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[Simon_T]

Hi all,
having a problem with speed dropping off as soon as I change in to 4th gear.

setup as follows:

gt 200 kit no work done on it
60x110 crank
pacemaker gearbox
30 phbh carb
franspeed race
varitronic kit

any suggestions please.

[ToBoldlyGo]

I don't know anything about that exhaust. But it sounds like you could do with moving the power further down the rev range.

[rossclark]

What are the sprockets?

[Simon_T]

16x47 as far as I'm aware up to 3rd gear goes like stink and gets up to about 63mph but as soon as I change to 4th it drops back down to about 55mph

[shane BBoys]

I had a pacemaker set as yours on a muggy 186 with an AF Rayspeed clubby 22 spaco and it was like rocket up to and including 3rd the revs died of in 4th but sat well at 65 mph even on the motorway.
Shane

[dickie]

I had pacemaker and 17/47 on my gt186 with bgm clubman. That was perfect. Same set up with jl3 curly was good too. I'd imagine you've got a decent combination there, but it does sound like you're over geared.

I think that pipe peaks around 8000rpm which would give you about 75mph on that set up. Might be a tall order from an untouched kit.

Has it been on a dyno?

[Norrie Bodge]

With your crank 60x110 what base packer is used?

[rossclark]

Mate of mine had the same issue on an RT195 with 16/46 with the Li150 box and JL3 we changed it to the Pacemaker box and he says it's much better and he gets better economy as he's not constantly ragging it to get on the pipe in 4th.

[martyn dwane]

13.37,9.25,6.73,5.40. are the overall ratio`s with that box and sprocket arrangement, apart from the new close ratio boxes the pacemaker has the least % rise between 3rd + 4th gears , i would have thought that engine set up would pull that with ease
i would check the sprockets first then the gearbox, to make sure you have what you think you have in there.

[Simon_T]

I had pacemaker and 17/47 on my gt186 with bgm clubman. That was perfect. Same set up with jl3 curly was good too. I'd imagine you've got a decent combination there, but it does sound like you're over geared.

I think that pipe peaks around 8000rpm which would give you about 75mph on that set up. Might be a tall order from an untouched kit.

Has it been on a dyno?

Hi Dickie,

had it dynode yesterday by John Gilbert said its almost bang on and made 20.5 bhp.

[Simon_T]

With your crank 60x110 what base packer is used?

norrie,

it has a 3mm base packer as far as im aware or 2.5mm plus two paper gaskets

[holty]

you have a reasonable bit of power as proved by your dyno run, it must be the combination of exhaust and final drive ratio which is your problem, the exhaust wants the engine to rev, but your gearing in 4th wont allow it, I would drop 1 tooth size on your front sprocket, you might be able to use a pull down tensioner and retain your old chain as well, and it should then pull 4th gear.

[MickYork]

I had pacemaker and 17/47 on my gt186 with bgm clubman. That was perfect. Same set up with jl3 curly was good too. I'd imagine you've got a decent combination there, but it does sound like you're over geared.

I think that pipe peaks around 8000rpm which would give you about 75mph on that set up. Might be a tall order from an untouched kit.

Has it been on a dyno?

Hi Dickie,

had it dynode yesterday by John Gilbert said its almost bang on and made 20.5 bhp.

At what rev's did it make it's power ?

[Simon_T]

I had pacemaker and 17/47 on my gt186 with bgm clubman. That was perfect. Same set up with jl3 curly was good too. I'd imagine you've got a decent combination there, but it does sound like you're over geared.

I think that pipe peaks around 8000rpm which would give you about 75mph on that set up. Might be a tall order from an untouched kit.

Has it been on a dyno?

Hi Dickie,

had it dynode yesterday by John Gilbert said its almost bang on and made 20.5 bhp.

At what rev's did it make it's power ?

about 7000 rpm

[Adam_Winstone]

Some of this may depend on how you are trying to ride it. The Fran Race will not really suit someone who just wants to put a bike into 4th gear and then potter around town, whereas it will love being ridden like it is stolen, thrashing it at higher revs around country lanes (on short gearing) or at higher revs on the open road.

Same goes for whether you weigh 7 stone or 17 stone, travel 1-up or 2-up.

Your advance/retard function on your ignition may be playing its part in this too, retarding too far at the higher revs, etc. I thought that Richard Taylor didn't recommend advance/retard ignitions with the GT kits?

If the motor is putting out 20+ BHP then I imagine that it is doing so at reasonably high revs, which also makes me think that it may be short of power at lower revs... but that would take me back to how and where you ride it.


Please note that all of the components are very good and my thoughts above are not to find fault in any of them, rather just reflecting on the how the combination may or may not suit your intended use/riding style/requirement. Indeed, I have experience of all of those components and know them all to be good at the tasks that they are intended for. Knowing that some of my clubmates would love riding such a setup, whilst others would hate it... horses for courses.

Good luck getting it sorted.

Adam

[Simon_T]

Some of this may depend on how you are trying to ride it. The Fran Race will not really suit someone who just wants to put a bike into 4th gear and then potter around town, whereas it will love being ridden like it is stolen, thrashing it at higher revs around country lanes (on short gearing) or at higher revs on the open road.

Same goes for whether you weigh 7 stone or 17 stone, travel 1-up or 2-up.

Your advance/retard function on your ignition may be playing its part in this too, retarding too far at the higher revs, etc. I thought that Richard Taylor didn't recommend advance/retard ignitions with the GT kits?

If the motor is putting out 20+ BHP then I imagine that it is doing so at reasonably high revs, which also makes me think that it may be short of power at lower revs... but that would take me back to how and where you ride it.


Please note that all of the components are very good and my thoughts above are not to find fault in any of them, rather just reflecting on the how the combination may or may not suit your intended use/riding style/requirement. Indeed, I have experience of all of those components and know them all to be good at the tasks that they are intended for. Knowing that some of my clubmates would love riding such a setup, whilst others would hate it... horses for courses.


Good luck getting it sorted.

Adam

[Simon_T]

Thanks for your input Adam,

Like I say it seems to want to go in 1st 2nd and 3rd gear and reaching a high R.P.M and then dies, I have tried 18x47 li 125 with same exhaust and also tried mb clubman and now on a pacemaker box and come down from a 17 sprocket to a 16 sprocket now but unfortunately it still sees the same result as slowing down, so do you see this as a timing issue with the Varitronic I know Richard don't recommend them but I thought I would try it although I haven't tried a static 17 degrees ignition on it

[ULC Soulagent]

Stick a 15 teeth front sprocket on it and see how ya go

[Adam_Winstone]

Thanks for your input Adam,

Like I say it seems to want to go in 1st 2nd and 3rd gear and reaching a high R.P.M and then dies, I have tried 18x47 li 125 with same exhaust and also tried mb clubman and now on a pacemaker box and come down from a 17 sprocket to a 16 sprocket now but unfortunately it still sees the same result as slowing down, so do you see this as a timing issue with the Varitronic I know Richard don't recommend them but I thought I would try it although I haven't tried a static 17 degrees ignition on it

TBH it shouldn't be an ignition issue if it is set and functioning correctly... but could be if not. The whole idea of the auto advance/retard should be to get you the grunt back when revs drop as you change up, however, I know that Richard doesn't recommend them.

Re: pipe choice, I am aware that Eden likes the Fran Race pipes on GTs but I am sure that he'll hear and set them up to suit. Might be worth looking for info from him?

At this stage I would start to consider what else it could be as I would expect your motor to pull 5.2 with the Race, certainly the 5.4 that I think you mentioned. That said, don't forget that AF recommend 5.2 for TS1225s when running a revvy pipe, that has greater CC than your 186.

Good luck with it.

Adam

[Adam_Winstone]

I do note that Cam Lam do recommend straight 5.7 for some of their smallblock kits when running revvy expansions so it may simply be that the gearing is too long for the Race pipe.