SRX620

[Timthetooth]

Hi all,

I bought myself an SRX620 which had spent the last 10 years as a part time exhibit in a a motor museum.  It's only been run occasionally and is aesthetically in great nick.  The work was done on it by Slipstream back in the mid 90's and comprises 620 overbore with wiseco piston, yoshimura cam, keihin CR33's, K&N's and a Supertrapp.  When I bought it I took it for a ride and was well pleased, although it stuttered a little and was really edgy about ticking over.  I left it in the garage for a month.  Since then when I come to start it, it fires up after the third kick, runs for half a minute then dies.  This is then followed by me doing the dance of the 7 kickstarts and no further engine activity.  If I go away and leave it, it'll perform the same routine when I return.  It's had the carbs cleaned out but to no avail. 

I suspect the carbs are the problem, although I don't undertand why it starts, runs then stops.  I was going to try and fit a standard carb, just to see if I could get it going.  Anybody tried the Teikei Y27PV off a kick start XT600 or the Y27PV off a XTZ660?  Better yet, if there's something obvious that I'm missing then feel free to suggest a remedy

Cheers

Tim 

[tim]

Hi Tim
It may not be the carbs atall It could posibly be the coil breaking down this would fit in with the hesitance you had at the begining

regards
Tim

[tommy]

hi tim coil ,plugs and check to see if the choke is fully closed when you warm it up.could be slightly staying on .............yoshi

[themoudie]

Aye Tim,

Afore you go swapping carbies etc. Take the fuel tank off, empty it and throw the contents away! Clean out the fuel taps and their filters. Check the inside of the tank for loose rust, CLEAN, repair with Frost's repair kit if necessary(ordinary Petseal appears to be attacked by modern petrol! )
Put new filter in line between tank and the carbies. Put in 3 - 5 litres fuel and see if all is well. If not check all earths and wires to coil and igniter box. MINUTELY!!!!!!!!!!!! Because Shite flings up from the front wheel, any small cracks in the insulation of the wires may result in unseen corrosion, verdigris, make and break wire connections. Use a meter and be methodical. If you require a Yamaha workshop manual pdf, send me a PM via this site and I will try and send one as an attachment by return. A donation of your choice to the Rob Vine Memorial Trust would be appreciated. 

Hope this helps.

My regards, Bill.

[Steve Lake]

Funny...I've just picked up a very similar bike with an identical problem.....the engine has been completely rebuilt (now 634cc, twin carbs from a bmw something or other, oil cooler fitted etc etc....all in an effort to cure this problem) even stranger......I owned this bike 4 years ago, and did a good rebuild and cosmetic job on it, then sold it to my plumber mate, who put my central heating in as part of the deal (CH still workin fine by the way  )

he has done over 20k since getting it off me...then this problem started.....hence the rebuild etc etc.....got fed up with it and bunged it in the back of the shed....eventually selling it back to me for silly money....
So..... I guess we had better compare notes....first thing i'm doing is swopping out the carbs (I keep several spares about the place), then it'll be the electrics (although I did lend him a coil to help find the fault), the generator coils have been rewound (when he sent them away to be checked they found a problem) ...then, the much ignored PICKUP a little jobby ebedded in rubber and adjacent to the rear of the flywheel....

then i'm open to suggestions ...

[themoudie]

Aye Steve,

MMMMMMMMMMMMMMmmmmmmmmmmmmmmmmmmm!

Little jobbies encased in rubber! 

May I keep a watching brief? So far 'Sally' hasn't displayed this nasty! New regulator/rectifier from 'Electrexworld' Electrexworld_link cured the boiling battery syndrome, even with a brand new Yamaha unit!

I may lob suggestions from sideline and all cries of "FO!" and "On yer bike! " will be understood, but maybe ignored! 

Slainte, Bill.

[Timthetooth]

Hi folks,

Very many thanks for your input.  There's a lot of good common sense stuff there that I really should do first.  If I was honest (get that humility pill down you) I guess I was hoping it was the carb so that I could go:  "Undo one, bolt one on, problem fixed."  How nice would that be?  If I'm taking the fuel system to bits, I'll re-clean/set the carbs at the same time.  Will keep you posted.  By the by, and back to the original question - if it does turn out to be the Keihins, has anyone fitted an XT600 carb?

Tim

[Steve H]

As Bill says change the fuel before you start stripping stuff down. Even with standard carbs I found that if I left the bike more than a couple of months I had to drain the carbs first, otherwise it would fire up and then die as you describe.
In my opinion the CR33's work well and improve throttle response, the only negative being a slightly heavier throttle, I would recommend keeping them. 

[guest1155]

By the by, and back to the original question - if it does turn out to be the Keihins, has anyone fitted an XT600 carb?

yes, but it was to a standard engine. Worked fine though. you'll have to tweak out the fuel tap holding tab to gain access to the choke puller though.

Just a thought though. this reminds me aof a fault i had with an old gpz i had. it'd start up on all four, run perefctly for about a carbs worth of fuel then run intermitently on 1 2 3 or sometimes 4 cylinders. turned out to be the breather on the tank not letting any air in and vaccuum locking the tank. now when i have a problem like this i always try the engine with a open topped fuel source, or the tank open.

[Timthetooth]

Once again, some great suggestions.  Very many thanks.  Have had a chat with the blokes at Slipstream who did the original work and they also said that, once set up, the keihins were realtively trouble free but that they suffered from gunging up really easily if left standing but they'd recommend keeping them.  They also said to bear in mind that the keihins are part of a whole set-up ie piston, cam, carbs, K&N's and exhaust.  If I monkey with one part then I'll most likely have to monkey with another to achieve good running.

I'd love to say I'll crack it this weekend, but it's the wedding anniversary which does not equate to me coming in with black fingers and reeking of petrol (I generally save that for special occasions)

Will let you know if I get it fixed

Cheers again

Tim

[alice]

Feels like fuel to me, I had a VF 500 which did exactly what you describe. This bike had been stood, cleaned carb's fresh fuel to no avail. I finally sussed a problem with the vacuum side of the petrol tap. When left to stand with the tap on enough fuel trickled through to fill the carb's. But the reduced flow could not cope when the motor was running.

[Dogbad]

Just to add to a previous post  I had an idential problem on a bike I was buying (New from a dealer) as they were doing the pre sale checks.  Turned out to be the petrol tank breather pipe and the symptoms were the same.