SST 250 rebuild

Re: SST 250 rebuild

BaZa? said:
Out of interest Neil what colour red did you decide on? Getting muddled up with Chiefy's Chipper :D

So did you get the original colour?
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As close to the original plain red original colour as i can get made having it matched off that photo! Chiefys wants his a metallic red called sparking red:D which was a x90 specific i believe
 
Re: SST 250 rebuild

banquo said:
Much simpler in my day; imagine ruining that simple concept by adding an extra valve... even if it is a reed valve...

Good luck with that.

Old article here about the 125. Even that had a 34mm carb.
Click to expand...

Got my eye on a 34mm carb
 
Re: SST 250 rebuild

First off,wrap something round that piston,to stop it banging on the cases.:)
Has that new cylinder got a plated bore?By the size and spacing of the fins,it looks like the one used on the Harley MX250 around 1978.
If the bottom end feels ok you might get away with it.The weak point on 2 strokes that have been standing,is the crank seals,they go hard and tear when put back in use.You'll know when you go to start it,if the seals leak,you get no primary compression,and the fuel collects in the cases.
 
Re: SST 250 rebuild

Hi Dave Piston is off now i promise:D

The barrel has a nikasil lining yes i have decided to send it all back as i think its going to be to much fussing around to try and get it as it should be and still have the risk that it could possibly never work, have a colleague in Italy looking up a local friend of his who specialises in old Italian bikes, he may have a complete running engine which would be the better way to go i think
 
Re: SST 250 rebuild

chopper said:
Old Barrel

20120727_203340.jpg


New barrel

20120727_203344.jpg


Old intake

20120727_203416.jpg


New intake

20120727_203407.jpg
Click to expand...

Hi Chopper,

Do you know what year that Cagiva 250 barrel was (unless I missed something)? Normally the HD SS/SST250s were piston port only, so it appears Cagiva modded w/ reed valves.

Does it have anything written near the base of the cylinder?

I have another SS250 and am wondering if it is worth upgrading to a reed valve cylinder for smoother performance (although the piston port version does go quite well).

Thanks,

Ian B.
 
Re: SST 250 rebuild

Till his return,I'll take a punt.
As above,I believe that to be from the Harley MX250 around 1978.I don't know about smoothing out the runningof a standard SST.
The reed valve is usualy fitted to give back the bottom end power,that is lost with agressive port timing.
 
Re: SST 250 rebuild

Thanks Dave,

Ian no markings on the barrel but from the research i have done it looks to be from a early 80's cagiva as they changed the design of the top end around that time, i have decided to send it back for a refund as im concerned if it will ever run correctly, i have managed to source a complete late 70's working engine direct from Italy which is on its way at the moment and should be here later this week early next. From what i have found out the later cagiva engine fits perfectly as it has the same mounts (along with three or four other makes) and is apparently a better, smoother engine but if it where me i would be going for a complete motor instead of trying to graft on pieces.
 
Re: SST 250 rebuild

Urrell said:
Now I'm confused :frown:

Ports in barrel and a bare head :eek:

$%28KGrHqV,%21hUE7Vtk%21MqTBPHKid3k+w%7E%7E60_12.JPG


540289160_tp.jpg
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its more the shape of it that looks wrong, the 2 stroke is a square barrel and the exhaust is spring held instead of bolted as the 4 stroke is
 
Re: SST 250 rebuild

chopper said:
Thanks Dave,

Ian no markings on the barrel but from the research i have done it looks to be from a early 80's cagiva as they changed the design of the top end around that time, i have decided to send it back for a refund as im concerned if it will ever run correctly, i have managed to source a complete late 70's working engine direct from Italy which is on its way at the moment and should be here later this week early next. From what i have found out the later cagiva engine fits perfectly as it has the same mounts (along with three or four other makes) and is apparently a better, smoother engine but if it where me i would be going for a complete motor instead of trying to graft on pieces.
Click to expand...

Thanks gents for all responses. I know what you mean re. the top-end - i spend a fair amount of time looking on Italian sites and the later Cagiva SST250 / SST350 do have 6 head bolts vs. the earlier 4 bolts. I had previously not been able to determine whether they had also incorporated a reed valve-mod, but your pics seem to confirm they did. I would also guess they incorporated some of the work done on the AMF-HD MX250 motocross bikes as the head / barrel design seems very similar. Polini also appears to have made aftermarket cylinder blocks in the 70s/80s and these appear to have reed valves. Krizman (US) appeared to offer a reed valve conversion for the competitive flat-trackers.

My SST250 barrel also has considerable damage (scoring / broken fins) and I will have to source another for Nikasil / piston matching. All the AMF-HD SST250s should have either SX250 or SS250 at the base of the barrels (SX was for the Enduro version, but AMF-HD quality assurance was not exactly world class and you can have either, as the SST pre-Cagiva SSTs did not have any additional block mods to the SX/SS.

What I have not been able to determine are the dimensions for the SST350 cylinder / piston / crank, although apparently they use the same crankcases...

My own engine is next and undergoing a full rebuild w/ new bearings / seals / crank / piston etc. My own restoration (although slow) is progressing at AMFSST250. I just got the rims back which unfortunately were damaged in transit so this has slowed things a bit. The work done before shipment was superb. Shame.

Chopper - just out of interest, can you tell me what tires you have on your SST and what rear shocks you are planning to use?

Thanks,

Ian B.
 
Re: SST 250 rebuild

AMFSST250 said:
Thanks gents for all responses. I know what you mean re. the top-end - i spend a fair amount of time looking on Italian sites and the later Cagiva SST250 / SST350 do have 6 head bolts vs. the earlier 4 bolts. I had previously not been able to determine whether they had also incorporated a reed valve-mod, but your pics seem to confirm they did. I would also guess they incorporated some of the work done on the AMF-HD MX250 motocross bikes as the head / barrel design seems very similar. Polini also appears to have made aftermarket cylinder blocks in the 70s/80s and these appear to have reed valves. Krizman (US) appeared to offer a reed valve conversion for the competitive flat-trackers.

My SST250 barrel also has considerable damage (scoring / broken fins) and I will have to source another for Nikasil / piston matching. All the AMF-HD SST250s should have either SX250 or SS250 at the base of the barrels (SX was for the Enduro version, but AMF-HD quality assurance was not exactly world class and you can have either, as the SST pre-Cagiva SSTs did not have any additional block mods to the SX/SS.

What I have not been able to determine are the dimensions for the SST350 cylinder / piston / crank, although apparently they use the same crankcases...

My own engine is next and undergoing a full rebuild w/ new bearings / seals / crank / piston etc. My own restoration (although slow) is progressing at AMFSST250. I just got the rims back which unfortunately were damaged in transit so this has slowed things a bit. The work done before shipment was superb. Shame.

Chopper - just out of interest, can you tell me what tires you have on your SST and what rear shocks you are planning to use?

Thanks,

Ian B.
Click to expand...

Hi Ian,

i am using Avon road runners, nice grippy road tyre that should make it fun to ride in the twisty's, as for rear shocks i was going for Hagons originally but ended up getting some SHOX all black ones as i managed to get them really cheap (M and P) and they were recommended by a friend who uses them on vintage bikes so they were worth a gamble if they are no good then I will get some Hagons later on.

As for a replacement barrel you will be hard pressed to find one from my experience of the last few weeks. they are very few and far between, i was contemplating getting my fins re-built and the barrel Nikasiled etc as i couldnt get one anywhere. My barrel (original) has no markings on it that i can see

Ian, is the one your restoring the metallic brown one i have seen on 250cc forum? i posted on your thread if so.

cheers
Neil
 
Re: SST 250 rebuild

chopper said:
Hi Ian,

i am using Avon road runners, nice grippy road tyre that should make it fun to ride in the twisty's, as for rear shocks i was going for Hagons originally but ended up getting some SHOX all black ones as i managed to get them really cheap (M and P) and they were recommended by a friend who uses them on vintage bikes so they were worth a gamble if they are no good then I will get some Hagons later on.

As for a replacement barrel you will be hard pressed to find one from my experience of the last few weeks. they are very few and far between, i was contemplating getting my fins re-built and the barrel Nikasiled etc as i couldnt get one anywhere. My barrel (original) has no markings on it that i can see

Ian, is the one your restoring the metallic brown one i have seen on 250cc forum? i posted on your thread if so.

cheers
Neil
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Hi Neil,

Thanks for the information. Yes - mine is the bronze SST250 on 2fiftycc.com and the link I sent. There are not many people redoing SSTs and there can't be that many left after 30 years, so I am interested to see what others are doing.

My block is not as messed up as yours - there are a couple of places in the US that repair / port etc. for classic flat-trackers. I got a quote for welding / Nikasil / fin repair and helicoil / thread repair, but it is pricy, especially after all the shipping. My piston is toast and I want to replace the piston the bike came with (I believe it was a VERTEX) as it has bigger skirt ports than the earlier AMF pistons. I will have to make a decision soon as it will soon be time to reassemble (finally).

What did you decide to do re. the front brake setup?

BRGDS,

Ian B.
 
Re: SST 250 rebuild

Have ignored the brake for now as i have enough to get on to get the thing a runner etc. have new pads and a braided line to fit when i get it going but if its really bad will look at upgrading it
 
Re: SST 250 rebuild

Guess what I found in my porch when i got home from work last night!

motor.jpg


was posted from Italy Thursday last week!

and an hour later after i had eaten my dinner and put the kids to bed

motor1.jpg



Had the head off to check out the state of the barrel and piston and they are both in excellent condition, its an exact match for my earlier motor, intake and exhaust are the same etc, only difference so far is the electrics from the alternator but i can transfer over the ones from my motor so no problem with that!

Motor spins over on the kicker easily with no issues so will get the carb cleaned up and fitted and the wiring sorted and may even have it running in the next week or so.

need to check/replace my coil as im getting no spark from it at the moment but that could be a wiring issue
 
Re: SST 250 rebuild

Nice. Definitely the AMF engine or looks like a crossover '78/79 Cagiva engine, as it has the unmodded clutch cable assy by the looks of it. Good score - should save you a lot of hassle. Looking forward to seeing this SST back up and running.

Ian B.
 
Re: SST 250 rebuild

I know where there is another motor the same (from the same seller) if anybody knows anyone who wants one.
 
Re: SST 250 rebuild

Too much work for me but fair play to you for the work so far :wink:
 
Re: SST 250 rebuild

Paint is back at last!

20120927_135149.jpg


20120927_135156.jpg



all the panels were in a proper state and needed alot of work to get them to where they are now. Very pleased with the results and the colour!

Just need to sort the engine now!
 
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