Dead RB kit

[soullad]

Heat does seem to be the evil enemy of these kits. Im wondering if its the inadequate cooling of the barrel via the flywheel fan rather than the design thats at fault. At the recent Calafat 6hr enduro race a standard rb225 with a water cooled head performed brilliantly, taking fastest lap and was thrashed for 6hrs non-stop in the Spanish sun... Obviously i haven't been able to see what wear if any resulted. I could ask? or is there an issue with port time area - i mean do the bridges, although on the face of it inc. port size, actually impede gas flow (eddy?) and so reduce port time area eficiency ??
Maybe the designers failed to take into account the questionable efficiency of the lambretta cooling system - maybe its time to design a more efficient fan?
The savvy RB riders are also now using EGT's etc to keep an eye on the temps reached, as it appears they do run really close to the edge of whats possible heat wise.
Anyway , just the ramblings of an enquiring mind.......

[carlos fandango]

Maybe the designers failed to take into account the questionable efficiency of the lambretta cooling system - maybe its time to design a more efficient fan?

Hallaluya This is what i was trying to get at in my thread about fans (fans cooling techies wanted) But after ten pages of replies, it got nowhere.
Russell

[Diablo]

I take on board what people are saying about the design of the kit but the kit design hasn't caused this.
The exhaust has come loose which has almost certainly damaged the gasket. This has caused the motor to run hot and seize.
This isn't just any old seize its a total meltdown and I'd bet my mortgage that there was plenty of warning coming from the motor if you know what to listen for.
This will happen on a 25hp TS1 or any other barrel for that matter if the circumstances were the same.

[RICSPEED]

Maybe the designers failed to take into account the questionable efficiency of the lambretta cooling system - maybe its time to design a more efficient fan?

Hallaluya This is what i was trying to get at in my thread about fans (fans cooling techies wanted) But after ten pages of replies, it got nowhere.
Russell

yes your right the fan could be redesigned ,no more talk of ducts

[red]

Now the TS1 barrels are around again I'd be inclined to cut your losses and get one of them if you want to stick with a reed kit.

I've got a TS1 250 kit which will be used,taking it over to Jason Frost in the morning.
may still go and buy another couple of TS1 225 kits for other projects I've got.
We've talked about keeping the RB barrel and water cooling it and putting it in the cutdown he's building for me.

[J1MS]

I take on board what people are saying about the design of the kit but the kit design hasn't caused this.
The exhaust has come loose which has almost certainly damaged the gasket. This has caused the motor to run hot and seize.
This isn't just any old seize its a total meltdown and I'd bet my mortgage that there was plenty of warning coming from the motor if you know what to listen for.
This will happen on a 25hp TS1 or any other barrel for that matter if the circumstances were the same.

I would second that... My totally reliable SX melted a piston when an exhaust stud came loose... wasnt as bad as this but till the exhaust stub came loose it had run well.....

[alcoholic maniacs sc]

a lot of people have had RB kits that lasted under 1000 miles, at that kind of logevity you need to be seriously monied up. Ive ragged TS1 kits to death with exhausts hanging off and totally inappropriate carbs and they seem to soldier on well. I suspect its simply a better design for the Lambretta cooling system and the RB is a basis for a bespoke tuner built bike and not a bolt it on in the garage or restoration scooter shop attempt. The vast majority of RB kitted scoots do 100 miles a year and TS1 owners cover big mileages. thats just my assessment during pub talk. just fitted a genuine tv200 barrel to my Gp with modified piston skimmed head and 19 tooth front spocket,PM pipe and 30mm dell'orto. It does a genuine 75 happily and doesnt seem to overheat, it being IRON an'all, so id be very pissed off if your RB had drunk as much of my beer money as yours seems to have done!!!

[ArmandTanzarian]

Has anyone ever done any testing to monitor temperature differences with panel vents etc? The heat build up inside must be significant and a couple of well placed holes to create air-flow might make a lot of difference.

[johnd]

a lot of people have had RB kits that lasted under 1000 miles, at that kind of logevity you need to be seriously monied up. Ive ragged TS1 kits to death with exhausts hanging off and totally inappropriate carbs and they seem to soldier on well. I suspect its simply a better design for the Lambretta cooling system and the RB is a basis for a bespoke tuner built bike and not a bolt it on in the garage or restoration scooter shop attempt. The vast majority of RB kitted scoots do 100 miles a year and TS1 owners cover big mileages. thats just my assessment during pub talk. just fitted a genuine tv200 barrel to my Gp with modified piston skimmed head and 19 tooth front spocket,PM pipe and 30mm dell'orto. It does a genuine 75 happily and doesnt seem to overheat, it being IRON an'all, so id be very pissed off if your RB had drunk as much of my beer money as yours seems to have done!!!

I've just got back from lincoln to my home in belgium on my RB22. I've ragged it now for 2000klms and only changed the plug and gear oil once since i built it in my shed. Its got a top speed similar to a tuned TS1 and more power for in the wind and overtaking. And to top it off it does about 100/120 kilometers on a seven litre tank. Yes, it has surprised me that my engine has been so fast, dependable and economical, and so far totally reliable. I would have another one over a TS1 any day of the week.
I understand that this cylinder isn't as well made as the TS1 is but if its set up correctly it will do the same job (only a bit better ).
I have to say that i'd have given up before i'd bought three of them though!!!

[alcoholic maniacs sc]

properly sorted with an owner who has a good knowledge of the technical aspects of a two stroke im sure the RB is a more advanced design and 15 years in advance, so it should. I was just thinking that there are a lot more variables that a competant amateur could turn into a wrecked barrel and piston combo.Youve done more miles on one trip on that RB than most ive spoke too.I would definatly buy the RB kit over the TS1 when i need one just for the extra torque.got to agree about the casting tho, its not very good next to the finely defined internal structure of the TS.