large center plug head no cowlings

[simon k]

evening lad's,
I am looking to improve the running temperature of my rb25 over long distances & considering running a large square center plug head, no cowlings or flywheel fan. i know it's commonplace on the track but any good for touring?
any advice or experience of this set up welcomed.
cheers Simon

[byron]

will be interested in replies as I was thinking about doing this, on a cutdown, with no legshields, or even the frame struts, so airflow would be as good as it could be.
what bodywork have you got ?

[soulsurfer]

They don't use finned flywheels on the track either but use air scoops where I can see this head helping but I wouldn't have thought it would be any good on the road, the cowlings are better designed than you think and play a big part in directing air to the right places.

[rbgaz]

hav u a egt gauge simon ? if so on my rb if going long distance once over 50 mph i turn the choke on it drops the temps from about 645 to about 600
p.s i also run a 10 plug in mine

[vicvega]

Was at Amiens over the weekend and there were a group of lads from hayling island who were running that set up. They said it ran very well, can't remember the figures but said onhis egt it ran cooler than cowlings. I sure he said they use JB to get them dyno'd so possibly give him a shout for advice.

[GP Kevo]

Direct air cooling works very well especially when the air is directed in with a scoop or "ram air" system. Problem is that the bike must be moving fast enough for enough air to move past the cooling fins to cool the engine. That's not an issue on a track racer. But road bikes have to contend with traffic, red stoplights, slow speed limits, etc. When you're held up by traffic or sat at a long red light after a fast run is where you'll have overheating problems and road bikes do a fair amount of time running slowly through towns or trying to get through long cues of holiday traffic.

[simon k]

cheers for the reply's. yeah i was in Amiens too and saw those two very well thought out & engineered gp's, cruising figure of 450 c on the egt i believe with full bodywork. i will be speaking to John soon. just keen to hear other first hand experience.
the bike has full body work apart from no side panels or splash plate. around town it hardly registers on the egt, however cruising at 60 out of the powerband it's getting up to 650+ c :shocking:
sitting in the sweet spot between 70-85+ mph with lot's of cool fuel more like 550-600 c.
the bike performs well as a fast tourer however running temps are a bit alarming. i was considering going water cooled on the head but the simplicity of this air cooled set up appeals. sitting in traffic could be a problem but if the bike is mainly used for motorways or a roads this may be a much smaller percentage of time..

[rbgaz]

taller gearing has cooled mine alot as it now dosnt rev so much and u are opening the throttle more , hav seen a 100 drop in temps at the same speed 55

[sydduckett]

taller gearing has cooled mine alot as it now dosnt rev so much and u are opening the throttle more , hav seen a 100 drop in temps at the same speed 55

Yeah but you cant get into 4th, thats why....lol

Also it will be a bit of a pain to change plugs by the side of the road....

[rbgaz]

taller gearing has cooled mine alot as it now dosnt rev so much and u are opening the throttle more , hav seen a 100 drop in temps at the same speed 55

Yeah but you cant get into 4th, thats why....lol

Also it will be a bit of a pain to change plugs by the side of the road....

lol who says i cant get into 4th !! if i was in 3rd all the time i think my temps would be lot higher
what has changing a plug got to do with it sef ?
lol