|
|
Post by churchman on Feb 17, 2017 17:14:31 GMT
1982 HONDA CB250N SUPERDREAM. MILEAGE 35000
Hi
Could anyone suggest a possible remedy for High Fuel Consumption
on a Superdream.
Engine is giving about 45 Miles to the Gallon.
Bike Starts OK and runs well.
I know there are Mixture Setting Screws at the Base of each Carb.
Does one Screw In to weaken the Mixture?
Any Tips?
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 17, 2017 17:45:18 GMT
Someone syphoning your fuel?
|
|
|
|
Post by wazzbo on Feb 17, 2017 17:51:52 GMT
The screws are only for setting the slow running and won`t make a difference to the mpg.
I don`t know what the 250`s average as I haven`t ridden mine much yet, I`m sure some of the 250 lads will tell you what to expect from it but my 400 is only a similar mpg to yours so I would think your mpg is about average.
|
|
|
|
Post by Somersetdreamer on Feb 17, 2017 18:08:08 GMT
I only get about that if I rode it slower I suppose it would go up a bit but I don't like going slow so 45 mpg giving it a handful now & again it seems to like going up to red line at least once every trip, when engine has warmed up  |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 17, 2017 18:10:37 GMT
Does it show signs of running rich? What do the plugs look like? Have you defo got a 250N CDI in there? Is the gearing still standard?
To keep up with modern traffic you do have to thrash the 250's- and of course we are no longer svelte 9 stone teenagers.
In 1980 Bike mag tested the 250NA and got 51.3mpg overall and 46.2mpg ridden hard. So you are not too far away from 37 years and 35,000 miles ago.
First rule of carb tweaking with SD's is leave them alone if at all possible. If the bike is running well I would leave well alone.
|
|
|
|
Post by Somersetdreamer on Feb 17, 2017 18:14:20 GMT
I agree with Paul you say your bike is starting & running well & I think 45 is pretty normal mpg best left alone, keep sticking the fun juice in & wind the right grip right back & enjoy as Spring is around the corner  |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Feb 17, 2017 18:23:09 GMT
Yep , about 50mpg unless you are really making an effort to economise , you'd expect more mpg but as above if it's running well best left alone . Think on a run and not "thrashing" it you might get about 60 mpg . Suspect mine was bad as I spent 50% of the time trying to sort various dirty carb issues that had arisen during its storage . |
|
|
|
Post by churchman on Feb 17, 2017 18:48:42 GMT
My experience of previous CB250n Superdreams is that it
is possible to get a Fuel Consumption of 60MPG Plus.
I believe 45 MPG is very High and indicates a defect.
From Full Tank to when it is necessary to change over to the RESERVE
I found that my Mileage was between 160 to 180 Miles. (This is 2.66 Gallons of Petrol used from a 3 Gallon Tank)
(The Reserve is about 0.33 Gallons) 1 Imp Gallon is 4.54 Litres
****************************************************
I do not have the Honda Service Manual available, but my understanding is that there are
2 Mixture Adjusting Screws under each Carburettor. (the are Brass,about 2mm diameter)
Screw in to Weaken the Mixture.
Any Comment?
|
|
|
|
Post by wazzbo on Feb 17, 2017 20:20:32 GMT
Which 2 screws are you meaning? There is only one on each carb as I said earlier, these are the pilot screws that control the fuel/air mixture at tickover., for the 250 they should be 2 turns out as a start point to setting the tickover.  |
|
|
|
Post by kickstart on Feb 17, 2017 20:24:33 GMT
Does sound a bit thirsty , I reckon I average around 55 to 60 to the gallon .....
|
|
|
|
Post by bodie on Feb 17, 2017 20:41:35 GMT
i have just turned to reserve at 135 miles and carbs were so far out of balance it was basically working on one and a third carbs and all of that millage has been in 30-40 mph winds so I think not bad mph going to fill up tomora and see what I get now carbs at spot on  |
|
|
|
Post by wazzbo on Feb 17, 2017 20:47:34 GMT
I only get about that if I rode it slower I suppose it would go up a bit but I don't like going slow so 45 mpg giving it a handful now & again it seems to like going up to red line at least once every trip, when engine has warmed up Thats the way to ride `em rich. |
|
|
|
Post by wazzbo on Feb 17, 2017 20:50:15 GMT
i have just turned to reserve at 135 miles and carbs were so far out of balance it was basically working on one and a third carbs and all of that millage has been in 30-40 mph winds so I think not bad mph going to fill up tomora and see what I get now carbs at spot on It makes a hell of a difference when they are balanced doesn`t it bodie, it`ll be like a different bike now. |
|
|
|
Post by bodie on Feb 17, 2017 20:52:39 GMT
i have just turned to reserve at 135 miles and carbs were so far out of balance it was basically working on one and a third carbs and all of that millage has been in 30-40 mph winds so I think not bad mph going to fill up tomora and see what I get now carbs at spot on It makes a hell of a difference when they are balanced doesn`t it bodie, it`ll be like a different bike now. yes 1carb was about 180 the other down at60 its like its on three cylinders now lol |
|
ian
Member Of The Year 2019 
Isle of Man
Posts: 5,400 
mini-profile background: {"image":"","color":"29908d"}
|
Post by ian on Feb 17, 2017 21:37:02 GMT
Does sound a bit thirsty , I reckon I average around 55 to 60 to the gallon ..... That's about what I get out of my 250, but no dual carriageways or motorways here, so typically 45-55 mph & no traffic jams either. What about the gearing? People seem to traise the gearing rather than lower it, but might be worth checking |
|
