Honda H100S... Feeling a bit gutless or purely psychological

[eunos20b]

HI all,

Recently bought a H100S, has been converted to run premix (I found that out the hard way) running about 30:1 atm as I was told the more oil the better on these old ones. I'm newbie to bikes let alone 2 strokes.

Anyway it runs brilliantly but I've seen/read that it's meant to be able to hit 60mph. Now I don't care about going fast but stretches of road between my house and work are 50mph, and to even get to 50 - and this is if I'm lucky - I have to lie on the tank with no wind and a slight downhill. I've also always been led to believe that 2-strokes enjoy being revved, but this bike either doesn't feel happy to rev or the peak power is very low in the range. It's very torquey as well.

Apart from that, starts first kick every time and is in great working order. Any ideas? Thanks
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'90 Honda H100SII (SJ)
Learning something new everyday

[-]

Where to start? Are the carb and jets totally clean, check reeds, compression, decoke pipe. What does the plug look like? What jetting? Standard pipe? Air filter present and condition?

How heavy are you? 60mph with a skinny teenager is nearer to 50mph with an average middle aged bloke on it.
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TZR250 2MA road, TZR250 1KT road, TZR250 2MA race, TDR250, YZF-750R Boost colours.
Jaguar S Type 3.0 V6 Sport R, VW Transporter T5 GP LWB Shuttle 140ps DSG.

[Kickstart]

Hi

H100 is not really that revvy. Peak power is at 6500rpm, which is 50mph in top gear. If I remember correctly the listed speed when they were new was 58mph (not sure how accurate the speedo is). Because of the ludicrously low standard gearing the top speed isn't affected that much by the size of the rider.

It is difficult to get higher gearing for the H100. You can now get a front sprocket 1 tooth larger. Wish they had been available when I had mine.

Have you cleaned the exhaust out? Is it a standard exhaust? Is the air filter clean? Is the jetting standard (should be richer jetting to compensate for running premix)?

All the best

Katy
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Pete.]

My dad had one, couldn't pull the skin off a rice pudding. I loosened the downpipe and off it went. Exhaust was badly coked up.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[eunos20b]

[redeem ouzzer]

Why is it running premix? I would be tempted to find an automatic oiler and and a tank and put it back to stock.
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Be a REAL MAN!

[bypass2]

Try a new plug. give the baffle a clean then give it a try.

[eunos20b]

It's running premix because... Well because I can only assume the previous owner wanted it to or the pump got knackered. I only got it last week.

Got a new plug in it now and going to try and clean the exhaust out tomorrow.

Thanks
____________________
'90 Honda H100SII (SJ)
Learning something new everyday

[Pete.]

Most likely he ran it out of 2 stroke and didn't know to bleed the pump, so assumed it had packed up.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[Polarbear]

Best thing that ever happened to 2 strokes was the oil injection pump. Why anyone would change to premix is beyond me.

Oh look, I've just gone down this long hill with the throttle shut and partially seized my bike.
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Triumph Trophy Launch Edition

[Kickstart]

[redeem ouzzer]

[eunos20b]

[eunos20b]

[Kickstart]

Hi

While the H100 top speed is quite limited, at lower speeds they are quite spritely. I would expect up to 50 it would be noticeably quicker than the DR125.

All the best

Katy
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[eunos20b]

[eunos20b]

[eunos20b]

[Pete.]

[stevo as b4]

It definitely needs looking at from what you have said. My mate used to have a low mileage H100S and though it's geared low and the engine peaks quite early. It should rev to 8000rpm on the flat and do just over 60mph indicated , maybe closer to 65 in favourable conditions.

My mates one would easily wheelie off the throttle in 1'st and 2nd if it's loading and unloading the forks with a tug on the bars is classed as a power wheelie? (some think a power wheelie is hiding face behind a fairing nose on the clocks with the front wheel coming up)

It used to leave our mate on his nearly new TZR 125 away from the lights, especially when he first got the bike and wasn't used to giving evil abuse to the clutch, because of the pinned open powervalve the previous owner had messed with.

The only thing I remember him saying is that a hot summer day would knock 10mph off the top speed when it got hot and faded a bit.

Definitely fun little bikes, but the motor would be far more fun in a beefed up MT5 chassis, which we might get to see an example of sometime this decade if Fladdem gets his arse in gear?

[stinkwheel]

They should rev up nicely with a definate kick in the pants as you hit the powerband (a sharp snapping open of the throttle from walking pace in first sees the front wheel in the air on my one and I'm a big, heavy guy).

I can't remember which models were CDI and which were points.

If it's a points one, check the timing. Over retarded ignition timing does them no favours. From memory, there isn't actually a movable stator plate, you set the gap so it's a starting to open at the timing point then check it when fully open. if it's too big, you need a new set of points.

Also worth checking the reed valve is in good order.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[eunos20b]

A sort of reply to everyone...

I got 55 indicated today, lying flat on the tank, WOT round a nice, very slightly downhill corner that I like. Was still going but I backed off as I couldn't see shit. Would have seen 60.

I've yet to find any power band and I can't tell you what rpm it's doing as the tachometer is broke (ironically it seems to have snapped and got stuck at what would be indicated 11k).

We tried to get the baffle out today but seems it's riveted in from underneath!

I think I'm going to have to give it a bit more riding time, check the points, get the tacho fixed, find an oil pump or a decent premix ratio and then come back with more relevant info. Bike is brilliant fun with upside down bars though
____________________
'90 Honda H100SII (SJ)
Learning something new everyday

[stevo as b4]

It needs the exhaust hanging up for 24hours filled with caustic soda solution or drain cleaner.

While your at it you can look at the exhaust port and gently scrape out any carbon lumps or oily gunge. I'd also do a compression test to see if your getting a decent amount of compression compared to the factory specs range. If it's less than say 100-110psi it's probably a bit worn, and wants a piston and rings.

Also if your running a rich oil:fuel ratio like the 20:1 you mentioned, your just clogging it all up and it won't rev for shit. You want probably 35-40:1 with a good oil,
and go up no more than 1-2sizes on the main jet at the most, or you'll still be too rich, as 40:1 doesn't really weaken off the mixture by much over petrol alone IMO.

But put a pump on it and get it set up and working right, as riding a pre-mix stroker particularly a performance one on the street is a ball ache, and distracts you too much from good riding, worrying about making sure your keeping the motor oiled enough under high speed no load conditions etc.

[eunos20b]