XBR Carb iceing.

[eightcans]

Just wondered if anyone elses XBR suffers from carb iceing?? I can feel it starting to develop and by the time I`ve done a couple of miles it won`t tick over and is running very ruch. Stop for a fairly short period of time and the engine heat does its magic and it runs much better. Any hints/cures please. I use the bike for work so have no other transport options. Thanks, Guy.

[niblue]

Today is the first time I've used mine in really cold weather and I didn't see any signs of carb-icing despite it being very cold here today.

[guest146]

Is there any way you can channel some warm air from the engine up to the air filter inlet. On cars it happens automaticaly. I would bet there is some addative you can get.

Yes I found this have a look

http://www.mcnninjas.co.uk/docs/Carb_Icing


Ken

[Steve Lake]

Erm....you'll need to ask #1 (onepot) about this....I lent him a carb heater for his bike prior to him going on a winter rally (elephant?) I think it did the job.....runs on 12v, fits inside the intake. I had it in a Reece Fish carb i used when i raced in the 850 mini racing series.....(too long ago !!) sadly, Leanord Reece died a few years ago, so I have no idea where he sourced these heater elements from. But the general idea is to lift the air temperature slightly to compensate for the (a) the lower winter air temperature and (b) the temperature drop inside the carb due to pressure drop through the venturi,
I guess some carefully chosen resistance wire wound onto, say a 1" long plastic tibe of a similar diameter to the carb would do it. As i remember....the one i lent #1 drew between 1.5 and 2 amps... I know the reccommendation was, to run it through the ignition so it was only heating up when the engine was running, I didn't as it was on my race car....and sometimes there was an awful hot smell when i left it on by mistake!

[eightcans]

Thanks folks. Will try the super unleaded and additive option first. Fingers crossed

[niblue]

Running the XBR on the commute to work this morning in falling snow and I encountered what appeared to be carb icing with it for the first time. Not a massive problem but still somewhat of a pain in the arse in traffic.

[guest7]

I think modern petrol doesn't help. I am in the position of having run XBRs since 1987 so I can compare how they used to behave with now. In the late 80s I never suffered any carb icing on my XBRs, they only started to misbehave from the mid 90s onwards.

I think Steve's heating element did help, but didn't cure the problem. I wondered about lagging the sides of the carb with some form of insulation (tank lagging came to mind) so that at least the carb is receiving (and retaining?) some of the engine heat. In germany one year I used the covers of a notebook to stop cold air geting at the carb and that helped a bit.

Of course the problem is with cold wet air coming through the airbox and short of making a heating element for the 'box I'm not sure how you can combat this.

Modern Triumph Bonnevilles have neat little heaters that screw into a boss on the carb and I always fancied having a look to see if one can be grafted onto the XBR carb.

GC