R 90 S Idling Issues

byron

byron

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I have had the bike for a couple of months now and all was going well. Just fitted new discs and pads and I can stop at last ! But now it has decided not to idle well, particularly when hot and I come to a halt on the road .Adjustments made to the idle screw and the mixture screw seem to have little affect. So I suspect there is some muck in somewhere?
I am going to take them apart and clean them tomorrow --so is there anything with these 40 year old Italians that I should watch out for?

PS This bike handles so precisely , much better that my 1200 rt
 
byron said:
PS This bike handles so precisely , much better that my 1200 rt
Click to expand...

Sssh! Its supposed to be a secret, they'll all want one if your not careful.

New float bowl fibre washers are a good idea if you're messing with Dells. one of mine has just broken up so I'm walking round in boots that smell of petrol.
 
Great bike but poor carburettors

I'm so pleased to have acquired the bike it is so pretty I just smile each time I look at it. I'm just going to run until the end of the summer and then it's gonna have a bit of a makeover across the winter. I have just bought a new fairing and comfort seat and the grey ghost will become a 'ginger'overnight. However back to the carbs they look pretty shot I think diaphragms just about had it. Anyway a bit more exploration before I have to make some decisions in the morning.
 
Diaphragm on the r 90 s

As far as I can tell there is the accelerator pump near the top of the carb which appears to have a very thin diaphragm and mine look worse for wear.
There also appears to be another port on the engine side of the carb near to the fuel banjo--could that be a take off port for synching the carbs?
 
Port ?

Hopefully here is a picture of the port without the end cap sealing screw--anyone any ideas?
 
Thats the vacuum take off point for balancing the carbs. When I rode Laverdas years ago it was common to link the carbs for supposed improved primary air balance, I always thought it was bollox but did it anyway. Did you find a stray tube linking them?

The Screw is Part 71 on the microfiche http://www.stein-dinse.biz/images/product_images/popup_images/6434-36.jpg

6d68705f67.gif
 
Try a stiff dose of fuel injector cleaner in the tank - it might clean out any crud without needing to strip the carbs, and possibly damaging an O ring or fibre washer, or something. The owners manual for my Subaru car recommends that you use a cleaner every 3000 km, so they must think it works.

You also might have a tankfull of bad gas - I had similar problems with a VFR which were cured buy draining the tank and refilling with good fresh stuff.
 
byron said:
As far as I can tell there is the accelerator pump near the top of the carb which appears to have a very thin diaphragm and mine look worse for wear.
There also appears to be another port on the engine side of the carb near to the fuel banjo--could that be a take off port for synching the carbs?
Click to expand...
A knackered accelerator pump diaphragm won't affect the idle, just give you a flat spot when you open up the throttle.
 
Still Problems

Well there are still running problems with the R90S. I have stripped and cleaned both of the carbs and did note the diaphrams were not in the best of order but I did not disturb them and reassembled. I have also replaced the points ,plugs, leads and condenser and set up the timing both statically and dynamically. The fuel flows freely from the tank and I have fitted 2 inline filters .The bike now starts easily and idles really well, but when I take it out on the road it is fine up to 2000 rpm and the it splutters and hunts up to 3000 rpm and the flies or up the revs. It restarts easily when hot and does not need choke as previously. When the bike is on the stand it revs freely without a flat spot.
Any thoughts on where to go?
 
If the accelerator pump diaphragms ain't working properly, theres your problem.
If they don't squirt properly, you don't go, hence flat spot.
Bite the bullet, send them to JRS, you know it makes sense !!
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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