Will I get my 100 ready in time for Taupo?

[speedpro]

My method with a head plate with under the studs and then small brackets to connect it to the chassis works well. I transferred my engine to Dave's RS50 and just made another plate and little brackets to connect to his chassis. The plate is at right angles to the bore so the worst vibration is fed solidly to the chassis which has worked well for me. Plus it provides a handy place to mount ignition coils and stuff.

[F5 Dave]

OK so epic fail. Did practice, few drips. Topped it up. Race one it started off ok but was making a funny noise, few laps in I was spending more time looking down so decided to pull in. Was in comfortable lead but something wasn't right. Didn't get to go head to head with Rich to see if fast or not.


had a quick look. . .

Side of jacket was missing. Oops. Couldn't swap to ac head as forgot shorter head sleeve bolts.

ok weld it time. 50 did the biz for rest of day.

[kel]

I transferred my engine to Dave's RS50

About that, isn't it time the motor was returned to the FZR chassis? Those boys can't be trusted don't you know.

[mr bucketracer]

Yeah I haven't ridden the F4 many times, but one of the more memorable races was Taupo that year it rained cats & dogfish. I crashed the H on the old turn 1 flat out & had to kick the bike away 3 times before I was free of it & hit the dirt still sliding fast. I got to it pulled the clutch & jumped back on & tried to take off in 6th Bwooah, change change Bwoahhh, change change & was off again, left side of bar twisted in 30degrees.

I was running old Yoko 110s, but the front was virtually bereft of tread so I figured I'd just go for it. There was quite an attrition rate but I also found a groove & was hauling in people, not that it mattered I figured. But I saw Dave ahead in the distance & the red mist came down so I passed him & gapped a little. No doubt this caused Dave to figure there was some more traction & he started hauling me back bit by bit & I was getting the feeling my luck was running fine every time the front tucked on T1.

I got taken a bit off the track by a madman Grifith on the hubcentre 100 when he passed me & promptly crashed & I think that's when Dave got close enough to pass. We only had a couple of laps to go but I figured there was no point battling for a nowhere position. Little did I know I'd been in 2nd place for a good deal of the race.

But the funny part of the story is when I came back to the pits someone said Gee Dave, - your bleeding! Eh? Sure enough dripping out of my leathers. Sheet!, didn't even know I was hurt! Took the leathers off which now weighed about 40kg, remember it had been raining heavily & I'd done the F5 & F4 GP. My leathers were leaking a heap of red dye. Phew!
....( the bad griffiths got the best crash of the day award to ) what a slide!! ) sorry old post

[F5 Dave]

I can still remember it pretty clearly , brave,but you were never going to stay on long on slicks at that speed in that deluge of rain. Or if you did what would I have done for an excuse?

[mr bucketracer]

I can still remember it pretty clearly , brave,but you were never going to stay on long on slick at that speed in that deluge of rain. Or if you did what would I have done for an excuse?

as i remember it went for alot of laps , i was thinking where is the limit on this bike so pushed it harder and harder . coming off had to happen some time . just peed off the ziffle bike broke a wire . i was leading it up to then . then thought dam it i will ride the centre humb for the rest ever though 2 laps down. l know dennis that won it was not pulling away from us . coilen never told me it empteyed the float boil all the time to.

[F5 Dave]

ok well here is Mk2 version. Same same but different.

Bottom where it attaches to the casting has gone a little porous, but is to be expected with crap 70s Honda castings. 2 stroke gets impregnated in holes, could be smelt when welding apparently.

Either way I'll chemweld treat it & hopefully it will do the biz. Shouldn't fall apart this time! Hope it hasn't gotten too soft.

[F5 Dave]

Well a bit of luck, as I pansied out of riding in the wet I figured I'd take a quick trip to the dyno instead. Ran the bike up. Temp was slowly increasing (sensor in top of Rad not head as it gets interference from plug + its std RS position). But put hand on head. Hmm, that's hot! much hotter than before when it was realll cool. Then it got really quite hot. Carefully took the cap off & localised boiling.

Put a battery on & turned it on. No noise from the pump. Tried the spare pump I just bought (isn't fitted to swap over yet). It worked.

Got it home & found a wire broken. Pump juts against engine, so vibation at the interface could have broken it. Rewired it & made a pad + shortened a hose to reduce the issue.

Glad I didn't race it, I wouldn't have noticed.


Which made me wonder. Obviously this had happened in the last race meet. A contributing factor in my Devcon'd head falling apart?

[Drew]

Which made me wonder. Obviously this had happened in the last race meet. A contributing factor in my Devcon'd head falling apart?

The rattle from the devcon'd head was there on lap one. Got worse on lap two. Next time or time after that you came round, and the bit bounced out and accorss the track. After one lap, I wouldn't haved thought it would be over heating...other than not having any water in it.

[F5 Dave]

Could have stopped working in practise session before. Warm up laps would have easily overheated a non circulating system. It was quick to get real hot.

[Drew]

Could have stopped working in practise session before. Warm up laps would have easily overheated a non circulating system. It was quick to get real hot.

True. I would have thought that the radiator cap would have vented before the pressure pushed the head apart. But the system is hardly tried and true, so maybe not.

Lets work on the theory that the welded head will stay flat, and never speak of it again aye?

[F5 Dave]

Well here's the next inevitable step. Milling the fins took several hours & although I would have preferred the have a central inlet & outlet I opted for diagonally opposed for packaging reasons, like the outlet at the front has to go through a formed bit of Rad hose to the head & the bend is too tight to do it centrally. Similarly the rear entry (ooerr!) has to miss the head stay to remove barrel in situ.

The front above the ex is narrower but it is deeper so shouldn't be a restriction so hopefully flow around both sides will be equal.

I now have some toque plates so we'll clamp the barrel & jam it in front of a fan heater before we hone it. Hopefully this will reduce the ring seal leakage to, . . .well a lot less than 35% it is now, target 8% like a KT.

Next run Kaitoke 15th, then BOB Ruapuna.


I've also made up an inlet manifold for the 36mm carb so I hope I get the chance to try that out & perhaps gain some enormous advantage.

[jasonu]

Well here's the next inevitable step. Milling the fins took several hours.

Why did you mill the fins off? I used to somewhat carefully bust them off by using a prybar between the fins then finished off the stubborn buts with an angle grinder with a 4.5" hard disk. Never took more than an hour.

[F5 Dave]

The Honda ones are a bit keen. I angle cut off the main work, but I wanted to retain the top & some of the 4th. i wanted to get them a bit flush so the passage could be fairly narrow which is better than a big bucket. Esp as the water pump I'm using isn't particularly high volume.

[F5 Dave]

Well back together & pump seems to circulate water ok, if not super enthusiastically, the rad is large. Anything 70degrees or under is worthwhile doing for 80% of the effect. I'm hoping for 50, but I might need the flash pump & not sure the stator would drive that, the ignitech & the PJ solenoid all at once. + its a bit too spendy at the moment.

jammed the barrel in the heat chamber with the mondo torque plates a mate made up & whisked it up to be honed, but sat it in front of a fan heater. Hone came up best its been, but need to see if this translates to better sealing. 35% leak is miserable.