Bailey

[Alan H]

30 miles in 20 years? It'll want a good run to clear all the crap out.

[PaulD738]

To be fair the 380 will never be a flyer! little power and lots of weight