#6

[koba]

I wouldn't bother, there are many cheap slide carbs about that would be OK on a 125 4V cylinder to get them going...

[speedpro]

Another lesson learned. Actually it's an old lesson that I have been reminded of. I've measured the cam timing as installed using the marks. It was way off and made no sense. Amazing it ran actually it was so far off, with the intake closing VERY late, hence the blowback from the carbs. I spent a bit of time trying to find why and finally found it. The holes in the end bosses which I used as timing marks aren't timing marks. They are probably used in the manufacture of the cams as the holes line up with the lobes.

The timing marks are actually little indents in the outer rim of the bosses on the end of the cams which line up with little nipples on the top of the cam bearing caps on the left of the engine. The left of the engine is gone but the cams still needed to be located in the head so I flipped them over. They now actually rotate backwards compared to original. It's OK as the cam lobes are symmetrical. The problem is that I can't line up the proper timing marks as when the cams are installed originally the lobes will be at a certain angle and the valve stems and tappets are at another angle. With the cams flipped over the lobes are still the same angle but from the cams point of view the vavle angle is now in the other direction. I have to make an allowance of twice the valve inclined angle.

I had to give it up earlier as it was doing my head in. I've found the problem though so it's just a matter of getting it back together properly, and measuring it to make sure. I'll punch a mark in each bearing cap for cam alignment once I have it sorted.

[Grumph]

Ha - normal yamaha....They're masters of three things.

Timing marks you have to search for - hard.

The last hidden bolt in the cases....

Orphan bearings - I've had a theory for decades now that a yamaha designer has a brother in law who owns a bearing company.

[speedpro]

Cam timing all sorted. It seems that Yamaha measure their timing at .2mm. It's ended up at about where it was originally setup which is no real surprise. The intake is now advanced about 45 crankshaft degrees and the exhaust is retarded about the same amount.

I had a look at the carbs and moved the needle up one as it seemed lean to me just as the slides came up. It started fine at about the 4th push and revved a bit better. Took it to JC's this arvo and ran it up on the dyno. It fired up OK and seemed to rev OK without load but wasn't happy having to work. John retarded the timing which helped it take throttle under load. We did one run which sounded OK to a point. The slides moved up as the revs rose and than stalled as the motor hesitated badly. It made a whopping 3hp. I thought it was running lean so chucked bigger mains in. Next run saw the slides move fully up though #2 seemed to stick at about 3/4. Finally as the revs climbed it popped fully open. The motor finally pulled decent revs and was starting to sound serious. This time it had about 8hp I think. After a couple of bigger mains we had it making 13.?hp and revving real clean. John has had 600s on the dyno and builds the mighty JCR CB150Ts which rev pretty hard. Even he was impressed with the revs and suggested a tacho might be a good idea. I was wondering a bit myself. The power only dropped off when I shut the throttle after chickening out. It has huge standoff, about 2-300mm when on song. The carbs are open with no stacks or airbox. We had to call it quits after an o-ring failed on a coolant pipe and it sprung a leak.

Anyway it seems like it will be good enough to try as it is though an airbox would be ideal. After a couple more dyno runs, jets and timing it should be good to go.

I check out the EcoTrans system for the Ninja 250R. The throttle body will drop straight in as the dimensions are spot on and I'm hoping with a 3bar MAP sensor it'll handle running boost.

With standard FZR250 gearing it pulled to over 160K. Definitely going to need an even bigger rear sprocket.

[speedpro]

The new engine has been tweaked but the carbs are still a problem as they don't respond properly to throttle and revs. We can tune them and get good responses on the dyno but they aren't right. I've parked it until I can get the fuel injection and engine management installed. There's a video but it cuts out at 15,???rpm as the camera didn't like the noise in the room. Currently the pipes are just a length of pipe on each cylinder. The power climbs all the way to 18,000rpm. The engine likes 10,000rpm to get the roller turning in first but is quite happy at 4-5,000rpm after that. At full throttle the carb slides start to pick up at about 5,000rpm and don't top out until about 14,000rpm and #1 beats #2 to top by about 2,000rpm so obviously a lot of work required there. I've always intended FI so this seems a good time to go for it.

http://youtu.be/3hwezxF-Jmo

[goose8]

I would like to thank Mike Green for letting me use his motor, an Dave Manuell for letting use his bike now the fun starts getting the motor in and everything together before the gp Team Shnanny Green is going to give it a good crack this year.
Cheers Gary

[richban]

I would like to thank Mike Green for letting me use his motor, an Dave Manuell for letting use his bike now the fun starts getting the motor in and everything together before the gp Team Shnanny Green is going to give it a good crack this year.
Cheers Gary

Shit........

[koba]

I would like to thank Mike Green for letting me use his motor, an Dave Manuell for letting use his bike now the fun starts getting the motor in and everything together before the gp Team Shnanny Green is going to give it a good crack this year.
Cheers Gary

Hmm, if this is the 30hp jobbie it could get interesting!

[ac3_snow]

Awesome! there is going to be a lot of fast bastards on very quick bikes by the sounds of it.

[Rick 52]

Haha Great news Gaz, I know who to vote for now

[bucketracer]

This has to be one of the most exciting GP's

[TZ350]

Awesome! there is going to be a lot of fast bastards on very quick bikes.

Ditto 2 what he said, this is the must see GP.

[speedpro]

Couple of hours ar Darren's last Sunday making brackets, 1-2 hours each night Mon-Thu after work and all day today, 7:30-4, but it's ready. Gaz bought a new shock(with damping) so it should handle a lot better and let him get on the power earlier.

[husaberg]

Couple of hours ar Darren's last Sunday making brackets, 1-2 hours each night Mon-Thu after work and all day today, 7:30-4, but it's ready. Gaz bought a new shock(with damping) so it should handle a lot better and let him get on the power earlier.

That radiator seems rather Big for a thermosiphon head only setup? ductape?
I love the look of those Aprilia chassis, they seem to mimic the GP 125 for geometry to i think.
Back old school it was all bigger engines in smaller light chassis we seem to be making stuff stiffer but heavier now?

[Sketchy_Racer]

Yeeeahh buddy, can't wait to see/hear about the GP with garry on that and richban on his FXR, it's going to be ferral out there, gutted my bike is so far away from being ready to race. Damn work!