nheather

I have a new body for my son's Hyper 7. When you apply the stickers do you seal it with a varnish? If so what do you use - do you just use a generic polyurethane varnish spray or something specific. Cheers, Nigel

Great - thanks for the help. Cheers, Nigel

Yes I appreciate that. My question was whether the STNV should be set with the 1mm gap or whether I should temporariliy remove it (since it was siad that the adjustment should be done with throttle closed). Cheers, Nigel

Many thanks - final question. The throttle stop is currently set at 1mm gap with throttle closed. Should I set the STNV like this or should I remove the throttle stop so that the throttle can close all the way? Cheers, Nigel

Many thanks, I got that bit - it comes after the 'close off the throttle body against the screw' bit that I don't understand. Does it mean I have to hold the throttle closed and then start turning the needle? Cheers, Nigel

I've just finished sealing a troublesome Mach 28 and want to put the carb back to factor settings. For the Sub Throttle Needle Valve the manual says this My immediate question is what does 'close off the throttle body against the screw' actually mean. Cheers, Nigel

I have been following this excellent guide http://www.msuk-forum.co.uk/index.php?showtopic=70981 I have done my backplate and the blanking screw for the booster bottle. Just the carb left to do, but I have a question first. In the photographs, it shows the part of the carb that slides into the engine without an O-Ring. Mine has an O-Ring. So is this deliberate - you will acheive a better seal with the gasket than with the O-Ring. Should I remove the O-Ring and use sealent or should I keep the O-Ring aswell as the sealent? Cheers, Nigel

2 years ago £1 = $2.00 Then at £140, the engine cost $280 Now £1 = $1.50 So now, at £190, the engine costs $285 So the price of the engine has stayed pretty much the same for the last 2 years. Cheers, Nigel

Will do - many thanks. Nigel

Many thanks - mystery solved. So given I'm not going to be fitting the Boost Chamber what is the best way to seal the screw - I have some copper based silicone gasket - should I use it with or without the fibre washer. Cheers, Nigel

You can see it in this picture No nut on the end - the crankcase is threaded. Cheers, Nigel

It's a Mach 8. Not an idle gap - this screw is in the engine crankcase, not in the carb. No it isn't the cinch bolt that holds the carb in. I'll try and sort out a picture. Cheers, Nigel

My engine has a screw just below the carb. It doesn't fix anything, just fills a hole. So a couple of questions 1 - What is it for. The only thing I can think of is a lubrication hole for the crankshaft - but you can do that by squirting oil down the carb throat. 2 - I'm ready to seal my engine. None of the tutorials mention this. The screw has a fibre washer - is that sufficient or should I add copper gasket material. If I do then should I keep the fibre washer in place or remove it? Many thanks for the help. Cheers, Nigel

No not stuck on top of liner or on old button - that was the first place I checked. The problem is not which ones to buy but which ones to fit. As you say, they are cheap and I actually have the full range Brass 0.1mm Copper 0.1mm Copper 0.2mm Aluminium 0.3mm I have the copper ones because at the time there were none to be had in the UK at all so I ordered from the US. They supply the Dynamite parts. WHilst they were in transit the UK stock became available so I also have the Hobao parts. The problem is that I don't know which ones to fit? The dynamite exploded diagram shows 0.1mm and 0.2mm copper The hobao exploded diagram shows 0.1mm brass and 0.3 mm aluminium What neither of them show is whether they should both be fitted or just one. And if just one, which one under which conditions. Cheers, Nigel

Many thanks, Agree, that isn't where it shows. The manual shows Heatsink (Cylinder Head) Button 0.3mm aluminium gasket (shim) 0.1mm brass gasket (shim) Cylinder lining But it doesn't make it clear whether both should be fitted or just one. I've been researching a bit more and found that you should put an extra shim in if you are using >25% or sometimes when breaking the engine in. So if I need only one, should it be the 0.3mm or the 0.1mm ? Cheers, Nigel

A question about head gaskets. I have a Hobao\Mach 28 but I guess this question is quite generic. When I got my 2nd hand car, the previous own had cross-threaded a glow plug (he told me about this up front). So I got a new head button, but when I removed the old one, I found that there were no head gaskets fitted. I found the Hobao Mach 28 instructions and this shows two gaskets a brass 0.1mm which goes next to the button. an aluminium 0.3mm which goes on top of the liner so liner > 0.3mm alum > 0.1mm brass > button Also when googling I found the Dynamite Mach 28 instructions and this also shows two gaskets but these are 0.1mm copper 0.2mm copper Now my question as a newbie is "Should I fit both gaskets or just one?" I was wondering whether you just fit one depending on what power fuel you intend to use? If just one, which should I fit for 20% Can anyone advise please.? Cheers, Nigel

Many thanks I assume this is for the backplate etc. And the green slime is for the needles. Is that right? Cheers, Nigel

Many thanks that is great. Few more questions 1 - what is the slime they talk about for the needles. 2 - Do you ever both sealing the head or do you assume that the brass\aluminimum gaskets will be good enough. 3 - Is the high temp sealent specific to model cars or do you just use stuff from Halfords Cheers, Nigel

Many thanks for the support. Here is what I've decided to do with your advice 1 - Return the evilbay engine for refund 2 - Work on the Mach 28, especially looking at the sealing 3 - If no luck then buy a new engine - probably a Picco - I see they do one with a rotostart backplate, although out of stock at the moment. Big Question though. I've looked through the Pinned Threads and done a search for 'engine sealing' but I can't find any of the threads that the replies have suggested I look at. So I would really appreciate it if someone could provide an actual link\links to the thread\s I should be looking at. Many thanks, Nigel

Yes, I didn't mean it quite like that. I fly nitro helicopters so I know full well that you get what you pay for. What I meant is that my son just uses it to mess around in the park or common ground - he isn't into racing so he doesn't need the best and it won't be heavily used. So I was looking for a good quality 2nd hand engine rather than paying £100+ for a new one. Cheers, Nigel

Must admit that air leaks were my first thought and I changed all the fuel pipes and the o-rings. Is there a way for checking for air leaks? If I do find one, how do you go about selaing it? Cheers, Nigel

Thanks for my replies - you have pretty much echoed my feelings anyway. Next question - where to go next. Do I keep perservering with the Mach 28? OR Do I go for something else? If something else then do I go new or old? And if I want to reuse my RotoStart does this mean I have to stick with Hobao\Mach or are all backplates pretty much standard. The rotostart I have is this one http://www.modelsport.co.uk/?CallFunction=ShowSpecification&ItemID=25032 Cheers, Nigel

Last year I bought my son a used Hyper 28 from this forum - great package but the Mach 28 engine is very tempremental - well tuned it runs well but takes a lot of attention between each run as it doesn't hold tune well. Tried everything to resolve this but no go and researching, this seems to be a common feature of Mach 28 engines. It's frustrating enough if I'm with my son but it would be too much for him to do on his own. Anyway, I decided to replace it with a 21 (which I have read are a lot better) and decided it must be a Hobao because I have a Rotostart with a Hobao back plate (I assume different makes would require different backplates - is this true?). But needs to be on a budget becuase this is really only a toy. After looking here with no joy I bought a Hyper 21 Pro 8 port from evilbay. It was advertised as good performance, runs well, good compression, only 2 gallons. What I received has done way more that 2 gallons. The pullstart (although I don't need it) is showing loads of wear, scuffing, ingrained dirt. The carb is also showing a load of wear with scuff on the intake and the blacking on the barrel has been warn away - also the needle screw heads show some chewing. When I removed the pullstart, I noticed that the screw threads in the backplate are warn (perhaps has ssen several pullstarts) Not sure about the body, it's reasonably clean but I would need to take apart to inspect piston and liner which I'm not prepared to do. I have tried running it - it took quite a bit to start initially because the settings were way off 20% or factory default. When I did get it started it seems to run okay. I have raised these issues with the seller. At first he stuck to his story, but gradually he admited that he had bought the engine from a friend and that the engine could have seen a lot more action than advertised. Now the seller is a decent chap and has offered to accept the return and refund the purcahse price and postage costs. So what would you do - it runs, it was reasonably cheap (

Clutch bell spins freely - that right isn't it? I double checked the install direction and it matches the manual. You may have misread - the clutch isn't engaging until the revs get very high - throttle barrel open over 50%. Like thye spings are so strong they are stopping the arms from flinging out - but I've looked at the videos and I have the spings installed correctly. No idea what size - they are the ones that come with the Hyper 7. Cheers, Nigel

May be a little rich but it is reving very high when clutch engages. Clutch is little used so not wear. This leaves, fitted wrong, which I'm more than happy to beleive, though I've had a look at the instructions and can't see that I've down anything wrong. I fly Nitro Helicopters and the clutch bell on those has a lining. The clutch bell on the hyper 7 is just metal - is that right? Cheers, Nigel