Motorcycle and Scooter appreciation

It could be one of these three things:

• pilot jet passage
  
• needle height
  
• cable synch leading to butterfly openings
  
  

Anyone got an ultrasonic bath for cleaning awkward areas like the pilot jet passage?

Single cylinder FTW.

Efi ftw

^^ The fuel/air screw and pilot jet only affect what happens at idle and 'just open' throttle, not 4000 rpm. The emulsion tube above the main jet is what makes the difference at that sort of engine speed. Did you take them out with the main jets when cleaning them out? They can get so gummed up that the fuel doesn't atomise properly.

Having the cables out of balance won't affect high rpm running that much, unless they are comically out. It will run rough, particularly at very small throttle openings, but it shouldn't cause it to cut out.

It could also be electrical. R80s had a habit of splitting their coils and letting moisture cock the sparks, but I'd be surprised to see an 'old type' coil still around. If the coil is grey, suspect it, if it is black it should be ok. Besides, it would be a pig to start, particularly in the wet.

I'd love to come and take a gander, but can't until next week.

I'm having trouble with my BMW R80's bing carbs. Is anyone a bing guru and willing to come drink a beer and tickle a carb with me?

Good luck.

I'm having trouble with my BMW R80's bing carbs. Is anyone a bing guru and willing to come drink a beer and tickle a carb with me?

Good luck.

When do the carbs go from the pilot to the main jets?

I've had an R80 for 11 years, always maintained it myself so I'll pitch in. Have a look at the rubbers in the top of the carb (unscrew the 2 screws on either side of the top plate) Sometimes they fold over or come loose. Otherwise could be 2 problems operating together, low idle setting/unbalanced and float height causing starvation.

Where are you based, I'm under massive time pressure at the moment but might be able to help.

Replaced rubbers in the top of the carb just now. All passages seem to be clear. Rebuilt the carbs and ensured all jets are clear.

I'm going to make sure both float bowls have right fuel height now and that butterfly's and cables are synched.

I have discovered a damaged mixture screw o-ring. Could that have been the cause? Seems unlikely. I'm going to have another go tomorrow morning and then check the coil.

I can now confirm it is not:

• pilot jet passage
  
• needle height
  
  

Could be:

• cable synch leading to butterfly openings
  
• fuel-bowl fuel height
  
• mixture screw o-ring
  
• coil
  
  

Thanks, MrAndyJones. I may take you up on the offer next week if my fettling and new mixtures screw o-ring do not solve it.

Replaced rubbers in the top of the carb just now. All passages seem to be clear. Rebuilt the carbs and ensured all jets are clear.

I'm going to make sure both float bowls have right fuel height now and that butterfly's and cables are synched.

I have discovered a damaged mixture screw o-ring. Could that have been the cause? Seems unlikely. I'm going to have another go tomorrow morning and then check the coil.

I can now confirm it is not:

• pilot jet passage
  
• needle height
  
  

Could be:

• cable synch leading to butterfly openings
  
• fuel-bowl fuel height
  
• mixture screw o-ring
  
• coil
  
  

Thanks, MrAndyJones. I may take you up on the offer next week if my fettling and new mixtures screw o-ring do not solve it.

Buy an o ring kit...http://cpc.farnell.com/jsp/search/productdetail.jsp?sku=FN02645 it is quite handy.

Oh and check for leaking/cracked inlets...

Good idea. Will pop to Halfords in the morning.

Halfords is really expensive, they only do the small packets with 6 various size O rings..look at toolstation

http://www.toolstation.com/shop/Plumbing/Washers%20&%20Fixings/O%20Ring%20Pack/d20/sd2703/p53005

http://www.toolstation.com/shop/Plumbing/Washers%20&%20Fixings/O%20Ring%20Kit/d20/sd2703/p80033

Perhaps I should have qualified my experience with old BMWs. I worked on them for ten years professionally, in and out of the dealership network. Not a Bing guru, but hopefully qualified to comment.

Thanks, 36x18. I'll PM you if I don't sort under my own steam this weekend.

I love the amount of knowledge on this forum.

an old fashioned +1 to that, nurseholiday

After a soaking cycle this morning I returned home and as the clouds parted and the sun made an appearance, the new exhaust and Stompgrip pads were fitted. Totally forgot how grin inducing a fruity exhaust is, and first impressions of the pads are fantastic. Already looking at booking my 2nd track day :/

https://www.youtube.com/watch?v=TKUgMA6V50g

Anyone got a 125 they don't need because they bought a real bike / pinarello / dog / etc?

snoops how did you get on and can we have a picture please? thanks

You most certainly can have a picture.

38x11 came around tonight and tickled my carbs good. It's running, sounds good to me but lumpy to Richard. He's a gent and very skilled.

I was dreaming all sorts of expensive reasons as to why it wasn't running but of course it was the simplest problem: a tune up by someone with experience.

I'll put it in for a full service next week for piece of mind.

can we have a picture please?

Working on it. On the weekend. Looking for a nice angle.

Wait til we've made the new rear subframe.. that thing is fugly right now

Valve clearances in the air heads are a piece of piss by the way.

can we have a picture please?

This morning was my first ride. Took it in to work. It's running but it definitely needs a once over. The power delivery is not smooth. This is the first carbureted bike I have ridden so I'm not sure quite what to expect but I thought it would be smoother than fuel injection. Should it be?

The handling and riding position is great though. It's fun.

Full service should happen next week. And I hope to tidy up the rear end this weekend.

Last update:

New subframe by Max and further tinkering by Richard to make it "go like buggery". It feels great now. Thanks, Forum! Every now and then LFGSS reminds you how great people are.