GT250 build

[Eden]

I had a laps of concentration today on the M5
The GT250 made it to Dorset and back today, nearly run in now




this is a very short video clip

[Dom]

Fuck me , that's impressive

[Eden]

its running like they do just before they blow their self to pieces but ye I have to admit I was a little surprised as you can see from the motion of my left hand it defiantly pulls 4.7 better than the 230

[Eden]

some footage still not quite run in but riding in really shit weather. heavy head wind, met office says that in that area the wind yesterday was mean 28mph gusting to 55mph. it wasn't nice at all.

Video from the journey home yesterday from the trade fare and custom show in Coventry
,, shows the A45, a bit by J9 M42 and a bit on the A38. its long but after watching it ive decided that im not going to put a longer box in it because it just about right, it needs to be able to ride in shit weather in top gear and if I make it longer it wont!

Im happy with how it pulled, or rather that it did manage to pull 4th in that wind. Not the best conditions to be putting the engine through as its all new, its still set up rich which you can hear later in the video as I pull away from an island.

[Mr G in NYC]

Looking good that Sounds nice as well ! G.

[Captain Pugwash]

What sort of average MPG are you getting now as its run in a little more and the speeds are picking up ?

Certainly does sound good, and looks like it's a very smooth pulling engine from very low down RPM

[Eden]

Ill make a note next weekend what mpg it does compared to the others ill be riding with, currently I don't think its as economical as the 230, but it does have a little weep on the fuel tap, I've got a new one to fit but not had time to fit it yet

[Eden]

I changed the fuel tap and while doing so noticed that the step down carb rubber had split. I had intended to use my 35mm Airstriker carb on the 250 so I fitted the 35mm manifold but because I didn't want to run it in on the airstriker I had fitted a step down rubber and used the PHBH30mm. As the rubber was split and the motor had nearly 900 miles on it I decided to fit the airstriker.
I took it out with the same settings as I run on my cast 240 just to get an idea of how far off the jetting would be on the GT250 and found that it was rich at 1/8 to 1/4 throttle and then weak from then all the way to wide open. I have about 12 needles for that carb so chose the one that slightly weakened it at 1/8-1/4 and richend it 10% from 1/4 to 3/4 and also put the largest main jet I had in, I knew the main would still be too weak but as the carb has a power jet I figured I would be able to work around the main using the power jet, I also put a larger pilot jet in too so I had a rich area to drop into for safety.

Not a great idea the day before doing a 350 mile day trip to Scarborough but that's the position I found myself in so off I went.

it only took a few miles on the open road to make it obvious that even though I had richened it up as much as I could with what I had, it wasn't enough. When I used any throttle position above 1/4 the temps went up steadily and as the only rich area I had was at 1/8 I had to ride at that throttle position. not great but, it got me there and back.

This is the video from the first fuel stop, it shows how much fuel I used compared to a TS230, a TS225 and a slightly ported GT200.

PG rating on my language

[Scarborough Col]

Enjoying this thread Eden,
That's Woodall services M1 northbound isn't it...???? is that only 59 miles from you lot... I struggle to get from Woodall to Tamworth services heading south....
Isn`t Woodall the services you got some shite fuel from en route back from Catcliffe last summer.....???

keep the video`s coming..

[Eden]

yes it is Woodall, the bad fuel last year was fuelsaver from the southbound side, its 59 miles from the fuel station we all meet up at near Lichfield. Our next stop going the direct route would be the small place on the right near Malton, however, we didn't go the direct route on the way there as we had to sticker bomb a sign post in a certain village, we actually filled up on the other side of Beverley on Saturday.

You would carry on down the M1 to the 42 to Tamworth I presume, we go down the A38.

[Eden]

Bit of an update on my GT250...

Ive mainly rode it all year but had to make some changes after the head gasket blew out at the end of April. I was running a head gasket to get the squish with the port timings I had intended. As I had ordered a new lathe I didn't bother to get the head sorted by someone else as I wanted to do it myself so I just ran the motor with more packing at the base and no head gasket. This increased the exhaust and transfer timing to much but as I thought it wouldn't be for long I was happy to run it like that.
The lathe didn't come till September so I have ended up running with the over long timings all year, however I have now done the work to the head, rebuilt the top end with the intended port timings and taken it out for the first time today.

It runs slightly leaner than it did before but it has regained the mid range pull that it had before the gasket failure.





I've cut the recess deeper so I can run the piston higher in the bore... its only 0.7mm deeper, but that's enough to get the transfers to where I want them




Just in time to blow it up over Brid weekend

[Stevepshipley]

Jeez, that looks quick and sounds good

[LateAgain]

Good stuff Eden.

[Dimitrios_231]

[Eden]

Last Friday going to Cleethorpes two up with luggage on my GT250, 130 miles in 2.5 hours.

Video is a bit long so I doubt anyone will watch it all but I uploaded all of the trip to give a real world view of a typical journey on this motor.

I needed to get to the camp site before dark to pitch my tent.