XR 70 BLEW UP?

So me and my dad got an early 200s xr 70 that was in ruff but rideable shape now it won't start we took the spark plug out and kicked it and no air came out of the spark plug hole we think it needs a new top end, if it does where can we get a top in rebuild kit online

Sorry I put this in the wrong thing but I still need help any is appreciated

Um try looking for someone that knows how to work on motorcycles. It might save you a lot in the long run. 

Um try looking for someone that knows how to work on motorcycles. It might save you a lot in the long run. 


There are no bike shops around here or we would take it and getting a top end rebuild kit with a new piston rings gaskets the whole deal but we've never rebuilt an engine before, do you think the bottom end is messed up too or just a top end rebuild

Well there are measurements and checks that need to be done with a shop manual to know. 

You really need to know more or less what your doing when working on a motor. You might even try a lawnmower shop. 

You will likely find more help in this forum. https://thumpertalk.com/forums/forum/65-xrcrf-5070110/

Thank you but my dad said we can get a top end rebuild kit for about 70 or 80 dollars and we can do it I just wanted some tips and if we needed to do anything on the bottom end

YouTube it. 

 

Okay thanks you

YouTube it. 
 


We might get a engine from tboltsusa are they reliable we looked at a 90cc Parahna engine or is it aftermarket junk

Some of the Pit bike engines work. 

Working on MC engines isn't that hard if you know which end of the screwdriver to hold onto.  That said, you can also screw things up if you aren't careful.  Think smashing the piston into the valves due to bad assembly.  A good manual is worth its weight in gold...even if you know what you're doing.

There are a ton of YouTube videos on rebuilding bike engines.  Even videos showing other makes and models will give you some insight.  Go look at the Honda forum and you should be able to find 'the guy' who seems to know what he's talking about and is willing to share his knowledge.

That bike is likely worth $700-$900 depending on year and condition so that makes it cost prohibitive to take it to a shop for anything serious.

This will be an excellent bike to learn how to work on a simple four stroke engine.  Hopefully you dad has some mechanical experience to lead the way.

I haven't seen your bike but I would say that there's a better than average chance that the bottom end of that engine is still fine.  All the small Honda XR/CRF engines are super reliable, easy to work on and haven't changed much in nearly 50 years.

 

find a better video, that one sucks

find another XR70 and use it for spares the parts you don't use can be sold

find another XR70 and use it for spares the parts you don't use can be sold


We can't do that we are tight on money and. An barely afford to rebuild it


We might get a engine from tboltsusa are they reliable we looked at a 90cc Parahna engine or is it aftermarket junk

TBoltUSA doesn't sell junk. The Piranha engines are very reliable as far as China race engines go. I used both the TBParts 88 big bore and race head for many, many years of hard back yard mini Moto action. I now currently have a built, high compression Piranha 140 in my 70. They are good quality, you could certainly do far worse.

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TBoltUSA doesn't sell junk. The Piranha engines are very reliable as far as China race engines go. I used both the TBParts 88 big bore and race head for many, many years of hard back yard mini Moto action. I now currently have a built, high compression Piranha 140 in my 70. They are good quality, you could certainly do far worse.

Sent from my XT1650 using ThumperTalk mobile app



Okay thanks for the info. In your opinion should we buy a top end kit I saw some online for about 100 dollars or spend the 300 on the tbolts engine

Hard to say. You can get a 88cc kit( cylinder , piston, gasket kit ) for around $125. I don't know the condition of your head or bottom end.

 

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I don't really want to bore it out because it will make it weaker and the bottom end is good the bearing is good we just need a top end and maybe new valves I saw a rebuild kit with the rings piston gadgets for 85 and a 1 bucks would you trust it or think it will fail again soon

Hard to say. You can get a 88cc kit( cylinder , piston, gasket kit ) for around $125. I don't know the condition of your head or bottom end.
 
Sent from my XT1650 using ThumperTalk mobile app
 
 
 
 


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