I was recently told by Skellerns in Cheltenham that buying a 4FL head from a TZR would be beneficial to the cylinder / piston combination I will be running, but I'm not entirely sure what they mean by 4FL. From what I've read, 4FL is a model of the bike not the number written on the head / cylinder.
Anyone know what number head I should be looking for? Is it called a 4FU? 4DL? Or as they told me, 4FL?
I don't understand why they said That!? Very Shocked! The 4fl I was under the impression that this was the same as the 4hw which is the name given to the European spec tzr 125 r. Which if you look at the head has a combustion ring on it which is not good for performance. So I'm at a loss. Scrim may be able to shed more light on this.
As far as I know there is no 4FL. The closest would be the 4FU head. I don't even think there was a 4DL head. The barrel was marked 4DL ( the real 4dl barrel) but the head had no markings at all.
I thought the 4FL was the R model that used the tzr250 3XV fairings and frame. The fairings looked almost the same as the series 3 4DL but were slightly different.
The frame was similar to the 4DL but again was slightly different. If you compare you'll see a triangular gap in the 4FL Frame just below the tank. On the 4DL ( 3MA) there is no gap.
I think it's a flat top piston with 4FU barrel and head atm but the 2 stroke expert at Skellerns said I could see between 5-7 hp increase running the TZR 125 R 4FL head.
Yes they do exist the part number is 4FL-11111-00 from 93 and 94 only models of Japanese built TZR125R never seen one and have no idea what it looks like. It mates to the same cylinder barrel 4FU-11311-01-00 used on the Deltabox frame TDR125.............
Oh and they cost 253 quid new available to back order so you MIGHT be able to get one.
Ive tried google images but cant find any pics, I would try the TZR forums might be something on them info wise.
Now I'm interested Mightyman. get us a photo up. I knew skellerns would chat pure ****. I know that two strokes make most of their power in the cylinder head. So this is interesting
Well if they can actually live up to what skellerns are quoting I would definitely be willing to buy one brand new! Was actually considering it but wasn't too sure if they existed so thank you for confirming! Now the hunt begins ;)
Or pay a specialist two stroke tuning £30 to port your cylinder head....In fact £170 will port and gas flow your barrel and head and modify the powervalve
Better mate. The 4fl head will be ported for a road bike. £30 you can have it ported for a track setup. Check my build thread and you'll see the porting work to the head and barrel of my 4dl engine. The exhaust port has been enlarged significantly. The head reworked.
Mate you sound quite enthusiastic. Buy a book called Graham Bell's two stroke tuning. So interesting and I think you will enjoy it. Really technical but explained simply.
Well worth paying the £30 and have it race spec tuned. As for reliability and fuel economy I'd say it's the same. Ride my ported bike every day and it's never missed a beat.
