L reg yamaha diversion problems

[tyer0667]

just wondering what can cause my bike after 4 days standing to have difficulty starting, it seems like fuel issue, when i first try the starter it will turn for a while before firing, then when i get it to start it will idle at 1000 revs then gradualy build up to 3500, it seems like it is doing it in stages with slight backfire every time it builds up, if i use it on a daily basis it starts ok. somone told me it could be a filter prob or a weak vacume on the fuel side of things. cheers

[marshallman72]

Yes I've heard the same thing. Its something to do with the vacuum fuel pump. They are prone to this problem. According t the haynes manual you can fit the electric fuel pump off the later models. Also, it doesn't necessarily have to be a divvy 600 specific pump either. I've heard that most yamaha fuel pumps will do the job just fine. It grates me that the only reason this issue exists is that Yamaha in their infinite wisdom decided to cant the engine forwards in the frame to lower the centre of gravity, supposedly improving stabilty etc. As a result, the carbs are now higher than the fuel tank outlet, necessitating the fuel pump in order to shove the fuel back uphill to the carbs. Why didn't they just leave the motor as it was pre divvy? It had more power, and didn't need a fuel pump at all, just let gravity do it. Progress eh?!

[pilgrim]

Oct 25, 2010 20:27:45 GMT marshallman72 said:

Yes I've heard the same thing. Its something to do with the vacuum fuel pump. They are prone to this problem. According t the haynes manual you can fit the electric fuel pump off the later models. Also, it doesn't necessarily have to be a divvy 600 specific pump either. I've heard that most yamaha fuel pumps will do the job just fine. It grates me that the only reason this issue exists is that Yamaha in their infinite wisdom decided to cant the engine forwards in the frame to lower the centre of gravity, supposedly improving stabilty etc. As a result, the carbs are now higher than the fuel tank outlet, necessitating the fuel pump in order to shove the fuel back uphill to the carbs. Why didn't they just leave the motor as it was pre divvy? It had more power, and didn't need a fuel pump at all, just let gravity do it. Progress eh?!

Good reasoning.

But it wouldn't be a Diversion otherwise, would it??



;D

[amorti]

Could also be the battery, test your voltages.

ps. that's my standard answer to starting problems when a cold snap shows up.

[bobh]

Or water in the petrol. That's my standard answer.

[neilmud Lord Protector]

They all wobble at 40mph

Thats my standard answer

Neil

[vmas]

How weird Is that my 94 Divvy does the same a pig to start after its been stood a few days but ok ish if used daily Ive got time next week so i'm going to get to the bottom of it.

[billywhizz]

problems with starting the ole 600, if stood the petrol soon evaporates, or leaks !
then when trying to start, there is no fuel to ignite, with the fuel pump being a vacuum variety... so whilst turning over the petrol only just starts coming through.
ANSWER
put fuel tap to prime postion as soon as you get to bike, get kitted up, etc, return tap to on and should fire up nicely, assuming everything else is ok of course..

You could revert to electric pump, but seems a biggish job for a minor 'fault' on starting.
hth

[meerkat]

Oct 25, 2010 15:03:06 GMT tyer0667 said:

just wondering what can cause my bike after 4 days standing to have difficulty starting, it seems like fuel issue, when i first try the starter it will turn for a while before firing, then when i get it to start it will idle at 1000 revs then gradualy build up to 3500, it seems like it is doing it in stages with slight backfire every time it builds up, if i use it on a daily basis it starts ok. somone told me it could be a filter prob or a weak vacume on the fuel side of things. cheers

Glad its not just mine that does this... also a 'L' Reg......