Original or trials ?
- SideValve
- Posts: 189
- Joined: Wed Jan 05, 2011 10:37 pm
- Location: OXON UK
Re: Original or trials ?
The advance/retard disc being loose on its spindle seems a common fault. My G2 had the problem and would stick in different positions depending on its mood. I'd re-time it, all good. Couple of miles down the road, timing is too advanced. Re-time it, all good, couple of miles later too retarded. It was only when I looked once while it wasn't jammed that i noticed it could turn about 30 deg on the shaft.
Give it a firm wiggle.
Oh, and check the fuel rate, might be some debris wandering about the tank.
And yep, apart from maybe lining the back mudguard up better I'd leave well alone. I saw it go through ebay, nice that its gone to a good home.
Give it a firm wiggle.
Oh, and check the fuel rate, might be some debris wandering about the tank.
And yep, apart from maybe lining the back mudguard up better I'd leave well alone. I saw it go through ebay, nice that its gone to a good home.
Peter W
- Ozmadman
- Posts: 2651
- Joined: Wed Dec 14, 2011 1:02 am
- Location: ESSEX UK
Re: Original or trials ?
The bad running on my model 8 was a combination of (1) carb trouble, (2) air leak (3) adv/rtd unit/ timing
(1) Despite "cleaning the carb"out twice I still had problems with erratic running/bad tick over etc . I took the carb apart for the third time and was meticulous with carb cleaner making sure all the drilling's were clear (including the tiny one in the intake venturi) I fitted all new jets, needles and float valve and also a new jet block gasket and made sure the block was very securely tightened down.
(2) Things were better but still a bit erratic and I with the forum members help and direction went looking for a leak probably where the carb joins the head. Whilst running (not me but the bike ! ) I smeared some bathroom silicon (that's all I had to hand) around the carb flange/spacer block area and that seemed to help so I let it run for a while and then left it to cool down and took the carb off yet again and lo and behold there was a leak, you could see where the silicon had been sucked in and spread itself around the flange o ring seal. I have an old oil stone so I used that to flatten the flange (the ends where the bolts go through were higher than the rest due to over tightening) using a steel rule across the flats to ensure all was flat. I got a new o ring and gasket, put it back, with spring washers on the studs, being careful just to tighten enough to flatten the o ring and sweet as a nut.
(3) I had a lot of banging in the exhaust, backfiring, blow backs from the carb etc along with the problems above so I suspected timing etc, no matter how much I fiddled around it wasn't going too well and in frustration after changing points, condensor etc I removed the adv/rtd unit. Two things I noticed.. 1) one end of one of the springs wasn't attached to it's weight and.. 2) both weights had a lot of play on the spindles meaning that they tilted forward quite a bit. People say that these units can't be serviced but I removed the small circlips securing the weights to the spindles, found some very small thin washers, put one over each spindle and then replaced the circlips, added a small amount of grease and excellent!! free moving weights with little forward tilt.
As Janet has previously mentioned, getting the adv/rtd unit back in the right place and re-setting the timing is a bit of a mission but once you get your head around it with the help of the manual it is not difficult just time consuming.
I still don't know exactly which one (or a combination) of these things made the bike run like rubbish as all the above were going on in the same period of time but having done all these things the bike runs great and ticks over as regular as a Swiss watch now. Maybe some of these tips will help you?
Paul
(1) Despite "cleaning the carb"out twice I still had problems with erratic running/bad tick over etc . I took the carb apart for the third time and was meticulous with carb cleaner making sure all the drilling's were clear (including the tiny one in the intake venturi) I fitted all new jets, needles and float valve and also a new jet block gasket and made sure the block was very securely tightened down.
(2) Things were better but still a bit erratic and I with the forum members help and direction went looking for a leak probably where the carb joins the head. Whilst running (not me but the bike ! ) I smeared some bathroom silicon (that's all I had to hand) around the carb flange/spacer block area and that seemed to help so I let it run for a while and then left it to cool down and took the carb off yet again and lo and behold there was a leak, you could see where the silicon had been sucked in and spread itself around the flange o ring seal. I have an old oil stone so I used that to flatten the flange (the ends where the bolts go through were higher than the rest due to over tightening) using a steel rule across the flats to ensure all was flat. I got a new o ring and gasket, put it back, with spring washers on the studs, being careful just to tighten enough to flatten the o ring and sweet as a nut.
(3) I had a lot of banging in the exhaust, backfiring, blow backs from the carb etc along with the problems above so I suspected timing etc, no matter how much I fiddled around it wasn't going too well and in frustration after changing points, condensor etc I removed the adv/rtd unit. Two things I noticed.. 1) one end of one of the springs wasn't attached to it's weight and.. 2) both weights had a lot of play on the spindles meaning that they tilted forward quite a bit. People say that these units can't be serviced but I removed the small circlips securing the weights to the spindles, found some very small thin washers, put one over each spindle and then replaced the circlips, added a small amount of grease and excellent!! free moving weights with little forward tilt.
As Janet has previously mentioned, getting the adv/rtd unit back in the right place and re-setting the timing is a bit of a mission but once you get your head around it with the help of the manual it is not difficult just time consuming.
I still don't know exactly which one (or a combination) of these things made the bike run like rubbish as all the above were going on in the same period of time but having done all these things the bike runs great and ticks over as regular as a Swiss watch now. Maybe some of these tips will help you?
Paul
Paul
1960 Model 8
1974 Yamaha RD250B US Model 6 speed
1960 Model 8
1974 Yamaha RD250B US Model 6 speed
- clive
- Member
- Posts: 5671
- Joined: Mon Jan 01, 1990 12:00 am
- Location: LONDON UK
Re: Original or trials ?
I would leave it as it is not go back to original. However you might want to fit some sort of heat guard to the silencer. Difficult to tell how well tucked in it is but if you can reach it with the inside of your leg, sometime you will do so and wish it was not so hot. nice looking bike.
clive
if it ain't broke don't fix
if it ain't broke don't fix
-
- Member
- Posts: 1902
- Joined: Wed Jan 01, 1992 12:00 am
- Location: SURREY UK
Re: Original or trials ?
Maybe it's a stupid question but have you checked the CB points gap, they should be .015" (fifteen thou).
-
- Posts: 42
- Joined: Fri Mar 29, 2013 10:11 pm
- Location: CAMBS UK
Re: Original or trials ?
clive wrote:I would leave it as it is not go back to original. However you might want to fit some sort of heat guard to the silencer. Difficult to tell how well tucked in it is but if you can reach it with the inside of your leg, sometime you will do so and wish it was not so hot. nice looking bike.
Yes i do have a heat shield, was the first thing i ordered for it
-
- Posts: 42
- Joined: Fri Mar 29, 2013 10:11 pm
- Location: CAMBS UK
Re: Original or trials ?
SideValve wrote:The advance/retard disc being loose on its spindle seems a common fault. My G2 had the problem and would stick in different positions depending on its mood. I'd re-time it, all good. Couple of miles down the road, timing is too advanced. Re-time it, all good, couple of miles later too retarded. It was only when I looked once while it wasn't jammed that i noticed it could turn about 30 deg on the shaft.
Give it a firm wiggle.
Oh, and check the fuel rate, might be some debris wandering about the tank.
And yep, apart from maybe lining the back mudguard up better I'd leave well alone. I saw it go through ebay, nice that its gone to a good home.
This has all been checked. Thank you for telling me about it. Unfortunately it wasn't this, we think its the tappets
- Janet
- Member
- Posts: 4131
- Joined: Mon Jan 01, 1996 12:00 am
- Location: EAST YORKSHIRE UK
Re: Original or trials ?
Tappet adjustment on them is simple but a bit fiddly. Do you know any keyhole surgeons?
-
- Posts: 42
- Joined: Fri Mar 29, 2013 10:11 pm
- Location: CAMBS UK
Re: Original or trials ?
AJ Has been fixed thanks to cbranni !!!! What an amazing man ! Can't wait to take my Aj out next weekend
- Ozmadman
- Posts: 2651
- Joined: Wed Dec 14, 2011 1:02 am
- Location: ESSEX UK
Re: Original or trials ?
What was it?lil welshy wrote:AJ Has been fixed thanks to cbranni !!!! What an amazing man ! Can't wait to take my Aj out next weekend
Paul
Paul
1960 Model 8
1974 Yamaha RD250B US Model 6 speed
1960 Model 8
1974 Yamaha RD250B US Model 6 speed
- Janet
- Member
- Posts: 4131
- Joined: Mon Jan 01, 1996 12:00 am
- Location: EAST YORKSHIRE UK
Re: Original or trials ?
It would be useful (and maybe polite ) to let us know what was wrong and how it was fixed 1) in case we develop the same problem and 2) to put us out of our misery.