Hybrid Project - RD250 AC/F2

[toffee]

got a few hours in the garage today to tighten up the engine mountings, fit a new powerdynamo and fab up some simple brackets for the coil and rectifier.

I used some 4mm plate aluminium offcuts and repurposed a previously discarded bracket. So a bit of cutting and grinding and some bolt cutting was done today.

I am a bit dissapointed, I managed to damage the paintwork on the front engine mounts while tightening up today. Ill get a small can of touch up paint somewhere...

[toffee]

Spent a good bit of time in the garage yesterday working on the electrics.
I have a few problems which need attention.

I have on key position I working high and low headlight with indicator light on the clocks,
I have a flashing stop lamp indicator but no taillight or brake light.

on key position II I only have the clocks illuminating.

The last thing I fitted was the neutral switch cable and realised I have the selector drum fitted incorrectly.
I have a neutral light coming on in 1st.

looks like it will be engine out and crankcases opened, 1 step forward and 2 steps back

[toffee]

yup, but it wasnt too bad, so far.

The engine is back out and on the bench after a big clean up of the electrical mess on the bench.

Gonna investigate what is going on with the gearbox.

[toffee]

With the engine out and neutral position in the gearbox resolved I cleaned the cases again and applied fresh gasket cement.
The engine was buttoned up, the stator reassembled after some modifications and fitted.
here is the thread http://www.2strokeworld.net/forum/index.php?topic=855.0

The mods included removing part of the crankcase to help the base plate sit flush. Fitting 2 extra countersunk screws to two plates where
there was initially 2 screws and applying some gasket cement to prevent a possible shorting event from wires vibrating against the housing.


With the engine in the frame I started assembling the wet side of the engine, Kickstart and gear change mechanism fitted.
[/div][div]I had to fit 2 new screws/bolts to one of the retaining collars, 7 years ago when I disassembled the engine the original screws
[/div][div]had to be forceably removed. I used stainless bolts with blue thread lock.



I am a bit confused [again] I see to be missing some sort of retaining collar from the clutch shaft, there are 3 screw holes,
2 can be seen to the left of the shaft. I cannot see this part on any schematics.



So moving on I decided to prep the clutch basket, I filed down the groves on the basket and give all the parts a good clean in
some fresh petrol, next up is the clutch build.

[1976RD400C]

Here's a pic of the plate with 3 holes. Number 41 on the parts breakdown of the transmission. Looks like you have a plate with 2 holes? Does that fit there? I've never seen that part.

[m in sc]

the 2 hole plate with the return is for the shift drum end. luckily, you dont have to split the cases.

the 3 hole goes behind the clutch, its the bearing retainer.

[toffee]

Thank you sirs! I got one ordered today, turns out I was missing
the circlip to hold the gear change shaft along with the rubber protector
for the shaft.

thanks for the help.

[toffee]

Waiting for parts to arrive so got a few bits done in between tinkering with the electrics . . .

When I bought the engine years ago there was no clutch cable holder and they cant be got
as a spare part that I know of.  So from a 25mm diameter aluminium rod I cut a slice off
drilled a hole and dremeled the under side to slide into the crankcase location,
works perfectly!





The clutch push mechanism needed a good clean, and it turned out quite well from all the
insulating crap which was on it there was surprisingly very little rust or corrosion.

[toffee]

working towards the timing I got the intake installed on the barrels after some cleaning and de-oxidization of the reed cage. I used a stainless steel dremel brush in a tap handle to clean up the cages.





Installed the pistons and barrels. These were vapour blasted a few years ago and still looking great (after being wrapped in brown paper and stored under the bed)

The pistons are "speed" branded and marked for 250DX. 2 rings with the bottom ring slightly thicker than the top, I cant find any info about them.

[toffee]

Small update while waiting for parts, I fitted a different Aprilia front caliper (ive a few of them with new seals) as I didnt feel the red didnt suit the dull gold of the rear. I made up a new Goodridge braided line with stainless banjos. I was short a stainless banjo bolt with the right thread pitch so fitted an old one anyway.

Got the reservoir relocated for a better pipe connection to the master cylinder with new clips.

[toffee]

Im using a standard YPVS F2 airbox but an issue has arisen and I see a problem ahead connecting the carbs to the airbox rubbers.

The carb to cylinder inlet rubbers dont line up with the airbox rubbers, hopefully there is enough play in the rubbers to make everything connect.

I need to setup the carbs after the ultrasonic clean and rebuild the had recently.

Im thinking I may have to get an angled reed block spacer made up to correct the angle of the carb?

[toffee]

apologies for jumping over and back on various parts of the build.
I received the bearing retaining collar last week and needed to pick up a
29mm socket for the clutch centre nut. I was hoping to get the clutch
basket installed last night but proceedings were halted fairly swiftly.

When the centre nut is torqued to 60nm the clutch is fully locked up,
nothing will turn (easily) the inner basket will turn seperate to the outer
only with a ratchet on it. the two are obviously mated together.

I recon I have all the parts in the right place though....



Bearing retaining collar
stepped washer which sits into the above collar
spacer with worm groove
Outer basket
Thrust washer
Inner basket
Domed washer
Nut

the first image below shoes the nut on the shaft, forgot to remove it for the pic.

[m in sc]

2 things:

yes, try angles spacers or you may rip one of the boots.

there's differences in washers and spacers from earlier to later motors. the earlier motors used the stepped washer behind the basket, the later ones didn't, they were just flat if i  recall correctly. .i suspect you have the years crossed somewhere. there are thickness differences.  you will need a washer from 74 or 75 i think.

[toffee]

Yes correct, thanks m in sc!

I did a bit of tricking around with it this evening, I think I have the wrong thrust washer.
I recon the correct washer is quite thin.
I can tighten up the nut to 60nm and the centre hub still turns, I going to order a 74/75
thrust washer and see what happens.

Hub with thrust washer fitted behind pushes it out over the splines by quite a bit


Hub without the thrust washer sits flush with the splines,
it seems the nut and dome washer actually tighten up against the splines rather than against the centre hub!

[toffee]

Finished the ignition system today by setting the timing and fitting the flywheel followed by fitting and torquing the heads.

The gap betwen the pickup and the ramp on the flywheel is set to 0.016 and the timing set to 1.89mm BTDC.

The heads were fitted and the newely coated red head bolts torqued to 19nm.