Forde's 1980 Honda H100A

[forde]

Well,

Got this wee honey on sunday. 1980 H100A. Needs some work but overall a nice wee bike! Has oil injection, the fuel tank is cool its a split tank with part of it for the 2T oil instead of a seperate 2T tank somewhere else.

Ive already removed the gross indicators and reflectors, hope to start the real work this week.

[forde]

well had my carb apart last nite, pilot jet was mangled and corroded in place too. explains why bike only was running with choke on.

anyway i got it out but its too mangled to see the number?

anyone know what size it should be?

or have a H100 they can check for me LOL

[gazjon]

Nice looking bike, a bloke I worked with cafe racerd his and it look great.

I have used NRP carbs in the past and they have always had what i want

NRP Carbs

[jonw]

Try talking to David Silver. I've found him very knowledgeable in the past.

[dodgerover]

Those engines used to fit into MB50 and MT50's making them a little bit more able to keep up with the traffic

[forde]

Yeah that's why there are hardly any h100 left lol I have been offered an m b to do a swap but not going to do it

[dodgerover]

I can still remember how slow standard MT/MB's were - so slow in fact they made my home tuned Suzuki ZR50-X1 look like a positive rocketship at least i could hit 45 mph (indicated) on a long flat road with no head wind my mates MB used to do 32mph.

It looks a well tidy H100 though, like you say there aren't many left in the same condition as yours.

[forde]

Lol yeah I would love an m t though but it's seriously hard to get a good one now

[forde]

So first thing to sort is the bike only ran with either the choke or throttle on so there was something up with pilot circuit.

Removed tank and carb, going to clean the tank.

Touched up various worn spots of paint on frame with black hammerite, will probably strip it and get frame blasted this or next winter but wanted to prevent it rusting.

Ordered new pilot jet for the carb as it was blocked and also wrecked.

Carb apparently is a Keihin PF25a. But it says PF18 on it, but apparently this is because it is a 18mm carb in spite of being called the PF25a. But carbs are usually named by size that they actually are. I.e. mikuni VM20 is 20mm, dellorto phbg17 is 17m, etc. So I thought it was called the PF18 but apparently not. I managed to get a early haynes that only covers the A model and it states PF25A as well but does not give pilot size.

Can only find info online for the H100S but apparently it uses the same carb? Anyway H100S manual says a 42, and mike on nibikers has an S and checked and he had a 42.

Hole in new jet noticeably bigger than old one. And threads in different place. But all online resources I read stated that all the carbs used the same pilot jets in different hole sizes but same fitting, and this jet was listed as a keihin PF jet (but not officially made by keihin, made by some other company to fit keihin). The threads appear to be the same pitch so it should screw in so going to give it a go.











Thats all for now!

[forde]

[gazjon]

Sounding good.....looks like you have a few other projects in the shed lol

[forde]

Lol yeah and that's not all there is one in the storage shed and the 600 is on the driveway lol

the wee maxi you see there is ongoing at the minute as well, I have a thread up for it too

And the Kwak in the corner is next in line afterththis honda

the scooter I have from years ago might part it out I'm more into older bikes now

[Deleted]

looks good and starts easy enough!

With the jet, it's not just the size of the hole on the end but also the emulsion holes on the side that will alter the mix. A smaller hole with less emulsion holes will flow more due the greater suction through the tube. The mix will also depend on how high up the jet the fuel normally sits as some emulsion holes would be below the fuel level. This can give an initial rich mix on opening the throttle. Your new jet appears to have more emulsion holes so may not be much richer than the old one.As its the pilot jet it shouldn't make much difference.

[forde]

Thanks for the info chip!

Yeah it seems to be alright so I'm not gonna argue lol, it'll not be running on the pilot much anyway when I'm out shredding the streets on it

[Deleted]

Just had another look at your photos, I think the actual jet orifice is the hole at the other end as that is the one that would sit in the fuel. Looks a bit like a choke jet as well although I don't have much experience on Keihin, I'm more used to old dellortos and amals.

Just keep an eye on the plug colour once you head out on the highway! (In the words of Steppen Wolf)

[forde]

Well lads

sorry for no updates in ages, was going to order my parts i need at the start of the month but my work curse word my pay over so waiting until my next pay at start of sept now.

in the mean time i just cleaned up the fork bottoms and headlight brackets as it didnt cost anything. they were painted silver and starting to rust through the paint.

bare metalled with wire wheel



one of the fork bottoms was severely pitted. maybe you can see in pic? its the top one. so painted it with my mates special recipe of fibreglass resin and P45 mixture then left to dry.



Then sanded smooth, and all pits were filled.

Primed with plasti-kote metal primer, then sprayed with hycote satin black and hit it with a few coats of hycote clear lacquer.

Looks mint, thought i took a pic of it finished but must not have, will do so later today.

Havent done headlight brackets yet thinking of leaving them bare metal/polished.

[forde]

thinking about gettin a set of h100s forks as the stanchions for them are still available and mine arent great but no h100a stanchions available. anyone know how much re chroming is i imagine its dear?

[forde]

heres that fork leg i filled the pits and painted, it is the top one in the before photo, the worst one.