ludde

Thanks for the info. I'll check the cylinder when I get home tonight.

Ok, I'll probably have to do that. The strange thing is that the old rings that were on before has the correct gap, about 0.4 mm. So I'm leaning towards using the old rings again but it feels wrong to put old parts in when I have new ones.

Ok, I'll see if I can find any info on that restrictor. Another problem showed up yesterday. The new piston rings, the ones with a different number than the originals, has a larger piston ring end gap than there should be. According to the manual the gap should be 0.3-0.4 mm when new, but the new ones are 0.5 mm same as the service limit. Could I damage something with a larger end gap??? As far as I know there are no oversize pistons available so the cylinder can't be bored out, so why are these piston rings different???

Oil restrictor??? Can you give me more detailes where this restrictor should be. There is alot of oil around the area of the valves but I thought it should be like that to enhance cooling.

An update on the Honda. Well, the engine is in pieces again. This time I'm replacing everything I can think of, valve guides, piston rings, o-rings, head gasket. Actually, the head gasket together with the valve guide reamer were the parts that took the longest time to get hold of. This time, to avoid missfit between the head and valve guides, we will heat up the head enough to fit the valve guides without having to knock them into place with high force. I just hope that the o-rings don't get damaged when installing the valve guides. The piston rings were little hard to get a hold of. The original part number 131A0-KR9-003 is discontinued but I found another number 131A1-KR9-003 which fits nice but look abit different from the ones that were on before. Anyone know if why there is a different number on the piston rings? I hope this works because I don't know what else to do.

The problem is that the RTLs are mostly owned by collectors, who own them for their rarety. The RTL was very expensive to begin with, almost twice the price of the two strokes, and Honda only made a couple hundred bikes per year. Today the problem for those using the bikes in competition, myself included, is the lack of spares. There are no original rear fenders or tank shelters left, the piston rings and cylinder gaskets are the same as the TLR250 so those you can get hold of but they are expensive. Luckily most of the parts in the engine is taken from other Honda engines so you can easily get hold of these, but often thaey are pricy. All these factors drives the price up and sadly some people are not willing to use a bike they paid so much money for. I think the main problem for the RTL is that it feels very awkward the first time you ride it and it takes alot of time to get used to. This is mainly a chassis problem, the engine is brilliant, so much better than the TLRs. My dad had a RTL as his main bike for twelve years and rode it better than any other bike his ever had. The grip he could find on that bike was amazing, even snow and ice was no problem. But he says it took him 2-3 years to work out how to ride the bike. I think the RTL was ahead of its time in some ways, I don't think you could get much more out of a 2 valve four stroke at that time. Now I have babbled enough...Just one more thing...For those of you that have a RTL, RIDE THE BL**DY BIKE, how else can you fully appreciate it?

Last year HRC Japan had a kit for updating 05 and 06 4rt to 07 specs. I think it's the same kit as the one on Lewisport, so there is clearly a new cam on the 07 bike. I would bet my money on that the 14100-NN4-C00 is the new cam. Can't anyone with alot of money buy it so we can find out

Here's three more: Bou rock hoping: I think Bou is filming his minders here:

If Conny bought it in Sweden and it originated from the USA, then I would put my money on that it was Jonny Andersson who bought it in the USA and rode it in the American trials championship. Does it have a steeper steering head angle than original? Because I know Jonny changed that on some of his Hondas.

BJ I saw your comment on youtube, and I agree, nothing wrong with the bike when it's hot and has vomited out all the excess oil, then it runs brilliantly And you have three very nice looking bikes there, the RTL looks like a minter. I think Conny bought my bike from John Shirt but not exactly sure, is it the same with yours?

I've uploaded a clip with me riding my 4rt with Mitani 280 kit, Mitani exhaust and Mitani mapping (I like Mitani ). In case you're wondering I'm riding all of it in 2nd gear, standard gearing.

For those of you who are interested. This is me and my dad riding my Honda after we put it back together the last time.

Is it just me or doesn't S3 280 kit look very much the same as the Mitani 280 kit? Looks like it even has the same piston to up the comp ratio

Could you explain this a little more? Any ideas of an easy way to do it? As I see it the two reasonable faults would be bad fitting of the valve guies and uneven contact point between head and cylinder, but the compression is very good so I'm leaning towards the valve guides

I'm wondering if there is a very small leak all the time but it's only when the engine has been turned off for a while that the amount of oil gets big enough to produce smoke. But what can cause such a small leak

I have the Mitani 280 kit and I love it, just that bit more grunt in low revs that I needed. BUT you have to find a good PTB mapping for the kit, otherwise its rubbish. A question, maybe also for munch. Every map that I've used in my bike, both 250cc and 280cc, I have to reduce the fuel about 6-8% in order to get the right response from the engine and to get a nice color on the spark plug. The map I use for the 280 kit was originally from Mitani, the spark plug was sooty so I started to reduce the fuel. Now I'm done to 8% under the Mitani original, the plug is still abit sooty but the engine response is much better. I don't know if I should reduce any more, don't want to destroy anything. Does anyone know if the PTB has a vacuum sensor which can compensate for the added cylinder volume?

Ehh... I only had the top one off, never checked the other two... should have done that. But if they were upside down wouldn't it smoke all the time. It only smokes when it has been turned off a while.

Just wanted to you all that the parts I changed didn't work. It is still smoking as much as before. I just can't understand where the oil is coming from. I've changed the valve stem seals, meassured the valves and the valve guides. Now I'm thinking there is a crack somewhere, but I can't understand where. It seems like the oil is only dripping into the combustion chamber when the engine is off. I just can't get my head around it

Are you sure about the swing arm being from a gasser? To me it looks very much like the original one, though a bit reworked on the right side to fit the brake caliper. Yes it's pretty tight around the rear master cylinder, especially near the middle exhuast box, which cooked the brake fluid the first time I rode the bike. But solved that with a bit of isolation material. Sorry about talking badly about Nigel, he should get credit for even bothering to do so much work on an old bike. I think that the bike was involved in some crash before I got it, which could explain the bad alignment of the brakes. Any clue why Nigel fitted old hydraulic brake parts, from the same era the bike? The Grimaldi front brake was standard on Fantic in the late 80s I've been told. Has it anything to do with classification of bikes in the UK? Anyway, I got a new cylinder head gasket and valve stem seals today. Didn't find anything wrong with valve stems or valve guides, both in mint condition. So I'm hoping that there was something wrong with the stem seals. Just the assembly left, will try todo it this weekend. This is what happend in the last section at the last trial I rode with the bike. It almost broke my heart The bad thing was that it was so slippery I couldn't even stand up strait nor could I keep the bike from falling to the ground

That would explain why the finish wasn't top notch. We had some work getting the calipers lined up with the discs, so now it brakes more than it squeaks. As I don't use it that often and we almost never have any sections with deep water anymore, I could have had the drum brakes on, and kept it as close to original as possible. But the original wheels and drums got sold by the previous owner, so I have no chance of converting it back.

Yes it is, a very good bike and if I hadn't bought it, it would have ended up in Scotland somewhere . The only thing I have to fix sometime, except the engine, is the front fork springs which have got a bit weak over the years. Hm, can't remember if it puffs when shutting off from high revs, would that be the oil seals aswell?

I need help from all you RTL experienced people out there!!! I got a bit of a problem. Everytime I cold start the engine it smokes alot, eventually it clears out and runs just fine but there's a smell of burnt oil in the exhuast gases. I think the problem is the valve guides , anyone have any other theories?? If I take the cylinder head of I have to replace the gasket, is it the same as one the TLR250 and is it hard to get a hold on? Cheers Ludde

So here is my findings. It looks like when you use a bigger bore exhaust it is better to retard the ignition at low revs. This seems to make the bike breath better and this makes it sharper. Most have something to do with the later ignition giving a higher pressure in the cylinder when the exhaust valves open, thus pushing out the exhausts. I knew that this tuning effect could make a difference, but didn't think it would be this much. Anyway, the old man like the new map, which is almost the same one I got from Mitani. At low rev it is a bit more calm than before but dad wants it like that. I think the ignition is a little bit too retarded for the standard bike but it works on the 280kit, but then the 280 has higher compression ratio. A little tip for those who have problem starting their bikes: try advancing the ignition at idle and below by 2 or 3 degrees, seems to make it easier to start

Just a little comment: You can get performance benefits from the Mitani pipes IF you remap the PTB. I had both the Mitani pipe and silencer on and thought that it was really good, until I rode a bike that was exactly the same as mine but with the standard exhaust on... The standard bike was sharper on the bottom end, not stronger but it reacted quicker than mine. I messed around with the mapping and got mine better but not really good as it could be. So I bought the 280kit from Mitani to get more torque from the bottom end, and the bike became worse, really bad. It didn't pick up revs as I wanted, it felt slow and weak So I sent a email to Mitani wondering if they had a map that cure my problem. And they sent me a map that didn't look like the other ones I have. It really transformed the bike, now its really sharp of the bottom end and its torquey. Now I can use 2nd gear even in the tight stuff without working the clutch to much. I have some ideas about what has changed see if you can use it on the standard bike, I will try to check if I am right tomorrow on my dad bike with everthing standard and a Mitani silencer on. Will let you know what I find out.

Yes, the knocking went away when I switched to 98 octane fuel. I guess with the higher compression ratio 95 is on the limit. Got a map from Mitani today, it is supposed be for 280cc kit, just hope nothing has been translated wrong, because they don't have the best english.