chefclancy

So I am just getting into racing (2wd SCT) and had a sc10 got a really good deal on for 190 dollars and didn't plan on doing anything with it so I traded it for a brand new Hyper 7.5. The things is brand new, the only thing the previous owner done was put a roto start on the engine. Well I am an electric guy and have been trying to get it tuned for a week, its only had 1 idle tank ran through it. Today I went out to work on it and hooked the roto up and the motor started spinning then a few seconds later NOTHING! something went wrong in the bottom of the motor as the pinion gear wont spin when I hook the rotor up. The motor no longer turns over but spins freely now. Any ideas guys on what this could be? I am a complete nitro noob, I should have kept my sc10!

JoeMaxx

Ok you have lost me a little because the HoBao Hyper 7 is kinda brand new and only been offered by HPI since December of last year.

Since this is your first post we will need a little more information.

The Roto Start systems use a battery pack and if it is not fully charged it will not turn the motor over that turns the engine over.

The Nitro engine could have become flooded with fuel since you are new to nitro engines this is not uncommon for you to flood the engine when attempting to start it.Clean aroundthe plug with a blast of nitro cleaner then pull the glow plugthen stuff a piece of paper towel down into the head. Turn the engine over until it is clear of fuel.

Did you charge the Roto Starter Battery pack up? If not it will need charging.

If you charged your battery pack then it is something else like the roto start system installed on to your nitro engine.

The one way bearing is the key to starting a nitro engine and might be slipping.

But I more think that is a battery charging problem on the Roto Start.

chefclancy

Well I made sure the roto was charged. You can tell something came loose from under the motor. It no longer turns the piston. The roto just spins freely. The pinion gear doesn't move but the flywheel that is used for started boxes does spin.

nitroexpress

The flywheel should belocked onto the crankshaft. If the flywheelis turning, it should be turning the crankshaft. Ifthe pistonis not moving, guess you got a broken rod.

Foxy

The Hobao Hyper 7 is one of the longest running unchanged models in RC. Still available brand new, it has been hanging around virtually unchanged for around 10 years. I haven't even seen the HPI model which you refer to (totally disgusted with HPI the last year or so, this is part of the reason why), I'm talking about the Hobao original sold under the OFNA brand in the US, and now under HPI.

The Hyper 7 spawned a whole range of 1/8th buggies, and despite never discontinuing the base model, many new generations were produced, including the 7.5, 8, 8.5, 9, 9.5 and the Star. Always primarily a racing vehicle in more expensive kit form, RTRs were also produced with lower spec components of many of the range of models.

HPI recently acquired the distribution rights for Hobao from OFNA, who replaced Hobao with another OEM which I can't remember at the moment. From that moment, the Hyper side of things has gone awfully quiet, and I just hope HPI get their act together with the new Hobao products soon. Hobao assumedly continues to distribute their own products in Europe (I hope, I need to study the relationship with HPI closer), and Hong Nor remains under OFNA in the US.

Just FYI

Anthoop

Sounds like the one way bearing needs looking at....remove the roto start and the backplate...there is a thing that looks like a fan, inside that is the one way bearing.

The Hyper7 has been around for years...HPI is the new distributor.

Foxy

Haha, beat ya to it.

Anthoop

Yeye...

chefclancy

I think I am going to convert it to electric. Anyone wanna buy a new .28 motor? Haha

JohnP2

Why are you going to convert it to electric?

chefclancy

I don't have the skill to tune a nitro. The money I would spend getting a starter box would pay for a motor mount for brushless. I have a 1/8 scale flux system sitting around anyways and a couple 3's

JoeMaxx

I knew that HoBao was carried by Ofna for many years Ofna Dropped themaround September or October of lastyearand changed hands to HPI inlate November of last year. SO it is new to find parts for. Parts are hard to come by right now unless you buy them from Japan. Tower Hobbiesstartedto sell them again under the HPIbrand but has no parts available since HPIpicked up the Brand. I considered buying a new Hyper 7 this year but because the parts are still On Order in Tower Hobbies I chose a different RTRBuggy.

If I were the owner I would spend some time learning how to tune a nitro engine. It is really easy once you learn the basics and temp gauges help alot to keep them from over heating.

I remember the first nitro engines I bought they did not have temp guages back then and we would spit on the engine to see if it sizzled off quick or just sat on the engine. That was our temp guage


Dude you do have the skills to tune a Nitro engine and takes time to learn it. Once you perform some research and purchase a temp guage it becomes a lot easier to tune them. Keep the engine temps on this engine below 260 degrees and not less then 220 then it will run well. Daily tuning is just a tweak and only takes the first tank of fuel to perform. I can get mine tuned in for the day in about 1/2 tank of fuel.

chefclancy

It really takes a half tank of fuel just to tune it for the day? Wow....thank goodness ive already ordered the pieces to convert it to brushless. I don't knock you nitro guys, I am honestly jealous that you guys have the skills to make it happen. Being a chef and having a new baby I just don't have the time to learn. I wanted to and gave up a really nice sc10 in the attempt to. our 2wd sct went from about 12 people to 3. This sport is brutal and I am actually close to just throwing in the towel. I bought an HPI Apache and came to the realization that there will never be a 1/8 sct race class so I traded it for a new in the box fly sky radio and an axial ridgecrest. well the ridgecrest turned out to be a piece of **** and the guy ended up with a 2 week old brand new apache. leaves a bad taste in my mouth for this hobby that I honestly love..

JoeMaxx

It is more of a patience level where I live and nitros.   Some Days I struggle to tune my engines in the Spring and Fall weather because the outdoor temps can fluctuate by 20 degrees between the weekends I take out my NItro R/Cs.   Sometimes I have to adjust a full half turn to a 3/4 turn on my HSN needle before I get it right.  Lean to Rich mixtures.   I live in the mountains and out door temps swing a lot in the spring and fall.   Summer it is consistent and just a minor tweak to keep the engine a range of temps and performance.

chefclancy

I commend your ability to stick with the ntiro, I wish I had it. I guess the technology has me spoiled. Its easier (for me) to charge a few batteries and plug and go. I really wanted to get back into nitro again from my old tmaxx but after messing with this hyper7.5 a few days and spending hours watching videos on hwo to tune it to only have it break without me getting to wheel it even once has broken me. I will convert it to electric and try to sell off the motor

JoeMaxx

I have more Electrics then Nitros in my collection so if I cannot tune one of my Nitros I have too many to play with.  I take about 5 to track each time I go out to play.  My budget is higher than others and I have lots of toys. I have a toy for most classes of R/Cs   I can always get one of my nitros to play nice that day and I can always play

chefclancy

Well today I watched a few videos and had a friend that is a nitro guy help me with taking the bottom of the motor apart(was easier than I thought). It has a cracked one way bearing, a 25 dollar part that is available. You can apparently still run the car without this part using a starter box. The one way bearing is a very simple and easy fix and I am glad I learned it. I am still selling the motor though and converting the car to electric!